:root {
  --ink: #17233b;
  --muted: #65718a;
  --blue: #2f8fcf;
  --blue-deep: #176b9f;
  --blue-pale: #eaf6fd;
  --mint: #64b89c;
  --yellow: #f4c94e;
  --paper: #ffffff;
  --canvas: #f5f7fb;
  --line: #dfe6ef;
  --shadow: 0 18px 60px rgba(23, 35, 59, 0.11);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { color: inherit; }
a { color: inherit; }
img { display: block; max-width: 100%; }
h1, h2, h3, h4, h5, h6 { font-size: inherit; font-weight: inherit; }

.site-shell { min-height: 100vh; }
.topbar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 28px;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}
.brand { display: inline-flex; align-items: center; gap: 12px; padding: 0; border: 0; background: transparent; text-align: left; text-decoration: none; cursor: pointer; }
.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 13px;
  object-fit: cover;
  box-shadow: 0 8px 18px rgba(47, 143, 207, .24);
}
.brand strong, .brand small { display: block; line-height: 1.12; }
.brand strong { font-size: 16px; }
.brand small { margin-top: 4px; color: var(--muted); font-size: 12px; }
.app-link {
  padding: 10px 15px;
  border: 1px solid var(--line);
  border-radius: 10px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 750;
  transition: .2s ease;
}
.app-link:hover { border-color: var(--blue); color: var(--blue-deep); transform: translateY(-1px); }
.view-nav { position: absolute; left: 50%; display: inline-flex; gap: 3px; padding: 4px; border: 1px solid var(--line); border-radius: 11px; background: #f4f7fa; transform: translateX(-50%); }
.view-nav button, .view-nav a { padding: 7px 12px; border: 0; border-radius: 8px; background: transparent; color: var(--muted); font-size: 12px; font-weight: 800; text-decoration: none; cursor: pointer; transition: .2s ease; }
.view-nav button:hover, .view-nav button:focus-visible, .view-nav button.is-active, .view-nav a:hover, .view-nav a:focus-visible { background: white; color: var(--blue-deep); box-shadow: 0 3px 12px rgba(23,35,59,.08); }
.menu-toggle { display: none; }

.sidebar {
  position: fixed;
  z-index: 40;
  top: 76px;
  left: 0;
  bottom: 0;
  width: 270px;
  padding: 26px 20px 24px;
  overflow-y: auto;
  background: #13233d;
  color: #dfe9f4;
}
.sidebar-tutorials { display: grid; grid-template-columns: 1fr; gap: 6px; padding: 0 0 18px; border-bottom: 1px solid rgba(255,255,255,.12); }
.sidebar-tutorial-group { display: grid; gap: 6px; }
.sidebar-tutorial-group > span { padding: 0 5px 3px; color: #8297b2; font-size: 10px; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.sidebar-tutorial-dropdown { min-width: 0; }
.sidebar-tutorial-dropdown summary { display: grid; grid-template-columns: 24px minmax(0, 1fr) 18px; gap: 7px; align-items: center; min-width: 0; padding: 9px; border: 1px solid rgba(244,201,78,.55); border-radius: 9px; background: rgba(244,201,78,.13); color: white; list-style: none; cursor: pointer; }
.sidebar-tutorial-dropdown summary::-webkit-details-marker { display: none; }
.sidebar-tutorial-dropdown summary:hover, .sidebar-tutorial-dropdown summary:focus-visible { background: rgba(244,201,78,.2); outline: none; }
.sidebar-tutorial-dropdown summary strong { display: grid; place-items: center; width: 23px; height: 23px; border-radius: 7px; background: var(--yellow); color: #27344a; font-size: 9px; }
.sidebar-tutorial-dropdown summary span { overflow: hidden; font-size: 12.5px; font-weight: 800; line-height: 1.25; text-overflow: ellipsis; white-space: nowrap; }
.sidebar-tutorial-dropdown summary i { color: var(--yellow); font-size: 18px; font-style: normal; text-align: center; transition: transform .2s ease; }
.sidebar-tutorial-dropdown[open] summary i { transform: rotate(180deg); }
.sidebar-tutorial-options { display: grid; gap: 5px; padding-top: 6px; }
.sidebar-tutorials button { display: grid; grid-template-columns: 24px 1fr; gap: 6px; align-items: center; min-width: 0; padding: 8px; border: 1px solid rgba(255,255,255,.1); border-radius: 9px; background: rgba(255,255,255,.04); color: #aebed1; text-align: left; cursor: pointer; }
.sidebar-tutorials button:hover { background: rgba(255,255,255,.09); color: white; }
.sidebar-tutorials button.is-active { border-color: rgba(244,201,78,.55); background: rgba(244,201,78,.13); color: white; }
.sidebar-tutorials button strong { display: grid; place-items: center; width: 23px; height: 23px; border-radius: 7px; background: rgba(255,255,255,.11); color: #b9cee1; font-size: 9px; }
.sidebar-tutorials button.is-active strong { background: var(--yellow); color: #27344a; }
.sidebar-tutorials button span { overflow: hidden; font-size: 12.5px; font-weight: 800; line-height: 1.25; text-overflow: ellipsis; }
.sidebar-progress { padding: 4px 8px 23px; border-bottom: 1px solid rgba(255,255,255,.12); }
.sidebar-tutorials + .sidebar-progress { padding-top: 18px; }
.progress-label { display: flex; justify-content: space-between; align-items: center; font-size: 13px; }
.progress-label span { color: #9fb1c8; }
.progress-label strong { color: white; }
.progress-track { height: 6px; margin: 10px 0 8px; overflow: hidden; border-radius: 999px; background: rgba(255,255,255,.12); }
.progress-track span { display: block; height: 100%; border-radius: inherit; background: var(--yellow); transition: width .35s ease; }
.sidebar-progress small { color: #8297b2; font-size: 12px; }
.sidebar nav { display: grid; gap: 3px; padding: 18px 0; }
.sidebar nav button {
  width: 100%;
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 8px;
  align-items: center;
  padding: 9px 10px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  color: #c6d3e3;
  text-align: left;
  font-size: 12px;
  font-weight: 650;
  line-height: 1.25;
  cursor: pointer;
}
.sidebar nav button:hover { background: rgba(255,255,255,.08); color: white; }
.sidebar nav button span { color: #7e96b3; font-size: 11px; font-variant-numeric: tabular-nums; }
.sidebar nav button.is-complete span { color: var(--yellow); font-size: 15px; }
.sidebar-reference { width: 100%; display: grid; grid-template-columns: 34px 1fr; gap: 8px; align-items: center; margin: 0 0 18px; padding: 12px 10px; border: 1px solid rgba(255,255,255,.15); border-radius: 11px; background: rgba(47,143,207,.16); color: white; text-align: left; font-size: 12px; font-weight: 800; cursor: pointer; }
.sidebar-reference:hover { border-color: rgba(255,255,255,.35); background: rgba(47,143,207,.28); }
.sidebar-reference span { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 8px; background: var(--yellow); color: #24314a; font-size: 18px; }
.privacy-note { margin: 0 8px; padding-top: 17px; border-top: 1px solid rgba(255,255,255,.1); color: #91a4bb; font-size: 12px; line-height: 1.5; }

.view-main { padding-top: 76px; }
.view-tutorial .view-main { margin-left: 270px; }
.view-home .sidebar,
.view-home .search-section,
.view-home .chapters,
.view-home .next-learning,
.view-home .reference,
.view-home footer,
.view-tutorial .hero,
.view-tutorial .reference,
.view-reference .sidebar,
.view-reference .hero,
.view-reference .search-section,
.view-reference .chapters,
.view-reference .next-learning { display: none; }
.hero {
  min-height: 650px;
  display: grid;
  grid-template-columns: minmax(0, .85fr) minmax(420px, 1.15fr);
  gap: 54px;
  align-items: center;
  padding: 82px clamp(42px, 6vw, 96px) 74px;
  overflow: hidden;
  background:
    radial-gradient(circle at 78% 12%, rgba(244, 201, 78, .22), transparent 26%),
    linear-gradient(135deg, #eaf6fd 0%, #f9fbfe 58%, #eef7f4 100%);
  border-bottom: 1px solid var(--line);
}
.eyebrow { margin: 0 0 12px; color: var(--blue-deep); font-size: 12px; font-weight: 850; letter-spacing: .12em; text-transform: uppercase; }
.hero h1 { max-width: 640px; margin: 0; font-size: clamp(44px, 5.2vw, 76px); line-height: .98; letter-spacing: -.055em; }
.hero-lead { max-width: 620px; margin: 26px 0 0; color: #53617a; font-size: 18px; line-height: 1.65; }
.tutorial-picker-reference button, .empty-state button {
  min-height: 48px;
  padding: 0 19px;
  border-radius: 12px;
  font-weight: 800;
  cursor: pointer;
  transition: .2s ease;
}
.primary-action, .empty-state button { border: 1px solid var(--blue); background: var(--blue); color: white; box-shadow: 0 10px 24px rgba(47,143,207,.25); }
.secondary-action { border: 1px solid #cbd8e6; background: rgba(255,255,255,.65); }
.tutorial-picker-reference button:hover, .empty-state button:hover { transform: translateY(-2px); }
.updated { margin: 20px 0 0; color: #8490a4; font-size: 12px; }
.hero-visual { position: relative; }
.hero-visual > button {
  width: 100%;
  padding: 0;
  overflow: hidden;
  border: 8px solid rgba(255,255,255,.85);
  border-radius: 24px;
  background: white;
  box-shadow: 0 28px 70px rgba(32, 63, 91, .22);
  cursor: zoom-in;
  transform: rotate(1.4deg);
}
.hero-visual img { width: 100%; aspect-ratio: 16/9; object-fit: cover; }
.zoom-hint {
  position: absolute;
  right: 14px;
  bottom: 14px;
  padding: 7px 10px;
  border-radius: 8px;
  background: rgba(16,30,50,.86);
  color: white;
  font-size: 11px;
  font-weight: 750;
  opacity: 0;
  transform: translateY(5px);
  transition: .2s ease;
}
.hero-visual > button:hover .zoom-hint, .screenshot-card button:hover .zoom-hint { opacity: 1; transform: none; }
.floating-card { position: absolute; display: flex; align-items: center; gap: 8px; padding: 12px 15px; border-radius: 13px; background: white; box-shadow: var(--shadow); font-size: 12px; }
.floating-card strong { display: grid; place-items: center; width: 29px; height: 29px; border-radius: 9px; color: white; }
.floating-card span { font-weight: 750; }
.card-one { left: -24px; bottom: -22px; }
.card-one strong { background: var(--blue); }
.card-two { top: -25px; right: -18px; }
.card-two strong { background: var(--mint); }

.tutorial-picker { align-self: center; display: grid; gap: 11px; padding: 16px; border: 1px solid rgba(23,35,59,.1); border-radius: 22px; background: rgba(255,255,255,.77); box-shadow: 0 28px 70px rgba(32,63,91,.16); backdrop-filter: blur(16px); }
.tutorial-picker-heading { display: flex; justify-content: space-between; align-items: center; padding: 3px 4px 8px; }
.tutorial-picker-heading span { color: var(--blue-deep); font-size: 11px; font-weight: 900; letter-spacing: .1em; text-transform: uppercase; }
.tutorial-picker-heading strong { font-size: 15px; }
.tutorial-picker-reference { display: flex; justify-content: flex-start; padding: 8px 4px 2px; }
.tutorial-card { position: relative; display: grid; grid-template-columns: 70px minmax(0, 1fr) 32px; gap: 16px; align-items: center; width: 100%; min-height: 110px; padding: 14px 16px; overflow: hidden; border: 1px solid #d7e2eb; border-radius: 15px; background: white; text-align: left; cursor: pointer; box-shadow: 0 8px 22px rgba(23,35,59,.06); transition: .2s ease; }
.tutorial-card:hover { border-color: #8fc3e1; box-shadow: 0 13px 30px rgba(23,35,59,.12); transform: translateY(-2px); }
.tutorial-card.is-active { border-color: var(--blue); box-shadow: inset 4px 0 var(--blue), 0 10px 25px rgba(47,143,207,.13); }
.tutorial-card-copy { display: grid; gap: 6px; min-width: 0; }
.tutorial-card-copy small { color: var(--blue-deep); font-size: 10.5px; font-weight: 900; letter-spacing: .055em; text-transform: uppercase; }
.tutorial-card-copy strong { font-size: 17px; line-height: 1.15; letter-spacing: -.02em; }
.tutorial-card-copy > span { color: var(--muted); font-size: 14px; line-height: 1.5; }
.tutorial-arrow { display: grid; place-items: center; width: 30px; height: 30px; border-radius: 50%; background: var(--blue-pale); color: var(--blue-deep); font-weight: 900; }
.tutorial-progress-badge {
  position: relative;
  display: grid;
  place-items: center;
  width: 70px;
  height: 70px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: conic-gradient(var(--yellow) var(--tutorial-progress, 0deg), #dce7ef 0);
  box-shadow: 0 8px 20px rgba(196, 151, 18, .16);
}
.tutorial-progress-badge::before {
  position: absolute;
  inset: 6px;
  border-radius: 50%;
  background: white;
  box-shadow: inset 0 0 0 1px #e2e9ef;
  content: "";
}
.tutorial-progress-badge > span {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  line-height: 1;
}
.tutorial-progress-badge strong { font-size: 22px; letter-spacing: -.04em; }
.tutorial-progress-badge small { margin-top: 4px; color: #7a6217; font-size: 8px; font-weight: 900; }

.view-home .hero {
  min-height: calc(100vh - 76px);
  grid-template-columns: minmax(0, 1fr);
  gap: 42px;
  align-items: start;
  padding: 64px clamp(32px, 7vw, 112px) 90px;
  overflow: visible;
}
.view-home .hero-copy { width: min(1120px, 100%); margin: 0 auto; }
.view-home .hero h1 { max-width: 920px; font-size: clamp(44px, 5vw, 70px); }
.view-home .hero-lead { max-width: 820px; margin-top: 22px; font-size: 16px; line-height: 1.6; }
.view-home .updated { margin-top: 16px; }
.view-home .tutorial-picker {
  width: min(1120px, 100%);
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  margin: 0 auto;
  padding: 18px;
}
.view-home .tutorial-picker-heading { padding: 3px 5px 9px; }
.tutorial-area { overflow: hidden; border: 1px solid #d6e2eb; border-radius: 19px; background: #f7fafc; }
.tutorial-area > header { display: grid; grid-template-columns: 54px minmax(0, 1fr) auto; gap: 18px; align-items: start; padding: 24px; border-bottom: 1px solid #d6e2eb; background: white; }
.tutorial-area-number { display: grid; place-items: center; width: 50px; height: 50px; border-radius: 14px; background: var(--blue); color: white; font-size: 12px; font-weight: 900; letter-spacing: .08em; }
.tutorial-area > header p { margin: 0 0 5px; color: var(--blue-deep); font-size: 10px; font-weight: 900; letter-spacing: .09em; text-transform: uppercase; }
.tutorial-area > header h2 { margin: 0; font-size: 25px; font-weight: 780; line-height: 1.15; letter-spacing: -.025em; }
.tutorial-area > header div > div { max-width: 740px; margin-top: 8px; color: var(--muted); font-size: 14px; line-height: 1.55; }
.tutorial-area-cards { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; padding: 14px; }
.tutorial-area.is-unterricht { border-color: #c6ded4; background: #f1f8f5; }
.tutorial-area.is-unterricht > header { border-color: #c6ded4; background: linear-gradient(115deg, #f0faf6, #fff9e5); }
.tutorial-area.is-unterricht .tutorial-area-number { background: #24775f; }
.tutorial-area.is-unterricht > header p { color: #24775f; }
.tutorial-area.is-unterricht .tutorial-area-cards { grid-template-columns: minmax(0, 1fr); }
.tutorial-area-future { align-self: center; min-width: 250px; padding: 12px 14px; border: 1px dashed #a9cdbf; border-radius: 12px; background: rgba(255,255,255,.7); }
.tutorial-area-future > span { display: block; color: #547067; font-size: 10px; font-weight: 850; letter-spacing: .06em; text-transform: uppercase; }
.tutorial-area-future ul { display: flex; flex-wrap: wrap; gap: 6px; margin: 8px 0 0; padding: 0; list-style: none; }
.tutorial-area-future li { padding: 5px 8px; border-radius: 999px; background: #deefe8; color: #23644f; font-size: 11px; font-weight: 800; }
.practice-area > header { grid-template-columns: 54px minmax(0, 1fr); }
.practice-area .practice-area-intro { max-width: 780px; margin-top: 9px; }
.tutorial-area.is-unterricht .practice-area-intro p { margin: 0; color: #526b63; font-size: 14px; font-weight: 450; letter-spacing: normal; line-height: 1.6; text-transform: none; }
.practice-area-content { padding: 14px; }
.practice-card-list { display: grid; gap: 9px; }
.practice-card { overflow: hidden; border: 1px solid #d8e3e8; border-radius: 13px; background: white; box-shadow: 0 5px 16px rgba(23,35,59,.04); transition: border-color .18s ease, box-shadow .18s ease; }
.practice-card[open] { border-color: #9fc8ba; box-shadow: 0 12px 28px rgba(35,91,72,.09); }
.practice-card summary { display: grid; grid-template-columns: minmax(0, 1fr) 36px; gap: 18px; align-items: center; padding: 18px 20px; list-style: none; cursor: pointer; transition: background .18s ease; }
.practice-card summary::-webkit-details-marker { display: none; }
.practice-card summary:hover { background: #f8fcfa; }
.practice-card summary:focus-visible { position: relative; z-index: 1; outline: 3px solid var(--yellow); outline-offset: -3px; }
.practice-card-heading { min-width: 0; }
.practice-card-heading h3 { margin: 0 0 9px; color: var(--ink); font-size: 19px; font-weight: 820; line-height: 1.25; letter-spacing: -.02em; }
.practice-card-heading > span { display: block; margin-bottom: 4px; color: #24775f; font-size: 9.5px; font-weight: 900; letter-spacing: .085em; text-transform: uppercase; }
.practice-card-heading p { max-width: 900px; margin: 0; color: #304d45; font-size: 16px; font-weight: 720; line-height: 1.5; }
.practice-card-toggle { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: #e5f3ed; color: #24775f; font-size: 22px; font-weight: 500; transition: transform .2s ease, background .2s ease; }
.practice-card[open] .practice-card-toggle { background: #24775f; color: white; transform: rotate(45deg); }
.practice-card-body { display: grid; grid-template-columns: minmax(0, 1fr) minmax(280px, .72fr); gap: 16px 22px; padding: 18px 20px 20px; border-top: 1px solid #e3ebe8; }
.practice-card-explanation { grid-column: 1 / -1; max-width: 920px; margin: 0; color: #4d5f5a; font-size: 14px; line-height: 1.65; }
.practice-card-tutorials h4, .practice-pedagogical-note h4 { margin: 0; color: var(--ink); font-size: 13px; font-weight: 900; letter-spacing: .015em; }
.practice-tutorial-links { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 11px; }
.practice-tutorial-links button { display: inline-flex; align-items: center; justify-content: space-between; gap: 9px; min-height: 36px; padding: 7px 11px; border: 1px solid #9bc8e0; border-radius: 999px; background: #f5fbfe; color: var(--blue-deep); font-size: 12px; font-weight: 820; line-height: 1.3; text-align: left; cursor: pointer; transition: .18s ease; }
.practice-tutorial-links button:hover { border-color: var(--blue); background: var(--blue-pale); transform: translateY(-1px); }
.practice-tutorial-links button:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; }
.practice-tutorial-links button b { font-size: 14px; }
.practice-pedagogical-note { padding: 14px 15px; border-left: 4px solid var(--yellow); border-radius: 0 10px 10px 0; background: #fff9df; }
.practice-pedagogical-note h4 { color: #66551d; }
.practice-pedagogical-note p { margin: 6px 0 0; color: #655d42; font-size: 13px; line-height: 1.55; }
.practice-principle { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(280px, .9fr); gap: 16px 26px; margin-top: 12px; padding: 20px; border: 1px solid #d6e2eb; border-radius: 14px; background: white; box-shadow: 0 5px 16px rgba(23,35,59,.04); }
.practice-principle h3 { margin: 0; font-size: 20px; font-weight: 820; letter-spacing: -.025em; }
.practice-principle > div:first-child > p:last-child { margin: 8px 0 0; color: var(--muted); font-size: 13px; line-height: 1.6; }
.practice-principle > ul { display: grid; gap: 8px; align-content: start; margin: 0; padding: 0; list-style: none; }
.practice-principle > ul li { position: relative; padding-left: 20px; color: #46566e; font-size: 13px; line-height: 1.45; }
.practice-principle > ul li::before { position: absolute; top: .55em; left: 1px; width: 7px; height: 7px; border-radius: 50%; background: var(--mint); content: ""; }
.practice-principle-tutorials { grid-column: 1 / -1; padding-top: 14px; border-top: 1px solid var(--line); }
.practice-principle-tutorials > span { color: var(--ink); font-size: 12px; font-weight: 900; letter-spacing: .04em; text-transform: uppercase; }
.view-home .tutorial-card {
  grid-template-columns: 76px minmax(0, 1fr) 32px;
  gap: 20px;
  min-height: 112px;
  padding: 16px 20px;
}
.view-home .tutorial-card-copy { gap: 6px; }
.view-home .tutorial-card-copy strong { font-size: 20px; }
.view-home .tutorial-card-copy > span { font-size: 14px; line-height: 1.55; }

.search-section { display: flex; justify-content: space-between; align-items: end; gap: 40px; padding: 68px clamp(42px, 6vw, 96px) 38px; background: var(--paper); }
.search-section h2, .section-heading h2 { margin: 0; font-size: clamp(32px, 3.5vw, 50px); line-height: 1.05; letter-spacing: -.035em; }
.search-box { width: min(520px, 50%); display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 10px; padding: 0 16px; border: 1px solid #cfdbe8; border-radius: 14px; background: var(--canvas); }
.search-box > span { color: var(--blue); font-size: 25px; line-height: 1; transform: rotate(-20deg); }
.search-box input { width: 100%; height: 54px; border: 0; outline: 0; background: transparent; color: var(--ink); }
.search-box button { width: 30px; height: 30px; border: 0; border-radius: 50%; background: #dfe7ef; cursor: pointer; }

.tutorial-introduction { padding: 8px clamp(42px, 6vw, 96px) 72px; background: var(--paper); }
.tutorial-introduction-card { padding: clamp(28px, 4vw, 52px); border: 1px solid #cfe0ec; border-radius: 24px; background: linear-gradient(135deg, #edf8fe 0%, #f8fbfd 58%, #fff9e4 100%); box-shadow: 0 18px 48px rgba(23,35,59,.08); }
.tutorial-introduction-heading { max-width: 900px; }
.tutorial-introduction-heading h2 { max-width: 820px; margin: 0; font-size: clamp(32px, 3.7vw, 52px); line-height: 1.05; letter-spacing: -.04em; }
.tutorial-introduction-heading > p:last-child { max-width: 880px; margin: 20px 0 0; color: #52627a; font-size: 16px; line-height: 1.7; }
.tutorial-introduction-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; margin-top: 34px; }
.tutorial-introduction-grid article { min-width: 0; padding: 22px; border: 1px solid rgba(169,199,218,.72); border-radius: 16px; background: rgba(255,255,255,.86); box-shadow: 0 8px 22px rgba(23,35,59,.05); }
.tutorial-introduction-grid article > span { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 10px; background: var(--blue); color: white; font-size: 10px; font-weight: 900; letter-spacing: .06em; }
.tutorial-introduction-grid h3 { margin: 16px 0 0; font-size: 17px; line-height: 1.25; letter-spacing: -.02em; }
.tutorial-introduction-grid p { margin: 9px 0 0; color: var(--muted); font-size: 15px; line-height: 1.65; }
.tutorial-introduction-bottom { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(280px, .85fr); gap: 14px; margin-top: 14px; }
.tutorial-introduction-comparison, .tutorial-introduction-use-cases { padding: 20px 22px; border-radius: 15px; }
.tutorial-introduction-comparison { border-left: 4px solid var(--yellow); background: #fff9df; }
.tutorial-introduction-use-cases { border: 1px solid #cfe0ec; background: rgba(234,246,253,.85); }
.tutorial-introduction-comparison > span, .tutorial-introduction-use-cases > span { color: var(--ink); font-size: 12px; font-weight: 900; letter-spacing: .07em; text-transform: uppercase; }
.tutorial-introduction-comparison p { margin: 8px 0 0; color: #5b5336; font-size: 15px; line-height: 1.65; }
.tutorial-introduction-use-cases ul { display: flex; flex-wrap: wrap; gap: 7px; margin: 10px 0 0; padding: 0; list-style: none; }
.tutorial-introduction-use-cases li { padding: 7px 10px; border: 1px solid #b8d7e9; border-radius: 999px; background: white; color: var(--blue-deep); font-size: 13px; font-weight: 800; }
.tutorial-introduction-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.tutorial-introduction-start, .tutorial-introduction-video { display: inline-flex; align-items: center; gap: 12px; min-height: 50px; padding: 0 19px; border-radius: 12px; font-size: 14px; font-weight: 900; cursor: pointer; transition: .18s ease; }
.tutorial-introduction-start { border: 0; background: var(--blue); color: white; box-shadow: 0 9px 22px rgba(47,143,207,.22); }
.tutorial-introduction-video { border: 1px solid #9ac8e2; background: white; color: var(--blue-deep); box-shadow: 0 8px 20px rgba(23,35,59,.07); }
.tutorial-introduction-start:hover { background: var(--blue-deep); transform: translateY(-1px); }
.tutorial-introduction-video:hover { border-color: var(--blue); background: var(--blue-pale); transform: translateY(-1px); }
.tutorial-introduction-start:focus-visible, .tutorial-introduction-video:focus-visible { outline: 3px solid var(--yellow); outline-offset: 3px; }
.tutorial-introduction-start span { font-size: 17px; }
.tutorial-introduction-video span { display: grid; place-items: center; width: 25px; height: 25px; border-radius: 50%; background: var(--blue); color: white; font-size: 9px; }

.chapters { background: var(--paper); }
.chapter { scroll-margin-top: 74px; padding: 80px clamp(42px, 6vw, 96px); border-top: 1px solid var(--line); transition: background .3s ease, box-shadow .3s ease; }
.chapter:nth-child(even) { background: #f8fafc; }
.chapter.tour-active { position: relative; z-index: 1; background: #fffdf4; box-shadow: inset 5px 0 var(--yellow); }
.chapter-heading { display: grid; grid-template-columns: 72px minmax(0, 850px); gap: 24px; margin-bottom: 42px; }
.chapter-number { color: #9bacbf; font-size: 14px; font-weight: 850; letter-spacing: .12em; }
.chapter-heading h2 { margin: 0; font-size: clamp(32px, 3.8vw, 55px); line-height: 1.04; letter-spacing: -.04em; }
.chapter-heading > div > p:last-child { max-width: 830px; margin: 20px 0 0; color: var(--muted); font-size: 16px; line-height: 1.7; }
.chapter-layout { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(390px, .95fr); gap: clamp(34px, 5vw, 76px); align-items: start; }
.chapter-layout-single { grid-template-columns: minmax(0, 760px); justify-content: center; }
.chapter-layout-single .chapter-primary-link { width: min(100%, 640px); margin: 12px auto 0; }
.chapter-content { min-width: 0; }
.steps-card h3, .function-grid h3 { margin: 0; font-size: 17px; }
.steps-card ol { display: grid; gap: 14px; margin: 20px 0 0; padding: 0; list-style: none; }
.steps-card li { display: grid; grid-template-columns: 34px 1fr; gap: 13px; align-items: start; }
.steps-card li > span { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 10px; background: var(--blue); color: white; font-size: 12px; font-weight: 850; }
.step-copy { min-width: 0; }
.steps-card li p { margin: 3px 0 0; color: #40506a; font-size: 15.5px; line-height: 1.6; }
.steps-card .chapter-primary-link { width: 100%; margin: 16px 0 4px; }
.chapter-inline-link { display: inline-flex; align-items: center; gap: 7px; margin: 9px 0 2px; padding: 0; border: 0; border-bottom: 1px solid #8fc3e1; background: transparent; color: var(--blue-deep); font-size: 14px; font-weight: 800; line-height: 1.5; text-align: left; cursor: pointer; }
.chapter-inline-link:hover { border-color: var(--blue-deep); color: #104f76; }
.chapter-inline-link:focus-visible { outline: 3px solid var(--yellow); outline-offset: 3px; }
.chapter-inline-link span { font-size: 15px; }
.steps-card p .chapter-inline-link { display: inline; margin: 0 1px; font-size: inherit; line-height: inherit; }
.steps-card p .chapter-inline-link span { font-size: inherit; }
.chapter-primary-link { display: grid; grid-template-columns: 38px minmax(0, 1fr) auto; gap: 13px; align-items: center; width: 100%; margin-top: 24px; padding: 16px 18px; border: 1px solid var(--blue); border-radius: 13px; background: linear-gradient(115deg, var(--blue), #2479ad); color: white; font: inherit; text-align: left; text-decoration: none; box-shadow: 0 10px 24px rgba(47,143,207,.22); cursor: pointer; transition: .2s ease; }
.chapter-primary-link:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(47,143,207,.29); }
.chapter-primary-link > span:first-child { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; background: rgba(255,255,255,.16); font-size: 18px; }
.chapter-primary-link > span:nth-child(2) { display: grid; gap: 2px; }
.chapter-primary-link strong { font-size: 15px; }
.chapter-primary-link small { color: #d8eef9; font-size: 12.5px; line-height: 1.45; }
.chapter-primary-link > span:last-child { font-size: 18px; font-weight: 900; }
.role-section { margin-top: 30px; }
.role-section > h3 { margin: 0 0 12px; font-size: 16px; }
.role-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.role-card { padding: 18px; border: 1px solid #cbdfea; border-radius: 14px; background: #eff8fd; }
.role-card.is-learners { border-color: #bfe0d1; background: #eff9f4; }
.role-card > span { display: inline-flex; padding: 5px 8px; border-radius: 7px; background: var(--blue); color: white; font-size: 10px; font-weight: 900; letter-spacing: .07em; text-transform: uppercase; }
.role-card.is-learners > span { background: #24775f; }
.role-card h3 { margin: 13px 0 0; font-size: 17px; line-height: 1.3; }
.role-card p { margin: 8px 0 0; color: #4b5d73; font-size: 15px; line-height: 1.6; }
.learning-plan-example { margin-top: 30px; overflow: hidden; border: 1px solid #cddbe6; border-radius: 17px; background: white; box-shadow: 0 12px 30px rgba(23,35,59,.08); }
.learning-plan-example header { padding: 20px 22px; background: linear-gradient(115deg, #13233d, #24506c); color: white; }
.learning-plan-example header > span { display: block; margin-bottom: 6px; color: #b9d8e9; font-size: 10px; font-weight: 900; letter-spacing: .09em; text-transform: uppercase; }
.learning-plan-example header h3 { margin: 0; font-size: 20px; line-height: 1.3; }
.learning-plan-example header p { margin: 8px 0 0; color: #dcebf4; font-size: 14px; line-height: 1.55; }
.learning-plan-example-grid { display: grid; grid-template-columns: minmax(0, 1fr); }
.learning-plan-example-grid article { padding: 18px 20px; border-bottom: 1px solid var(--line); }
.learning-plan-example-grid article:last-child { border-bottom: 0; }
.learning-plan-example-grid article > span { display: block; margin-bottom: 7px; color: var(--blue-deep); font-size: 10px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.learning-plan-example-grid p, .learning-plan-example-grid ul { margin: 0; color: #42536a; font-size: 14.5px; line-height: 1.6; }
.learning-plan-example-grid ul { display: grid; gap: 6px; padding-left: 21px; }
.function-section { margin-top: 32px; }
.function-section-title { margin: 0 0 12px; color: var(--ink); font-size: 16px; }
.function-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.function-grid article { min-height: 122px; padding: 18px; border: 1px solid var(--line); border-radius: 13px; background: white; }
.function-grid p { margin: 8px 0 0; color: var(--muted); font-size: 15px; line-height: 1.6; }
.tip-box { display: grid; grid-template-columns: auto 1fr; gap: 13px; margin-top: 20px; padding: 17px 18px; border-left: 4px solid var(--yellow); border-radius: 0 12px 12px 0; background: #fff9df; }
.tip-box span { align-self: start; padding: 4px 8px; border-radius: 6px; background: var(--yellow); font-size: 11px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.tip-box p { margin: 0; color: #5b5336; font-size: 15px; line-height: 1.6; }
.chapter-media { position: sticky; top: 108px; min-width: 0; }
.screenshot-card { margin: 0; }
.screenshot-card button { position: relative; width: 100%; padding: 0; overflow: hidden; border: 7px solid white; border-radius: 18px; background: white; box-shadow: var(--shadow); cursor: zoom-in; }
.screenshot-card img { width: 100%; aspect-ratio: 16/9; object-fit: cover; object-position: center top; background: #e9eef4; }
.screenshot-card figcaption { padding: 10px 8px 0; color: #758397; font-size: 12px; letter-spacing: .04em; text-transform: uppercase; }
.chapter-video-card { margin: 0; overflow: hidden; border: 7px solid white; border-radius: 18px; background: white; box-shadow: var(--shadow); }
.chapter-video-card video { display: block; width: 100%; aspect-ratio: 1280 / 824; border-radius: 11px; background: #0d1728; object-fit: cover; }
.chapter-video-card figcaption { display: flex; justify-content: space-between; align-items: center; gap: 14px; padding: 11px 7px 5px; }
.chapter-video-card figcaption > span { color: #66748a; font-size: 12px; font-weight: 800; line-height: 1.4; letter-spacing: .035em; text-transform: uppercase; }
.chapter-video-caption { display: grid; gap: 3px; }
.chapter-video-caption .video-silent-note { display: block; color: #8794a4; font-size: 10px; font-weight: 700; line-height: 1.3; letter-spacing: .08em; text-transform: uppercase; }
.chapter-video-card figcaption button { display: inline-flex; flex: 0 0 auto; align-items: center; gap: 7px; min-height: 38px; padding: 0 13px; border: 1px solid #b8d7e9; border-radius: 9px; background: var(--blue-pale); color: var(--blue-deep); font-size: 12px; font-weight: 850; cursor: pointer; transition: .18s ease; }
.chapter-video-card figcaption button:hover { border-color: var(--blue); background: #dff2fc; transform: translateY(-1px); }
.chapter-video-card figcaption button:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; }
.screenshot-gallery { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 9px; margin-top: 15px; }
.screenshot-gallery button { display: grid; gap: 7px; min-width: 0; padding: 6px 6px 9px; overflow: hidden; border: 1px solid var(--line); border-radius: 11px; background: white; color: #40506a; text-align: left; cursor: zoom-in; transition: .18s ease; }
.screenshot-gallery button:hover { border-color: #9bc8df; transform: translateY(-1px); }
.screenshot-gallery img { width: 100%; aspect-ratio: 16/9; border-radius: 7px; object-fit: cover; object-position: top; background: #e9eef4; }
.screenshot-gallery span { padding: 0 4px; overflow: hidden; font-size: 12px; font-weight: 800; line-height: 1.35; text-overflow: ellipsis; }
.chapter-footer { display: flex; justify-content: center; margin-top: 56px; padding-top: 32px; border-top: 1px solid var(--line); }
.complete-button { display: inline-flex; justify-content: center; align-items: center; gap: 11px; width: min(100%, 390px); min-height: 54px; padding: 13px 24px; border: 1px solid #d4ab27; border-radius: 14px; background: var(--yellow); color: #3f3310; box-shadow: 0 10px 24px rgba(196,151,18,.2); font-size: 15px; font-weight: 900; cursor: pointer; transition: transform .18s ease, box-shadow .18s ease, background .18s ease; }
.complete-button:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(196,151,18,.28); }
.complete-button:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.complete-button span { display: grid; place-items: center; width: 28px; height: 28px; border: 1px solid rgba(63,51,16,.25); border-radius: 50%; background: rgba(255,255,255,.3); font-size: 15px; }
.complete-button.done { border-color: #8fcbb7; background: #dff4ec; color: #176b52; box-shadow: 0 10px 24px rgba(36,130,100,.14); }
.complete-button.done span { border-color: #8fcbb7; background: white; }

.next-learning { display: grid; grid-template-columns: minmax(260px, .72fr) minmax(0, 1.28fr); gap: clamp(34px, 5vw, 76px); padding: 82px clamp(42px, 6vw, 96px); border-top: 1px solid var(--line); background: linear-gradient(135deg, #eaf6fd 0%, #f7fbfd 52%, #fff8df 100%); }
.next-learning-heading h2 { max-width: 560px; margin: 0; font-size: clamp(32px, 3.7vw, 54px); line-height: 1.04; letter-spacing: -.04em; }
.next-learning-heading > p:last-child { max-width: 550px; margin: 20px 0 0; color: var(--muted); font-size: 15px; line-height: 1.65; }
.next-learning-grid { display: grid; gap: 12px; }
.next-learning-grid button { position: relative; display: grid; gap: 6px; width: 100%; padding: 20px 56px 20px 22px; border: 1px solid #cfdeea; border-radius: 15px; background: rgba(255,255,255,.86); color: var(--ink); text-align: left; cursor: pointer; box-shadow: 0 8px 22px rgba(23,35,59,.06); transition: .2s ease; }
.next-learning-grid button:hover { border-color: #8fc3e1; background: white; transform: translateY(-2px); box-shadow: 0 13px 30px rgba(23,35,59,.11); }
.next-learning-grid button > span { color: var(--blue-deep); font-size: 11px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.next-learning-grid button > strong { font-size: 18px; line-height: 1.2; letter-spacing: -.02em; }
.next-learning-grid button > p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.55; }
.next-learning-grid button > b { position: absolute; top: 50%; right: 19px; display: grid; place-items: center; width: 30px; height: 30px; border-radius: 50%; background: var(--blue-pale); color: var(--blue-deep); transform: translateY(-50%); }

footer { display: flex; justify-content: space-between; align-items: center; padding: 34px clamp(42px, 6vw, 96px); background: #0d192b; color: white; }
footer strong { font-size: 14px; }
footer p { margin: 2px 0 0; color: #7f93ac; font-size: 11px; }
footer a { font-size: 12px; font-weight: 800; text-decoration: none; }

.empty-state { padding: 90px 30px; text-align: center; border-top: 1px solid var(--line); }
.empty-state > span { display: grid; place-items: center; width: 58px; height: 58px; margin: 0 auto 18px; border-radius: 18px; background: var(--blue-pale); color: var(--blue); font-size: 28px; font-weight: 900; }
.empty-state h2 { margin: 0; font-size: 30px; }
.empty-state p { color: var(--muted); }
.empty-state button { margin-top: 10px; }

.lightbox { position: fixed; inset: 0; z-index: 100; display: grid; place-items: center; padding: 42px; background: rgba(7,16,29,.9); backdrop-filter: blur(10px); }
.lightbox > div { width: min(1460px, 94vw); max-height: 90vh; overflow: auto; border-radius: 16px; background: white; box-shadow: 0 30px 90px rgba(0,0,0,.45); }
.lightbox img { width: 100%; height: auto; }
.lightbox p { display: flex; justify-content: space-between; gap: 30px; margin: 0; padding: 17px 20px; font-size: 13px; }
.lightbox p span { color: var(--muted); font-size: 11px; }
.lightbox-close { position: fixed; top: 18px; right: 22px; width: 42px; height: 42px; border: 0; border-radius: 50%; background: white; font-size: 25px; cursor: pointer; }
.video-modal { position: fixed; inset: 0; z-index: 110; display: grid; place-items: center; padding: 42px; background: rgba(7,16,29,.9); backdrop-filter: blur(10px); }
.video-modal-card { width: min(1050px, 94vw); max-height: 90vh; overflow: auto; padding: 22px; border-radius: 20px; background: white; box-shadow: 0 30px 90px rgba(0,0,0,.45); }
.video-modal-card header { padding: 3px 4px 18px; }
.video-modal-card h2 { margin: 5px 0 0; font-size: clamp(24px, 3vw, 36px); letter-spacing: -.035em; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }
.video-modal-card video { display: block; width: 100%; aspect-ratio: 1280 / 824; border-radius: 14px; background: #0d1728; }
.video-modal-card-source-ratio video { height: auto; max-height: 70vh; aspect-ratio: auto; object-fit: contain; }
.video-modal-close { position: fixed; top: 18px; right: 22px; z-index: 1; width: 42px; height: 42px; border: 0; border-radius: 50%; background: white; font-size: 25px; cursor: pointer; }
.tour-bar { position: fixed; z-index: 80; left: 294px; right: 24px; bottom: 20px; display: flex; justify-content: space-between; align-items: center; gap: 20px; padding: 13px 14px 13px 18px; border: 1px solid #d6e0e9; border-radius: 16px; background: rgba(255,255,255,.96); box-shadow: 0 18px 55px rgba(23,35,59,.22); backdrop-filter: blur(14px); }
.tour-bar > div:first-child { display: grid; gap: 1px; }
.tour-bar span { color: var(--blue-deep); font-size: 9px; font-weight: 900; letter-spacing: .1em; text-transform: uppercase; }
.tour-bar strong { font-size: 13px; }
.tour-bar > div:last-child { display: flex; gap: 7px; }
.tour-bar button { min-width: 36px; height: 36px; padding: 0 12px; border: 1px solid var(--line); border-radius: 9px; background: var(--canvas); font-weight: 850; cursor: pointer; }
.tour-bar button:disabled { opacity: .35; cursor: default; }
.tour-bar .tour-finish { background: var(--yellow); color: #3f3310; border-color: #d4ab27; }

.reference { scroll-margin-top: 76px; padding-bottom: 90px; background: #f3f7fb; }
.reference-hero { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(420px, .85fr); gap: 64px; align-items: end; padding: 94px clamp(42px, 6vw, 96px) 62px; background: linear-gradient(135deg, #e8f5fc 0%, #f8fbfd 52%, #fff8df 100%); border-bottom: 1px solid var(--line); }
.reference-hero-single { grid-template-columns: minmax(0, 900px); }
.reference-hero h2 { max-width: 850px; margin: 0; font-size: clamp(42px, 5vw, 72px); line-height: 1; letter-spacing: -.05em; }
.reference-hero > div:first-child > p:last-child { max-width: 790px; margin: 24px 0 0; color: #58667d; font-size: 17px; line-height: 1.7; }
.reference-stats { display: grid; grid-template-columns: repeat(3, 1fr); overflow: hidden; border: 1px solid rgba(23,35,59,.1); border-radius: 16px; background: rgba(255,255,255,.75); box-shadow: 0 18px 50px rgba(23,35,59,.08); backdrop-filter: blur(12px); }
.reference-stats div { padding: 22px 16px; border-right: 1px solid var(--line); text-align: center; }
.reference-stats div:last-child { border-right: 0; }
.reference-stats strong, .reference-stats span { display: block; }
.reference-stats strong { font-size: 23px; letter-spacing: -.03em; }
.reference-stats span { margin-top: 4px; color: var(--muted); font-size: 10px; }

.reference-directory { padding: 58px clamp(42px, 6vw, 96px) 64px; border-bottom: 1px solid var(--line); background: #f7fafc; }
.reference-directory > header { max-width: 800px; margin-bottom: 28px; }
.reference-directory > header h3 { margin: 0; font-size: clamp(30px, 4vw, 48px); line-height: 1.08; letter-spacing: -.04em; }
.reference-directory > header > p:last-child { margin: 14px 0 0; color: var(--muted); font-size: 16px; line-height: 1.65; }
.reference-directory-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.reference-directory-grid > button { display: grid; grid-template-columns: 46px minmax(0, 1fr) auto 28px; gap: 14px; align-items: center; min-height: 104px; padding: 17px 18px; border: 1px solid var(--line); border-radius: 15px; background: white; color: var(--ink); text-align: left; box-shadow: 0 9px 26px rgba(23,35,59,.045); cursor: pointer; transition: border-color .18s ease, box-shadow .18s ease, transform .18s ease; }
.reference-directory-grid > button:hover { border-color: #9bc9e4; box-shadow: 0 14px 30px rgba(23,35,59,.09); transform: translateY(-2px); }
.reference-directory-grid > button:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; }
.reference-directory-number { display: grid; place-items: center; width: 44px; height: 44px; border-radius: 13px; background: #13233d; color: white; font-size: 11px; font-weight: 900; letter-spacing: .07em; }
.reference-directory-copy { display: grid; gap: 5px; }
.reference-directory-copy strong { font-size: 18px; line-height: 1.25; }
.reference-directory-copy small { color: var(--muted); font-size: 14px; line-height: 1.5; }
.reference-directory-count { display: grid; place-items: center; min-width: 30px; height: 30px; padding: 0 8px; border-radius: 999px; background: #edf6fb; color: var(--blue-deep); font-size: 12px; font-weight: 850; }
.reference-directory-arrow { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--blue-pale); color: var(--blue-deep); font-size: 14px; font-weight: 900; }

.reference-scenarios { padding: 58px clamp(42px, 6vw, 96px) 64px; border-bottom: 1px solid var(--line); background: white; }
.reference-scenarios-heading { display: flex; align-items: end; justify-content: space-between; gap: 32px; margin-bottom: 30px; }
.reference-scenarios-heading h3 { max-width: 850px; margin: 0; font-size: clamp(30px, 4vw, 48px); line-height: 1.08; letter-spacing: -.04em; }
.reference-scenarios-heading > div > p:last-child { max-width: 760px; margin: 14px 0 0; color: var(--muted); font-size: 16px; line-height: 1.65; }
.reference-scenarios-heading > span { flex: 0 0 auto; padding: 9px 12px; border-radius: 999px; background: #edf6fb; color: var(--blue-deep); font-size: 12px; font-weight: 850; }
.reference-scenario-tabs { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 9px; margin-bottom: 20px; }
.reference-scenario-tabs button { display: grid; gap: 4px; min-height: 76px; padding: 13px 14px; border: 1px solid var(--line); border-radius: 12px; background: #f7fafc; color: var(--ink); text-align: left; cursor: pointer; transition: border-color .18s ease, background .18s ease, transform .18s ease; }
.reference-scenario-tabs button:hover { border-color: #9bc9e4; transform: translateY(-1px); }
.reference-scenario-tabs button.is-active { border-color: #225778; background: #13233d; color: white; box-shadow: 0 9px 22px rgba(23,35,59,.16); }
.reference-scenario-tabs strong { font-size: 14px; }
.reference-scenario-tabs span { color: var(--muted); font-size: 12px; line-height: 1.45; }
.reference-scenario-tabs button.is-active span { color: #c5dbe8; }
.reference-scenario-areas { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; align-items: start; }
.reference-scenario-areas.is-single { grid-template-columns: minmax(0, 1fr); }
.reference-scenario-area { overflow: hidden; border: 1px solid var(--line); border-radius: 17px; background: #f8fafc; box-shadow: 0 12px 32px rgba(23,35,59,.055); }
.reference-scenario-area > header { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 19px 21px; border-bottom: 1px solid var(--line); background: linear-gradient(120deg, #13233d, #225778); color: white; }
.reference-scenario-area > header h4 { margin: 0; font-size: 19px; letter-spacing: -.02em; }
.reference-scenario-area > header p { margin: 3px 0 0; color: #c5dbe8; font-size: 13px; }
.reference-scenario-area > header > span { display: grid; place-items: center; min-width: 30px; height: 30px; border-radius: 9px; background: rgba(255,255,255,.14); font-size: 12px; font-weight: 900; }
.reference-scenario-list { display: grid; }
.reference-scenario { border-bottom: 1px solid var(--line); background: white; }
.reference-scenario:last-child { border-bottom: 0; }
.reference-scenario summary { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 18px; align-items: center; padding: 18px 20px; list-style: none; cursor: pointer; transition: background .18s ease; }
.reference-scenario summary::-webkit-details-marker { display: none; }
.reference-scenario summary:hover, .reference-scenario[open] summary { background: #f1f8fc; }
.reference-scenario summary h5 { margin: 0; font-size: 18px; line-height: 1.35; }
.reference-scenario summary p { margin: 6px 0 0; color: var(--muted); font-size: 14.5px; line-height: 1.55; }
.reference-scenario summary > span { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--blue-pale); color: var(--blue-deep); font-size: 18px; transition: transform .2s ease; }
.reference-scenario[open] summary > span { transform: rotate(45deg); }
.reference-scenario-body { display: grid; grid-template-columns: minmax(0, 1.18fr) minmax(0, .82fr); gap: 12px; padding: 0 20px 20px; background: #f1f8fc; }
.reference-scenario-body.is-single > section:first-child { grid-column: 1 / -1; }
.reference-scenario-body > section { padding: 15px 16px; border: 1px solid #d8e5ed; border-radius: 11px; background: white; }
.reference-scenario-body h6 { margin: 0 0 11px; color: #244963; font-size: 12px; letter-spacing: .07em; text-transform: uppercase; }
.reference-scenario-body ol { display: grid; gap: 8px; margin: 0; padding-left: 21px; color: #435369; font-size: 15px; line-height: 1.6; }
.reference-scenario-body p { margin: 0; color: #435369; font-size: 15px; line-height: 1.65; }
.reference-scenario-learners { border-color: #c4dfd3 !important; background: #f1faf6 !important; }
.reference-scenario-learners h6 { color: #28715c; }
.reference-scenario-check { grid-column: 1 / -1; padding: 12px 14px; border-left: 3px solid var(--yellow); background: #fff9df; color: #62593c !important; }
.reference-scenario-links { grid-column: 1 / -1; display: flex; flex-wrap: wrap; gap: 7px; }
.reference-scenario-links button { display: inline-flex; align-items: center; gap: 8px; padding: 9px 12px; border: 1px solid #bed7e6; border-radius: 9px; background: white; color: var(--blue-deep); font-size: 13px; font-weight: 800; cursor: pointer; transition: .18s ease; }
.reference-scenario-links button:hover { border-color: var(--blue); background: var(--blue); color: white; transform: translateY(-1px); }
.reference-scenario-links button span { font-size: 13px; }

.reference-controls { position: sticky; z-index: 20; top: 76px; display: grid; gap: 14px; padding: 24px clamp(42px, 6vw, 96px); border-bottom: 1px solid var(--line); background: rgba(255,255,255,.94); backdrop-filter: blur(16px); }
.reference-search { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 10px; width: min(760px, 100%); padding: 0 15px; border: 1px solid #cfdbe8; border-radius: 13px; background: #f7f9fc; }
.reference-search > span { color: var(--blue); font-size: 24px; transform: rotate(-18deg); }
.reference-search input { width: 100%; height: 50px; border: 0; outline: 0; background: transparent; color: var(--ink); }
.reference-search button { width: 30px; height: 30px; border: 0; border-radius: 50%; background: #dfe7ef; cursor: pointer; }
.category-filter { display: flex; flex-wrap: wrap; gap: 7px; }
.category-filter button { padding: 8px 12px; border: 1px solid var(--line); border-radius: 999px; background: white; color: var(--muted); font-size: 13px; font-weight: 750; cursor: pointer; transition: .18s ease; }
.category-filter button:hover { border-color: #a9cbe0; color: var(--blue-deep); }
.category-filter button.is-active { border-color: var(--blue); background: var(--blue); color: white; box-shadow: 0 6px 16px rgba(47,143,207,.2); }
.reference-result-line { display: flex; align-items: center; gap: 5px; padding: 25px clamp(42px, 6vw, 96px) 0; color: var(--muted); font-size: 14px; }
.reference-result-line strong { color: var(--ink); font-size: 15px; }
.reference-result-line button { margin-left: 10px; padding: 6px 9px; border: 0; border-radius: 7px; background: #dfeaf3; color: var(--blue-deep); font-size: 12px; font-weight: 800; cursor: pointer; }

.reference-groups { display: grid; gap: 42px; padding: 32px clamp(42px, 6vw, 96px) 0; }
.reference-group { scroll-margin-top: 215px; overflow: hidden; border: 1px solid var(--line); border-radius: 20px; background: white; box-shadow: 0 16px 46px rgba(23,35,59,.07); }
.reference-group-heading { display: grid; grid-template-columns: 54px minmax(0, 1fr) 190px; gap: 20px; align-items: center; min-height: 150px; padding: 24px 28px; border-bottom: 1px solid var(--line); background: linear-gradient(115deg, #f7fafc, white); }
.reference-number { display: grid; place-items: center; width: 48px; height: 48px; border-radius: 14px; background: #13233d; color: white; font-size: 12px; font-weight: 900; letter-spacing: .08em; }
.reference-group-heading h3 { margin: 0; font-size: clamp(25px, 2.8vw, 40px); line-height: 1.05; letter-spacing: -.035em; }
.reference-group-heading p { margin: 9px 0 0; color: var(--muted); font-size: 15px; line-height: 1.5; }
.reference-image { position: relative; width: 190px; padding: 0; overflow: hidden; border: 5px solid white; border-radius: 13px; background: white; box-shadow: 0 8px 24px rgba(23,35,59,.15); cursor: zoom-in; }
.reference-image img { width: 100%; aspect-ratio: 16/9; object-fit: cover; object-position: top; }
.reference-image span { position: absolute; right: 7px; bottom: 7px; padding: 4px 6px; border-radius: 6px; background: rgba(13,25,43,.86); color: white; font-size: 9px; font-weight: 800; }
.reference-external { width: 190px; min-height: 108px; padding: 16px; display: flex; flex-direction: column; justify-content: center; gap: 5px; border: 1px solid #174f71; border-radius: 13px; background: linear-gradient(135deg, #123e5c, #176f98); color: white; text-decoration: none; box-shadow: 0 8px 24px rgba(23,35,59,.15); transition: transform .18s ease, box-shadow .18s ease; }
.reference-external:hover { transform: translateY(-2px); box-shadow: 0 12px 28px rgba(23,35,59,.22); }
.reference-external span { color: #bfe8f8; font-size: 9px; font-weight: 850; letter-spacing: .08em; text-transform: uppercase; }
.reference-external strong { font-size: 13px; line-height: 1.25; overflow-wrap: anywhere; }
.reference-external small { color: #d8eef7; font-size: 10px; }
.reference-topic-sections { display: grid; }
.reference-topic-section { display: grid; }
.reference-topic-section + .reference-topic-section { border-top: 5px solid #edf3f7; }
.reference-topic-section-heading { padding: 14px 28px; border-bottom: 1px solid var(--line); background: #f8fafc; }
.reference-topic-section-heading h4 { margin: 0; color: var(--blue-deep); font-size: 12px; font-weight: 900; letter-spacing: .11em; text-transform: uppercase; }
.reference-topic-list { display: grid; }
.reference-topic { border-bottom: 1px solid var(--line); }
.reference-topic:last-child { border-bottom: 0; }
.reference-topic summary { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 22px; align-items: center; padding: 24px 28px; list-style: none; cursor: pointer; transition: background .18s ease; }
.reference-topic summary::-webkit-details-marker { display: none; }
.reference-topic summary:hover { background: #f8fbfd; }
.reference-topic[open] summary { background: #f3f9fc; }
.reference-topic h4 { margin: 0; font-size: 20px; line-height: 1.25; }
.reference-topic summary p { max-width: 900px; margin: 7px 0 0; color: var(--muted); font-size: 15px; line-height: 1.6; }
.reference-plus { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 50%; background: var(--blue-pale); color: var(--blue-deep); font-size: 20px; transition: transform .2s ease; }
.reference-topic[open] .reference-plus { transform: rotate(45deg); }
.reference-topic-body { display: grid; gap: 22px; padding: 4px 28px 30px; background: #f3f9fc; }
.reference-topic-content { display: grid; min-width: 0; gap: 22px; }
.reference-topic-visual { display: grid; place-items: center; overflow: hidden; border: 1px solid #c8d9e3; border-radius: 15px; background: #e9f1f5; box-shadow: 0 12px 28px rgba(18,43,62,.12); }
.reference-topic-visual-button { position: relative; display: block; width: 100%; padding: 14px; border: 0; background: transparent; cursor: zoom-in; }
.reference-topic-visual-button img { display: block; width: auto; max-width: 100%; height: auto; max-height: 520px; margin: 0 auto; object-fit: contain; border-radius: 8px; box-shadow: 0 5px 18px rgba(18,43,62,.12); transition: filter .18s ease; }
.reference-topic-visual-static { display: grid; place-items: center; width: 100%; padding: 14px; }
.reference-topic-visual-static img { display: block; width: auto; max-width: 100%; height: auto; margin: 0 auto; }
.reference-topic-visual.is-compact { justify-items: start; box-shadow: none; }
.reference-topic-visual.is-compact .reference-topic-visual-static { justify-items: start; }
.reference-topic-visual.is-dialog-crop, .reference-topic-visual.is-dark-topic-crop { padding: 14px; box-shadow: none; }
.reference-topic-visual-crop { position: relative; overflow: hidden; border-radius: 12px; background: white; box-shadow: 0 5px 18px rgba(18,43,62,.16); }
.reference-topic-visual-crop.is-center-dialog { width: min(448px, 100%); aspect-ratio: 432 / 492; }
.reference-topic-visual-crop.is-center-dialog img { position: absolute; top: 50%; left: 50%; width: 333.333%; max-width: none; height: auto; transform: translate(-50%, -50%); }
.reference-topic-visual-crop.is-dark-topic { width: min(1212px, 100%); aspect-ratio: 2424 / 760; }
.reference-topic-visual-crop.is-dark-topic img { position: absolute; top: 0; left: 0; width: 105.611%; max-width: none; height: auto; transform: translate(-2.656%, -34.028%); }
.reference-topic-visual-button:hover img { filter: brightness(.94); }
.reference-topic-visual-button:focus-visible { outline: 3px solid var(--yellow); outline-offset: -4px; }
.reference-topic-visual-zoom { position: absolute; right: 10px; bottom: 10px; z-index: 1; padding: 5px 8px; border-radius: 7px; background: rgba(11,28,42,.88); color: white; font-size: 8.5px; font-weight: 850; letter-spacing: .04em; text-transform: uppercase; }
.reference-topic-external { display: grid; grid-template-columns: 42px minmax(0, 1fr) auto; gap: 16px; align-items: center; padding: 20px; border: 1px solid #174f71; border-radius: 15px; background: linear-gradient(125deg, #123e5c, #176f98); color: white; }
.reference-topic-external-icon { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 12px; background: rgba(255,255,255,.14); font-size: 20px; font-weight: 900; }
.reference-topic-external > div > span { display: block; margin-bottom: 5px; color: #aee1f4; font-size: 11px; font-weight: 900; letter-spacing: .09em; text-transform: uppercase; }
.reference-topic-body .reference-topic-external h5 { color: white; font-size: 17px; }
.reference-topic-external p { margin: 7px 0 0; color: #d8eef7; font-size: 14px; line-height: 1.55; }
.reference-topic-external a { padding: 10px 12px; border: 1px solid rgba(255,255,255,.3); border-radius: 9px; background: rgba(255,255,255,.1); color: white; font-size: 13px; font-weight: 850; text-decoration: none; white-space: nowrap; }
.reference-topic-external a:hover { background: rgba(255,255,255,.18); }
.reference-intro-grid { display: grid; grid-template-columns: minmax(220px, .72fr) minmax(0, 1.28fr); gap: 18px; }
.reference-path { padding: 16px; border: 1px solid #d7e8f2; border-radius: 12px; background: white; }
.reference-path span, .reference-path strong { display: block; }
.reference-path span { margin-bottom: 6px; color: var(--blue-deep); font-size: 11px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.reference-path strong { font-size: 15px; line-height: 1.5; }
.reference-effect { padding: 16px 18px; border: 1px solid #cce1ed; border-radius: 12px; background: #e9f5fa; }
.reference-effect span { display: block; margin-bottom: 6px; color: var(--blue-deep); font-size: 11px; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.reference-effect p { margin: 0; color: #304961; font-size: 15px; line-height: 1.65; }
.reference-topic-link { display: grid; grid-template-columns: 34px minmax(0, 1fr) auto; gap: 12px; align-items: center; width: min(620px, 100%); padding: 13px 15px; border: 1px solid var(--blue); border-radius: 12px; background: linear-gradient(115deg, var(--blue), #2479ad); color: white; text-decoration: none; box-shadow: 0 9px 22px rgba(47,143,207,.2); transition: transform .18s ease, box-shadow .18s ease; }
.reference-topic-link[type="button"] { font: inherit; text-align: left; cursor: pointer; }
.reference-topic-link:hover { transform: translateY(-2px); box-shadow: 0 13px 28px rgba(47,143,207,.28); }
.reference-topic-link > span:first-child { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 9px; background: rgba(255,255,255,.16); font-size: 17px; }
.reference-topic-link > span:nth-child(2) { display: grid; gap: 2px; }
.reference-topic-link strong { font-size: 14px; }
.reference-topic-link small { color: #d8eef9; font-size: 12px; line-height: 1.45; }
.reference-topic-link > span:last-child { font-size: 17px; font-weight: 900; }
.reference-topic-body h5 { margin: 0; color: var(--ink); font-size: 17px; letter-spacing: -.01em; }
.reference-howto { padding: 19px 20px; border: 1px solid #d7e3ec; border-radius: 14px; background: white; }
.reference-howto h5 { margin-bottom: 12px; }
.reference-topic-body ol, .reference-topic-body ul { display: grid; gap: 9px; margin: 0; padding-left: 22px; color: #42516a; font-size: 15px; line-height: 1.6; }
.reference-student-view { display: grid; grid-template-columns: 38px minmax(0, 1fr); gap: 14px; padding: 20px; border: 1px solid #bfe0d1; border-radius: 14px; background: #eff9f4; }
.reference-section-icon { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 11px; background: #24775f; color: white; font-size: 12px; font-weight: 900; }
.reference-student-view h5 { margin: 1px 0 10px; color: #195f4c; }
.reference-student-view ul { color: #315f53; }
.reference-options-section { overflow: hidden; border: 1px solid #ccdbe6; border-radius: 16px; background: white; }
.reference-section-heading { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 18px 20px; border-bottom: 1px solid #dbe5ec; background: linear-gradient(115deg, #13233d, #24506c); color: white; }
.reference-section-heading span { display: block; margin-bottom: 4px; color: #bcd7e7; font-size: 11px; font-weight: 900; letter-spacing: .09em; text-transform: uppercase; }
.reference-section-heading h5 { color: white; font-size: 17px; }
.reference-section-heading strong { flex: 0 0 auto; padding: 6px 9px; border-radius: 999px; background: rgba(255,255,255,.14); color: white; font-size: 11px; letter-spacing: .04em; }
.reference-options { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.reference-option { padding: 19px 20px; border-right: 1px solid #e0e7ed; border-bottom: 1px solid #e0e7ed; }
.reference-option:nth-child(2n) { border-right: 0; }
.reference-option:nth-last-child(-n+2) { border-bottom: 0; }
.reference-option:nth-last-child(1):nth-child(odd) { grid-column: 1 / -1; border-right: 0; }
.reference-option h6 { margin: 0 0 13px; color: #153d57; font-size: 16px; }
.reference-option dl { display: grid; gap: 10px; margin: 0; }
.reference-option dl > div { display: grid; grid-template-columns: 82px minmax(0, 1fr); gap: 9px; }
.reference-option dt { color: #657489; font-size: 10.5px; font-weight: 900; letter-spacing: .07em; text-transform: uppercase; }
.reference-option dd { margin: 0; color: #46566c; font-size: 14px; line-height: 1.55; }
.reference-option-caution { margin-top: 1px; padding-top: 9px; border-top: 1px dashed #e4cf76; }
.reference-option-caution dt, .reference-option-caution dd { color: #76601d; }
.reference-note { grid-column: 1 / -1; margin: 0; padding: 13px 15px; border-left: 3px solid var(--yellow); background: #fff9df; color: #62593c; font-size: 14px; line-height: 1.6; }
.reference-empty { padding: 80px 24px; border: 1px solid var(--line); border-radius: 18px; background: white; text-align: center; }
.reference-empty > span { display: grid; place-items: center; width: 54px; height: 54px; margin: 0 auto 16px; border-radius: 16px; background: var(--blue-pale); color: var(--blue); font-size: 26px; font-weight: 900; }
.reference-empty h3 { margin: 0; font-size: 25px; }
.reference-empty p { color: var(--muted); }
.reference-empty button { margin-top: 8px; padding: 11px 14px; border: 0; border-radius: 9px; background: var(--blue); color: white; font-weight: 800; cursor: pointer; }

@media (min-width: 1280px) {
  .reference-topic-body.has-screenshot {
    grid-template-columns: minmax(0, 1fr) minmax(420px, .86fr);
    gap: 26px 30px;
    align-items: start;
    padding-top: 18px;
  }
  .reference-topic-body.has-screenshot > .reference-topic-content {
    grid-column: 1;
    grid-row: 1;
  }
  .reference-topic-body.has-screenshot > .reference-topic-visual {
    grid-column: 2;
    grid-row: 1;
    min-width: 0;
    align-self: start;
  }
  .reference-topic-body.has-screenshot .reference-topic-visual-button { padding: 10px; }
  .reference-topic-body.has-screenshot .reference-topic-visual-button img { max-height: 440px; }
}

@media (max-width: 1120px) {
  .hero { grid-template-columns: 1fr; min-height: 0; }
  .view-home .hero {
    gap: 34px;
    padding: 52px 32px 74px;
  }
  .view-home .hero h1 { font-size: clamp(40px, 6vw, 62px); }
  .view-home .hero-lead { margin-top: 18px; font-size: 15px; }
  .view-home .tutorial-picker { width: min(900px, 100%); }
  .view-home .tutorial-card { grid-template-columns: 70px minmax(0, 1fr) 30px; gap: 16px; }
  .hero-copy { max-width: 760px; }
  .hero-visual { max-width: 760px; }
  .tutorial-picker { width: min(760px, 100%); }
  .chapter-layout { grid-template-columns: 1fr; }
  .chapter-media { position: static; order: -1; }
  .screenshot-card button { max-width: 900px; }
  .reference-hero { grid-template-columns: 1fr; }
  .reference-stats { max-width: 680px; }
  .next-learning { grid-template-columns: 1fr; }
}

@media (max-width: 820px) {
  .topbar { height: 68px; padding: 0 16px; }
  .brand small { display: none; }
  .view-nav { position: static; margin-left: auto; transform: none; }
  .view-nav button, .view-nav a { padding: 6px 9px; font-size: 10px; }
  .app-link { display: none; }
  .menu-toggle { display: inline-flex; padding: 9px 13px; border: 1px solid var(--line); border-radius: 9px; background: white; font-weight: 750; cursor: pointer; }
  .sidebar { top: 68px; width: min(330px, 88vw); transform: translateX(-105%); transition: transform .25s ease; box-shadow: 20px 0 50px rgba(0,0,0,.2); }
  .sidebar.is-open { transform: none; }
  .view-main, .view-tutorial .view-main { margin-left: 0; padding-top: 68px; }
  .hero { padding: 58px 24px 64px; gap: 42px; }
  .view-home .hero {
    min-height: calc(100vh - 68px);
    gap: 30px;
    padding: 42px 24px 64px;
  }
  .view-home .hero h1 { max-width: 760px; font-size: clamp(34px, 7vw, 48px); }
  .view-home .hero-lead { max-width: 760px; margin-top: 14px; font-size: 15px; }
  .view-home .tutorial-picker { width: 100%; }
  .view-home .tutorial-card {
    grid-template-columns: 60px minmax(0, 1fr) 28px;
    gap: 14px;
    min-height: 100px;
    padding: 13px 15px;
  }
  .view-home .tutorial-card-copy strong { font-size: 17px; }
  .tutorial-area > header { grid-template-columns: 50px minmax(0, 1fr); }
  .practice-area-content { padding: 12px; }
  .practice-card-body { grid-template-columns: 1fr; }
  .practice-card-explanation { grid-column: auto; }
  .practice-principle { grid-template-columns: 1fr; }
  .practice-principle-tutorials { grid-column: auto; }
  .tutorial-area-future { grid-column: 1 / -1; width: 100%; }
  .tutorial-area-cards { grid-template-columns: 1fr; }
  .tutorial-progress-badge { width: 58px; height: 58px; }
  .tutorial-progress-badge strong { font-size: 19px; }
  .hero h1 { font-size: clamp(42px, 12vw, 68px); }
  .hero-lead { font-size: 16px; }
  .floating-card { display: none; }
  .search-section { display: grid; padding: 55px 24px 28px; }
  .search-box { width: 100%; }
  .tutorial-introduction { padding: 4px 24px 54px; }
  .tutorial-introduction-card { padding: 26px 20px; border-radius: 20px; }
  .tutorial-introduction-grid, .tutorial-introduction-bottom { grid-template-columns: 1fr; }
  .tutorial-introduction-actions { align-items: stretch; flex-direction: column; }
  .tutorial-introduction-start, .tutorial-introduction-video { justify-content: center; width: 100%; }
  .chapter { scroll-margin-top: 68px; padding: 60px 24px; }
  .chapter-heading { grid-template-columns: 1fr; gap: 9px; }
  .function-grid { grid-template-columns: 1fr; }
  .role-grid { grid-template-columns: 1fr; }
  footer { padding: 28px 24px; }
  .tour-bar { left: 14px; right: 14px; bottom: 12px; }
  .tour-bar strong { max-width: 52vw; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
  .lightbox { padding: 68px 12px 20px; }
  .lightbox p { display: grid; gap: 3px; }
  .video-modal { padding: 68px 12px 20px; }
  .video-modal-card { padding: 14px; }
  .chapter-video-card figcaption { align-items: stretch; flex-direction: column; }
  .chapter-video-card figcaption button { justify-content: center; width: 100%; }
  .reference { scroll-margin-top: 68px; }
  .reference-hero { padding: 70px 24px 45px; gap: 35px; }
  .next-learning { padding: 64px 24px; }
  .reference-hero h2 { font-size: clamp(39px, 10vw, 60px); }
  .reference-stats { width: 100%; }
  .reference-directory { padding: 48px 24px 54px; }
  .reference-directory-grid { grid-template-columns: 1fr; }
  .reference-scenarios { padding: 48px 24px 54px; }
  .reference-scenarios-heading { align-items: flex-start; flex-direction: column; gap: 16px; }
  .reference-scenario-tabs { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .reference-scenario-areas { grid-template-columns: 1fr; }
  .reference-controls { top: 68px; padding: 18px 24px; }
  .reference-result-line { padding: 22px 24px 0; }
  .reference-groups { padding: 28px 24px 0; }
  .reference-group { scroll-margin-top: 235px; }
  .reference-group-heading { grid-template-columns: 48px minmax(0, 1fr); padding: 22px; }
  .reference-image, .reference-external { grid-column: 1 / -1; width: min(360px, 100%); }
  .reference-topic summary { padding: 22px; }
  .reference-topic-body { grid-template-columns: 1fr; gap: 17px; padding: 4px 22px 24px; }
  .reference-topic-external { grid-template-columns: 42px minmax(0, 1fr); }
  .reference-topic-external a { grid-column: 2; justify-self: start; }
  .reference-intro-grid { grid-template-columns: 1fr; }
}

@media (max-width: 520px) {
  .hero-visual > button { border-width: 5px; border-radius: 16px; transform: none; }
  .tutorial-picker { padding: 11px; border-radius: 16px; }
  .tutorial-card { grid-template-columns: 50px minmax(0, 1fr) 24px; min-height: 0; padding: 12px; }
  .tutorial-card-copy strong { font-size: 15px; }
  .view-home .hero { gap: 12px; padding: 18px 14px; }
  .view-home .hero .eyebrow { margin-bottom: 7px; font-size: 9px; }
  .view-home .hero h1 { font-size: clamp(29px, 8.7vw, 38px); }
  .view-home .hero-lead { margin-top: 10px; font-size: 15px; line-height: 1.55; }
  .view-home .tutorial-picker { grid-template-columns: minmax(0, 1fr); gap: 8px; padding: 9px; }
  .view-home .tutorial-picker-reference { padding: 5px 2px 1px; }
  .view-home .tutorial-picker-reference button { min-height: 38px; padding: 0 13px; font-size: 11px; }
  .view-home .tutorial-picker-heading { padding: 0 2px 2px; }
  .tutorial-area { border-radius: 14px; }
  .tutorial-area > header { grid-template-columns: 42px minmax(0, 1fr); gap: 11px; padding: 15px; }
  .tutorial-area-number { width: 40px; height: 40px; border-radius: 11px; font-size: 10px; }
  .tutorial-area > header h2 { font-size: 20px; }
  .tutorial-area > header div > div { margin-top: 6px; font-size: 13px; }
  .practice-area .practice-area-intro { margin-top: 7px; }
  .tutorial-area.is-unterricht .practice-area-intro p { font-size: 12.5px; line-height: 1.55; }
  .practice-area-content { padding: 7px; }
  .practice-card-list { gap: 7px; }
  .practice-card summary { grid-template-columns: minmax(0, 1fr) 28px; gap: 10px; padding: 14px; }
  .practice-card-heading h3 { margin-bottom: 7px; font-size: 16px; }
  .practice-card-heading p { font-size: 14px; line-height: 1.45; }
  .practice-card-toggle { width: 28px; height: 28px; font-size: 18px; }
  .practice-card-body { gap: 14px; padding: 14px; }
  .practice-card-explanation { font-size: 13px; line-height: 1.6; }
  .practice-pedagogical-note p { font-size: 13px; line-height: 1.55; }
  .practice-tutorial-links { display: grid; grid-template-columns: 1fr; }
  .practice-tutorial-links button { width: 100%; }
  .practice-principle { gap: 17px; margin-top: 10px; padding: 17px 15px; border-radius: 12px; }
  .practice-principle h3 { font-size: 19px; }
  .tutorial-area-future { min-width: 0; padding: 10px; }
  .tutorial-area-cards { gap: 8px; padding: 8px; }
  .view-home .tutorial-card {
    grid-template-columns: 50px minmax(0, 1fr) 24px;
    gap: 9px;
    min-height: 88px;
    padding: 10px;
  }
  .view-home .tutorial-card-copy { gap: 3px; }
  .view-home .tutorial-card-copy small { font-size: 9px; line-height: 1.25; }
  .view-home .tutorial-card-copy strong { font-size: 15px; }
  .view-home .tutorial-card-copy > span {
    display: -webkit-box;
    overflow: hidden;
    font-size: 13px;
    line-height: 1.45;
    -webkit-box-orient: vertical;
    -webkit-line-clamp: 2;
  }
  .view-home .tutorial-arrow { width: 23px; height: 23px; font-size: 11px; }
  .view-home .tutorial-progress-badge { width: 48px; height: 48px; }
  .view-home .tutorial-progress-badge::before { inset: 5px; }
  .view-home .tutorial-progress-badge strong { font-size: 16px; }
  .view-home .tutorial-progress-badge small { margin-top: 2px; font-size: 6.5px; }
  .chapter-heading h2 { font-size: 34px; }
  .chapter-primary-link { grid-template-columns: 34px minmax(0, 1fr); }
  .chapter-primary-link > span:last-child { display: none; }
  .reference-topic-link { grid-template-columns: 34px minmax(0, 1fr); }
  .reference-topic-link > span:last-child { display: none; }
  .screenshot-gallery { grid-template-columns: 1fr; }
  .tip-box { grid-template-columns: 1fr; }
  .tip-box span { justify-self: start; }
  footer { align-items: flex-start; flex-direction: column; gap: 16px; }
  .tour-bar > div:first-child span { display: none; }
  .tour-bar strong { max-width: 42vw; font-size: 11px; }
  .view-tutorial .view-nav { display: none; }
  .reference-hero { padding-top: 58px; }
  .reference-stats { grid-template-columns: 1fr; }
  .reference-stats div { display: flex; justify-content: space-between; align-items: center; padding: 13px 16px; border-right: 0; border-bottom: 1px solid var(--line); text-align: left; }
  .reference-stats div:last-child { border-bottom: 0; }
  .reference-stats span { margin: 0; }
  .reference-scenarios { padding-top: 42px; }
  .reference-scenario-body { grid-template-columns: 1fr; }
  .reference-scenario-check, .reference-scenario-links { grid-column: auto; }
  .reference-controls { position: static; }
  .category-filter { flex-wrap: nowrap; margin-right: -24px; padding-right: 24px; overflow-x: auto; }
  .category-filter button { flex: 0 0 auto; }
  .reference-group-heading { grid-template-columns: 1fr; }
  .reference-number { width: 42px; height: 42px; }
  .reference-topic h4 { font-size: 18px; }
  .reference-topic summary p { font-size: 14px; }
  .reference-topic-external { grid-template-columns: 1fr; }
  .reference-topic-external a { grid-column: auto; }
  .reference-options { grid-template-columns: 1fr; }
  .reference-option, .reference-option:nth-child(2n), .reference-option:nth-last-child(-n+2), .reference-option:nth-last-child(1):nth-child(odd) { grid-column: auto; border-right: 0; border-bottom: 1px solid #e0e7ed; }
  .reference-option:last-child { border-bottom: 0; }
  .reference-option dl > div { grid-template-columns: 1fr; gap: 3px; }
  .reference-section-heading { align-items: flex-start; flex-direction: column; }
  .reference-directory-grid > button { grid-template-columns: 40px minmax(0, 1fr) 26px; padding: 15px; }
  .reference-directory-number { width: 40px; height: 40px; }
  .reference-directory-count { display: none; }
  .reference-scenario-tabs { grid-template-columns: 1fr; }
  .topbar { padding-inline: 10px; }
  .brand > span { display: none; }
  .view-nav button, .view-nav a { padding: 6px 6px; font-size: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; }
}

.app-loading, .app-error {
  min-height: calc(100vh - 76px);
  display: grid;
  place-content: center;
  padding: 40px;
  color: var(--muted);
  text-align: center;
}
.app-error h1 { margin: 0 0 10px; color: var(--ink); font-size: 28px; }
.app-error p { margin: 0; }