:root {
  --ink: #eaf1f7;
  --muted: #9fb0c0;
  --bg: #071018;
  --surface: #0d1822;
  --surface-2: #122330;
  --line: rgba(168, 194, 211, .16);
  --orange: #f7931a;
  --orange-soft: rgba(247, 147, 26, .13);
  --cyan: #36d3c5;
  --blue: #6ea8fe;
  --shadow: 0 22px 70px rgba(0, 0, 0, .28);
  --radius: 20px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% -8%, rgba(247,147,26,.18), transparent 32rem),
    radial-gradient(circle at 92% 10%, rgba(54,211,197,.09), transparent 28rem),
    var(--bg);
  font: 16px/1.55 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a { color: inherit; }
button, input, select { font: inherit; }
button, .button { min-height: 44px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--line);
  background: rgba(7,16,24,.86);
  backdrop-filter: blur(18px);
}
.site-header__inner, .shell { width: min(1180px, calc(100% - 32px)); margin-inline: auto; }
.site-header__inner { min-height: 68px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; font-weight: 850; letter-spacing: -.02em; }
.coin { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 50%; background: var(--orange); color: #1d1204; box-shadow: 0 0 0 6px var(--orange-soft); font-weight: 950; }
.brand small { display: block; color: var(--muted); font-weight: 600; letter-spacing: 0; }
.topnav { display: flex; flex-wrap: wrap; gap: 6px; }
.topnav a { color: var(--muted); text-decoration: none; padding: 9px 12px; border-radius: 10px; font-size: .9rem; }
.topnav a:hover, .topnav a[aria-current="page"] { color: var(--ink); background: var(--surface-2); }

.hero { padding: 70px 0 38px; display: grid; grid-template-columns: minmax(0,1.3fr) minmax(280px,.7fr); gap: 46px; align-items: center; }
.eyebrow { margin: 0 0 14px; color: var(--orange); font-size: .79rem; font-weight: 850; letter-spacing: .14em; text-transform: uppercase; }
h1, h2, h3 { line-height: 1.08; letter-spacing: -.035em; }
h1 { margin: 0; max-width: 820px; font-size: clamp(2.55rem, 6vw, 5.6rem); }
.bitcoin-word { color: var(--orange); text-shadow: 0 0 44px rgba(247,147,26,.18); }
.hero .lead { max-width: 720px; margin: 22px 0 28px; color: #c0ced8; font-size: clamp(1.05rem, 2vw, 1.28rem); }
.hero-pills { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; margin: -8px 0 24px; color: var(--muted); font-size: .82rem; font-weight: 760; }
.hero-pills span { padding: 6px 10px; border: 1px solid var(--line); border-radius: 999px; background: rgba(13,24,34,.72); }
.hero-pills i { color: var(--orange); font-style: normal; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; }
.button { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 11px 16px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); color: var(--ink); text-decoration: none; font-weight: 760; cursor: pointer; }
.button:hover { transform: translateY(-1px); border-color: rgba(247,147,26,.55); }
.button.primary { border-color: var(--orange); background: var(--orange); color: #1c1206; }
.button.subtle { background: transparent; }
.button-large { min-height: 50px; padding-inline: 19px; }

.hero-map { position: relative; min-height: 340px; border: 1px solid var(--line); border-radius: 28px; background: linear-gradient(145deg, rgba(18,35,48,.94), rgba(8,18,27,.82)); overflow: hidden; box-shadow: var(--shadow); }
.hero-map::before { content: ""; position: absolute; inset: 0; background-image: linear-gradient(rgba(255,255,255,.04) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,.04) 1px, transparent 1px); background-size: 34px 34px; mask-image: linear-gradient(to bottom, #000, transparent); }
.block-chain { position: absolute; inset: 0; display: grid; place-items: center; transform: rotate(-7deg); }
.block-chain__row { display: flex; align-items: center; gap: 12px; }
.mini-block { width: 72px; aspect-ratio: 1; display: grid; place-items: center; border: 1px solid rgba(247,147,26,.48); border-radius: 17px; background: rgba(247,147,26,.1); box-shadow: inset 0 0 24px rgba(247,147,26,.08); font-weight: 900; color: #ffc473; }
.link-line { width: 28px; height: 2px; background: linear-gradient(90deg,var(--orange),var(--cyan)); }
.network-stat { position: absolute; padding: 10px 12px; border: 1px solid var(--line); border-radius: 12px; background: rgba(7,16,24,.88); box-shadow: 0 10px 30px rgba(0,0,0,.22); }
.network-stat strong { display: block; color: var(--cyan); font-size: 1.05rem; }
.network-stat small { color: var(--muted); }
.network-stat.one { top: 24px; right: 24px; }
.network-stat.two { left: 24px; bottom: 26px; }

.entry-grid {
  display: grid;
  grid-template-columns: repeat(3,minmax(0,1fr));
  gap: 14px;
  margin: 6px 0 18px;
}
.entry-hub-heading {
  grid-column: 1 / -1;
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 28px;
  padding: 4px 2px 10px;
}
.entry-hub-heading > div { min-width: 0; }
.entry-kicker {
  margin: 0 0 5px;
  color: var(--orange);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .13em;
  text-transform: uppercase;
}
.entry-hub-heading h2 {
  margin: 0;
  font-size: clamp(1.45rem,2.2vw,2rem);
}
.entry-hub-heading > p {
  max-width: 560px;
  margin: 0;
  color: var(--muted);
  font-size: .9rem;
  line-height: 1.5;
  text-align: right;
}
.entry-card {
  position: relative;
  isolation: isolate;
  min-height: 146px;
  display: grid;
  grid-template-columns: 50px minmax(0,1fr);
  gap: 14px;
  align-items: center;
  overflow: hidden;
  padding: 22px 52px 20px 18px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: linear-gradient(145deg,rgba(18,35,48,.96),rgba(9,19,28,.96));
  color: var(--ink);
  text-decoration: none;
  box-shadow: 0 14px 38px rgba(0,0,0,.16);
  transition: transform .2s ease,border-color .2s ease,box-shadow .2s ease,background .2s ease;
}
.entry-card::before {
  content: "";
  position: absolute;
  z-index: -1;
  width: 190px;
  height: 190px;
  right: -95px;
  bottom: -120px;
  border-radius: 50%;
  background: radial-gradient(circle,rgba(54,211,197,.12),transparent 68%);
  opacity: .75;
  transition: transform .25s ease,opacity .25s ease;
}
.entry-card::after {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg,transparent,rgba(54,211,197,.62),transparent);
  opacity: .42;
}
.entry-card:hover {
  transform: translateY(-5px);
  border-color: rgba(54,211,197,.52);
  box-shadow: 0 20px 48px rgba(0,0,0,.24);
}
.entry-card:hover::before { transform: scale(1.14); opacity: 1; }
.entry-card:focus-visible {
  outline: 3px solid rgba(54,211,197,.5);
  outline-offset: 3px;
}
.entry-card--orange {
  background: linear-gradient(145deg,rgba(247,147,26,.20),rgba(13,24,34,.98));
  border-color: rgba(247,147,26,.44);
}
.entry-card--orange::before {
  background: radial-gradient(circle,rgba(247,147,26,.18),transparent 68%);
}
.entry-card--orange::after {
  background: linear-gradient(90deg,transparent,rgba(247,147,26,.8),transparent);
}
.entry-card--orange:hover {
  border-color: rgba(247,147,26,.72);
  box-shadow: 0 20px 50px rgba(247,147,26,.09),0 20px 48px rgba(0,0,0,.22);
}
.entry-card--accent {
  border-color: rgba(54,211,197,.34);
  background: linear-gradient(145deg,rgba(54,211,197,.10),rgba(9,19,28,.98));
}
.entry-card--accent:hover {
  border-color: rgba(54,211,197,.72);
  box-shadow: 0 20px 52px rgba(54,211,197,.07),0 20px 48px rgba(0,0,0,.22);
}
.entry-icon {
  width: 50px;
  height: 50px;
  display: grid;
  place-items: center;
  border-radius: 15px;
  background: rgba(54,211,197,.11);
  color: var(--cyan);
  font-size: 1.35rem;
  font-weight: 950;
  box-shadow: inset 0 0 0 1px rgba(54,211,197,.08);
}
.entry-card--orange .entry-icon {
  background: var(--orange);
  color: #1b1104;
  box-shadow: 0 8px 24px rgba(247,147,26,.16);
}
.entry-card--accent .entry-icon {
  background: rgba(54,211,197,.16);
  color: #61eee1;
}
.entry-card small,.entry-card strong,.entry-card em { display: block; }
.entry-card small {
  margin-bottom: 3px;
  color: var(--orange);
  font-size: .69rem;
  font-weight: 900;
  letter-spacing: .105em;
  text-transform: uppercase;
}
.entry-card strong {
  line-height: 1.18;
  font-size: 1.12rem;
  letter-spacing: -.018em;
}
.entry-card em {
  margin-top: 6px;
  color: var(--muted);
  font-size: .79rem;
  font-style: normal;
  line-height: 1.35;
}
.entry-step {
  position: absolute;
  top: 13px;
  right: 15px;
  color: rgba(234,241,247,.36);
  font-size: .67rem;
  font-weight: 900;
  letter-spacing: .12em;
}
.entry-arrow {
  position: absolute;
  right: 16px;
  bottom: 15px;
  color: var(--muted);
  font-size: 1.2rem;
  font-weight: 850;
  transition: transform .18s ease,color .18s ease;
}
.entry-card:hover .entry-arrow {
  transform: translateX(3px);
  color: var(--orange);
}

.quick-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; margin: 0 0 72px; }
.quick { padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: rgba(13,24,34,.78); }
.quick strong { display: block; margin-bottom: 4px; font-size: 1.15rem; }
.quick span { color: var(--muted); font-size: .9rem; }

.section { padding: 36px 0 58px; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 22px; }
.section-head h2 { margin: 0; font-size: clamp(1.9rem,4vw,3.2rem); }
.section-head p { max-width: 620px; margin: 0; color: var(--muted); }

.path { display: grid; grid-template-columns: repeat(auto-fit,minmax(220px,1fr)); gap: 14px; counter-reset: path; }
.path-card { position: relative; min-height: 235px; padding: 22px; border: 1px solid var(--line); border-radius: var(--radius); background: linear-gradient(155deg,var(--surface-2),var(--surface)); overflow: hidden; }
.path-card::after { counter-increment: path; content: "0" counter(path); position: absolute; right: 12px; bottom: -24px; color: rgba(255,255,255,.045); font-size: 7rem; font-weight: 950; line-height: 1; }
.path-card .tag { color: var(--orange); font-size: .76rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.path-card h3 { margin: 18px 0 10px; font-size: 1.42rem; }
.path-card p { position: relative; z-index: 1; color: var(--muted); }

.card-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 14px; }
.resource-card { display: flex; flex-direction: column; min-height: 240px; padding: 20px; border: 1px solid var(--line); border-radius: var(--radius); background: rgba(13,24,34,.84); text-decoration: none; transition: transform .18s ease, border-color .18s ease; }
.resource-card:hover { transform: translateY(-3px); border-color: rgba(247,147,26,.55); }
.resource-card .number { color: var(--orange); font-size: .78rem; font-weight: 900; letter-spacing: .1em; }
.resource-card h3 { margin: 18px 0 10px; font-size: 1.35rem; }
.resource-card p { margin: 0; color: var(--muted); }
.resource-card .meta { margin-top: auto; padding-top: 22px; color: var(--cyan); font-weight: 760; font-size: .9rem; }

.panel { padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: rgba(13,24,34,.86); box-shadow: var(--shadow); }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.checklist { display: grid; gap: 10px; margin-top: 18px; }
.check { display: grid; grid-template-columns: 28px 1fr; gap: 11px; align-items: start; color: #c4d1da; }
.check i { width: 24px; height: 24px; display: grid; place-items: center; border-radius: 7px; background: var(--orange-soft); color: var(--orange); font-style: normal; font-size: .8rem; }
.callout { border-left: 3px solid var(--orange); padding: 16px 18px; background: var(--orange-soft); color: #f2d5ac; border-radius: 0 14px 14px 0; }

.page-head { padding: 52px 0 28px; }
.page-head h1 { font-size: clamp(2.35rem,5vw,4.5rem); }
.page-head p { max-width: 760px; color: var(--muted); font-size: 1.08rem; }
.filterbar { display: flex; gap: 10px; flex-wrap: wrap; margin: 22px 0; }
.search { flex: 1 1 280px; min-height: 48px; padding: 0 15px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); color: var(--ink); }
.filter { padding: 10px 13px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); color: var(--muted); cursor: pointer; }
.filter.active { color: #1d1204; background: var(--orange); border-color: var(--orange); }

.term-list { display: grid; gap: 12px; }
.term { border: 1px solid var(--line); border-radius: 16px; background: rgba(13,24,34,.88); overflow: hidden; }
.term summary { display: grid; grid-template-columns: minmax(170px,.35fr) 1fr auto; gap: 18px; align-items: center; padding: 18px 20px; cursor: pointer; list-style: none; }
.term summary::-webkit-details-marker { display: none; }
.term-name { font-size: 1.08rem; font-weight: 850; color: #fff; }
.term-short { color: var(--muted); }
.term-category { color: var(--orange); font-size: .74rem; font-weight: 850; text-transform: uppercase; letter-spacing: .08em; }
.term-body { padding: 0 20px 20px; border-top: 1px solid var(--line); color: #c3d0d9; }
.term-body h4 { margin-bottom: 4px; color: var(--cyan); }

.quiz-layout { display: grid; grid-template-columns: 250px minmax(0,1fr); gap: 18px; align-items: start; }
.quiz-nav { position: sticky; top: 86px; padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); }
.progress-track { height: 8px; border-radius: 999px; background: #1d2a34; overflow: hidden; }
.progress-fill { height: 100%; width: 0; background: linear-gradient(90deg,var(--orange),#ffc36f); transition: width .25s ease; }
.question { padding: 24px; border: 1px solid var(--line); border-radius: var(--radius); background: rgba(13,24,34,.88); }
.question h2 { font-size: 1.42rem; }
.option { display: flex; gap: 10px; align-items: start; margin: 9px 0; padding: 12px; border: 1px solid var(--line); border-radius: 12px; cursor: pointer; }
.option:hover { background: var(--surface-2); }
.feedback { display: none; margin-top: 14px; padding: 16px; border-radius: 12px; background: rgba(54,211,197,.08); border-left: 3px solid var(--cyan); color: #c9e8e3; }
.feedback.show { display: block; }

.viewer-page { overflow-x: hidden; }
.viewer-layout { display: grid; grid-template-columns: 310px minmax(0,1fr); min-height: calc(100vh - 69px); }
.deck-list { padding: 28px 22px; border-right: 1px solid var(--line); background: linear-gradient(180deg,#09131c,#071018); }
.deck-list h1 { margin: 0; font-size: 2rem; }
.deck-intro { margin: 12px 0 22px; color: var(--muted); }
.deck-button { width: 100%; display: grid; grid-template-columns: 34px 1fr; gap: 11px; align-items: start; margin-bottom: 10px; padding: 14px; text-align: left; border: 1px solid var(--line); border-radius: 14px; background: var(--surface); color: var(--ink); cursor: pointer; transition: transform .18s ease,border-color .18s ease,background .18s ease; }
.deck-button:hover { transform: translateX(3px); border-color: rgba(247,147,26,.48); }
.deck-button strong { line-height: 1.25; }
.deck-button small { display: block; margin-top: 5px; color: var(--muted); line-height: 1.35; }
.deck-button.active { border-color: var(--orange); background: linear-gradient(135deg,var(--orange-soft),rgba(54,211,197,.06)); box-shadow: inset 3px 0 var(--orange); }
.deck-number { color: var(--orange); font-size: .76rem; font-weight: 900; letter-spacing: .08em; }
.deck-documents { display: grid; gap: 8px; margin-top: 28px; padding-top: 18px; border-top: 1px solid var(--line); }
.deck-documents__title { margin: 0 0 2px; color: var(--muted); font-size: .76rem; font-weight: 850; letter-spacing: .1em; text-transform: uppercase; }
.deck-documents .button { justify-content: flex-start; }

.viewer-stage { display: flex; flex-direction: column; min-width: 0; min-height: calc(100vh - 69px); padding: 22px; background: var(--bg); }
.viewer-heading { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin-bottom: 16px; }
.viewer-heading .eyebrow { margin-bottom: 6px; }
.viewer-heading h2 { margin: 0; font-size: clamp(1.45rem,3vw,2.35rem); }
.view-mode { display: inline-flex; flex: 0 0 auto; gap: 4px; padding: 4px; border: 1px solid var(--line); border-radius: 13px; background: #071018; }
.mode-button { min-height: 38px; padding: 7px 12px; border: 0; border-radius: 9px; background: transparent; color: var(--muted); cursor: pointer; font-weight: 760; }
.mode-button.active { background: var(--orange); color: #1b1104; box-shadow: 0 6px 18px rgba(247,147,26,.2); }
.mode-button:disabled { opacity: .42; cursor: not-allowed; }

.viewer-toolbar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 12px; padding: 9px; border: 1px solid var(--line); border-radius: 14px; background: rgba(13,24,34,.92); }
.viewer-toolbar button, .viewer-toolbar select { min-height: 40px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 10px; background: var(--surface-2); color: var(--ink); cursor: pointer; }
.viewer-toolbar button:hover, .viewer-toolbar select:hover { border-color: rgba(247,147,26,.55); }
.viewer-toolbar .play-button { border-color: var(--orange); background: var(--orange); color: #1d1204; font-weight: 850; }
.speed-control { display: inline-flex; align-items: center; gap: 7px; padding-left: 5px; color: var(--muted); font-size: .85rem; }
.viewer-toolbar #full { margin-left: auto; }
.control-hidden { display: none !important; }
.viewer-toolbar--slides #full { margin-left: auto; }

.viewer-surface { flex: 1; min-height: 0; }
.pdf-view { height: 100%; }
.canvas-wrap { position: relative; display: grid; place-items: center; width: 100%; min-height: clamp(340px,65vh,760px); border: 1px solid var(--line); border-radius: 18px; background: radial-gradient(circle at 50% 45%,#101b24,#020405 72%); overflow: hidden; }
#pdfCanvas { display: block; max-width: 100%; height: auto; box-shadow: 0 20px 70px rgba(0,0,0,.55); }
.slide-edge { position: absolute; z-index: 4; top: 50%; width: 48px; height: 74px; display: grid; place-items: center; transform: translateY(-50%); border: 1px solid rgba(255,255,255,.16); border-radius: 14px; background: rgba(7,16,24,.72); color: #fff; opacity: .4; cursor: pointer; font-size: 2.2rem; backdrop-filter: blur(10px); transition: opacity .18s ease,background .18s ease; }
.canvas-wrap:hover .slide-edge, .slide-edge:focus-visible, .is-fullscreen .slide-edge { opacity: 1; }
.slide-edge:hover { background: var(--orange); color: #1b1104; }
.slide-edge--prev { left: 14px; }
.slide-edge--next { right: 14px; }
.loading-indicator { position: absolute; z-index: 6; padding: 9px 13px; border: 1px solid var(--line); border-radius: 999px; background: rgba(7,16,24,.88); color: var(--muted); }
.pdf-fallback { max-width: 440px; padding: 20px; color: var(--muted); text-align: center; }
.viewer-progress { display: grid; grid-template-columns: auto minmax(160px,1fr) auto; gap: 14px; align-items: center; padding: 13px 4px 7px; }
.viewer-progress .status { color: var(--ink); font-weight: 760; white-space: nowrap; }
.viewer-progress input[type="range"] { width: 100%; accent-color: var(--orange); cursor: pointer; }
.keyboard-hint { color: var(--muted); font-size: .78rem; }
.autoplay-track { height: 3px; margin-inline: 4px; border-radius: 999px; background: rgba(255,255,255,.06); overflow: hidden; }
.autoplay-track span { display: block; width: 0; height: 100%; background: linear-gradient(90deg,var(--orange),#ffc36f); }
.autoplay-track span.running { animation: autoplay-countdown linear forwards; }
@keyframes autoplay-countdown { from { width: 0; } to { width: 100%; } }

.slides-view { height: 100%; min-height: 620px; display: grid; grid-template-rows: minmax(460px,1fr) auto; overflow: hidden; border: 1px solid var(--line); border-radius: 18px; background: #020405; }
.slides-view iframe { width: 100%; height: 100%; min-height: 520px; border: 0; background: #fff; }
.slides-actions { display: flex; align-items: center; gap: 10px; padding: 12px 14px; background: var(--surface); }
.slides-actions p { flex: 1; margin: 0; color: var(--muted); font-size: .9rem; }
.slides-actions strong { color: var(--ink); }

.viewer-stage:fullscreen { width: 100vw; height: 100vh; min-height: 100vh; padding: 14px; background: #020405; }
.viewer-stage:fullscreen .viewer-heading { margin-bottom: 8px; }
.viewer-stage:fullscreen .viewer-heading h2 { font-size: 1.4rem; }
.viewer-stage:fullscreen .viewer-toolbar { margin-bottom: 8px; }
.viewer-stage:fullscreen .viewer-surface { display: flex; min-height: 0; }
.viewer-stage:fullscreen .pdf-view, .viewer-stage:fullscreen .slides-view { flex: 1; min-height: 0; }
.viewer-stage:fullscreen .pdf-view { display: flex; flex-direction: column; }
.viewer-stage:fullscreen .canvas-wrap { flex: 1; min-height: 0; border-radius: 12px; }
.viewer-stage:fullscreen .slides-view { grid-template-rows: minmax(0,1fr) auto; }
.viewer-stage:fullscreen .slides-view iframe { min-height: 0; }


/* ── Bitcoin labs study guide ─────────────────────────────────────── */
.labs-hero { padding-bottom: 18px; }
.labs-hero strong { color: var(--ink); }
.compact-section { padding-top: 24px; }
.study-progress-card {
  max-width: 820px;
  display: grid;
  grid-template-columns: auto minmax(180px,1fr);
  gap: 10px 18px;
  align-items: center;
  margin-top: 24px;
  padding: 16px 18px;
  border: 1px solid rgba(247,147,26,.28);
  border-radius: 16px;
  background: linear-gradient(135deg,rgba(247,147,26,.09),rgba(13,24,34,.82));
}
.study-progress-card > div:first-child { display: flex; align-items: baseline; gap: 10px; }
.study-progress-card [data-progress-count] { color: var(--orange); font-size: 1.25rem; }
.study-progress-label { color: var(--ink); font-weight: 780; }
.study-progress-note { grid-column: 1 / -1; color: var(--muted); font-size: .82rem; }

.lab-access-card { position: relative; min-height: 220px; overflow: hidden; }
.lab-access-card::after {
  content: "○";
  position: absolute;
  right: 17px;
  top: 16px;
  color: rgba(159,176,192,.55);
  font-size: 1.05rem;
  font-weight: 900;
}
.lab-access-card.completed {
  border-color: rgba(54,211,197,.42);
  background: linear-gradient(155deg,rgba(54,211,197,.08),rgba(13,24,34,.9));
}
.lab-access-card.completed::after { content: "✓"; color: var(--cyan); }
.lab-access-card.completed .meta { color: var(--cyan); }

.study-method { padding-top: 30px; }
.study-method-grid {
  display: grid;
  grid-template-columns: repeat(4,minmax(0,1fr));
  gap: 12px;
}
.study-method-grid article {
  min-height: 170px;
  padding: 19px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(150deg,var(--surface-2),rgba(13,24,34,.84));
}
.study-method-grid article > span {
  display: inline-grid;
  place-items: center;
  min-width: 34px;
  height: 28px;
  padding-inline: 8px;
  border-radius: 999px;
  background: var(--orange-soft);
  color: var(--orange);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .08em;
}
.study-method-grid strong { display: block; margin: 14px 0 7px; font-size: 1.12rem; }
.study-method-grid p { margin: 0; color: var(--muted); font-size: .9rem; }

.guide-section { padding-top: 42px; }
.guide-head { align-items: center; }
.guide-actions { display: flex; flex-wrap: wrap; gap: 8px; }
.guide-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 9px 18px;
  margin: -4px 0 24px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(13,24,34,.62);
  color: var(--muted);
  font-size: .78rem;
}
.guide-legend span { display: inline-flex; align-items: center; gap: 6px; }
.guide-legend b { color: var(--ink); }
.precision-dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }
.precision-dot.protocol { background: var(--cyan); }
.precision-dot.model { background: var(--orange); }
.precision-dot.simulation { background: var(--blue); }

.study-block { margin: 34px 0 46px; }
.study-block-head {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 14px;
}
.study-block-number {
  width: 46px;
  height: 46px;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  border-radius: 14px;
  border: 1px solid rgba(247,147,26,.32);
  background: var(--orange-soft);
  color: var(--orange);
  font-size: .78rem;
  font-weight: 900;
  letter-spacing: .08em;
}
.study-block-head h3 { margin: 0 0 4px; font-size: clamp(1.35rem,2.3vw,1.8rem); }
.study-block-head p { margin: 0; color: var(--muted); font-size: .9rem; }

.lab-guide-list { display: grid; gap: 11px; }
.lab-guide {
  border: 1px solid var(--line);
  border-radius: 18px;
  background: rgba(13,24,34,.86);
  overflow: hidden;
  box-shadow: 0 12px 34px rgba(0,0,0,.12);
}
.lab-guide[open] {
  border-color: rgba(54,211,197,.3);
  box-shadow: 0 18px 46px rgba(0,0,0,.18);
}
.lab-guide summary {
  display: grid;
  grid-template-columns: 72px minmax(0,1fr) auto 24px;
  gap: 14px;
  align-items: center;
  min-height: 92px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  transition: background .18s ease;
}
.lab-guide summary::-webkit-details-marker { display: none; }
.lab-guide summary:hover { background: rgba(18,35,48,.72); }
.lab-guide summary:focus-visible { outline: 3px solid rgba(54,211,197,.45); outline-offset: -3px; }
.lab-guide-id {
  color: var(--orange);
  font-size: .76rem;
  font-weight: 900;
  letter-spacing: .1em;
}
.lab-guide-summary strong { display: block; font-size: 1.08rem; }
.lab-guide-summary small {
  display: block;
  max-width: 760px;
  margin-top: 5px;
  color: var(--muted);
  font-size: .78rem;
  line-height: 1.4;
}
.precision-badge {
  white-space: nowrap;
  padding: 6px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: .68rem;
  font-weight: 850;
  letter-spacing: .04em;
}
.precision-badge.protocol { color: var(--cyan); border-color: rgba(54,211,197,.36); background: rgba(54,211,197,.07); }
.precision-badge.model { color: #ffc473; border-color: rgba(247,147,26,.4); background: rgba(247,147,26,.08); }
.precision-badge.simulation { color: #a9c8ff; border-color: rgba(110,168,254,.4); background: rgba(110,168,254,.08); }
.guide-chevron { color: var(--muted); font-size: 1.1rem; transition: transform .18s ease,color .18s ease; }
.lab-guide[open] .guide-chevron { transform: rotate(180deg); color: var(--cyan); }

.lab-guide-body { border-top: 1px solid var(--line); padding: 18px; }
.guide-main {
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  gap: 12px;
}
.guide-panel {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: rgba(18,35,48,.52);
}
.guide-panel--wide, .guide-panel--glossary { grid-column: 1 / -1; }
.guide-panel--checkpoint {
  border-color: rgba(247,147,26,.34);
  background: linear-gradient(135deg,rgba(247,147,26,.08),rgba(18,35,48,.55));
}
.guide-label {
  display: block;
  margin-bottom: 8px;
  color: var(--cyan);
  font-size: .7rem;
  font-weight: 900;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.guide-panel--checkpoint .guide-label { color: var(--orange); }
.guide-panel p { margin: 0; color: #c5d2dc; }
.guide-panel ul { margin: 0; padding-left: 1.15rem; color: #c5d2dc; }
.guide-panel li + li { margin-top: 7px; }

.lab-glossary {
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  gap: 8px 12px;
  margin: 0;
}
.lab-glossary > div {
  padding: 10px 12px;
  border: 1px solid rgba(168,194,211,.12);
  border-radius: 11px;
  background: rgba(7,16,24,.38);
}
.lab-glossary dt { color: var(--ink); font-weight: 820; font-size: .9rem; }
.lab-glossary dd { margin: 3px 0 0; color: var(--muted); font-size: .8rem; line-height: 1.42; }

.guide-footer {
  display: flex;
  align-items: center;
  gap: 9px;
  flex-wrap: wrap;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}
.mastery-button {
  border-color: rgba(54,211,197,.34);
  background: rgba(54,211,197,.06);
}
.mastery-button.is-complete {
  border-color: var(--cyan);
  background: rgba(54,211,197,.14);
  color: #d7fffa;
}
.mastery-state {
  margin-left: auto;
  color: var(--muted);
  font-size: .78rem;
  font-weight: 760;
}
.mastery-state.is-complete { color: var(--cyan); }

.site-footer { margin-top: 50px; padding: 28px 0; border-top: 1px solid var(--line); color: var(--muted); }
.site-footer strong { color: var(--ink); }
.hidden { display: none !important; }

@media (max-width: 980px) {
  .hero { grid-template-columns: 1fr; }
  .hero-map { min-height: 260px; }
  .quick-grid, .path, .entry-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .entry-hub-heading { grid-column: 1 / -1; }
  .card-grid { grid-template-columns: repeat(2,1fr); }
  .study-method-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .lab-guide summary { grid-template-columns: 62px minmax(0,1fr) 24px; }
  .precision-badge { grid-column: 2; justify-self: start; }
  .guide-chevron { grid-column: 3; grid-row: 1 / span 2; }
  .viewer-layout { grid-template-columns: 1fr; }
  .deck-list { border-right: 0; border-bottom: 1px solid var(--line); }
  .deck-list #deckList { display: grid; grid-template-columns: repeat(2,1fr); gap: 10px; }
  .deck-button { margin: 0; }
}
@media (max-width: 700px) {
  .site-header__inner { align-items: flex-start; padding-block: 12px; }
  .topnav { display: none; }
  .hero { padding-top: 42px; }
  .quick-grid, .path, .card-grid, .split, .quiz-layout, .entry-grid { grid-template-columns: 1fr; }
  .entry-hub-heading { align-items: flex-start; flex-direction: column; gap: 8px; }
  .entry-hub-heading > p { max-width: none; text-align: left; }
  .entry-card { min-height: 132px; padding-right: 48px; }
  .quiz-nav { position: static; }
  .section-head { align-items: start; flex-direction: column; }
  .term summary { grid-template-columns: 1fr auto; }
  .term-short { grid-column: 1 / -1; }
  .canvas-wrap { min-height: 300px; }
  .deck-list #deckList { grid-template-columns: 1fr; }
  .viewer-stage { padding: 14px; }
  .viewer-heading { align-items: stretch; flex-direction: column; }
  .view-mode { align-self: flex-start; }
  .viewer-toolbar #full { margin-left: 0; }
  .viewer-progress { grid-template-columns: 1fr; gap: 7px; }
  .keyboard-hint { display: none; }
  .slide-edge { width: 40px; height: 58px; }
  .slide-edge--prev { left: 7px; }
  .slide-edge--next { right: 7px; }
  .slides-view { min-height: 500px; grid-template-rows: minmax(360px,1fr) auto; }
  .slides-view iframe { min-height: 390px; }
  .slides-actions { align-items: stretch; flex-direction: column; }
  .slides-actions .button { width: 100%; }
  .study-progress-card { grid-template-columns: 1fr; }
  .study-progress-note { grid-column: 1; }
  .study-method-grid { grid-template-columns: 1fr; }
  .guide-head { align-items: flex-start; }
  .guide-actions { width: 100%; }
  .guide-actions .button { flex: 1 1 150px; }
  .lab-guide summary { grid-template-columns: 1fr auto; gap: 8px 12px; padding: 15px; }
  .lab-guide-id { grid-column: 1; }
  .lab-guide-summary { grid-column: 1 / -1; }
  .precision-badge { grid-column: 1; justify-self: start; }
  .guide-chevron { grid-column: 2; grid-row: 1; }
  .guide-main { grid-template-columns: 1fr; }
  .guide-panel--wide, .guide-panel--glossary { grid-column: 1; }
  .lab-glossary { grid-template-columns: 1fr; }
  .mastery-state { width: 100%; margin-left: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}