/* Tide & Transit — light, airy, crafted.
   Type: Fraunces (headings) + Inter (body), self-hosted from src/fonts/
   (build.mjs copies that directory to dist/assets/fonts/). Both are
   SIL Open Font License — free to redistribute. Falls back to the
   system stack below if a font file is ever missing. */

@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("./fonts/Inter-400.woff2") format("woff2");
}
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("./fonts/Inter-500.woff2") format("woff2");
}
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url("./fonts/Inter-600.woff2") format("woff2");
}
@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url("./fonts/Inter-700.woff2") format("woff2");
}
@font-face {
  font-family: "Fraunces";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("./fonts/Fraunces-500.woff2") format("woff2");
}
@font-face {
  font-family: "Fraunces";
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url("./fonts/Fraunces-600.woff2") format("woff2");
}

:root {
  --accent: #0e7490;
  --accent-soft: #e0f2fe;
  --ink: #14202b;
  --ink-soft: #4b5b68;
  --paper: #fbfcfd;
  --card: #ffffff;
  --line: #e7edf1;
  --ok: #0f766e;
  --maxw: 720px;
  --radius: 14px;
  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
  font-size: 18px;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* Header */
.site-head {
  padding: 28px 0 20px;
  border-bottom: 1px solid var(--line);
}
.site-head .wrap { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.brand { font-family: var(--serif); font-weight: 600; font-size: 1.35rem; color: var(--ink); text-decoration: none; letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
.nav a { color: var(--ink-soft); text-decoration: none; margin-left: 20px; font-size: 0.98rem; padding: 13px 0; }
.nav a:hover { color: var(--accent); }

/* Typography */
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.2; letter-spacing: -0.015em; color: var(--ink); }
h1 { font-size: 2.3rem; margin: 0 0 12px; }
h2 { font-size: 1.5rem; margin: 40px 0 12px; }
p { margin: 0 0 18px; }
a { color: var(--accent); }
strong { color: var(--accent); font-weight: 700; }

/* Hero */
.hero { padding: 72px 0 40px; }
.hero p.lede { font-size: 1.25rem; color: var(--ink-soft); max-width: 34ch; }
.eyebrow { text-transform: uppercase; letter-spacing: 0.14em; font-size: 0.75rem; font-weight: 600; color: var(--accent); margin: 0 0 14px; }
.hero-art { display: block; width: 100%; max-width: 560px; height: auto; margin: 40px auto 0; }

/* Diagrams */
.diagram { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; margin: 0 0 28px; text-align: center; }
.diagram svg { width: 100%; max-width: 280px; height: auto; }

/* Buttons */
.btn {
  display: inline-block; background: var(--accent); color: #fff; text-decoration: none;
  padding: 13px 22px; border-radius: 999px; font-weight: 500; font-size: 1rem;
  border: 0; cursor: pointer; transition: transform .08s ease, background .15s ease;
}
.btn:hover { background: #0b5f75; transform: translateY(-1px); }
.btn.ghost { background: transparent; color: var(--accent); border: 1px solid var(--line); }
.btn.ghost:hover { background: var(--accent-soft); }

/* Cards / lists */
.grid { display: grid; gap: 14px; margin: 8px 0 24px; }
.qcard {
  display: block; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 22px; text-decoration: none; color: var(--ink); transition: border-color .15s ease, transform .08s ease;
}
.qcard:hover { border-color: var(--accent); transform: translateY(-1px); }
.qcard .topic { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--accent); font-weight: 600; }
.qcard .qt { font-family: var(--serif); font-size: 1.15rem; margin: 6px 0 0; }

/* Answer block */
.answer { background: var(--accent-soft); border-radius: var(--radius); padding: 20px 22px; margin: 6px 0 28px; }
.answer .label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--accent); font-weight: 700; margin-bottom: 6px; }
.answer p { margin: 0; font-size: 1.1rem; }

/* Quiz */
.quiz { border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; margin: 12px 0 32px; background: var(--card); }
.quiz h3 { margin: 0 0 6px; font-size: 1.1rem; }
.q { margin: 18px 0; }
.q p.stem { font-weight: 500; margin: 0 0 10px; }
.opt { display: block; width: 100%; text-align: left; background: var(--paper); border: 1px solid var(--line); border-radius: 10px; padding: 11px 14px; margin: 8px 0; font: inherit; color: var(--ink); cursor: pointer; }
.opt:hover { border-color: var(--accent); }
.opt.correct { border-color: var(--ok); background: #ecfdf5; }
.opt.wrong { border-color: #dc2626; background: #fef2f2; }
.explain { font-size: 0.95rem; color: var(--ink-soft); margin: 6px 2px 0; display: none; }
.explain.show { display: block; }

/* Flashcards */
.flashcard { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 4px 22px; margin: 0; }
.flashcard summary { cursor: pointer; padding: 16px 28px 16px 0; list-style: none; position: relative; }
.flashcard summary::-webkit-details-marker { display: none; }
.flashcard summary::after {
  content: "";
  position: absolute;
  right: 2px;
  top: 50%;
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--ink-soft);
  border-bottom: 2px solid var(--ink-soft);
  transform: translateY(-50%) rotate(45deg);
  transition: transform .15s ease;
}
.flashcard[open] summary::after { transform: translateY(-50%) rotate(225deg); }
.flashcard summary .topic { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--accent); font-weight: 600; display: block; }
.flashcard summary .qt { font-family: var(--serif); font-size: 1.15rem; margin: 6px 0 0; }
.flashcard .fc-back { padding-bottom: 18px; margin: 0; color: var(--ink-soft); }

/* Study app (/exam/) */
.tabs { display: flex; gap: 8px; margin: 24px 0 4px; flex-wrap: wrap; }
.tab-btn { background: var(--card); border: 1px solid var(--line); border-radius: 999px; padding: 10px 18px; font: inherit; color: var(--ink-soft); cursor: pointer; }
.tab-btn.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.tab-panel { padding-top: 12px; }
.study-question { border-bottom: 1px solid var(--line); padding-bottom: 8px; margin-bottom: 32px; }
.opt.picked { border-color: var(--accent); background: var(--accent-soft); }
#exam-result { font-weight: 500; }

/* Flashcard review (spaced repetition) */
.review-layout { display: grid; grid-template-columns: 1.5fr 1fr; gap: 20px; align-items: start; }
@media (max-width: 640px) { .review-layout { grid-template-columns: 1fr; } }
.review-card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; }
.review-meta-row { display: flex; justify-content: flex-end; }
.review-count { font-size: 0.85rem; color: var(--ink-soft); font-variant-numeric: tabular-nums; }
.review-progress-track { height: 4px; border-radius: 999px; background: var(--line); margin: 8px 0 22px; overflow: hidden; }
.review-progress-fill { height: 100%; background: var(--accent); border-radius: 999px; }
.review-q-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--ink-soft); font-weight: 600; margin: 0 0 10px; }
.review-question { font-family: var(--serif); font-size: 1.4rem; line-height: 1.4; margin: 0 0 20px; }
.review-answer { margin: 0 0 20px; padding-top: 18px; border-top: 1px solid var(--line); }
.review-a-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--ok); font-weight: 700; margin: 0 0 8px; }
.review-answer-text { margin: 0; color: var(--ink-soft); }
.review-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.btn.again { background: var(--accent-soft); color: var(--accent); }
.btn.good { background: var(--accent); color: #fff; }
.review-side { display: flex; flex-direction: column; gap: 14px; }
.stat-card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; }
.stat-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--ink-soft); font-weight: 600; margin: 0 0 8px; }
.stat-value { font-family: var(--serif); font-size: 1.8rem; }
.stat-value small { font-family: var(--sans); font-size: 0.78rem; color: var(--ink-soft); font-weight: 400; margin-left: 6px; }
.stat-value-sm { font-size: 1.1rem; }
.mastery-bar { height: 8px; border-radius: 999px; background: var(--accent-soft); overflow: hidden; margin-top: 10px; }
.mastery-fill { height: 100%; background: var(--accent); border-radius: 999px; }
.review-empty { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 32px; margin-bottom: 14px; }
.review-error { color: #dc2626; font-size: 0.9rem; }

/* Features list */
.features { list-style: none; padding: 0; margin: 24px 0; }
.features li { position: relative; padding-left: 28px; margin: 0 0 12px; color: var(--ink-soft); }
.features li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 700; }

/* Buy box */
.buy-box { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; margin: 28px 0; max-width: 380px; }
.buy-box .price { font-family: var(--serif); font-size: 1.8rem; margin: 0 0 20px; }
.buy-box .price span { display: block; font-family: var(--sans); font-size: 0.85rem; color: var(--ink-soft); font-weight: 400; margin-top: 4px; }
.buy-label { display: block; font-size: 0.85rem; color: var(--ink-soft); margin-bottom: 6px; }
.buy-box input { width: 100%; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; font: inherit; margin-bottom: 14px; }
.buy-box .btn { width: 100%; text-align: center; }
.buy-error { color: #dc2626; font-size: 0.9rem; margin: 12px 0 0; }
.buy-note { font-size: 0.8rem; color: var(--ink-soft); margin: 14px 0 0; text-align: center; }

/* Access recovery ("already bought access?") */
.restore-prompt { font-size: 0.9rem; color: var(--ink-soft); margin: 16px 0; }
.linklike { background: none; border: none; padding: 0; font: inherit; color: var(--accent); text-decoration: underline; cursor: pointer; }

/* CTA */
.cta { text-align: center; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 32px 24px; margin: 32px 0; }
.cta h2 { margin-top: 0; }
.cta p { color: var(--ink-soft); }

/* Footer */
.site-foot { border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0 48px; color: var(--ink-soft); font-size: 0.9rem; }
.site-foot p { margin: 0 0 10px; }
.site-foot .disclaimer { font-size: 0.82rem; }

/* Breadcrumb */
.crumb { font-size: 0.9rem; color: var(--ink-soft); padding-top: 22px; }
.crumb a { color: var(--ink-soft); }

@media (max-width: 480px) {
  body { font-size: 17px; }
  h1 { font-size: 1.9rem; }
  .hero { padding: 48px 0 28px; }
}

/* ==========================================================================
   Homepage — "The Log" fanned/flip flashcard deck. Per DESIGN.md's decision
   log (2026-08-16), the homepage-only Spectral/deep-teal treatment was
   retired in favor of the site-wide Fraunces + Inter + #0e7490 system; the
   deck's layout/interaction is kept as the one deliberate category
   differentiator, restyled onto the shared tokens rather than dropped.
   ========================================================================== */
body.home .home-hero { padding: 30px 0 56px; border-bottom: 1px solid var(--line); }
body.home .home-eyebrow { font-family: var(--sans); font-weight: 600; font-size: .78rem; letter-spacing: .12em; text-transform: uppercase; color: var(--accent); margin: 0 0 20px; }
body.home .home-lede { color: var(--ink-soft); font-size: 1.05rem; line-height: 1.65; max-width: 52ch; margin: 0 0 34px; }
body.home .home-hero-actions { margin: 0; }

body.home .home-deck { padding: 52px 0; border-bottom: 1px solid var(--line); }
body.home .home-kicker { font-family: var(--sans); font-weight: 600; font-size: .78rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin: 0 0 10px; }
body.home .home-deck h2 { font-size: 1.55rem; margin: 0 0 8px; }
body.home .home-sub { color: var(--ink-soft); font-size: .95rem; margin: 0 0 30px; }

body.home .home-fan-wrap { max-width: 1040px; margin: 0 auto; padding: 26px 28px 10px; }
body.home .home-fan { list-style: none; margin: 0; padding: 14px 0 26px; display: flex; justify-content: center; }
body.home .home-fan > li { flex: none; }
body.home .home-card { display: block; position: relative; flex: none; width: 180px; height: 258px; margin-left: -64px; perspective: 1200px; cursor: pointer; transition: margin .28s cubic-bezier(.2,.8,.2,1), transform .28s cubic-bezier(.2,.8,.2,1); }
body.home .home-fan li:first-child .home-card { margin-left: 0; }
@media (hover: hover) and (pointer: fine) {
  body.home .home-card:hover { margin-left: 22px; margin-right: 86px; transform: translateY(-18px); z-index: 30; }
}
body.home .home-card input { position: absolute; opacity: 0; width: 100%; height: 100%; margin: 0; cursor: pointer; }
body.home .home-card input:focus-visible ~ .home-card-inner .home-face { outline: 2px solid var(--accent); outline-offset: 3px; }
body.home .home-card-inner { position: relative; width: 100%; height: 100%; transform-style: preserve-3d; transition: transform .55s cubic-bezier(.2,.8,.2,1); }
body.home .home-card input:checked ~ .home-card-inner { transform: rotateY(180deg); }
body.home .home-face { position: absolute; inset: 0; backface-visibility: hidden; border-radius: 16px; padding: 22px 20px; display: flex; flex-direction: column; box-shadow: 0 1px 2px rgba(20,32,43,.05), 0 16px 32px rgba(20,32,43,.12); }
body.home .home-face.front { background: var(--card); border: 1px solid var(--line); }
body.home .home-face.back { background: var(--accent); border: 1px solid var(--accent); transform: rotateY(180deg); }
body.home .home-badge { flex: none; width: 34px; height: 34px; border-radius: 50%; background: var(--accent); display: flex; align-items: center; justify-content: center; margin-bottom: 16px; }
body.home .home-face.back .home-badge { background: #fff; }
body.home .home-badge svg { width: 18px; height: 18px; stroke: #fff; fill: none; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
body.home .home-face.back .home-badge svg { stroke: var(--accent); }
body.home .home-qt { font-family: var(--serif); font-size: 1.05rem; line-height: 1.45; margin: 0; color: var(--ink); }
body.home .home-qt::before { content: '\201C'; color: var(--accent); }
body.home .home-qt::after { content: '\201D'; color: var(--accent); }
body.home .home-ans { font-family: var(--serif); font-size: .94rem; line-height: 1.5; margin: 0; color: #fff; }
body.home .home-ans strong { color: #fff; }
body.home .home-hint { margin-top: auto; font-family: var(--sans); font-size: .65rem; letter-spacing: .05em; text-transform: uppercase; }
body.home .home-face.front .home-hint { color: var(--ink-soft); opacity: .7; }
body.home .home-face.back .home-hint { color: var(--accent-soft); opacity: .85; }
@media (max-width: 600px) {
  body.home .home-fan { flex-wrap: wrap; justify-content: center; gap: 16px; padding: 8px 0 20px; }
  body.home .home-card { width: 150px; height: 224px; margin: 0 !important; transform: none !important; }
}

body.home .home-cta { padding: 56px 0; background: var(--accent-soft); border-bottom: 1px solid var(--line); }
body.home .home-cta h2 { font-size: 1.55rem; }
body.home .home-cta p { color: var(--ink-soft); max-width: 52ch; font-size: .98rem; }

body.home .home-footer-video { display: block; width: 100%; border-radius: 12px; border: 1px solid var(--line); margin: 18px 0 20px; box-shadow: 0 1px 2px rgba(20,32,43,.05), 0 10px 24px rgba(20,32,43,.06); }

@media (prefers-reduced-motion: reduce) {
  body.home .home-card, body.home .home-card-inner { transition: none !important; }
}