/* ============================================================
   Question Everything — Public site + Hub
   Phase 2 styles. Static, no build step, bilingual.
   ============================================================ */

:root {
  --ink:        #1c2536;
  --ink-soft:   #475569;
  --bg:         #ffffff;
  --bg-soft:    #f5f7fa;
  --line:       #e2e8f0;

  --brand:      #4f46e5;   /* shared program indigo */
  --brand-dark: #3730a3;
  --a-accent:   #f97316;   /* Track A — Primary  */
  --b-accent:   #4f46e5;   /* Track B — Junior High */

  --maxw: 1040px;
  --radius: 16px;
  --shadow: 0 6px 24px rgba(28,37,54,.09);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", system-ui, "PingFang SC",
               "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--brand); }

/* ---- bilingual: hide the inactive language ---- */
.zh { display: none; }
body.lang-zh .en { display: none; }
body.lang-zh .zh { display: revert; }

img { max-width: 100%; }

/* ---- layout helpers ---- */
.wrap   { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
.section { padding: 64px 0; }
.section.tight { padding: 40px 0; }
.bg-soft { background: var(--bg-soft); }
.center  { text-align: center; }

/* ============================================================
   Header / nav
   ============================================================ */
.site-header {
  border-bottom: 1px solid var(--line);
  background: rgba(255,255,255,.94);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(180%) blur(8px);
}
.nav {
  display: flex; align-items: center; gap: 18px;
  padding: 14px 22px; flex-wrap: wrap;
}
.brand {
  font-weight: 800; font-size: 1.05rem; text-decoration: none;
  color: var(--ink); display: flex; align-items: center; gap: 9px;
}
.brand .mark {
  width: 30px; height: 30px; border-radius: 9px;
  background: var(--brand); color: #fff; font-size: 1rem;
  display: grid; place-items: center; font-weight: 900;
}
.nav .spacer { flex: 1; }
.nav a.navlink {
  text-decoration: none; color: var(--ink-soft);
  font-weight: 600; font-size: .95rem; padding: 6px 2px;
}
.nav a.navlink:hover, .nav a.navlink.active { color: var(--brand); }
.nav a.nav-cta {
  background: var(--brand); color: #fff; border-radius: 999px;
  padding: 10px 16px; white-space: nowrap;
}
.nav a.nav-cta:hover, .nav a.nav-cta.active { background: var(--brand-dark); color: #fff; }

.lang-btn {
  background: var(--bg-soft); border: 1px solid var(--line);
  color: var(--ink); border-radius: 999px; padding: 6px 14px;
  cursor: pointer; font-weight: 700; font-size: .85rem;
}
.lang-btn:hover { border-color: var(--brand); color: var(--brand); }

/* mobile nav: simple wrap, links shrink */
@media (max-width: 720px) {
  .nav a.navlink { font-size: .88rem; }
  .nav { gap: 12px; }
}
@media (max-width: 600px) {
  .nav { display: grid; grid-template-columns: 1fr 1fr auto; gap: 10px 8px; }
  .nav .brand { grid-column: 1 / 3; grid-row: 1; }
  .nav .spacer { display: none; }
  .nav .lang-btn { grid-column: 3; grid-row: 1; justify-self: end; }
  .nav a.navlink { grid-row: 2; white-space: nowrap; }
}
@media (max-width: 360px) {
  .nav { padding-inline: 16px; gap: 10px 6px; }
  .nav a.navlink { font-size: .8rem; }
  .nav a.nav-cta { padding-inline: 12px; }
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-block; text-decoration: none; cursor: pointer;
  font-family: inherit;
  font-weight: 700; font-size: 1rem; padding: 13px 26px;
  border-radius: 999px; border: 2px solid transparent;
}
.btn.primary  { background: var(--brand); color: #fff; }
.btn.primary:hover { background: var(--brand-dark); }
.btn.ghost    { background: transparent; color: var(--brand); border-color: var(--brand); }
.btn.ghost:hover { background: var(--brand); color: #fff; }
.btn.a        { background: var(--a-accent); color: #fff; }
.btn.a:hover  { background: #c2410c; }
.btn-row { display: flex; gap: 14px; flex-wrap: wrap; }
.btn-row.center { justify-content: center; }

/* ============================================================
   Hero
   ============================================================ */
.hero {
  background:
    radial-gradient(900px 400px at 80% -10%, #e0e7ff 0%, transparent 70%),
    radial-gradient(700px 350px at 0% 10%, #ffedd5 0%, transparent 65%);
  padding: 72px 0 60px;
}
.hero h1 {
  font-size: 2.55rem; line-height: 1.18; margin: 0 0 16px;
  letter-spacing: -.01em;
}
.hero .lead { font-size: 1.2rem; color: var(--ink-soft); max-width: 620px; }
.hero .kicker {
  font-weight: 800; letter-spacing: .12em; text-transform: uppercase;
  font-size: .8rem; color: var(--brand); margin-bottom: 14px;
}
@media (max-width: 620px) { .hero h1 { font-size: 1.9rem; } }

/* ============================================================
   Generic typographic blocks
   ============================================================ */
.section h2 { font-size: 1.8rem; margin: 0 0 10px; letter-spacing: -.01em; }
.section .sub { color: var(--ink-soft); max-width: 640px; }
.section.center .sub { margin-left: auto; margin-right: auto; }
.eyebrow {
  font-weight: 800; letter-spacing: .1em; text-transform: uppercase;
  font-size: .76rem; color: var(--brand); margin-bottom: 8px;
}
.lede { font-size: 1.12rem; }
.prose { max-width: 680px; }
.prose p { margin: 0 0 1em; }
.prose h3 { font-size: 1.2rem; margin: 1.6em 0 .4em; }

/* ============================================================
   Card grids
   ============================================================ */
.grid { display: grid; gap: 22px; }
.grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 800px) {
  .grid.cols-2, .grid.cols-3 { grid-template-columns: 1fr; }
}

.card {
  background: var(--bg); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px;
}
.card.soft { background: var(--bg-soft); border-color: transparent; }
.card h3 { margin: 0 0 8px; font-size: 1.18rem; }
.card .icon { font-size: 1.8rem; }
.card p { color: var(--ink-soft); margin: 8px 0 0; }

/* track-flavoured cards */
.card.track-a { border-top: 5px solid var(--a-accent); }
.card.track-b { border-top: 5px solid var(--b-accent); }
.tagline {
  display: inline-block; font-size: .74rem; font-weight: 800;
  letter-spacing: .07em; text-transform: uppercase;
  padding: 3px 10px; border-radius: 999px;
}
.tagline.a { background: #ffedd5; color: #c2410c; }
.tagline.b { background: #e0e7ff; color: #3730a3; }

/* ============================================================
   Steps / numbered list
   ============================================================ */
.steps { display: grid; gap: 18px; counter-reset: s; }
.steps .stp {
  display: flex; gap: 16px; align-items: flex-start;
}
.steps .stp::before {
  counter-increment: s; content: counter(s);
  flex: 0 0 38px; height: 38px; border-radius: 50%;
  background: var(--brand); color: #fff; font-weight: 800;
  display: grid; place-items: center;
}
.steps .stp h3 { margin: 4px 0 4px; font-size: 1.1rem; }
.steps .stp p { margin: 0; color: var(--ink-soft); }

/* ============================================================
   Lesson tables
   ============================================================ */
.lesson-table { width: 100%; border-collapse: collapse; font-size: .95rem; }
.lesson-table th, .lesson-table td {
  text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line);
  vertical-align: top;
}
.lesson-table th { font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-soft); }
.lesson-table td:first-child { font-weight: 800; color: var(--brand); width: 42px; }

/* ============================================================
   Callout / quote
   ============================================================ */
.callout {
  border-left: 5px solid var(--brand); background: var(--bg-soft);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 20px 24px; margin: 24px 0;
}
.callout.warn { border-left-color: var(--a-accent); }
.bigquote {
  font-size: 1.5rem; font-weight: 700; line-height: 1.4;
  max-width: 720px;
}

/* ============================================================
   Hub-specific
   ============================================================ */
.hub-banner {
  background: var(--ink); color: #fff; padding: 44px 0;
}
.hub-banner h1 { margin: 0 0 8px; font-size: 1.9rem; }
.hub-banner p { color: #cbd5e1; margin: 0; }

.resource-row {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 0; border-bottom: 1px solid var(--line);
}
.resource-row .ico { font-size: 1.3rem; }
.resource-row .meta { flex: 1; }
.resource-row .meta strong { display: block; }
.resource-row .meta span { color: var(--ink-soft); font-size: .9rem; }
.pill {
  font-size: .72rem; font-weight: 800; padding: 3px 9px;
  border-radius: 999px; background: var(--bg-soft); color: var(--ink-soft);
  text-transform: uppercase; letter-spacing: .05em;
}

details.lesson-acc {
  border: 1px solid var(--line); border-radius: var(--radius);
  margin: 12px 0; overflow: hidden; background: var(--bg);
}
details.lesson-acc summary {
  cursor: pointer; padding: 16px 20px; font-weight: 700;
  list-style: none; display: flex; align-items: center; gap: 12px;
}
details.lesson-acc summary::-webkit-details-marker { display: none; }
details.lesson-acc summary .num {
  flex: 0 0 30px; height: 30px; border-radius: 8px; color: #fff;
  display: grid; place-items: center; font-weight: 900; font-size: .9rem;
}
details.lesson-acc.a summary .num { background: var(--a-accent); }
details.lesson-acc.b summary .num { background: var(--b-accent); }
details.lesson-acc summary .chev { margin-left: auto; transition: transform .2s; }
details.lesson-acc[open] summary .chev { transform: rotate(90deg); }
details.lesson-acc .body {
  padding: 4px 20px 20px; border-top: 1px solid var(--line);
}
details.lesson-acc .body p { color: var(--ink-soft); margin: 12px 0; }
.file-links { display: flex; gap: 10px; flex-wrap: wrap; }
.file-links a {
  text-decoration: none; font-size: .88rem; font-weight: 700;
  padding: 7px 14px; border-radius: 999px;
  background: var(--bg-soft); color: var(--brand);
  border: 1px solid var(--line);
}
.file-links a:hover { border-color: var(--brand); }

/* ============================================================
   Notice / honesty boxes
   ============================================================ */
.notice {
  background: #fffbeb; border: 1px solid #fde68a;
  border-radius: var(--radius); padding: 18px 22px; margin: 20px 0;
  font-size: .95rem;
}
.notice strong { color: #b45309; }

/* ============================================================
   FAQ
   ============================================================ */
details.faq {
  border-bottom: 1px solid var(--line); padding: 6px 0;
}
details.faq summary {
  cursor: pointer; padding: 14px 4px; font-weight: 700; list-style: none;
  display: flex; align-items: center; gap: 10px;
}
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::before { content: "+"; color: var(--brand); font-weight: 900; }
details.faq[open] summary::before { content: "–"; }
details.faq .ans { padding: 0 4px 16px 24px; color: var(--ink-soft); }

/* ============================================================
   Contact / forms (static — mailto, no backend)
   ============================================================ */
.contact-card {
  background: var(--bg-soft); border-radius: var(--radius);
  padding: 30px; max-width: 520px;
}

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  background: var(--ink); color: #cbd5e1; padding: 44px 0; margin-top: 40px;
  font-size: .92rem;
}
.site-footer a { color: #c7d2fe; }
.footer-cols { display: flex; gap: 48px; flex-wrap: wrap; }
.footer-cols h4 { color: #fff; font-size: .95rem; margin: 0 0 10px; }
.footer-cols ul { list-style: none; padding: 0; margin: 0; }
.footer-cols li { margin: 6px 0; }
.footer-cols a { text-decoration: none; }
.footer-cols a:hover { text-decoration: underline; }
.footer-bottom {
  border-top: 1px solid #334155; margin-top: 30px; padding-top: 20px;
  color: #94a3b8; font-size: .85rem;
}