/* AI University — "Atlas of Intelligence" brand.
   Knowledge-graph identity: deep-space ink, violet→cyan signature gradient, Fraunces + Manrope. */
:root {
  --paper: #f7f8fc;
  --panel: #ffffff;
  --panel-alt: #eef0f7;
  --ink: #1a2036;
  --ink-strong: #0b1020;
  --muted: #5b6480;
  --line: #e3e6f0;
  --line-strong: #cbd0e3;

  --accent: #6d5ef6;
  --accent-hover: #5b4ee0;
  --accent-soft: #eeecff;
  --cyan: #22d3ee;
  --grad: linear-gradient(120deg, #6d5ef6 0%, #22d3ee 100%);

  --radius-sm: 0.5rem; --radius: 0.75rem; --radius-lg: 1rem;
  --shadow: 0 1px 3px rgba(11,16,32,0.08), 0 1px 2px -1px rgba(11,16,32,0.06);
  --shadow-lg: 0 18px 40px -18px rgba(109,94,246,0.35), 0 8px 18px -10px rgba(11,16,32,0.12);
  --font-body: 'Manrope', ui-sans-serif, system-ui, sans-serif;
  --font-display: 'Fraunces', ui-serif, Georgia, serif;
  font-size: 16px;
}
:root[data-theme="dark"] {
  --paper: #0b1020;
  --panel: #141a30;
  --panel-alt: #0f1526;
  --ink: #e7eaf5;
  --ink-strong: #ffffff;
  --muted: #9aa3c0;
  --line: #252c47;
  --line-strong: #3a4266;
  --accent: #8b7dff;
  --accent-hover: #a99dff;
  --accent-soft: #1a1f3a;
  --cyan: #5ee7f5;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
img, svg { max-width: 100%; }
body { font-family: var(--font-body); line-height: 1.6; color: var(--ink); background: var(--paper); -webkit-font-smoothing: antialiased; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
h1, h2, h3 { font-family: var(--font-display); color: var(--ink-strong); line-height: 1.1; letter-spacing: -0.02em; }
.container { max-width: 1120px; margin: 0 auto; padding: 0 1.25rem; }
.grad-text { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* ==== shared site navbar (OFO "stores" pattern) =========================== */
header.site { position: sticky; top: 0; z-index: 50; background: color-mix(in srgb, var(--paper) 85%, transparent); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); border-bottom: 1px solid var(--line); }
header.site > .container { display: flex; align-items: center; gap: 1rem; min-height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 0.6rem; text-decoration: none; color: inherit; }
.brand-mark { width: 40px; height: 40px; flex-shrink: 0; display: inline-flex; align-items: center; justify-content: center; }
.brand-mark svg { width: 40px; height: 40px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.12; }
.brand-name { font-family: var(--font-display); font-weight: 800; font-size: 1.18rem; color: var(--ink-strong); letter-spacing: -0.01em; }
.brand-tag { font-size: 0.72rem; color: var(--muted); font-weight: 600; letter-spacing: 0.01em; }
nav.site-links { display: flex; align-items: center; gap: 1.35rem; margin-left: auto; }
nav.site-links > a { color: var(--muted); font-weight: 600; font-size: 0.9rem; white-space: nowrap; }
nav.site-links > a:hover { color: var(--ink-strong); }
.header-right { display: flex; align-items: center; gap: 0.55rem; }
.theme-toggle, .icon-btn { width: 40px; height: 40px; display: inline-grid; place-items: center; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel); color: var(--ink); cursor: pointer; font-size: 1.05rem; font-family: inherit; }
.theme-toggle:hover, .icon-btn:hover { border-color: var(--line-strong); }
.nav-cta { display: inline-flex; align-items: center; justify-content: center; padding: 0.55rem 1.1rem; border-radius: 999px; background: var(--grad, var(--accent)); color: #fff; font-weight: 700; font-size: 0.85rem; border: 1px solid transparent; white-space: nowrap; box-shadow: 0 6px 16px -8px rgba(109,94,246,0.6); }
.nav-cta:hover { color: #fff; transform: translateY(-1px); }
.nav-toggle { display: none; width: 40px; height: 40px; margin-left: auto; place-items: center; border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--panel); color: var(--ink); cursor: pointer; font-size: 1.25rem; }
.nav-close { display: none; }
.nav-overlay { position: fixed; inset: 0; background: rgba(3,6,18,0.45); z-index: 55; opacity: 0; pointer-events: none; transition: opacity .2s; }
.nav-overlay.open { opacity: 1; pointer-events: auto; }
.drawer-tools { display: none; }

@media (max-width: 720px) {
  .brand-tag { display: none; }
  .header-right { display: none; }
  .nav-toggle { display: grid; }
  nav.site-links {
    position: fixed; top: 0; right: 0; width: min(80vw, 300px); height: 100dvh;
    margin: 0; flex-direction: column; align-items: stretch; gap: 0.1rem;
    background: var(--panel); border-left: 1px solid var(--line);
    padding: 1rem 1.2rem 2rem; transform: translateX(100%);
    transition: transform .22s ease; z-index: 60; box-shadow: -8px 0 28px rgba(0,0,0,0.22);
    overflow-y: auto;
  }
  nav.site-links.open { transform: translateX(0); }
  nav.site-links > a { width: 100%; padding: 0.75rem 0; font-size: 1.05rem; font-weight: 700; color: var(--ink-strong); border-bottom: 1px solid var(--line); }
  .nav-close { display: inline-flex; align-self: flex-end; background: none; border: none; color: var(--muted); font-size: 1.6rem; line-height: 1; cursor: pointer; padding: 0 0.2rem 0.4rem; }
  .drawer-tools { display: flex; flex-wrap: wrap; align-items: center; gap: 0.6rem; margin-top: 1.1rem; }
  .drawer-tools .nav-cta { flex: 1; padding: 0.7rem 1rem; font-size: 0.95rem; }
}

/* ---- buttons ---- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem; padding: 0.72rem 1.4rem; border-radius: var(--radius); font-weight: 700; font-size: 0.95rem; background: var(--grad); color: #fff; border: 1px solid transparent; cursor: pointer; font-family: var(--font-body); transition: transform .15s, box-shadow .15s; box-shadow: 0 6px 18px -8px rgba(109,94,246,0.6); }
.btn:hover { color: #fff; transform: translateY(-1px); box-shadow: 0 10px 24px -8px rgba(109,94,246,0.7); }
.btn-lg { padding: 0.95rem 1.8rem; font-size: 1.05rem; }
.btn-ghost { background: transparent; color: var(--ink-strong); border-color: var(--line-strong); box-shadow: none; }
.btn-ghost:hover { background: var(--panel-alt); color: var(--ink-strong); box-shadow: none; }

.pill { display: inline-flex; align-items: center; gap: 0.4rem; padding: 0.35rem 0.9rem; border-radius: 999px; background: var(--accent-soft); color: var(--accent-hover); font-weight: 700; font-size: 0.8rem; border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent); }
.pill .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 25%, transparent); }
.tag { display: inline-block; font-size: 0.72rem; font-weight: 700; color: var(--muted); background: var(--panel-alt); border: 1px solid var(--line); padding: 0.2rem 0.6rem; border-radius: var(--radius-sm); }

/* ---- hero ---- */
.hero { position: relative; padding: 5.5rem 0 3.5rem; overflow: hidden; }
.hero::before { content: ''; position: absolute; inset: 0; background:
  radial-gradient(600px 340px at 80% -10%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 70%),
  radial-gradient(520px 320px at 10% 10%, color-mix(in srgb, var(--cyan) 16%, transparent), transparent 70%);
  pointer-events: none; }
.hero .container { position: relative; }
.hero h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); font-weight: 800; max-width: 16ch; }
.hero p.lead { font-size: 1.2rem; color: var(--muted); max-width: 54ch; margin: 1.2rem 0 2rem; }
.hero-cta { display: flex; gap: 0.8rem; flex-wrap: wrap; }
.hero-meta { display: flex; gap: 1.6rem; margin-top: 2.4rem; flex-wrap: wrap; color: var(--muted); font-size: 0.9rem; font-weight: 600; }
.hero-meta strong { color: var(--ink-strong); font-family: var(--font-display); }

/* ---- sections ---- */
section { padding: 3.5rem 0; }
.section-head { margin-bottom: 2rem; }
.section-head h2 { font-size: clamp(1.7rem, 3.2vw, 2.4rem); font-weight: 700; }
.section-head p { color: var(--muted); margin-top: 0.6rem; max-width: 60ch; }
.grid { display: grid; gap: 1.2rem; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius-lg); padding: 1.6rem; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 0.75rem; align-items: flex-start; transition: transform .15s, box-shadow .15s, border-color .15s; }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); border-color: color-mix(in srgb, var(--accent) 40%, var(--line)); }
.card h3 { font-size: 1.3rem; }
.card p { color: var(--muted); font-size: 0.96rem; }
.card.live { border-color: color-mix(in srgb, var(--accent) 55%, var(--line)); background: linear-gradient(180deg, var(--accent-soft), var(--panel) 55%); }
.card.map { grid-column: 1 / -1; display: grid; grid-template-columns: 1.2fr 1fr; gap: 1.5rem; align-items: center; background: var(--ink-strong); color: #fff; border: none; }
.card.map h3, .card.map p { color: #fff; }
.card.map p { opacity: 0.8; }
.constellation { width: 100%; height: auto; max-height: 220px; }

footer { border-top: 1px solid var(--line); padding: 2.5rem 0; color: var(--muted); font-size: 0.88rem; margin-top: 2rem; }
footer .container { display: flex; flex-wrap: wrap; gap: 1rem; justify-content: space-between; align-items: center; }
.muted { color: var(--muted); }
@media (max-width: 720px) {
  .card.map { grid-template-columns: 1fr; }
  .hero { padding: 3.5rem 0 2.5rem; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .hero-cta .btn { width: 100%; }
}

/* ==== certified courses (learn) ========================================== */
#learn-auth { display: inline-flex; align-items: center; gap: 0.5rem; }
.userchip { font-size: 0.85rem; color: var(--muted); font-weight: 700; }
.btn-link { background: none; border: none; color: var(--muted); font-weight: 700; cursor: pointer; font-family: inherit; font-size: 0.85rem; text-decoration: underline; }
.btn-link:hover { color: var(--ink-strong); }

.learn-card { position: relative; }
.learn-card .emoji { font-size: 2rem; }
.learn-card .card-foot { margin-top: auto; display: flex; align-items: center; justify-content: space-between; gap: 0.6rem; width: 100%; padding-top: 0.6rem; }
.badge { display: inline-block; padding: 0.2rem 0.6rem; border-radius: 999px; font-size: 0.75rem; font-weight: 800; background: var(--panel-alt); border: 1px solid var(--line); color: var(--muted); }
.badge.live { background: #dcfce7; color: #166534; border-color: #bbf7d0; }
:root[data-theme="dark"] .badge.live { background: #052e16; color: #86efac; border-color: #14532d; }

.course-head { display: flex; gap: 1rem; align-items: flex-start; margin: 1.5rem 0; }
.emoji-lg { font-size: 3rem; line-height: 1; }
.course-head h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); margin: 0.3rem 0; }
.prose { color: var(--ink); line-height: 1.7; }
.prose.intro { color: var(--muted); font-size: 1.05rem; margin-bottom: 1.5rem; }
.prose h2, .prose h3, .prose h4 { margin: 1.2rem 0 0.5rem; }
.prose p { margin: 0.7rem 0; }
.prose ul, .prose ol { margin: 0.7rem 0 0.7rem 1.3rem; }
.prose li { margin: 0.3rem 0; }
.prose code { background: var(--panel-alt); padding: 0.1rem 0.4rem; border-radius: 5px; font-size: 0.9em; }
.prose a { text-decoration: underline; }

.lesson { border: 1px solid var(--line); border-radius: var(--radius-lg); padding: 1.3rem 1.5rem; margin: 1rem 0; background: var(--panel); }
.lesson h3 { display: flex; align-items: center; gap: 0.6rem; font-size: 1.2rem; margin-bottom: 0.5rem; }
.lnum { display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--grad); color: #fff; font-size: 0.85rem; font-weight: 800; font-family: var(--font-body); flex-shrink: 0; }

#quiz { margin-top: 1rem; }
.q { border: 1px solid var(--line); border-radius: var(--radius); padding: 1.1rem 1.3rem; margin: 0.8rem 0; background: var(--panel); transition: border-color .15s; }
.q.correct { border-color: #16a34a; background: color-mix(in srgb, #16a34a 8%, var(--panel)); }
.q.wrong { border-color: #dc2626; background: color-mix(in srgb, #dc2626 8%, var(--panel)); }
.q-prompt { font-weight: 600; margin-bottom: 0.7rem; }
.choices { display: flex; flex-direction: column; gap: 0.4rem; }
.choice { display: flex; align-items: flex-start; gap: 0.6rem; padding: 0.5rem 0.7rem; border: 1px solid var(--line); border-radius: var(--radius-sm); cursor: pointer; transition: border-color .15s, background .15s; }
.choice:hover { border-color: var(--line-strong); background: var(--panel-alt); }
.choice input { margin-top: 0.2rem; }
.q-explain { margin-top: 0.6rem; font-size: 0.9rem; font-weight: 600; color: var(--muted); }
.note { padding: 0.8rem 1rem; border-radius: var(--radius-sm); font-weight: 600; font-size: 0.9rem; margin: 0.8rem 0; }
.note.err { background: #fee2e2; color: #991b1b; }
.note.ok { background: #dcfce7; color: #166534; }
.note.info { background: var(--accent-soft); color: var(--accent-hover); }

.result-card { border-radius: var(--radius-lg); padding: 1.8rem; margin: 1.5rem 0; text-align: center; border: 2px solid; }
.result-card.pass { border-color: #16a34a; background: color-mix(in srgb, #16a34a 10%, var(--panel)); }
.result-card.fail { border-color: var(--line-strong); background: var(--panel-alt); }
.result-card h2 { margin-bottom: 0.4rem; }

/* certificate */
.cert { max-width: 760px; margin: 2rem auto; aspect-ratio: 1200/630; background: linear-gradient(135deg, #0b1020, #0f1526); color: #fff; border-radius: var(--radius-lg); border: 3px solid transparent; background-origin: border-box; box-shadow: var(--shadow-lg); display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; padding: 2rem; position: relative; overflow: hidden; }
.cert::before { content: ''; position: absolute; inset: 0; border-radius: var(--radius-lg); padding: 3px; background: var(--grad); -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0); -webkit-mask-composite: xor; mask-composite: exclude; pointer-events: none; }
.cert-kicker { color: #9aa3c0; font-size: 0.8rem; letter-spacing: 0.25em; font-weight: 700; }
.cert-sub { color: #5b6480; font-size: 0.95rem; margin: 0.4rem 0; }
.cert-name { font-family: var(--font-display); font-size: clamp(1.6rem, 5vw, 2.8rem); color: #fff; margin: 0.2rem 0; }
.cert-course { font-family: var(--font-display); font-size: clamp(1.1rem, 3vw, 1.7rem); margin: 0.2rem 0; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.cert-meta { color: #cbd5e1; font-weight: 600; margin-top: 0.6rem; }
.cert-code { color: #5b6480; font-size: 0.75rem; letter-spacing: 0.15em; margin-top: 0.4rem; }
.cert-actions { display: flex; flex-wrap: wrap; gap: 0.6rem; justify-content: center; margin: 1.2rem 0; }

/* learn: catalog filters + printable certificate */
.learn-filters { display: flex; gap: 0.6rem; margin-bottom: 1.5rem; flex-wrap: wrap; }
.learn-filters input, .learn-filters select { padding: 0.6rem 0.8rem; border: 1px solid var(--line-strong); border-radius: var(--radius-sm); background: var(--panel); color: var(--ink); font: inherit; }
.learn-filters input { flex: 1; min-width: 220px; }
@media print {
  header.site, footer, .cert-actions, .nav-overlay { display: none !important; }
  body { background: #fff; }
  .cert { box-shadow: none; margin: 0 auto; }
}

/* Text-size control (shared stores-text-size key; scales all rem-based text). */
:root[data-text="lg"] { font-size: 18px; }
:root[data-text="sm"] { font-size: 14px; }

/* Sign-in provider modal (GitHub / Google). */
.aiu-modal {
  position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center;
  background: color-mix(in srgb, #0b1020 62%, transparent); padding: 1.2rem;
  animation: aiu-fade 0.15s ease;
}
@keyframes aiu-fade { from { opacity: 0; } to { opacity: 1; } }
.aiu-modal-card {
  background: var(--panel); color: var(--ink); border: 1px solid var(--line);
  border-radius: 18px; padding: 1.6rem; width: min(24rem, 100%);
  box-shadow: 0 24px 60px -20px rgba(11,16,32,0.6); text-align: center;
}
.aiu-modal-card h3 { margin: 0 0 0.3rem; font-size: 1.25rem; }
.aiu-modal-card .muted { margin: 0 0 1.1rem; font-size: 0.9rem; }
.btn-provider {
  display: flex; align-items: center; justify-content: center; gap: 0.6rem;
  width: 100%; margin-bottom: 0.6rem; padding: 0.7rem 1rem;
  background: var(--panel); color: var(--ink); border: 1px solid var(--line); font-weight: 700;
}
.btn-provider:hover { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--panel)); }
.btn-provider svg { flex: none; }
.aiu-modal-card .btn-link { margin-top: 0.3rem; }

/* Keyboard focus ring — consistent with the school/admin design system. */
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 6px;
}
input:focus, select:focus, textarea:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 25%, transparent);
}