:root {
  --ink: #0E1312;
  --ink-2: #3D4644;
  --muted: #66706E;
  --line: #EBEDEC;
  --line-2: #E3E8E6;
  --bg: #FFFFFF;
  --bg-soft: #F6F8F7;
  --bg-card: #F5F7F6;
  --teal: #1D6A66;
  --teal-dark: #134B48;
  --teal-ink: #0F3B37;
  --teal-soft: #E8F3F1;
  --mint: #5FD3C1;
  --amber: #E3B23C;
  --rust: #C2410C;
  --rust-text: #9A3412;
  --kw: #B4531A;
  --num: #7A4FB0;
  --sans: Geist, ui-sans-serif, system-ui, sans-serif;
  --mono: 'Geist Mono', ui-monospace, monospace;
  --serif: 'Source Serif 4', Georgia, serif;
}

*, *::before, *::after { box-sizing: border-box; }
[hidden] { display: none !important; }
html { -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }
body { margin: 0; font-family: var(--sans); color: var(--ink); background: var(--bg); }
body:has(dialog[open]) { overflow: hidden; }
a { color: var(--teal); }
a:hover { color: var(--teal-dark); }
:focus-visible { outline: 2px solid var(--teal); outline-offset: 2px; }
[id] { scroll-margin-top: 80px; }
p { margin: 0; }
h1, h2 { margin: 0; font-weight: 600; text-wrap: balance; }
h1 { font-size: clamp(40px, 4.5vw + 18px, 60px); line-height: 1.02; letter-spacing: -0.04em; }
h2 { font-size: clamp(28px, 1.5vw + 22px, 36px); line-height: 1.12; letter-spacing: -0.03em; }

.wrap { max-width: 1180px; margin: 0 auto; padding-left: 24px; padding-right: 24px; }
.section { padding-top: 80px; padding-bottom: 80px; }
.soft { background: var(--bg-soft); }
.stack { display: flex; flex-direction: column; }
.intro { display: flex; flex-direction: column; gap: 10px; max-width: 640px; }
.eyebrow { font-size: 13px; font-weight: 500; color: var(--teal); }
.grid { display: grid; gap: 16px; }
.cols-2 { grid-template-columns: repeat(auto-fit, minmax(min(420px, 100%), 1fr)); gap: 48px; }
.cols-4 { grid-template-columns: repeat(auto-fit, minmax(min(250px, 100%), 1fr)); }
.cols-3 { grid-template-columns: repeat(auto-fit, minmax(min(300px, 100%), 1fr)); }
.plain-list { margin: 0; padding: 0; list-style: none; }
.code {
  border-radius: 10px; padding: 10px 14px; font-family: var(--mono); font-size: 13px; line-height: 1.7;
  white-space: pre; overflow-x: auto;
}
.kw { color: var(--kw); } .fn { color: var(--teal); } .num { color: var(--num); }

.btn {
  height: 48px; padding: 0 22px; border-radius: 11px; border: none; background: var(--ink); color: #FFFFFF;
  font: inherit; font-size: 15.5px; font-weight: 500; display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer; text-decoration: none;
}
.btn:hover { background: #26302E; color: #FFFFFF; }
.btn:disabled { opacity: 0.6; cursor: progress; }
.btn-sm { height: 44px; padding: 0 16px; border-radius: 9px; font-size: 14px; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 10; background: rgba(255, 255, 255, 0.92); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.site-header .wrap { padding-top: 10px; padding-bottom: 10px; display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.logo { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font-size: 17px; font-weight: 600; letter-spacing: -0.01em; }
.logo:hover { color: var(--ink); }
.logo-mark { width: 28px; height: 28px; border-radius: 8px; background: var(--ink); display: flex; align-items: center; justify-content: center; }
.site-nav { display: flex; align-items: center; gap: 22px; font-size: 14px; }
.site-nav a:not(.btn) { color: var(--ink-2); text-decoration: none; }
.site-nav a:not(.btn):hover { color: var(--ink); }

/* Hero */
.hero { padding-top: 64px; padding-bottom: 64px; display: grid; grid-template-columns: repeat(auto-fit, minmax(min(400px, 100%), 1fr)); gap: 56px; align-items: center; }
.hero-copy { gap: 24px; }
.pill { align-self: flex-start; display: inline-flex; align-items: center; gap: 8px; min-height: 30px; padding: 4px 12px; border-radius: 999px; background: var(--teal-soft); color: var(--teal-dark); font-size: 13px; font-weight: 500; }
.pill::before { content: ''; width: 6px; height: 6px; border-radius: 50%; background: var(--teal); }
.lead { font-size: 19px; line-height: 1.55; color: var(--ink-2); max-width: 520px; text-wrap: pretty; }
.small-note { font-size: 13.5px; color: var(--muted); }

.hero-visual { display: flex; flex-direction: column; }
.viva-card {
  align-self: flex-end; width: 88%; border-radius: 18px; background: var(--bg-card); border: 1px solid var(--line-2);
  padding: 22px; display: flex; flex-direction: column; gap: 14px;
}
.viva-meta { display: flex; justify-content: space-between; gap: 12px; font-size: 12.5px; color: var(--muted); }
.viva-q { font-size: 18px; font-weight: 600; line-height: 1.35; }
.viva-card .code { background: #FFFFFF; border: 1px solid var(--line-2); }
.mic-row { display: flex; align-items: center; gap: 12px; }
.mic { width: 40px; height: 40px; flex: none; border-radius: 50%; background: var(--teal); display: flex; align-items: center; justify-content: center; }
.wave { flex: 1; display: flex; align-items: center; gap: 3px; height: 30px; }
.wave span { flex: 1; border-radius: 2px; background: var(--teal); transform-origin: center; animation: wave 0.8s ease-in-out infinite; }
@keyframes wave { 0%, 100% { transform: scaleY(0.3); } 50% { transform: scaleY(1); } }
@media (prefers-reduced-motion: reduce) { .wave span { animation: none; } }
.answer { padding: 12px 14px; border-radius: 10px; background: #FFFFFF; font-size: 14.5px; line-height: 1.55; }
.followup { align-self: flex-start; max-width: 80%; padding: 10px 14px; border-radius: 4px 14px 14px 14px; background: var(--teal-soft); color: var(--teal-ink); font-size: 14px; }

.class-card {
  position: relative; z-index: 1; margin-top: -14px; width: 62%; border-radius: 16px; background: #FFFFFF; border: 1px solid #E3E6E5;
  box-shadow: 0 18px 44px rgba(14, 19, 18, 0.12); padding: 18px; display: flex; flex-direction: column; gap: 12px;
}
.class-card .meta { font-size: 12.5px; color: var(--muted); }
.class-card .title { font-size: 15px; font-weight: 600; line-height: 1.35; }
.topic { display: grid; grid-template-columns: 110px 1fr 34px; gap: 10px; align-items: center; font-size: 12.5px; }
.bar { display: flex; height: 7px; border-radius: 4px; overflow: hidden; gap: 1px; }
.u { background: var(--teal); } .p { background: var(--amber); } .g { background: var(--rust); }
.topic .pct { font-family: var(--mono); text-align: right; }
.topic .pct.low { color: var(--rust-text); }

/* Problem */
.problem .cols-2 { align-items: start; }
.problem-body { gap: 16px; font-size: 17px; line-height: 1.6; color: var(--ink-2); }
.section.problem-pad { padding-top: 72px; padding-bottom: 72px; }

/* Steps / cards */
.card { border: 1px solid var(--line); border-radius: 16px; padding: 22px; display: flex; flex-direction: column; gap: 10px; }
.step-n { font-family: var(--mono); font-size: 13px; color: var(--muted); }
.step-title { font-size: 18px; font-weight: 600; letter-spacing: -0.01em; }
.step-text { font-size: 14.5px; line-height: 1.55; color: var(--ink-2); }
.step-time { margin-top: auto; padding-top: 6px; font-size: 13px; color: var(--muted); }

/* Dark section */
.dark { background: var(--ink); color: #FFFFFF; }
.dark .cols-2 { align-items: center; }
.dark .eyebrow { color: var(--mint); }
.dark-list { display: flex; flex-direction: column; gap: 12px; font-size: 15.5px; line-height: 1.5; color: #C9D4D1; }
.map-card { border-radius: 18px; background: #FFFFFF; color: var(--ink); padding: 22px; display: flex; flex-direction: column; gap: 14px; }
.map-head { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; font-size: 13px; }
.map-head .mono { color: var(--muted); font-family: var(--mono); }
.dots { display: grid; grid-template-columns: repeat(30, minmax(0, 1fr)); gap: 3px; }
.dots span { aspect-ratio: 1; border-radius: 2px; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: 12px; color: var(--ink-2); }
.legend span { display: inline-flex; align-items: center; gap: 5px; }
.legend i { width: 9px; height: 9px; border-radius: 2px; }
.quote-box { padding: 12px 14px; border-radius: 10px; background: #F6F7F6; font-size: 14px; line-height: 1.55; }
.quote-box mark { background: #FAD9C9; padding: 1px 3px; border-radius: 3px; }
.quote-box .note { color: var(--muted); }

/* Subjects */
.subject { gap: 12px; }
.subject .label { font-size: 13px; color: var(--muted); }
.subject .q { font-size: 16.5px; font-weight: 600; line-height: 1.4; }
.subject .code { background: #F6F7F6; font-size: 12.5px; }
.subject .hint { border-radius: 10px; background: #F6F7F6; padding: 10px 14px; font-size: 13px; line-height: 1.6; color: var(--ink-2); }
.subject .cite { border-radius: 10px; background: #F6F7F6; padding: 12px 14px; font-family: var(--serif); font-size: 14.5px; line-height: 1.55; }

/* Facts */
.fact { border-radius: 14px; background: #FFFFFF; padding: 20px; display: flex; flex-direction: column; gap: 6px; }
.fact strong { font-size: 15.5px; font-weight: 600; }
.fact span { font-size: 14px; line-height: 1.55; color: var(--ink-2); }

/* Trust */
.checks { display: flex; flex-direction: column; gap: 14px; font-size: 15.5px; line-height: 1.55; color: var(--ink-2); }
.checks li { display: flex; gap: 12px; }
.checks li::before { content: '✓'; color: var(--teal); }

/* Quotes */
.quotes { padding-top: 0; }
.quote { margin: 0; border-radius: 16px; background: var(--bg-soft); padding: 28px; display: flex; flex-direction: column; justify-content: space-between; gap: 24px; }
.quote blockquote { margin: 0; font-family: var(--serif); font-size: 19px; line-height: 1.55; color: var(--ink); text-wrap: pretty; }
.quote figcaption { display: flex; flex-direction: column; gap: 2px; font-size: 14px; }
.quote figcaption strong { font-weight: 600; }
.quote figcaption span { color: var(--muted); }

/* CTA + footer */
.cta { background: var(--teal-soft); }
.cta .wrap { padding-top: 72px; padding-bottom: 72px; display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: 24px; }
.cta h2 { color: var(--teal-ink); }
.cta p { font-size: 16px; color: var(--teal-dark); }
.site-footer { padding-top: 28px; padding-bottom: 40px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; font-size: 13px; color: var(--muted); }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 18px; }
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--ink); }

/* Early-access dialog */
.dialog { width: calc(100% - 32px); max-width: 440px; padding: 0; border: none; border-radius: 18px; box-shadow: 0 24px 60px rgba(14, 19, 18, 0.25); color: var(--ink); }
.dialog::backdrop { background: rgba(14, 19, 18, 0.45); }
.dialog-inner { padding: 28px; display: flex; flex-direction: column; gap: 18px; }
.dialog-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.dialog h2 { font-size: 22px; letter-spacing: -0.02em; }
.close { width: 44px; height: 44px; margin: -6px -6px 0 0; border-radius: 8px; border: none; background: var(--bg-card); color: var(--ink-2); font: inherit; font-size: 20px; line-height: 1; cursor: pointer; }
.ea-form { display: flex; flex-direction: column; gap: 10px; }
.ea-form label { font-size: 14px; color: var(--ink-2); }
.ea-form input[type='email'] { height: 46px; padding: 0 14px; border-radius: 10px; border: 1px solid #D5DAD8; font: inherit; font-size: 16px; }
.ea-form .btn { height: 46px; font-size: 15px; }
.ea-error { color: var(--rust-text); font-size: 14px; }
.ea-error:empty { display: none; }
.ea-done { font-size: 15px; line-height: 1.55; color: var(--ink-2); }
.ea-legal { font-size: 12.5px; line-height: 1.5; color: var(--muted); }
.ea-legal a { color: var(--ink-2); }

/* Privacy / Terms */
.legal { max-width: 760px; padding-top: 72px; padding-bottom: 80px; }
.legal h1 { font-size: clamp(36px, 3vw + 22px, 48px); line-height: 1.08; letter-spacing: -0.035em; }
.legal .updated { margin-top: 14px; font-size: 14px; color: var(--muted); }
.legal .summary { margin-top: 28px; padding: 18px 20px; border-radius: 14px; background: var(--teal-soft); color: var(--teal-ink); font-size: 15.5px; line-height: 1.6; }
.legal h2 { margin-top: 44px; font-size: 22px; letter-spacing: -0.02em; }
.legal p, .legal li { font-size: 16px; line-height: 1.7; color: var(--ink-2); }
.legal p { margin-top: 12px; }
.legal ul { margin: 12px 0 0; padding-left: 22px; }
.legal li + li { margin-top: 6px; }
.legal strong { color: var(--ink); font-weight: 600; }
@media (max-width: 640px) { .legal { padding-top: 48px; padding-bottom: 56px; } }

.hp { position: absolute; left: -10000px; width: 1px; height: 1px; overflow: hidden; }

/* Tablet and phone */
@media (max-width: 760px) {
  .site-nav a:not(.btn) { display: none; }
}
@media (max-width: 640px) {
  .wrap { padding-left: 20px; padding-right: 20px; }
  .section, .section.problem-pad { padding-top: 56px; padding-bottom: 56px; }
  .quotes { padding-top: 0; }
  .hero { padding-top: 48px; padding-bottom: 56px; gap: 40px; }
  .lead { font-size: 17px; }
  .hero-visual { gap: 16px; }
  .viva-card, .class-card { width: 100%; margin-top: 0; }
  .viva-card { padding: 18px; }
  .topic { grid-template-columns: 90px 1fr 34px; }
  .cta .wrap { padding-top: 56px; padding-bottom: 56px; }
  .cta .btn { width: 100%; }
  .dialog-inner { padding: 22px; }
}