/* ===== WantAi Landing Page ===== */
:root {
  --bg: oklch(0.985 0.005 85);
  --bg-2: oklch(0.965 0.008 85);
  --bg-3: oklch(0.945 0.01 85);
  --ink: oklch(0.22 0.01 85);
  --ink-2: oklch(0.38 0.01 85);
  --ink-3: oklch(0.55 0.008 85);
  --ink-4: oklch(0.7 0.006 85);
  --hairline: oklch(0.9 0.005 85);
  --hairline-2: oklch(0.85 0.006 85);
  --accent: oklch(0.52 0.12 155);
  --accent-tint: oklch(0.96 0.03 155);
  --accent-line: oklch(0.78 0.08 155);
  --warn: oklch(0.6 0.14 60);
  --danger: oklch(0.55 0.18 25);
  --rail: oklch(0.16 0.008 85);

  --f-sans: 'Inter', ui-sans-serif, system-ui, -apple-system, sans-serif;
  --f-mono: 'JetBrains Mono', ui-monospace, monospace;
  --f-serif: 'Instrument Serif', 'Noto Serif SC', 'Source Han Serif SC', serif;

  --max: 1200px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--f-sans);
  background: var(--bg);
  color: var(--ink);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "ss01", "cv11";
}

a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 32px; }

/* === Nav === */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklch, var(--bg) 85%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--hairline);
}
.nav-inner {
  height: 60px;
  display: flex; align-items: center; justify-content: space-between;
  max-width: var(--max); margin: 0 auto; padding: 0 32px;
}
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--f-serif); font-size: 22px; }
.brand-mark {
  width: 26px; height: 26px;
  background: var(--ink); color: var(--bg);
  display: grid; place-items: center;
  border-radius: 6px;
  font-family: var(--f-serif);
  font-size: 14px; font-style: italic;
}
.nav-links { display: flex; gap: 28px; font-size: 13px; color: var(--ink-2); }
.nav-links a:hover { color: var(--ink); }
.nav-cta { display: flex; gap: 10px; align-items: center; }

.btn {
  padding: 8px 16px;
  border-radius: 6px;
  font-size: 13px; font-weight: 500;
  border: 1px solid var(--hairline-2);
  background: var(--bg);
  transition: all .15s;
  display: inline-flex; align-items: center; gap: 6px;
}
.btn:hover { border-color: var(--ink-3); }
.btn.primary { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.btn.primary:hover { background: oklch(0.32 0.01 85); border-color: oklch(0.32 0.01 85); }
.btn.accent { background: var(--accent); color: white; border-color: var(--accent); }
.btn.ghost { background: transparent; border-color: transparent; }
.btn.lg { padding: 12px 22px; font-size: 14px; }

/* === Hero === */
.hero { padding: 80px 0 100px; position: relative; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: 64px; align-items: center; }
.kicker {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--f-mono); font-size: 11px;
  text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--accent); margin-bottom: 20px;
  padding: 4px 10px;
  background: var(--accent-tint);
  border: 1px solid var(--accent-line);
  border-radius: 100px;
}
.kicker .dot { width: 6px; height: 6px; background: var(--accent); border-radius: 50%; animation: pulse 1.6s ease-in-out infinite; }
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.4; } }

h1.hero-title {
  font-family: var(--f-serif);
  font-size: 64px;
  line-height: 1.05;
  letter-spacing: 0;
  margin: 0 0 24px;
  font-weight: 400;
}
h1.hero-title em { font-style: italic; color: var(--accent); }
h1.hero-title .strike { position: relative; display: inline-block; }
h1.hero-title .strike::after { content: ''; position: absolute; left: -2%; right: -2%; top: 55%; height: 2px; background: var(--ink-3); transform: rotate(-2deg); }

.hero-sub {
  font-size: 17px; color: var(--ink-2); max-width: 520px; line-height: 1.6;
  margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 12px; align-items: center; }
.hero-stats {
  display: flex; gap: 32px; margin-top: 56px; padding-top: 32px;
  border-top: 1px solid var(--hairline);
}
.stat .v { font-family: var(--f-serif); font-size: 28px; line-height: 1; }
.stat .l { font-size: 12px; color: var(--ink-3); margin-top: 6px; font-family: var(--f-mono); text-transform: uppercase; letter-spacing: 0.06em; }

/* === Hero visual === */
.hero-visual {
  background: var(--bg-2);
  border: 1px solid var(--hairline);
  border-radius: 12px;
  padding: 18px;
  font-family: var(--f-mono);
  font-size: 11px;
  box-shadow: 0 32px 80px -32px oklch(0.2 0.01 80 / 0.18), 0 4px 16px -4px oklch(0.2 0.01 80 / 0.06);
}
.hv-header {
  display: flex; align-items: center; gap: 8px;
  padding-bottom: 12px; border-bottom: 1px solid var(--hairline);
  margin-bottom: 14px;
}
.hv-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 8px var(--accent); animation: pulse 1.4s infinite; }
.hv-title { font-size: 11px; color: var(--ink-2); flex: 1; }
.hv-tag { color: var(--ink-4); font-size: 10px; }

.hv-line {
  display: grid; grid-template-columns: 38px 70px 1fr; gap: 8px;
  padding: 4px 0; line-height: 1.5;
}
.hv-line .t { color: var(--ink-4); }
.hv-line .src { color: var(--accent); }
.hv-line .msg { color: var(--ink-2); }
.hv-line.warn .src { color: var(--warn); }
.hv-line.warn .msg { color: var(--warn); }
.hv-line.ok .src { color: var(--accent); }

.hv-section-label {
  font-size: 10px; text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--ink-4); margin: 14px 0 6px; padding-top: 10px;
  border-top: 1px dashed var(--hairline-2);
}

.hv-pipeline {
  display: grid; grid-template-columns: repeat(8, 1fr);
  gap: 4px; margin-top: 8px;
}
.hv-step {
  height: 40px;
  background: var(--bg-3);
  border-radius: 4px;
  position: relative;
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  font-size: 9px;
  border: 1px solid var(--hairline);
}
.hv-step.done { background: var(--accent-tint); border-color: var(--accent-line); color: var(--accent); }
.hv-step.active { background: var(--ink); border-color: var(--ink); color: var(--bg); }
.hv-step.active::after { content: ''; position: absolute; inset: -2px; border-radius: 6px; border: 1px solid var(--ink); opacity: .25; animation: pulse 1.4s infinite; }

/* === Section common === */
section.s { padding: 100px 0; border-top: 1px solid var(--hairline); }
section.s.dark { background: var(--rail); color: oklch(0.92 0.005 85); border-top-color: oklch(0.25 0.01 85); }
.s-head { max-width: 720px; margin-bottom: 56px; }
.s-eyebrow {
  font-family: var(--f-mono); font-size: 11px;
  text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--accent); margin-bottom: 14px;
}
section.s.dark .s-eyebrow { color: oklch(0.78 0.12 155); }
.s-title {
  font-family: var(--f-serif);
  font-size: 44px;
  line-height: 1.15;
  letter-spacing: 0;
  margin: 0 0 16px;
  font-weight: 400;
}
.s-title em { font-style: italic; color: var(--accent); }
.s-sub { font-size: 16px; color: var(--ink-2); max-width: 600px; }
section.s.dark .s-sub { color: oklch(0.7 0.005 85); }

/* === Architecture (5 layers) === */
.arch-layers {
  display: flex; flex-direction: column; gap: 1px;
  background: var(--hairline);
  border-radius: 12px; overflow: hidden;
  border: 1px solid var(--hairline);
}
.layer {
  background: var(--bg);
  padding: 24px 28px;
  display: grid; grid-template-columns: 220px 1fr 200px;
  gap: 24px; align-items: center;
  transition: background .15s;
  position: relative;
}
.layer:hover { background: var(--bg-2); }
.layer-num {
  font-family: var(--f-mono); font-size: 11px; color: var(--ink-4);
  letter-spacing: 0.08em; text-transform: uppercase;
}
.layer-title { font-family: var(--f-serif); font-size: 22px; margin: 4px 0 6px; }
.layer-title em { font-style: italic; color: var(--accent); }
.layer-desc { font-size: 13px; color: var(--ink-3); line-height: 1.55; }
.layer-tags { display: flex; flex-wrap: wrap; gap: 4px; justify-content: flex-end; }
.layer-tag {
  font-family: var(--f-mono); font-size: 10px;
  padding: 2px 7px; border: 1px solid var(--hairline-2);
  border-radius: 3px; color: var(--ink-3);
}

/* === Capabilities grid === */
.cap-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.cap {
  background: var(--bg);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  padding: 24px;
  transition: all .15s;
}
.cap:hover { border-color: var(--ink-4); transform: translateY(-2px); }
.cap-icon {
  width: 36px; height: 36px;
  background: var(--accent-tint);
  color: var(--accent);
  border-radius: 8px;
  display: grid; place-items: center;
  font-family: var(--f-serif); font-size: 18px; font-style: italic;
  margin-bottom: 16px;
}
.cap h3 { font-size: 16px; font-weight: 600; margin: 0 0 8px; }
.cap p { font-size: 13px; color: var(--ink-3); margin: 0; line-height: 1.6; }
.cap .meta {
  margin-top: 14px; padding-top: 12px;
  border-top: 1px dashed var(--hairline);
  font-family: var(--f-mono); font-size: 10px;
  color: var(--ink-4); letter-spacing: 0.04em;
}

/* === Workflow timeline === */
.flow-grid {
  display: grid; grid-template-columns: 280px 1fr; gap: 48px;
  align-items: flex-start;
}
.flow-stages { display: flex; flex-direction: column; gap: 4px; }
.flow-stage {
  padding: 14px 16px;
  border-radius: 8px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all .15s;
  display: flex; gap: 12px; align-items: flex-start;
}
.flow-stage:hover { background: var(--bg-2); }
.flow-stage.active { background: var(--accent-tint); border-color: var(--accent-line); }
.fs-num { font-family: var(--f-mono); font-size: 11px; color: var(--ink-4); padding-top: 2px; min-width: 22px; }
.flow-stage.active .fs-num { color: var(--accent); }
.fs-name { font-size: 14px; font-weight: 500; }
.fs-desc { font-size: 12px; color: var(--ink-3); margin-top: 2px; }
.flow-stage.active .fs-name { color: var(--accent); }

.flow-detail {
  background: var(--bg-2);
  border: 1px solid var(--hairline);
  border-radius: 12px;
  padding: 32px;
  min-height: 420px;
}
.fd-eyebrow { font-family: var(--f-mono); font-size: 10px; color: var(--accent); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 8px; }
.fd-title { font-family: var(--f-serif); font-size: 28px; margin: 0 0 12px; }
.fd-desc { font-size: 14px; color: var(--ink-2); line-height: 1.7; max-width: 560px; }
.fd-mock {
  margin-top: 24px;
  background: var(--bg);
  border: 1px solid var(--hairline);
  border-radius: 8px;
  padding: 16px;
  font-family: var(--f-mono); font-size: 11px;
  color: var(--ink-2);
}

/* === Screens carousel === */
.screens {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.screen {
  background: var(--bg-2);
  border: 1px solid var(--hairline);
  border-radius: 10px;
  overflow: hidden;
  transition: all .15s;
}
.screen:hover { border-color: var(--ink-4); transform: translateY(-2px); }
.screen-frame {
  aspect-ratio: 16/10;
  background: var(--bg);
  border-bottom: 1px solid var(--hairline);
  position: relative; overflow: hidden;
  padding: 14px;
}
.screen-meta { padding: 14px 16px; }
.screen-num { font-family: var(--f-mono); font-size: 10px; color: var(--ink-4); letter-spacing: 0.08em; }
.screen-name { font-size: 14px; font-weight: 600; margin-top: 4px; }
.screen-desc { font-size: 12px; color: var(--ink-3); margin-top: 4px; }

/* mock screen contents */
.mock-bar { height: 6px; background: var(--bg-3); border-radius: 3px; margin-bottom: 4px; }
.mock-bar.short { width: 40%; }
.mock-bar.med { width: 65%; }
.mock-bar.accent { background: var(--accent-line); }
.mock-card {
  background: var(--bg-2); border: 1px solid var(--hairline);
  border-radius: 4px; padding: 6px; margin-bottom: 4px;
}

/* === Quote / Case === */
.case-block {
  background: var(--bg-2);
  border: 1px solid var(--hairline);
  border-radius: 12px;
  padding: 48px;
  display: grid; grid-template-columns: 1.4fr 1fr; gap: 48px;
  align-items: center;
}
.quote { font-family: var(--f-serif); font-size: 28px; line-height: 1.4; letter-spacing: 0; font-style: italic; }
.quote-meta { display: flex; align-items: center; gap: 12px; margin-top: 24px; }
.qm-avatar { width: 40px; height: 40px; border-radius: 50%; background: var(--ink); color: var(--bg); display: grid; place-items: center; font-family: var(--f-serif); }
.qm-name { font-size: 14px; font-weight: 500; }
.qm-title { font-size: 12px; color: var(--ink-3); }

.case-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--hairline); border-radius: 10px; overflow: hidden; }
.case-stat { background: var(--bg); padding: 24px; }
.cs-v { font-family: var(--f-serif); font-size: 36px; color: var(--accent); line-height: 1; }
.cs-l { font-size: 12px; color: var(--ink-3); margin-top: 8px; }

/* === Logos / partners === */
.logos { display: grid; grid-template-columns: repeat(6, 1fr); gap: 1px; background: var(--hairline); border: 1px solid var(--hairline); border-radius: 10px; overflow: hidden; }
.logo {
  background: var(--bg);
  height: 80px;
  display: grid; place-items: center;
  font-family: var(--f-serif);
  font-size: 17px;
  color: var(--ink-3);
  letter-spacing: 0;
}

/* === FAQ === */
.faq { display: flex; flex-direction: column; }
.faq-item {
  border-top: 1px solid var(--hairline);
  padding: 24px 0;
  cursor: pointer;
}
.faq-item:last-child { border-bottom: 1px solid var(--hairline); }
.faq-q {
  display: flex; align-items: center; justify-content: space-between;
  font-size: 17px; font-weight: 500;
}
.faq-q .pm { font-family: var(--f-serif); font-size: 22px; color: var(--ink-3); }
.faq-a {
  margin-top: 12px;
  font-size: 14px;
  color: var(--ink-2);
  max-width: 720px;
  line-height: 1.7;
  display: none;
}
.faq-item.open .faq-a { display: block; }
.faq-item.open .faq-q .pm { color: var(--accent); }

/* === CTA / footer === */
.cta-block {
  background: var(--rail);
  color: oklch(0.92 0.005 85);
  border-radius: 16px;
  padding: 80px 64px;
  text-align: center;
  margin: 80px auto 0;
  max-width: var(--max);
}
.cta-block h2 { font-family: var(--f-serif); font-size: 52px; margin: 0 0 20px; line-height: 1.1; font-weight: 400; }
.cta-block h2 em { font-style: italic; color: oklch(0.78 0.12 155); }
.cta-block p { font-size: 16px; color: oklch(0.7 0.005 85); max-width: 520px; margin: 0 auto 36px; }
.cta-block .btn { background: oklch(0.95 0.005 85); color: var(--rail); border-color: oklch(0.95 0.005 85); }
.cta-block .btn.ghost { background: transparent; color: oklch(0.92 0.005 85); border-color: oklch(0.4 0.01 85); }

footer { padding: 56px 0 40px; color: var(--ink-3); font-size: 13px; border-top: 1px solid var(--hairline); margin-top: 80px; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 40px; }
.footer-col h4 { font-size: 12px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ink-2); margin: 0 0 16px; font-family: var(--f-mono); font-weight: 500; }
.footer-col ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 10px; }
.footer-col a:hover { color: var(--ink); }
.footer-bottom {
  margin-top: 48px; padding-top: 24px;
  border-top: 1px solid var(--hairline);
  display: flex; justify-content: space-between; align-items: center;
  font-size: 12px; color: var(--ink-4);
}

/* small */
@media (max-width: 1100px) {
  .hero-grid { grid-template-columns: 1fr; }
  .layer { grid-template-columns: 1fr; }
  .layer-tags { justify-content: flex-start; }
  .cap-grid { grid-template-columns: repeat(2, 1fr); }
  .flow-grid { grid-template-columns: 1fr; }
  .case-block { grid-template-columns: 1fr; }
  .screens { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .logos { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 760px) {
  .container { padding: 0 20px; }
  .nav-inner { height: auto; min-height: 60px; padding: 10px 20px; gap: 12px; flex-wrap: wrap; }
  .brand { font-size: 20px; }
  .nav-links { order: 3; width: 100%; gap: 16px; overflow-x: auto; padding: 2px 0 4px; scrollbar-width: none; }
  .nav-links::-webkit-scrollbar { display: none; }
  .nav-cta { margin-left: auto; }
  .nav-cta .btn.ghost { display: none; }
  .hero { padding: 56px 0 72px; }
  .hero-grid { gap: 40px; }
  h1.hero-title { font-size: 44px; line-height: 1.08; }
  .hero-sub { font-size: 15px; }
  .hero-actions { flex-wrap: wrap; }
  .hero-actions .btn { justify-content: center; }
  .hero-stats { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; margin-top: 40px; padding-top: 24px; }
  .hero-visual { padding: 14px; overflow: hidden; }
  .hv-line { grid-template-columns: 38px 68px minmax(0, 1fr); }
  .hv-line .msg { min-width: 0; overflow-wrap: anywhere; }
  .hv-pipeline { grid-template-columns: repeat(4, 1fr); }
  section.s { padding: 72px 0; }
  .s-head { margin-bottom: 36px; }
  .s-title { font-size: 34px; }
  .cap-grid, .screens, .case-stats, .footer-grid { grid-template-columns: 1fr; }
  .logos { grid-template-columns: repeat(2, 1fr); }
  .layer { padding: 22px 20px; gap: 14px; }
  .flow-detail { padding: 24px 20px; min-height: 360px; }
  .case-block { padding: 32px 24px; gap: 32px; }
  .quote { font-size: 24px; }
  .cta-block { margin-top: 56px; padding: 56px 24px; border-radius: 12px; }
  .cta-block h2 { font-size: 38px; }
  .cta-block > div { flex-wrap: wrap; }
  .footer-bottom { align-items: flex-start; flex-direction: column; gap: 8px; }
}

@media (max-width: 520px) {
  .nav-cta .btn.primary { padding: 7px 12px; }
  .kicker { max-width: 100%; white-space: normal; }
  h1.hero-title { font-size: 38px; }
  .hero-sub br { display: none; }
  .btn.lg { width: 100%; justify-content: center; }
  .stat .v { font-size: 25px; }
  .hv-header { flex-wrap: wrap; }
  .hv-tag { width: 100%; }
  .hv-line { grid-template-columns: 1fr; gap: 0; padding: 7px 0; }
  .hv-line .t { display: none; }
  .hv-pipeline { grid-template-columns: repeat(2, 1fr); }
  .s-title { font-size: 30px; }
  .flow-stage { padding: 12px 10px; }
  .fd-title { font-size: 24px; }
  .fd-mock { overflow-x: auto; }
  .faq-q { gap: 16px; font-size: 16px; align-items: flex-start; }
  .cta-block h2 { font-size: 32px; }
  .logos { grid-template-columns: 1fr; }
}