/* ============================================================
   UnearthAI · www.unearthai.cn
   静态单页样式 —— 无外部依赖
   ============================================================ */

:root {
  --ink: #131c2e;
  --ink-soft: #46536b;
  --ink-faint: #7a8699;
  --paper: #ffffff;
  --paper-2: #f5f7fa;
  --line: #e4e9f0;
  --navy: #0a1220;
  --navy-2: #0e1830;
  --navy-line: #22314d;
  --amber: #e8992c;
  --amber-deep: #cf7a14;
  --amber-soft: #fdf3e2;
  --amber-line: #f3d9a8;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(19, 28, 46, .07);
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Source Han Sans SC", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

.container {
  width: min(1120px, 100% - 48px);
  margin-inline: auto;
}

/* ============ 通用 ============ */

.kicker {
  display: inline-block;
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .35em;
  text-transform: uppercase;
  color: var(--amber-deep);
  margin-bottom: 14px;
}

.section { padding: 96px 0; }
.section-light { background: var(--paper); }
.section-tint { background: var(--paper-2); }
.section-dark {
  background:
    radial-gradient(900px 480px at 85% -10%, rgba(232, 153, 44, .10), transparent 60%),
    var(--navy);
  color: #e8edf5;
}

.section h2 {
  font-size: clamp(1.6rem, 3.2vw, 2.2rem);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: .01em;
  margin-bottom: 28px;
}

.lead {
  font-size: 1.12rem;
  color: var(--ink-soft);
  max-width: 46em;
}

.subhead {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink-soft);
  margin: 44px 0 18px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.subhead::before {
  content: "";
  width: 22px;
  height: 3px;
  border-radius: 2px;
  background: var(--amber);
}
.subhead-dark { color: #b9c6da; }

/* ============ 按钮 ============ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 13px 26px;
  border-radius: 10px;
  font-size: .95rem;
  font-weight: 600;
  line-height: 1;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .15s ease, box-shadow .2s ease, background .2s ease, border-color .2s ease;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }

.btn-primary {
  background: linear-gradient(135deg, #f2ab3a, var(--amber-deep));
  color: #241503;
  box-shadow: 0 6px 18px rgba(232, 153, 44, .35);
}
.btn-primary:hover {
  box-shadow: 0 8px 24px rgba(232, 153, 44, .5);
  transform: translateY(-1px);
}

.btn-ghost {
  color: #eef2f8;
  border-color: rgba(255, 255, 255, .28);
  background: rgba(255, 255, 255, .04);
}
.btn-ghost:hover { border-color: rgba(255, 255, 255, .55); background: rgba(255, 255, 255, .09); }

.btn-outline {
  color: var(--ink);
  border-color: #cdd6e2;
  background: var(--paper);
}
.btn-outline:hover { border-color: var(--amber); color: var(--amber-deep); }

.btn-sm { padding: 9px 18px; font-size: .88rem; border-radius: 8px; }

/* ============ 顶栏 ============ */

.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  background: rgba(10, 18, 32, .72);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s ease, background .25s ease;
}
.site-header.scrolled { border-bottom-color: rgba(255, 255, 255, .09); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: #f2f5fa;
}
.brand-mark { width: 52px; height: auto; flex-shrink: 0; }
.brand-name {
  font-size: 1.12rem;
  font-weight: 700;
  letter-spacing: .015em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 30px;
}
.site-nav > a {
  font-size: .92rem;
  color: #c6d1e2;
  transition: color .2s ease;
  position: relative;
  padding: 4px 0;
}
.site-nav > a:hover { color: #fff; }
.site-nav > a.active { color: #fff; }
.site-nav > a.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -4px;
  height: 2px;
  border-radius: 2px;
  background: var(--amber);
}
.nav-cta { margin-left: 6px; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 0;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span {
  width: 22px;
  height: 2px;
  border-radius: 2px;
  background: #e7edf5;
  transition: transform .25s ease, opacity .25s ease;
}
.nav-open .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-open .nav-toggle span:nth-child(2) { opacity: 0; }
.nav-open .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============ Hero ============ */

.hero {
  position: relative;
  overflow: hidden;
  color: #eef2f8;
  background:
    radial-gradient(1100px 560px at 78% 12%, rgba(232, 153, 44, .16), transparent 62%),
    radial-gradient(800px 500px at 8% 100%, rgba(46, 89, 168, .22), transparent 60%),
    var(--navy);
  padding: 168px 0 72px;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, .035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .035) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(720px 480px at 70% 30%, #000 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(720px 480px at 70% 30%, #000 30%, transparent 75%);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  gap: 56px;
  align-items: center;
}

.eyebrow {
  display: inline-block;
  font-size: .84rem;
  font-weight: 600;
  letter-spacing: .22em;
  color: #f0c37a;
  border: 1px solid rgba(240, 195, 122, .35);
  background: rgba(240, 195, 122, .08);
  border-radius: 999px;
  padding: 6px 16px;
  margin-bottom: 26px;
}

.hero h1 {
  font-size: clamp(2rem, 4.4vw, 3.1rem);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: .01em;
  margin-bottom: 22px;
}

.hero-sub {
  font-size: 1.06rem;
  color: #b9c6da;
  max-width: 36em;
  margin-bottom: 34px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 38px;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.hero-tags li {
  font-size: .82rem;
  color: #9fb0c8;
  border: 1px solid rgba(159, 176, 200, .3);
  border-radius: 999px;
  padding: 5px 14px;
  transition: color .2s ease, border-color .2s ease;
}
.hero-tags li:hover { color: #fff; border-color: rgba(255, 255, 255, .5); }

/* Hero 插画 */
.hero-art { position: relative; }

.art-glow {
  position: absolute;
  inset: -12% -8%;
  background: radial-gradient(46% 46% at 52% 46%, rgba(232, 153, 44, .18), transparent 70%);
  filter: blur(6px);
  pointer-events: none;
}

.gpu-svg {
  position: relative;
  width: 100%;
  height: auto;
}
.board-main { filter: drop-shadow(0 24px 44px rgba(0, 0, 0, .45)); }

.art-chip {
  position: absolute;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: .82rem;
  font-weight: 600;
  color: #e9eef6;
  background: rgba(16, 27, 48, .82);
  border: 1px solid rgba(255, 255, 255, .14);
  border-radius: 999px;
  padding: 8px 16px;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  box-shadow: 0 10px 26px rgba(0, 0, 0, .35);
  animation: floaty 5.5s ease-in-out infinite;
}
.art-chip svg { width: 16px; height: 16px; color: var(--amber); }
.chip-a { top: 4%; right: 2%; }
.chip-b { bottom: 10%; left: 0; animation-delay: -2.7s; }

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-9px); }
}

.hero-tiers {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 56px;
  padding-top: 26px;
  border-top: 1px solid rgba(255, 255, 255, .08);
}
.tier-chip {
  font-size: .84rem;
  color: #9fb0c8;
  border: 1px solid rgba(159, 176, 200, .3);
  border-radius: 999px;
  padding: 6px 16px;
}
.tier-hot {
  color: #241503;
  background: linear-gradient(135deg, #f2ab3a, var(--amber-deep));
  border-color: transparent;
  font-weight: 700;
}
.tier-sep {
  width: 34px;
  height: 1px;
  background: rgba(255, 255, 255, .18);
}

/* ============ 愿景 ============ */

.vision-card {
  margin-top: 36px;
  padding: 34px 38px;
  border-radius: var(--radius);
  background: var(--navy);
  color: #dfe6f0;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}
.vision-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 3px;
  background: linear-gradient(90deg, #f2ab3a, var(--amber-deep));
}
.vision-card b { color: #f0c37a; }
.vision-card > p { font-size: 1.06rem; margin-bottom: 18px; }

.loop-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.loop-list li {
  font-size: .95rem;
  font-weight: 700;
  color: #fff;
  background: rgba(255, 255, 255, .07);
  border: 1px solid rgba(255, 255, 255, .14);
  padding: 8px 18px;
  border-radius: 999px;
}
.loop-list li:not(:last-child)::after {
  content: "→";
  margin-left: 16px;
  color: var(--amber);
  font-weight: 400;
}

/* ============ 产品总览表 ============ */

.table-wrap {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
  overflow-x: auto;
}

.overview-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 640px;
}
.overview-table th, .overview-table td {
  text-align: left;
  padding: 18px 24px;
  font-size: .95rem;
}
.overview-table thead th {
  font-size: .8rem;
  letter-spacing: .12em;
  color: var(--ink-faint);
  border-bottom: 1px solid var(--line);
  background: var(--paper-2);
}
.overview-table tbody tr + tr td { border-top: 1px solid var(--line); }
.overview-table tbody tr { transition: background .15s ease; }
.overview-table tbody tr:hover { background: #fafbfd; }

.overview-table td:first-child a {
  font-weight: 700;
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.overview-table td:first-child a::after {
  content: "→";
  color: var(--amber-deep);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity .2s ease, transform .2s ease;
}
.overview-table td:first-child a:hover::after { opacity: 1; transform: translateX(0); }
.overview-table td:last-child { color: var(--ink-soft); }

.hw-badge {
  display: inline-block;
  font-size: .8rem;
  font-weight: 700;
  color: var(--amber-deep);
  background: var(--amber-soft);
  border: 1px solid var(--amber-line);
  border-radius: 999px;
  padding: 3px 12px;
  white-space: nowrap;
}
.hw-badge-alt { color: #3a5180; background: #edf2fa; border-color: #cddaf0; }

/* ============ 产品详情 ============ */

.detail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 48px;
  align-items: start;
}
.detail-grid-reverse .detail-copy { order: 2; }
.detail-grid-reverse .detail-side { order: 1; }

.detail-copy > p { color: var(--ink-soft); font-size: 1.02rem; max-width: 40em; }
.research-head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 4px;
}
.status-badge {
  font-size: .78rem;
  font-weight: 600;
  color: #8a5a12;
  background: var(--amber-soft);
  border: 1px dashed var(--amber);
  border-radius: 999px;
  padding: 5px 14px;
}

.feature-list {
  margin-top: 30px;
  display: grid;
  gap: 14px;
}
.feature-list li {
  display: grid;
  grid-template-columns: 128px 1fr;
  gap: 14px;
  align-items: baseline;
  padding: 14px 18px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--paper);
  transition: border-color .2s ease, box-shadow .2s ease;
}
.feature-list li:hover { border-color: var(--amber-line); box-shadow: 0 6px 18px rgba(232, 153, 44, .10); }
.feature-list b { font-size: .92rem; color: var(--ink); white-space: nowrap; }
.feature-list span { font-size: .92rem; color: var(--ink-soft); }

/* 工作流程 */
.flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 6px;
  margin-bottom: 8px;
}
.flow li {
  font-size: .88rem;
  font-weight: 600;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 7px 15px;
}
.flow li:not(:last-child)::after {
  content: "→";
  margin-left: 15px;
  color: var(--amber-deep);
  font-weight: 400;
}

.callout {
  display: flex;
  gap: 14px;
  margin-top: 30px;
  padding: 20px 22px;
  border-radius: 12px;
  background: var(--amber-soft);
  border: 1px solid var(--amber-line);
}
.callout svg { width: 22px; height: 22px; flex-shrink: 0; color: var(--amber-deep); margin-top: 3px; }
.callout b { display: block; font-size: .9rem; color: #8a5a12; margin-bottom: 2px; }
.callout p { font-size: .92rem; color: #6b5426; }

.research-list {
  margin-top: 8px;
  display: grid;
  gap: 12px;
}
.research-list li {
  display: flex;
  gap: 16px;
  align-items: baseline;
  padding: 16px 20px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--paper);
}
.research-list b {
  font-size: .8rem;
  color: var(--amber-deep);
  letter-spacing: .08em;
  flex-shrink: 0;
}
.research-list span { color: var(--ink-soft); font-size: .96rem; }

/* 决策器场景卡片 */
.decision-demos {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}
.demo-card {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-2);
  scroll-margin-top: 88px;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.demo-card:hover { border-color: var(--amber-line); box-shadow: var(--shadow); }
.demo-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
}
.demo-label {
  font-size: .76rem;
  font-weight: 700;
  letter-spacing: .16em;
  color: var(--amber-deep);
}
.demo-status {
  font-size: .76rem;
  font-weight: 600;
  color: var(--ink-soft);
  border: 1px solid #d5dce7;
  border-radius: 999px;
  padding: 4px 11px;
  background: var(--paper);
}
.demo-card h3 {
  font-size: 1.22rem;
  line-height: 1.45;
  margin: 16px 0 12px;
}
.demo-summary { font-size: .95rem; color: var(--ink-soft); }
.demo-video-wrap { margin-top: 22px; }
.demo-video {
  display: block;
  width: 100%;
  height: auto;
  background: var(--navy);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.demo-video-caption {
  margin-top: 8px;
  font-size: .76rem;
  text-align: center;
  color: var(--ink-faint);
}
.demo-points {
  display: grid;
  gap: 14px;
  margin-top: 24px;
}
.demo-points li {
  position: relative;
  padding-left: 18px;
}
.demo-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .62em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--amber);
}
.demo-points b { display: block; font-size: .9rem; }
.demo-points span { display: block; font-size: .87rem; line-height: 1.65; color: var(--ink-soft); }
.demo-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: auto;
  padding-top: 26px;
}
.demo-metric {
  flex: 1 1 130px;
  min-width: 0;
  padding: 14px 15px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--paper);
}
.demo-metric strong {
  display: block;
  font-size: 1.08rem;
  line-height: 1.4;
  color: var(--amber-deep);
  white-space: nowrap;
}
.demo-metric span {
  display: block;
  margin-top: 4px;
  font-size: .75rem;
  line-height: 1.55;
  color: var(--ink-faint);
}
.demo-note {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: .8rem;
  line-height: 1.65;
  color: var(--ink-faint);
}

/* 侧栏卡片 */
.detail-side {
  display: grid;
  gap: 20px;
  position: sticky;
  top: 96px;
}
.side-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  padding: 26px 26px 22px;
  box-shadow: var(--shadow);
}
.side-card h3 {
  font-size: .88rem;
  letter-spacing: .14em;
  color: var(--ink-faint);
  margin-bottom: 16px;
}
.side-card-dark {
  background: var(--navy);
  border-color: var(--navy-line);
  color: #dfe6f0;
}
.side-card-dark h3 { color: #9fb0c8; }
.side-card-dark p { font-size: .9rem; color: #b9c6da; }

.chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.chip-list li {
  font-size: .86rem;
  color: var(--ink-soft);
  background: var(--paper-2);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 14px;
}
.chip-list-amber li {
  color: var(--amber-deep);
  background: var(--amber-soft);
  border-color: var(--amber-line);
  font-weight: 600;
}
.chip-list a:hover { color: var(--amber-deep); }

.trit-viz {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 6px 0 18px;
}
.trit {
  text-align: center;
  font-size: 1.3rem;
  font-weight: 800;
  font-family: ui-monospace, Consolas, monospace;
  border-radius: 10px;
  padding: 18px 0;
  border: 1px solid;
}
.t-neg { color: #ff9d7a; border-color: rgba(255, 157, 122, .35); background: rgba(255, 157, 122, .08); }
.t-zero { color: #9fb0c8; border-color: rgba(159, 176, 200, .3); background: rgba(159, 176, 200, .07); }
.t-pos { color: #f0c37a; border-color: rgba(240, 195, 122, .4); background: rgba(240, 195, 122, .08); }

/* ============ 技术底座 ============ */

.section-dark .kicker { color: #f0c37a; }

.runtime-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}
.runtime-card {
  background: rgba(255, 255, 255, .04);
  border: 1px solid rgba(255, 255, 255, .09);
  border-radius: var(--radius);
  padding: 26px 22px;
  transition: border-color .2s ease, background .2s ease, transform .2s ease;
}
.runtime-card:hover {
  border-color: rgba(240, 195, 122, .45);
  background: rgba(255, 255, 255, .06);
  transform: translateY(-3px);
}
.runtime-card svg { width: 30px; height: 30px; color: #f0c37a; margin-bottom: 16px; }
.runtime-card h3 { font-size: 1rem; margin-bottom: 8px; }
.runtime-card p { font-size: .88rem; color: #9fb0c8; }

.tier-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
.tier-card {
  position: relative;
  border: 1px solid rgba(255, 255, 255, .1);
  border-radius: var(--radius);
  padding: 28px 26px;
  background: rgba(255, 255, 255, .03);
  transition: transform .2s ease, border-color .2s ease;
}
.tier-card:hover { transform: translateY(-3px); border-color: rgba(255, 255, 255, .25); }
.tier-card-hot {
  border-color: rgba(240, 195, 122, .5);
  background: linear-gradient(160deg, rgba(240, 195, 122, .12), rgba(240, 195, 122, .03));
}
.tier-tag {
  font-size: .76rem;
  letter-spacing: .18em;
  color: #9fb0c8;
  margin-bottom: 10px;
}
.tier-card-hot .tier-tag { color: #f0c37a; }
.tier-name {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 8px;
}
.tier-card p { font-size: .9rem; color: #9fb0c8; }

.fallback-chain {
  display: flex;
  align-items: stretch;
  gap: 8px;
  flex-wrap: wrap;
}
.fb-node {
  flex: 1;
  min-width: 150px;
  border: 1px solid rgba(255, 255, 255, .12);
  border-radius: 12px;
  padding: 18px 22px;
  background: rgba(255, 255, 255, .03);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.fb-label { font-size: .76rem; letter-spacing: .1em; color: #9fb0c8; }
.fb-name { font-size: 1.15rem; font-weight: 800; color: #fff; }
.fb-node-final { border-color: rgba(240, 195, 122, .5); }
.fb-node-final .fb-name { color: #f0c37a; }

.fb-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  color: #6c7d99;
  padding: 0 4px;
}
.fb-arrow svg { width: 44px; height: 22px; }
.fb-hint { font-size: .72rem; white-space: nowrap; color: #8395b3; }

/* ============ 为什么选择我们 ============ */

.why-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
.why-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  padding: 28px 26px;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.why-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: var(--amber-line);
}
.why-card svg { width: 30px; height: 30px; color: var(--amber-deep); margin-bottom: 16px; }
.why-card h3 { font-size: 1.02rem; margin-bottom: 8px; }
.why-card p { font-size: .9rem; color: var(--ink-soft); }

/* ============ 应用场景 ============ */

.scenario-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}
.scenario-card {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  padding: 30px 28px 26px;
  overflow: hidden;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.scenario-card:hover { border-color: var(--amber-line); box-shadow: var(--shadow); }
.sc-num {
  font-family: ui-monospace, Consolas, monospace;
  font-size: 2rem;
  font-weight: 800;
  color: var(--amber);
  opacity: .35;
  display: block;
  margin-bottom: 10px;
}
.scenario-card p { font-size: 1.02rem; font-weight: 600; }

/* ============ 合作与联系 ============ */

.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 48px;
  align-items: start;
}

.coop-list { margin-top: 8px; display: grid; gap: 14px; }
.coop-list li {
  display: flex;
  align-items: baseline;
  gap: 20px;
  padding: 18px 22px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--paper);
}
.coop-list b { font-size: .96rem; white-space: nowrap; }
.coop-list span { font-size: .9rem; color: var(--ink-soft); }

.contact-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  box-shadow: var(--shadow);
  padding: 32px 30px;
}
.contact-card h3 {
  font-size: 1.15rem;
  margin-bottom: 20px;
}
.cta-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 28px;
}

.contact-info {
  display: grid;
  gap: 12px;
  border-top: 1px solid var(--line);
  padding-top: 22px;
}
.contact-info > div {
  display: grid;
  grid-template-columns: 130px 1fr;
  align-items: baseline;
}
.contact-info dt { font-size: .86rem; color: var(--ink-faint); }
.contact-info dd { font-size: .95rem; }
.contact-info a { color: var(--amber-deep); font-weight: 600; }
.contact-info a:hover { text-decoration: underline; }

em.todo {
  font-style: normal;
  color: var(--ink-faint);
  border-bottom: 1px dashed #b9c2d0;
  padding-bottom: 1px;
}

/* ============ 页脚 ============ */

.site-footer {
  background: #070d17;
  color: #8ea0bb;
  padding: 44px 0;
}
.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 18px;
}
.footer-brand { display: inline-block; }
.footer-brand img { width: 176px; height: auto; }
.footer-brand-story {
  max-width: 38em;
  font-size: .98rem;
  line-height: 1.8;
  color: #c2cddd;
}
.footer-line { font-size: .92rem; max-width: 44em; }
.footer-meta { font-size: .82rem; }

/* ============ 动效 ============ */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity .65s ease, transform .65s ease;
}
.reveal.in { opacity: 1; transform: none;}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .art-chip { animation: none; }
  .board-main circle { animation: none !important; }
}

/* ============ 响应式 ============ */

@media (max-width: 1020px) {
  .hero-grid { grid-template-columns: 1fr; gap: 48px; }
  .hero-art { max-width: 520px; margin-inline: auto; }
  .detail-grid, .detail-grid-reverse { grid-template-columns: 1fr; }
  .detail-grid-reverse .detail-copy { order: 1; }
  .detail-grid-reverse .detail-side { order: 2; }
  .detail-side { position: static; }
  .runtime-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; gap: 36px; }
}

@media (max-width: 760px) {
  .section { padding: 72px 0; }
  .hero { padding-top: 128px; }
  .container { width: min(1120px, 100% - 40px); }

  .nav-toggle { display: flex; }
  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(10, 18, 32, .97);
    border-bottom: 1px solid rgba(255, 255, 255, .1);
    padding: 10px 24px 20px;
    display: none;
  }
  .site-header.nav-open .site-nav { display: flex; }
  .site-nav > a { padding: 14px 0; border-bottom: 1px solid rgba(255, 255, 255, .06); }
  .site-nav > a.active::after { display: none; }
  .nav-cta { margin: 16px 0 2px; }

  .why-grid, .tier-grid, .scenario-grid, .runtime-grid, .decision-demos { grid-template-columns: 1fr; }
  .cta-grid { grid-template-columns: 1fr; }
  .hero-actions .btn { flex: 1; }

  .fallback-chain { flex-direction: column; }
  .fb-arrow { transform: rotate(90deg); padding: 8px 0; }
  .fb-arrow .fb-hint { display: none; }

  .feature-list li { grid-template-columns: 1fr; gap: 2px; }
  .footer-inner { flex-direction: column; align-items: flex-start; }

  .table-wrap { overflow-x: auto; }
  .overview-table { min-width: 560px; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.85rem; }
  .hero-art { max-width: 100%; }
  .vision-card { padding: 26px 22px; }
  .demo-card { padding: 24px 22px; }
  .demo-metric { flex-basis: 100%; }
  .contact-info > div { grid-template-columns: 110px 1fr; }
}