/* ============================================================
   壹玖科技 · AI 产品页 — 复古未来 / 深空蓝黑 + 电光青 + 琥珀
   ============================================================ */
:root {
  --bg: #060b16; --bg-deep: #04070f; --surface: #0b1322; --surface-2: #111b2e;
  --line: rgba(148, 168, 199, .14); --line-strong: rgba(148, 168, 199, .3);
  --text: #eaf1fb; --muted: #93a3bc; --on-accent: #06202b;
  --accent: #2fd8ff; --accent-dim: rgba(47, 216, 255, .14);
  --amber: #ffb454; --amber-dim: rgba(255, 180, 84, .12); --on-amber: #2b1804;
  --ok: #34d399;
  --font-display: "Chakra Petch", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "PingFang SC", monospace;
  --r-sm: 8px; --r-md: 14px; --r-lg: 22px;
  --sh-1: 0 2px 10px rgba(0, 0, 0, .3); --sh-3: 0 24px 60px rgba(0, 0, 0, .45);
  --ease: cubic-bezier(.22, 1, .36, 1); --fast: .18s; --base: .35s;
  --space-3: 20px; --space-4: 28px; --space-5: 40px; --space-6: 64px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body); color: var(--text); background: var(--bg);
  line-height: 1.7; font-size: 16px; -webkit-font-smoothing: antialiased; overflow-x: hidden;
}
img { max-width: 100%; }
.container { width: min(1160px, 92%); margin: 0 auto; }
a { color: var(--accent); text-decoration: none; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.br-desktop { display: none; }

/* 氛围 */
.grain { position: fixed; inset: 0; z-index: 90; pointer-events: none; opacity: .05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence baseFrequency='0.85'/%3E%3C/filter%3E%3Crect width='120' height='120' filter='url(%23n)'/%3E%3C/svg%3E"); }

/* ===== 排印 ===== */
h1, h2, h3, .price dt, .nav-cta { font-family: var(--font-display); }
h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); line-height: 1.14; letter-spacing: .01em; }
h2 { font-size: clamp(1.7rem, 3.6vw, 2.5rem); line-height: 1.25; }
h1 em, .accent-word { font-style: normal; color: var(--accent); }
.eyebrow { font-family: var(--font-mono); font-size: .72rem; letter-spacing: .22em; text-transform: uppercase; color: var(--accent); }
.lead { color: var(--muted); font-size: clamp(1rem, 1.6vw, 1.15rem); max-width: 38em; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px; min-height: 48px; padding: 0 26px;
  border-radius: var(--r-sm); font-weight: 600; font-family: var(--font-display); font-size: 1rem;
  border: 1px solid transparent; cursor: pointer;
  transition: transform var(--fast) var(--ease), box-shadow var(--base), background var(--fast), border-color var(--fast);
}
.btn-primary { background: var(--accent); color: var(--on-accent); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 0 0 1px rgba(47,216,255,.6), 0 12px 32px rgba(47,216,255,.32); }
.btn-ghost { background: rgba(234,241,251,.06); color: var(--text); border-color: var(--line-strong); }
.btn-ghost:hover { border-color: var(--accent); transform: translateY(-2px); }
.btn-amber { background: var(--amber); color: var(--on-amber); }
.btn-amber:hover { transform: translateY(-2px); box-shadow: 0 0 0 1px rgba(255,180,84,.6), 0 12px 32px rgba(255,180,84,.3); }
.btn .arrow { transition: transform var(--fast); }
.btn:hover .arrow { transform: translateX(4px); }

/* ===== 导航 ===== */
.header { position: fixed; inset: 0 0 auto; z-index: 100; border-bottom: 1px solid transparent; transition: background var(--base), border-color var(--base); }
.header.scrolled { background: rgba(6,11,22,.85); backdrop-filter: blur(12px); border-color: var(--line); }
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; gap: 20px; }
.brand-logo { height: 32px; width: auto; object-fit: contain; }
.nav-links { display: flex; align-items: center; gap: 22px; }
.nav-links > a { color: rgba(234,241,251,.86); font-weight: 500; min-height: 44px; display: inline-flex; align-items: center; transition: color var(--fast); }
.nav-links > a:hover { color: var(--accent); }
.nav-ghost { font-family: var(--font-mono); font-size: .86rem; }
.nav-cta { min-height: 40px; padding: 0 18px; color: var(--on-accent); background: var(--accent); }
.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 10px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 5px 0; transition: transform var(--base) var(--ease), opacity var(--fast); }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Hero ===== */
.hero { position: relative; padding: 170px 0 90px; overflow: hidden;
  background: radial-gradient(1000px 520px at 78% -12%, rgba(47,216,255,.16), transparent 60%),
              radial-gradient(760px 480px at 6% 6%, rgba(37,99,235,.28), transparent 58%), var(--bg); }
.hero-glow { position: absolute; inset: 0; pointer-events: none;
  background-image: radial-gradient(rgba(148,168,199,.13) 1px, transparent 1px); background-size: 26px 26px;
  mask-image: linear-gradient(#000 55%, transparent); }
.hero h1 { margin: 14px 0 18px; }
.hero-actions { display: flex; gap: 14px; margin-top: 30px; flex-wrap: wrap; }
.hero-stats { display: flex; gap: clamp(24px, 5vw, 56px); margin-top: 52px; padding-top: 26px; border-top: 1px solid var(--line); flex-wrap: wrap; }
.hero-stats dt { font-family: var(--font-mono); font-weight: 700; font-size: clamp(1.5rem, 3vw, 2.1rem); color: var(--accent); }
.hero-stats dd { color: var(--muted); font-size: .88rem; }

/* ===== 产品分区（编辑式非对称） ===== */
.section { padding: var(--space-6) 0; }
.section-alt { background: var(--bg-deep); border-block: 1px solid var(--line); }
.section-head { max-width: 40em; margin-bottom: var(--space-5); }
.section-head h2 { margin: 8px 0 10px; }
.section-head p { color: var(--muted); }

.product { padding: clamp(64px, 9vw, 110px) 0; }
.product-alt { background: var(--bg-deep); border-block: 1px solid var(--line); }
.product-split { display: grid; grid-template-columns: auto 1.15fr .85fr; gap: clamp(28px, 5vw, 64px); align-items: start; }
.split-rev { grid-template-columns: auto .85fr 1.15fr; }
.split-rev .product-body { order: 2; } .split-rev .product-visual { order: 1; }
.product-num {
  font-family: var(--font-mono); font-weight: 700; font-size: clamp(4rem, 9vw, 7.5rem); line-height: .9;
  color: transparent; -webkit-text-stroke: 1.5px var(--line-strong); user-select: none;
}
.product-head h2 { margin: 8px 0 12px; }
.product-head p { color: var(--muted); }
.feature-list { list-style: none; margin-top: var(--space-4); display: grid; gap: 16px; }
.feature-list li { display: flex; gap: 14px; align-items: flex-start; }
.fico { width: 22px; height: 22px; flex: 0 0 auto; margin-top: 5px; fill: none; stroke: var(--accent); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.feature-list strong { display: block; font-family: var(--font-display); font-size: 1.02rem; }
.feature-list span { color: var(--muted); font-size: .94rem; }
.product-cta { display: flex; align-items: center; gap: 16px; margin-top: var(--space-4); flex-wrap: wrap; }
.cta-note { font-family: var(--font-mono); font-size: .8rem; color: var(--muted); letter-spacing: .06em; }

/* 可视化占位卡 */
.product-visual { padding-top: 12px; }
.viz-card { background: var(--surface); border: 1px solid var(--line-strong); border-radius: var(--r-md); padding: 22px; display: grid; gap: 14px; box-shadow: var(--sh-3); }
.viz-line { display: flex; gap: 10px; align-items: baseline; font-size: .9rem; color: var(--text); }
.viz-key { font-family: var(--font-mono); font-size: .7rem; color: var(--accent); background: var(--accent-dim); border: 1px solid rgba(47,216,255,.3); border-radius: 4px; padding: 2px 8px; }
.viz-out { border-inline-start: 2px solid var(--accent); padding-left: 10px; color: var(--muted); }
.viz-flow .flow-node { background: var(--surface-2); border: 1px solid var(--line-strong); border-radius: var(--r-sm); padding: 10px 14px; font-size: .88rem; font-family: var(--font-mono); }
.viz-flow .flow-branch { border-color: var(--accent); color: var(--accent); }
.flow-arrow { text-align: center; color: var(--muted); line-height: 1; }
.meter-row { display: grid; grid-template-columns: 3.6em 1fr 2.4em; gap: 10px; align-items: center; font-family: var(--font-mono); font-size: .8rem; color: var(--muted); }
.meter { height: 8px; background: rgba(148,168,199,.14); border-radius: 99px; overflow: hidden; }
.meter i { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, var(--accent), #6ce4ff); }
.meter-row b { color: var(--text); text-align: right; }
.meter-foot { border-top: 1px dashed var(--line); padding-top: 12px; font-size: .76rem; color: var(--muted); font-family: var(--font-mono); }

/* 四角括号装饰 */
.corners { position: relative; }
.corners::before, .corners::after { content: ""; position: absolute; width: 18px; height: 18px; border: 1.5px solid var(--line-strong); transition: border-color var(--base), width var(--base) var(--ease), height var(--base) var(--ease); pointer-events: none; }
.corners::before { top: -1px; left: -1px; border-right: 0; border-bottom: 0; }
.corners::after { bottom: -1px; right: -1px; border-left: 0; border-top: 0; }
.corners:hover::before, .corners:hover::after { border-color: var(--accent); width: 30px; height: 30px; }

/* ===== 套餐对比表 ===== */
.plan-wrap { overflow-x: auto; }
.plan-table { width: 100%; border-collapse: collapse; background: var(--surface); border: 1px solid var(--line-strong); border-radius: var(--r-md); overflow: hidden; min-width: 640px; }
.plan-table th, .plan-table td { padding: 16px 22px; text-align: left; border-bottom: 1px solid var(--line); font-size: .95rem; }
.plan-table thead th { font-family: var(--font-display); font-size: 1.05rem; background: var(--surface-2); }
.plan-table thead th:first-child { font-family: var(--font-mono); font-size: .78rem; letter-spacing: .18em; color: var(--muted); }
.plan-table tbody th { font-weight: 500; color: var(--muted); font-size: .9rem; white-space: nowrap; }
.plan-table td b { color: var(--text); }
.price { font-family: var(--font-mono); font-weight: 700; font-size: 1.7rem; color: var(--text); }
.price i { font-style: normal; font-size: .8rem; color: var(--muted); font-weight: 400; }
.plan-hl { background: var(--amber-dim); }
thead .plan-hl { background: rgba(255,180,84,.16); border-bottom: 2px solid var(--amber); }
.hl-tag { display: inline-block; margin-left: 8px; font-family: var(--font-mono); font-size: .64rem; letter-spacing: .14em; color: var(--on-amber); background: var(--amber); border-radius: 4px; padding: 2px 8px; vertical-align: middle; }
tbody .plan-hl:not(thead .plan-hl) { color: var(--text); }
.ok { color: var(--ok); font-weight: 700; }
.plan-note { margin-top: 14px; font-size: .85rem; color: var(--muted); }
.plan-actions { display: flex; gap: 14px; margin-top: var(--space-4); flex-wrap: wrap; }

/* ===== 优势 ===== */
.why-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.why-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-md); padding: 26px 22px; transition: transform var(--fast) var(--ease), border-color var(--fast); }
.why-card:hover { transform: translateY(-4px); border-color: var(--line-strong); }
.why-num { font-family: var(--font-mono); font-size: .78rem; color: var(--accent); letter-spacing: .16em; }
.why-card h3 { font-size: 1.08rem; margin: 10px 0 8px; }
.why-card p { color: var(--muted); font-size: .92rem; }

/* ===== 视频首屏（产品详情页） ===== */
.hero-video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; z-index: 0; }
.hero-overlay { position: absolute; inset: 0; z-index: 1;
  background: linear-gradient(180deg, rgba(4,7,15,.62) 0%, rgba(4,7,15,.45) 45%, var(--bg) 96%); }
.hero.has-video { min-height: 78vh; display: flex; align-items: center; }
.hero.has-video .container { position: relative; z-index: 2; }

/* ===== CTA 横幅 ===== */
.cta-band { background: linear-gradient(120deg, rgba(47,216,255,.12), rgba(37,99,235,.18)), var(--bg-deep); border-top: 1px solid var(--line); padding: var(--space-6) 0; }
.cta-inner { display: flex; align-items: center; justify-content: space-between; gap: 32px; flex-wrap: wrap; }
.cta-inner h2 { margin: 6px 0 8px; }
.cta-inner p { color: var(--muted); }
.cta-actions { display: flex; gap: 14px; flex-wrap: wrap; }

/* ===== 页脚 ===== */
.footer { background: var(--bg-deep); border-top: 1px solid var(--line); color: var(--muted); padding-top: var(--space-5); }
.footer-inner { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: var(--space-5); padding-bottom: var(--space-5); }
.footer-logo { height: 30px; width: auto; object-fit: contain; margin-bottom: 12px; }
.footer-brand p { font-size: .9rem; max-width: 26em; }
.footer h4 { font-family: var(--font-display); color: var(--text); font-size: .95rem; margin-bottom: 12px; }
.footer-nav { display: grid; gap: 8px; }
.footer-nav a { color: var(--muted); font-size: .9rem; transition: color var(--fast); }
.footer-nav a:hover { color: var(--accent); }
.footer-bottom { border-top: 1px solid var(--line); padding: 18px 0; font-size: .82rem; text-align: center; }
.icp { color: var(--muted); margin-left: 10px; }
.icp:hover { color: var(--accent); }

.back-top { position: fixed; right: 22px; bottom: 22px; z-index: 110; width: 46px; height: 46px; border-radius: 50%;
  background: var(--accent); color: var(--on-accent); border: 0; font-size: 18px; cursor: pointer; opacity: 0; pointer-events: none;
  transition: opacity var(--base), transform var(--fast); }
.back-top.show { opacity: 1; pointer-events: auto; }
.back-top:hover { transform: translateY(-3px); }

/* ===== 进场动画 ===== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.visible { opacity: 1; transform: none; }

/* ===== 响应式 ===== */
@media (max-width: 1020px) {
  .product-split, .split-rev { grid-template-columns: 1fr; }
  .split-rev .product-body { order: 1; } .split-rev .product-visual { order: 2; }
  .product-num { font-size: 3.4rem; }
  .why-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 860px) {
  .br-desktop { display: none; }
  .nav-toggle { display: block; }
  .nav-links { position: fixed; inset: 68px 0 auto; flex-direction: column; align-items: stretch; gap: 0;
    background: var(--bg-deep); border-bottom: 1px solid var(--line); padding: 10px 4%;
    transform: translateY(-8px); opacity: 0; pointer-events: none; transition: opacity var(--base) var(--ease), transform var(--base) var(--ease); }
  .nav-links.open { opacity: 1; transform: none; pointer-events: auto; }
  .nav-links > a { padding: 14px 4px; border-bottom: 1px solid var(--line); }
  .nav-cta { margin: 14px 0; justify-content: center; }
}
@media (max-width: 640px) {
  .hero { padding: 140px 0 70px; }
  .why-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 22px; }
  /* 对比表降级为堆叠卡 */
  .plan-table { min-width: 0; }
  .plan-table thead { display: none; }
  .plan-table tbody tr { display: grid; grid-template-columns: 1fr 1fr; border-bottom: 1px solid var(--line-strong); }
  .plan-table tbody th { grid-column: 1 / -1; background: var(--surface-2); padding: 10px 16px; }
  .plan-table td { padding: 12px 16px; border: 0; }
  .plan-table td::before { content: attr(data-label); display: block; font-family: var(--font-mono); font-size: .68rem; letter-spacing: .14em; color: var(--muted); margin-bottom: 4px; }
  .plan-table td[ colspan ] { grid-column: 1 / -1; }
  .footer-inner { grid-template-columns: 1fr; }
  .cta-inner { flex-direction: column; align-items: flex-start; }
}
@media (min-width: 900px) { .br-desktop { display: inline; } }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}