/* 溯源方舟 TechLab 官网 · 浅色高级编辑感 */

:root {
  --bg: #ffffff;
  --paper: #f6f4ee;
  --paper-2: #efece3;
  --ink: #1b1a16;
  --ink-soft: #3c3a33;
  --muted: #79766c;
  --line: rgba(27, 26, 22, 0.12);
  --line-soft: rgba(27, 26, 22, 0.07);
  --accent: #9a5b34;
  --maxw: 1160px;
  --gut: 28px;
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Plus Jakarta Sans", "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.serif {
  font-family: "Noto Serif SC", Georgia, "Songti SC", "SimSun", serif;
  font-weight: 600;
  letter-spacing: -0.01em;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gut); }

.eyebrow {
  font-size: 12.5px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 500;
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 14.5px; font-weight: 500; line-height: 1;
  padding: 14px 26px; border-radius: 2px;
  border: 1px solid var(--ink); transition: all .2s ease;
  cursor: pointer; white-space: nowrap;
}
.btn-solid { background: var(--ink); color: #fff; }
.btn-solid:hover { background: #000; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--ink); }
.btn .arr { transition: transform .2s ease; }
.btn:hover .arr { transform: translateX(3px); }

/* ---------- nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.85);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent; transition: border-color .25s ease;
}
.nav.scrolled { border-bottom-color: var(--line); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 11px; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 7px; background: var(--ink);
  color: #fff; display: grid; place-items: center; font-size: 15px;
}
.brand-name { font-size: 16px; font-weight: 600; letter-spacing: .01em; }
.nav-links { display: flex; align-items: center; gap: 30px; }
.nav-links a { font-size: 14.5px; color: var(--ink-soft); transition: color .2s; }
.nav-links a:hover { color: var(--ink); }
.nav-cta { display: flex; align-items: center; gap: 14px; }
.nav-toggle { display: none; background: none; border: 0; font-size: 24px; color: var(--ink); cursor: pointer; }

/* ---------- hero ---------- */
.hero { padding: 86px 0 60px; }
.hero-grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 56px; align-items: center; }
.hero h1 {
  font-size: clamp(40px, 5.4vw, 66px); line-height: 1.08; margin: 20px 0 24px;
  color: var(--ink);
}
.hero p.lead { font-size: 17.5px; color: var(--ink-soft); max-width: 30em; margin-bottom: 34px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-meta { margin-top: 40px; display: flex; gap: 40px; }
.hero-meta .num { font-size: 30px; font-weight: 600; }
.hero-meta .lbl { font-size: 13px; color: var(--muted); margin-top: 2px; }

.hero-visual {
  position: relative; aspect-ratio: 4 / 5; border-radius: 4px; overflow: hidden;
  background: linear-gradient(150deg, var(--paper) 0%, var(--paper-2) 100%);
  border: 1px solid var(--line); display: grid; place-items: center;
}
.hero-visual .ph { text-align: center; color: var(--muted); }
.hero-visual .ph i { font-size: 34px; display: block; margin-bottom: 10px; opacity: .7; }
.hero-visual .ph span { font-size: 13px; letter-spacing: .04em; }
.hero-visual img { width: 100%; height: 100%; object-fit: cover; display: block; }
.hero-visual::after {
  content: ""; position: absolute; inset: 14px; border: 1px solid rgba(27,26,22,.10);
  border-radius: 2px; pointer-events: none;
}

/* ---------- section frame ---------- */
section.block { padding: 84px 0; border-top: 1px solid var(--line-soft); }
.sec-head { max-width: 720px; margin-bottom: 46px; }
.sec-head h2 { font-size: clamp(27px, 3.4vw, 40px); line-height: 1.18; margin: 14px 0 0; }
.sec-head p { color: var(--muted); margin-top: 14px; font-size: 16.5px; }

/* ---------- capability cards ---------- */
.cap-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--line); border-radius: 4px; overflow: hidden; }
.cap {
  padding: 30px 26px 34px; border-right: 1px solid var(--line-soft);
  background: var(--bg); transition: background .25s ease;
}
.cap:last-child { border-right: 0; }
.cap:hover { background: var(--paper); }
.cap i { font-size: 24px; color: var(--ink); }
.cap h3 { font-size: 16.5px; font-weight: 600; margin: 18px 0 8px; }
.cap p { font-size: 14px; color: var(--muted); line-height: 1.65; }

/* ---------- scenes ---------- */
.scene-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.scene {
  aspect-ratio: 3 / 4; border-radius: 4px; border: 1px solid var(--line);
  background: var(--paper); position: relative; overflow: hidden; display: flex;
  align-items: flex-end; padding: 18px; transition: transform .3s ease;
}
.scene:hover { transform: translateY(-4px); }
.scene img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; z-index: 0; transition: transform .5s ease; }
.scene:hover img { transform: scale(1.04); }
.scene::after { content: ""; position: absolute; inset: 0; background: linear-gradient(to top, rgba(20,19,16,.62), rgba(20,19,16,.1) 45%, rgba(20,19,16,0) 70%); z-index: 1; pointer-events: none; }
.scene span { font-size: 15px; font-weight: 600; position: relative; z-index: 2; color: #fff; text-shadow: 0 1px 8px rgba(0,0,0,.4); }
.scene .tag { position: absolute; top: 16px; left: 18px; font-size: 11.5px; letter-spacing: .14em; text-transform: uppercase; color: rgba(255,255,255,.92); z-index: 2; text-shadow: 0 1px 8px rgba(0,0,0,.4); }

/* ---------- works gallery ---------- */
.works-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.work { aspect-ratio: 3 / 4; border-radius: 4px; border: 1px solid var(--line); background: var(--paper); overflow: hidden; display: block; }
.work img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform .5s ease; }
.work:hover img { transform: scale(1.04); }

/* ---------- about strip ---------- */
.about { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 56px; align-items: start; }
.about .lead-q { font-size: clamp(22px, 2.6vw, 30px); line-height: 1.5; color: var(--ink); }
.about p { color: var(--ink-soft); margin-top: 18px; }
.about .facts { margin-top: 26px; display: grid; gap: 14px; }
.about .facts div { display: flex; gap: 14px; font-size: 15px; align-items: baseline; }
.about .facts b { font-weight: 600; min-width: 76px; color: var(--muted); font-size: 13px; letter-spacing: .04em; }

/* ---------- CTA band ---------- */
.cta-band { background: var(--ink); color: #fff; border-radius: 6px; padding: 64px 56px; text-align: center; }
.cta-band h2 { font-size: clamp(28px, 3.6vw, 44px); line-height: 1.15; }
.cta-band p { color: rgba(255,255,255,.7); margin: 16px auto 32px; max-width: 34em; }
.cta-band .btn-solid { background: #fff; color: var(--ink); border-color: #fff; }
.cta-band .btn-solid:hover { background: var(--paper); }

/* ---------- footer ---------- */
.foot { background: var(--paper); border-top: 1px solid var(--line); padding: 64px 0 30px; margin-top: 8px; }
.foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; }
.foot h4 { font-size: 13px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); margin-bottom: 16px; font-weight: 600; }
.foot ul { list-style: none; display: grid; gap: 10px; }
.foot ul a { font-size: 14.5px; color: var(--ink-soft); }
.foot ul a:hover { color: var(--ink); }
.foot .f-brand .brand { margin-bottom: 14px; }
.foot .f-desc { font-size: 14px; color: var(--muted); max-width: 26em; line-height: 1.7; }
.foot-bottom { margin-top: 48px; padding-top: 22px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; }
.foot-bottom, .foot-bottom a { font-size: 13px; color: var(--muted); }
.foot-bottom a:hover { color: var(--ink); text-decoration: underline; }

/* ---------- legal pages ---------- */
.legal { padding: 70px 0 40px; }
.legal .doc { max-width: 760px; }
.legal h1 { font-size: clamp(30px, 4vw, 44px); margin-bottom: 8px; }
.legal .updated { color: var(--muted); font-size: 14px; margin-bottom: 40px; }
.legal h2 { font-size: 20px; margin: 34px 0 12px; }
.legal p, .legal li { color: var(--ink-soft); font-size: 15.5px; }
.legal ul { margin: 10px 0 10px 22px; display: grid; gap: 8px; }

/* ---------- responsive ---------- */
@media (max-width: 880px) {
  .hero-grid, .about { grid-template-columns: 1fr; gap: 36px; }
  .hero-visual { aspect-ratio: 16 / 11; max-height: 360px; }
  .cap-grid { grid-template-columns: 1fr 1fr; }
  .cap:nth-child(2) { border-right: 0; }
  .cap:nth-child(1), .cap:nth-child(2) { border-bottom: 1px solid var(--line-soft); }
  .scene-grid { grid-template-columns: 1fr 1fr; }
  .works-grid { grid-template-columns: 1fr 1fr; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .nav-links { display: none; }
  .nav-toggle { display: block; }
  .nav.open .nav-links {
    display: flex; position: absolute; top: 68px; left: 0; right: 0;
    flex-direction: column; gap: 0; background: var(--bg);
    border-bottom: 1px solid var(--line); padding: 6px 0;
    box-shadow: 0 12px 24px rgba(27,26,22,.06);
  }
  .nav.open .nav-links a { padding: 13px var(--gut); }
  .cta-band { padding: 48px 26px; }
}
@media (max-width: 520px) {
  :root { --gut: 18px; }
  .hero { padding: 54px 0 40px; }
  .hero-meta { gap: 26px; }
  .cap-grid, .scene-grid, .works-grid, .foot-grid { grid-template-columns: 1fr; }
  .cap { border-right: 0; border-bottom: 1px solid var(--line-soft); }
  .nav-cta .btn-ghost { display: none; }
}