/* ===================================================================
   古四信息咨询 — v2 大厂化改版
   设计语言：深海军蓝 + 金铜色（OKLCH），玻璃拟态，大留白，编号系统
   参考基调：Vercel / Linear / Stripe 级排版节奏
   =================================================================== */

:root {
  /* OKLCH 色板 */
  --bg: oklch(0.99 0.004 96);
  --bg-alt: oklch(0.965 0.005 96);
  --navy-950: oklch(0.17 0.04 247);
  --navy-900: oklch(0.22 0.05 248);
  --navy-800: oklch(0.30 0.06 250);
  --navy-700: oklch(0.38 0.065 252);
  --gold-300: oklch(0.86 0.10 85);
  --gold-500: oklch(0.77 0.12 80);
  --ink: oklch(0.21 0.02 250);
  --ink-soft: oklch(0.35 0.02 250);
  --muted: oklch(0.55 0.02 250);
  --line: oklch(0.90 0.008 96);
  --line-strong: oklch(0.84 0.012 96);

  --radius-lg: 24px;
  --radius-md: 16px;
  --shadow-sm: 0 1px 2px oklch(0.20 0.04 250 / 0.05), 0 4px 16px oklch(0.20 0.04 250 / 0.06);
  --shadow-md: 0 2px 4px oklch(0.20 0.04 250 / 0.06), 0 16px 48px oklch(0.20 0.04 250 / 0.10);
  --shadow-gold: 0 0 0 1px oklch(0.77 0.12 80 / 0.35), 0 8px 32px oklch(0.77 0.12 80 / 0.18);

  --container: 1120px;
  --font-serif: "Noto Serif SC", "Songti SC", serif;
  --font-sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

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

.ph {
  font-style: normal;
  color: var(--muted);
  background: oklch(0.91 0.006 96);
  border-bottom: 1px dashed var(--line-strong);
  border-radius: 4px;
  padding: 0 6px;
  white-space: nowrap;
}

/* ===================== 导航 ===================== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: oklch(0.99 0.004 96 / 0.72);
  backdrop-filter: blur(18px) saturate(1.4);
  -webkit-backdrop-filter: blur(18px) saturate(1.4);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  display: grid; place-items: center;
  width: 36px; height: 36px;
  border-radius: 10px;
  background: linear-gradient(145deg, var(--navy-800), var(--navy-950));
  color: var(--gold-300);
  font-family: var(--font-serif); font-weight: 700; font-size: 13px;
  letter-spacing: 1px;
  box-shadow: inset 0 0 0 1px oklch(0.86 0.10 85 / 0.35);
}
.brand-name { font-size: 15px; font-weight: 600; letter-spacing: 3px; color: var(--ink); }
.nav { display: flex; gap: 4px; }
.nav a {
  font-size: 14px; color: var(--ink-soft);
  padding: 8px 14px; border-radius: 999px;
  transition: color .2s, background .2s;
}
.nav a:hover { color: var(--ink); background: oklch(0.93 0.01 96); }

.nav-toggle {
  display: none; flex-direction: column; justify-content: center; gap: 5px;
  width: 40px; height: 40px;
  border: 1px solid var(--line-strong); border-radius: 12px;
  background: transparent; cursor: pointer;
}
.nav-toggle span { width: 18px; height: 2px; background: var(--ink); margin-inline: auto; border-radius: 2px; transition: transform .25s, opacity .25s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===================== 首屏 ===================== */
.hero {
  position: relative;
  color: #fff;
  text-align: center;
  padding: clamp(96px, 13vw, 160px) 0 clamp(80px, 11vw, 130px);
  overflow: hidden;
  background:
    radial-gradient(1100px 560px at 12% -8%, oklch(0.38 0.065 252 / 0.55), transparent 62%),
    radial-gradient(900px 520px at 92% 108%, oklch(0.77 0.12 80 / 0.16), transparent 58%),
    linear-gradient(165deg, var(--navy-950) 0%, var(--navy-900) 58%, var(--navy-800) 100%);
}
.hero-grid {
  position: absolute; inset: 0;
  opacity: .4;
  background-image:
    linear-gradient(oklch(1 0 0 / 0.035) 1px, transparent 1px),
    linear-gradient(90deg, oklch(1 0 0 / 0.035) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse at center, #000 25%, transparent 72%);
  -webkit-mask-image: radial-gradient(ellipse at center, #000 25%, transparent 72%);
}
.hero-glow {
  position: absolute; left: 50%; top: 42%;
  width: 560px; height: 560px;
  transform: translate(-50%, -50%);
  background: radial-gradient(circle, oklch(0.77 0.12 80 / 0.20), transparent 65%);
  filter: blur(30px);
  pointer-events: none;
}
.hero-inner { position: relative; }

.hero-tag {
  display: inline-flex;
  border: 1px solid oklch(0.86 0.10 85 / 0.35);
  border-radius: 999px;
  padding: 7px 20px;
  font-size: 13px; letter-spacing: 2px;
  color: var(--gold-300);
  background: oklch(0.86 0.10 85 / 0.08);
  margin-bottom: clamp(28px, 4vw, 44px);
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(52px, 9.5vw, 104px);
  font-weight: 900;
  letter-spacing: 0.06em;
  color: #fff;
  line-height: 1.12;
  text-shadow: 0 2px 40px oklch(0.10 0.03 250 / 0.5);
}
.hero-title span { color: var(--gold-300); }

.hero-en {
  margin-top: 14px;
  font-size: clamp(11px, 1.4vw, 14px);
  letter-spacing: 0.42em;
  color: oklch(1 0 0 / 0.45);
  font-weight: 300;
}
.hero-sub {
  margin-top: 16px;
  font-size: 16px;
  letter-spacing: 5px;
  color: oklch(1 0 0 / 0.78);
}

.hero-actions {
  margin-top: clamp(30px, 4.5vw, 44px);
  display: flex; justify-content: center; gap: 14px; flex-wrap: wrap;
}
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 36px;
  border-radius: 999px;
  font-size: 15px; font-weight: 500; letter-spacing: 2px;
  transition: transform .2s, box-shadow .2s, background .2s;
}
.btn-primary {
  color: var(--navy-950);
  background: linear-gradient(135deg, oklch(0.86 0.10 85), oklch(0.70 0.11 78));
  box-shadow: 0 8px 32px oklch(0.77 0.12 80 / 0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 44px oklch(0.77 0.12 80 / 0.45); }
.btn-ghost {
  color: #fff;
  border: 1px solid oklch(1 0 0 / 0.28);
  background: oklch(1 0 0 / 0.04);
}
.btn-ghost:hover { background: oklch(1 0 0 / 0.10); }

/* 玻璃证照卡 */
.hero-card {
  margin: clamp(44px, 6vw, 64px) auto 0;
  max-width: 480px;
  display: flex; align-items: center; gap: 18px;
  padding: 20px 24px;
  border-radius: var(--radius-md);
  background: oklch(1 0 0 / 0.07);
  border: 1px solid oklch(1 0 0 / 0.14);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 24px 64px oklch(0.05 0.02 250 / 0.35);
  text-align: left;
}
.hero-card-mark {
  flex: 0 0 52px; height: 52px;
  display: grid; place-items: center;
  border-radius: 14px;
  background: linear-gradient(145deg, var(--navy-700), var(--navy-950));
  border: 1px solid oklch(0.86 0.10 85 / 0.4);
  color: var(--gold-300);
  font-family: var(--font-serif); font-weight: 700; font-size: 15px;
  letter-spacing: 1px;
}
.hero-card-body { flex: 1; line-height: 1.6; }
.hero-card-cn { font-size: 14px; color: #fff; letter-spacing: 2px; }
.hero-card-en { font-size: 10.5px; letter-spacing: 2.5px; color: oklch(1 0 0 / 0.45); margin-top: 2px; }
.hero-card-seal {
  flex: 0 0 auto;
  font-family: var(--font-serif);
  font-size: 12px; letter-spacing: 1px; line-height: 1.5;
  color: var(--gold-300);
  border: 1.5px solid oklch(0.86 0.10 85 / 0.45);
  border-radius: 8px;
  padding: 7px 8px;
  writing-mode: vertical-rl;
}

/* ===================== 数据条 ===================== */
.data-strip {
  margin-top: -46px;
  position: relative; z-index: 5;
}
.data-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  background: oklch(1 0 0 / 1);
}
.data-item {
  background: oklch(1 0 0 / 1);
  padding: 26px 20px;
  text-align: center;
  display: flex; flex-direction: column; gap: 2px;
}
.data-item strong {
  font-family: var(--font-serif);
  font-size: 30px; font-weight: 700;
  color: var(--navy-800);
  letter-spacing: 1px;
}
.data-item span { font-size: 13px; color: var(--ink); letter-spacing: 2px; }
.data-item em { font-size: 11px; color: var(--muted); font-style: normal; }

/* ===================== 通用区块 ===================== */
.section { padding: clamp(72px, 10vw, 120px) 0; }
.section-alt { background: var(--bg-alt); }
.section-alt .section-title { color: var(--ink); }
.section-alt .section-kicker { color: var(--gold-500); }

.section-kicker {
  font-size: 12px; font-weight: 500;
  letter-spacing: 5px;
  color: var(--gold-500);
  text-align: center;
  margin-bottom: 14px;
}
.section-title {
  font-family: var(--font-serif);
  font-size: clamp(30px, 4.6vw, 44px);
  font-weight: 700;
  color: var(--ink);
  text-align: center;
  letter-spacing: 2px;
  line-height: 1.3;
}
.section-lead {
  margin: 18px auto 0;
  max-width: 560px;
  text-align: center;
  font-size: 14.5px;
  color: var(--muted);
  line-height: 2;
  letter-spacing: 1px;
}

/* ===================== 简介 ===================== */
.about-grid {
  margin-top: clamp(40px, 5vw, 56px);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.about-card {
  position: relative;
  padding: 36px 28px 32px;
  border-radius: var(--radius-lg);
  background: oklch(1 0 0 / 1);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
  transition: transform .3s cubic-bezier(.2,.8,.2,1), box-shadow .3s, border-color .3s;
}
.about-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: oklch(0.77 0.12 80 / 0.5); }
.about-num {
  position: absolute; top: 22px; right: 24px;
  font-family: var(--font-serif);
  font-size: 42px; font-weight: 900;
  color: oklch(0.30 0.06 250 / 0.10);
  line-height: 1;
}
.about-card h3 {
  font-family: var(--font-serif);
  font-size: 24px; font-weight: 700;
  color: var(--ink);
  letter-spacing: 4px;
  margin-bottom: 10px;
}
.about-card h3::before {
  content: ""; display: block;
  width: 28px; height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--gold-500), transparent);
  margin-bottom: 14px;
}
.about-card p { font-size: 13.5px; color: var(--ink-soft); line-height: 1.9; }

/* ===================== 业务范围 ===================== */
.scope-grid {
  margin-top: clamp(40px, 5vw, 56px);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.scope-card {
  padding: 40px 30px 34px;
  border-radius: var(--radius-lg);
  background: oklch(1 0 0 / 1);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
  transition: transform .3s cubic-bezier(.2,.8,.2,1), box-shadow .3s, border-color .3s;
}
.scope-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: oklch(0.77 0.12 80 / 0.5); }
.scope-symbol {
  width: 60px; height: 60px;
  display: grid; place-items: center;
  border-radius: 18px;
  color: var(--gold-500);
  background: linear-gradient(145deg, oklch(0.94 0.05 88 / 0.7), oklch(0.97 0.02 90 / 0.4));
  border: 1px solid oklch(0.77 0.12 80 / 0.25);
  margin-bottom: 22px;
}
.scope-symbol svg { width: 32px; height: 32px; }
.scope-card h3 {
  font-family: var(--font-serif);
  font-size: 20px; font-weight: 700;
  letter-spacing: 3px;
  color: var(--ink);
  margin-bottom: 8px;
}
.scope-card p { font-size: 13.5px; color: var(--ink-soft); }
.scope-footnote {
  margin-top: 28px;
  text-align: center;
  font-size: 12.5px;
  line-height: 1.8;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
  color: var(--muted);
  letter-spacing: 0.5px;
}

/* ===================== 流程 ===================== */
.process {
  margin: clamp(40px, 5vw, 56px) auto 0;
  max-width: 900px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px;
  counter-reset: step;
}
.process li {
  position: relative;
  padding: 32px 20px;
  text-align: center;
  border-radius: var(--radius-lg);
  background: oklch(0.99 0.004 96);
  border: 1px dashed var(--line-strong);
  transition: transform .3s, border-color .3s, background .3s;
}
.process li:hover { transform: translateY(-4px); border-color: oklch(0.77 0.12 80 / 0.55); background: oklch(1 0 0 / 1); }
.process li::after {
  content: "→";
  position: absolute; top: 50%; right: -18px;
  transform: translateY(-50%);
  color: var(--gold-500);
  font-size: 18px;
  z-index: 2;
}
.process li:last-child::after { display: none; }
.process-num {
  display: inline-grid; place-items: center;
  width: 44px; height: 44px;
  border-radius: 50%;
  font-family: var(--font-serif);
  font-size: 15px; font-weight: 700;
  color: var(--gold-300);
  background: linear-gradient(145deg, var(--navy-700), var(--navy-950));
  box-shadow: 0 8px 24px oklch(0.22 0.05 248 / 0.35);
  margin-bottom: 16px;
}
.process h3 { font-size: 17px; font-weight: 600; letter-spacing: 4px; color: var(--ink); margin-bottom: 4px; }
.process p { font-size: 12.5px; color: var(--muted); }

/* ===================== 合规 ===================== */
.compliance-grid {
  margin-top: clamp(40px, 5vw, 56px);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.compliance-card {
  position: relative;
  padding: 32px 26px;
  border-radius: var(--radius-lg);
  background: oklch(1 0 0 / 1);
  border: 1px solid var(--line);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: transform .3s, box-shadow .3s, border-color .3s;
}
.compliance-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: oklch(0.30 0.06 250 / 0.35); }
.compliance-card::before {
  content: "";
  position: absolute; inset: 0 0 auto 0; height: 3px;
  background: linear-gradient(90deg, var(--navy-700), var(--gold-500));
}
.compliance-mark {
  display: inline-block;
  font-size: 11px; font-weight: 600; letter-spacing: 2px;
  color: var(--gold-500);
  border: 1px solid oklch(0.77 0.12 80 / 0.4);
  border-radius: 999px;
  padding: 3px 12px;
  margin-bottom: 16px;
}
.compliance-card h3 { font-family: var(--font-serif); font-size: 19px; font-weight: 700; letter-spacing: 4px; color: var(--ink); margin-bottom: 8px; }
.compliance-card p { font-size: 13px; color: var(--ink-soft); line-height: 1.9; }
.compliance-note {
  margin-top: 28px;
  text-align: center;
  font-size: 12.5px;
  color: var(--muted);
  letter-spacing: 1px;
}

/* ===================== 联系我们（深色区） ===================== */
.contact {
  background:
    radial-gradient(800px 420px at 88% -10%, oklch(0.77 0.12 80 / 0.14), transparent 60%),
    linear-gradient(168deg, var(--navy-950), var(--navy-900) 55%, var(--navy-800));
  color: #fff;
}
.contact .section-title { color: #fff; }
.contact .section-kicker { color: var(--gold-300); }
.contact .section-lead { color: oklch(1 0 0 / 0.6); }

.contact-grid {
  margin-top: clamp(40px, 5vw, 56px);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px;
}
.contact-item {
  padding: 34px 26px;
  text-align: center;
  border-radius: var(--radius-lg);
  background: oklch(1 0 0 / 0.055);
  border: 1px solid oklch(1 0 0 / 0.12);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: transform .3s, background .3s;
}
.contact-item:hover { transform: translateY(-4px); background: oklch(1 0 0 / 0.09); }
.contact-label {
  display: inline-block;
  font-size: 11px; letter-spacing: 4px;
  color: var(--gold-300);
  border: 1px solid oklch(0.86 0.10 85 / 0.3);
  border-radius: 999px;
  padding: 4px 16px;
  margin-bottom: 18px;
}
.contact-item p { font-size: 15.5px; color: #fff; letter-spacing: 1px; }
.contact-sub { margin-top: 8px; font-size: 12px !important; color: oklch(1 0 0 / 0.5) !important; }
.contact .ph { background: oklch(1 0 0 / 0.10); color: oklch(1 0 0 / 0.45); border-bottom-color: oklch(1 0 0 / 0.25); }

.contact-note2 {
  margin: 32px auto 0;
  max-width: 640px;
  text-align: center;
  font-size: 12.5px;
  color: oklch(1 0 0 / 0.5);
  border-top: 1px solid oklch(1 0 0 / 0.14);
  padding: 20px 16px 0;
  line-height: 1.9;
}

.contact-warn {
  margin: 32px auto 0;
  max-width: 720px;
  text-align: center;
  font-size: 12.5px;
  color: oklch(1 0 0 / 0.55);
  border: 1px solid oklch(0.86 0.10 85 / 0.3);
  border-radius: var(--radius-md);
  background: oklch(0.86 0.10 85 / 0.07);
  padding: 16px 22px;
  line-height: 1.9;
}

/* ===================== 页脚 ===================== */
.site-footer {
  background: oklch(0.13 0.03 248);
  color: oklch(1 0 0 / 0.5);
  font-size: 12.5px;
}
.footer-inner {
  padding: 44px 0 40px;
  text-align: center;
  line-height: 2;
}
.footer-brand { font-family: var(--font-serif); font-size: 17px; letter-spacing: 3px; color: #fff; margin-bottom: 10px; }
.footer-brand span { font-size: 10px; letter-spacing: 2px; color: oklch(1 0 0 / 0.35); font-family: var(--font-sans); }
.footer-line { color: oklch(1 0 0 / 0.42); letter-spacing: 1px; }
.footer-filing { margin-top: 6px; color: oklch(1 0 0 / 0.6); }
.footer-filing .ph { background: oklch(1 0 0 / 0.10); color: oklch(1 0 0 / 0.5); border-bottom-color: oklch(1 0 0 / 0.25); }
.footer-copy { margin-top: 16px; font-size: 11.5px; color: oklch(1 0 0 / 0.34); letter-spacing: 1px; }

/* ===================== 返回顶部 ===================== */
.back-top {
  position: fixed; right: 26px; bottom: 26px; z-index: 90;
  width: 44px; height: 44px;
  display: grid; place-items: center;
  border-radius: 50%;
  background: oklch(0.30 0.06 250 / 0.92);
  color: var(--gold-300);
  font-size: 17px;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  opacity: 0; transform: translateY(12px);
  transition: opacity .3s, transform .3s;
  pointer-events: none;
}
.back-top.show { opacity: 1; transform: none; pointer-events: auto; }
.back-top:hover { background: var(--navy-700); }

/* ===================== 入场动画 ===================== */
.about-card, .scope-card, .compliance-card, .process li, .contact-item {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .6s ease, transform .6s cubic-bezier(.2,.8,.2,1), box-shadow .3s, border-color .3s, background .3s;
}
.in { opacity: 1; transform: none; }

/* ===================== 响应式 ===================== */
@media (max-width: 960px) {
  .data-grid { grid-template-columns: repeat(2, 1fr); }
  .about-grid, .scope-grid, .compliance-grid, .contact-grid { grid-template-columns: 1fr; }
  .about-grid, .scope-grid, .compliance-grid, .contact-grid { max-width: 480px; margin-left: auto; margin-right: auto; }
  .process { grid-template-columns: repeat(2, 1fr); }
  .process li::after { display: none; }
}

@media (max-width: 700px) {
  .nav {
    position: fixed; inset: 64px 0 auto 0;
    flex-direction: column; align-items: stretch;
    background: oklch(0.99 0.004 96 / 0.97);
    border-bottom: 1px solid var(--line);
    padding: 10px 20px 18px;
    gap: 2px;
    display: none;
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
  }
  .nav.open { display: flex; }
  .nav a { padding: 12px 10px; font-size: 15px; border-radius: 10px; }
  .nav-toggle { display: flex; }
  .hero-title { font-size: clamp(44px, 14vw, 64px); }
  .hero-card { max-width: 100%; }
  .process { grid-template-columns: 1fr; }
  .data-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
  .about-card, .scope-card, .compliance-card, .process li, .contact-item { opacity: 1; transform: none; }
}