/* ============================================================
   BOTA TECH — corporate site
   Design tokens
   ============================================================ */
:root {
  --ink: #101418;            /* 近黑 */
  --ink-2: #3A414B;          /* 次级文字 */
  --ink-3: #6B7280;          /* 弱文字 */
  --paper: #FAFAF7;          /* 暖白底 */
  --paper-2: #F2F0EA;        /* 次级底 */
  --line: #E4E1D8;           /* 分隔线 */
  --navy: #0B1220;           /* 深夜蓝（深色区块） */
  --navy-2: #111B2E;
  --gold: #C8A96E;           /* 香槟金点缀 */
  --gold-strong: #B08F4F;
  --white: #FFFFFF;

  --serif: Georgia, "Times New Roman", "Songti SC", "STSong", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
          "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;

  --w: 1160px;
  --gutter: clamp(20px, 4vw, 48px);
  --sec-pad: clamp(88px, 11vw, 150px);
  --r: 4px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ============================================================
   Base
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
h1, h2, h3, h4, p, ul { margin: 0; }
ul { padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
img, svg { display: block; }
button { font: inherit; background: none; border: 0; cursor: pointer; color: inherit; }

.container { max-width: var(--w); margin-inline: auto; padding-inline: var(--gutter); }
.serif { font-family: var(--serif); font-style: italic; font-weight: 400; }

h2 {
  font-size: clamp(28px, 4vw, 44px);
  line-height: 1.22;
  font-weight: 600;
  letter-spacing: -0.01em;
}

/* 焦点可见性 */
:focus-visible { outline: 2px solid var(--gold-strong); outline-offset: 3px; }

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 200;
  background: var(--navy); color: #fff; padding: 10px 18px;
}
.skip-link:focus { left: 0; }

/* ============================================================
   眉标（编号小标签）
   ============================================================ */
.eyebrow {
  display: flex; align-items: center; gap: 14px;
  font-size: 12px; letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--ink-3); margin-bottom: 28px;
}
.eyebrow-num { color: var(--gold-strong); font-weight: 600; }
.eyebrow-line { width: 44px; height: 1px; background: currentColor; opacity: .4; }
.eyebrow.light { color: rgba(255,255,255,.55); }
.eyebrow.light .eyebrow-num { color: var(--gold); }

/* ============================================================
   Header / Nav
   ============================================================ */
.site-header {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  transition: background .35s var(--ease), box-shadow .35s var(--ease), backdrop-filter .35s var(--ease);
}
.site-header.scrolled {
  background: rgba(11, 18, 32, .82);
  -webkit-backdrop-filter: blur(14px); backdrop-filter: blur(14px);
  box-shadow: 0 1px 0 rgba(255,255,255,.08);
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 76px; }

.brand { display: flex; align-items: center; gap: 12px; color: #fff; }
.brand-mark { width: 32px; height: 32px; }
.brand-name { font-weight: 700; letter-spacing: .12em; font-size: 17px; }
.brand-name em { font-style: normal; color: var(--gold); font-weight: 400; margin-left: 2px; }

.site-nav { display: flex; align-items: center; gap: clamp(20px, 3vw, 38px); }
.site-nav > a {
  color: rgba(255,255,255,.78); font-size: 14.5px; letter-spacing: .04em;
  padding: 6px 0; position: relative; transition: color .25s;
}
.site-nav > a::after {
  content: ""; position: absolute; left: 0; bottom: 0; height: 1px; width: 0;
  background: var(--gold); transition: width .3s var(--ease);
}
.site-nav > a:hover { color: #fff; }
.site-nav > a:hover::after { width: 100%; }
.nav-cta {
  color: var(--navy) !important;
  background: var(--gold);
  padding: 9px 20px !important;
  border-radius: var(--r);
  font-weight: 600;
  transition: background .25s, transform .25s !important;
}
.nav-cta::after { display: none; }
.nav-cta:hover { background: #D6BA85; transform: translateY(-1px); }

.nav-tools { display: flex; align-items: center; gap: 10px; }
.lang-toggle {
  color: rgba(255,255,255,.85); font-size: 13px; letter-spacing: .08em;
  border: 1px solid rgba(255,255,255,.28); border-radius: 999px;
  padding: 6px 14px; transition: border-color .25s, color .25s;
}
.lang-toggle:hover { border-color: var(--gold); color: var(--gold); }

.menu-toggle { display: none; width: 40px; height: 40px; position: relative; }
.menu-toggle span {
  position: absolute; left: 10px; right: 10px; height: 1.5px;
  background: #fff; transition: transform .3s var(--ease), top .3s var(--ease);
}
.menu-toggle span:nth-child(1) { top: 15px; }
.menu-toggle span:nth-child(2) { top: 24px; }
.menu-toggle[aria-expanded="true"] span:nth-child(1) { top: 19px; transform: rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:nth-child(2) { top: 19px; transform: rotate(-45deg); }

/* ============================================================
   Hero
   ============================================================ */
.hero {
  position: relative; overflow: hidden;
  background: var(--navy); color: #fff;
  padding-top: clamp(150px, 20vh, 220px);
}
.hero-bg { position: absolute; inset: 0; pointer-events: none; }
.hero-grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.045) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: radial-gradient(ellipse 90% 75% at 50% 20%, #000 35%, transparent 78%);
  mask-image: radial-gradient(ellipse 90% 75% at 50% 20%, #000 35%, transparent 78%);
}
.hero-glow {
  position: absolute; inset: 0;
  background:
    radial-gradient(560px 420px at 82% 6%, rgba(200,169,110,.14), transparent 65%),
    radial-gradient(720px 540px at 8% 88%, rgba(58,90,148,.22), transparent 68%);
}
.hero-inner { position: relative; }
.hero-title {
  font-size: clamp(42px, 7.2vw, 84px);
  line-height: 1.12; font-weight: 600; letter-spacing: -0.015em;
  margin-bottom: clamp(24px, 3vw, 36px);
}
.hero-title .serif { color: var(--gold); font-weight: 400; padding-right: .06em; }
.hero-sub {
  max-width: 560px; font-size: clamp(16px, 1.6vw, 18px);
  color: rgba(255,255,255,.66); margin-bottom: clamp(32px, 4vw, 44px);
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 16px; margin-bottom: clamp(70px, 9vw, 120px); }

/* 按钮 */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 14px 30px; border-radius: var(--r);
  font-size: 15px; font-weight: 600; letter-spacing: .03em;
  transition: transform .25s var(--ease), background .25s, border-color .25s, color .25s;
}
.btn:active { transform: translateY(1px); }
.btn-gold { background: var(--gold); color: var(--navy); }
.btn-gold:hover { background: #D6BA85; transform: translateY(-2px); }
.btn-ghost { border: 1px solid rgba(255,255,255,.32); color: #fff; }
.btn-ghost:hover { border-color: var(--gold); color: var(--gold); transform: translateY(-2px); }
.btn-block { width: 100%; }

/* 数据条 */
.hero-stats {
  position: relative;
  display: grid; grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid rgba(255,255,255,.12);
  padding-bottom: clamp(40px, 6vw, 72px);
}
.stat { padding: 28px 20px 0 0; }
.stat + .stat { padding-left: 28px; border-left: 1px solid rgba(255,255,255,.12); }
.stat strong {
  display: block; font-size: clamp(26px, 3.4vw, 40px);
  font-weight: 600; letter-spacing: -0.02em; line-height: 1.1;
}
.stat strong span { color: var(--gold); font-weight: 400; }
.stat > span:last-child { font-size: 13px; color: rgba(255,255,255,.55); letter-spacing: .05em; }

/* ============================================================
   Sections 通用
   ============================================================ */
.section { padding-block: var(--sec-pad); }
.section-alt { background: var(--paper-2); }
.section-head {
  display: grid; grid-template-columns: 1.2fr .8fr; gap: clamp(28px, 5vw, 80px);
  align-items: end; margin-bottom: clamp(48px, 6vw, 80px);
}
.section-desc { color: var(--ink-3); font-size: 15.5px; }

/* ============================================================
   业务领域
   ============================================================ */
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.card {
  background: var(--white); border: 1px solid var(--line); border-radius: var(--r);
  padding: 34px 28px;
  transition: transform .35s var(--ease), box-shadow .35s var(--ease), border-color .35s;
}
.card:hover { transform: translateY(-6px); box-shadow: 0 22px 44px -18px rgba(16,20,24,.14); border-color: #D8D4C6; }
.card-icon { width: 42px; height: 42px; color: var(--gold-strong); margin-bottom: 24px; }
.card-icon svg { width: 100%; height: 100%; }
.card h3 { font-size: 18px; font-weight: 600; margin-bottom: 12px; letter-spacing: .01em; }
.card p { font-size: 14px; color: var(--ink-3); line-height: 1.8; }

/* ============================================================
   精选案例
   ============================================================ */
.cases { display: grid; gap: 28px; }
.case {
  display: grid; grid-template-columns: 5fr 7fr;
  background: var(--white); border: 1px solid var(--line); border-radius: var(--r);
  overflow: hidden;
  transition: transform .35s var(--ease), box-shadow .35s var(--ease);
}
.case:hover { transform: translateY(-5px); box-shadow: 0 26px 52px -22px rgba(16,20,24,.18); }
.case-visual {
  position: relative; min-height: 240px;
  display: flex; align-items: flex-end; padding: 24px;
}
.case-visual-1 { background: linear-gradient(135deg, #0B1220 0%, #1C2C4A 55%, #33507E 100%); }
.case-visual-2 { background: linear-gradient(135deg, #101418 0%, #2A2A24 55%, #6B5F3A 100%); }
.case-visual-3 { background: linear-gradient(135deg, #0B1220 0%, #23303F 55%, #4E6E64 100%); }
.case-visual::before {
  content: ""; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255,255,255,.06) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(255,255,255,.06) 1px, transparent 1px);
  background-size: 44px 44px;
  -webkit-mask-image: linear-gradient(115deg, transparent 30%, #000 100%);
  mask-image: linear-gradient(115deg, transparent 30%, #000 100%);
}
.case-tag {
  position: relative;
  font-size: 12px; letter-spacing: .14em; color: rgba(255,255,255,.85);
  border: 1px solid rgba(255,255,255,.3); border-radius: 999px; padding: 5px 14px;
  -webkit-backdrop-filter: blur(4px); backdrop-filter: blur(4px);
}
.case-body { padding: clamp(28px, 4vw, 44px); display: flex; flex-direction: column; gap: 14px; }
.case-body h3 { font-size: clamp(19px, 2vw, 22px); font-weight: 600; line-height: 1.4; }
.case-body > p { color: var(--ink-3); font-size: 15px; max-width: 52ch; }
.case-metric {
  margin-top: auto; padding-top: 18px; border-top: 1px solid var(--line);
  display: flex; align-items: baseline; gap: 14px;
}
.case-metric strong {
  font-family: var(--serif); font-style: italic; font-weight: 400;
  font-size: clamp(28px, 3vw, 36px); color: var(--gold-strong); letter-spacing: -0.01em;
}
.case-metric span { font-size: 13.5px; color: var(--ink-3); }

/* ============================================================
   关于我们
   ============================================================ */
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: clamp(40px, 7vw, 110px);
  align-items: start;
}
.about-claim {
  font-size: clamp(44px, 5.6vw, 68px); line-height: 1.15;
  color: var(--ink); font-weight: 400; margin: 8px 0 18px;
}
.about-claim .serif { letter-spacing: -0.01em; }
.about-claim-zh { font-size: clamp(17px, 2vw, 20px); color: var(--ink-3); letter-spacing: .3em; }
.about-text { color: var(--ink-2); margin-bottom: 20px; font-size: 15.5px; }
.values {
  margin-top: 36px; display: grid; grid-template-columns: 1fr 1fr;
  border-top: 1px solid var(--line);
}
.values li { padding: 20px 4px 0; border-bottom: 1px solid transparent; }
.values li:nth-child(odd) { border-right: 1px solid var(--line); padding-right: 24px; }
.values li:nth-child(even) { padding-left: 24px; }
.values strong { display: block; font-size: 16px; font-weight: 600; margin-bottom: 4px; }
.values span { font-size: 13.5px; color: var(--ink-3); }

/* ============================================================
   新闻
   ============================================================ */
.news-list { border-top: 1px solid var(--line); }
.news-item {
  display: grid; grid-template-columns: 110px 1fr; gap: 24px; align-items: baseline;
  padding: 26px 4px; border-bottom: 1px solid var(--line);
  transition: background .25s;
}
.news-item:hover { background: rgba(255,255,255,.65); }
.news-item time { font-family: var(--serif); font-style: italic; color: var(--gold-strong); font-size: 15px; }
.news-item p { font-size: 15.5px; color: var(--ink-2); }

/* ============================================================
   联系我们（深色）
   ============================================================ */
.section-dark { background: var(--navy); color: #fff; }
.contact-grid {
  display: grid; grid-template-columns: 1.1fr .9fr;
  gap: clamp(44px, 7vw, 110px); align-items: start;
}
.contact-title-lg, .contact-left h2 { font-size: clamp(30px, 4vw, 46px); line-height: 1.25; }
.contact-desc { color: rgba(255,255,255,.6); margin: 22px 0 36px; max-width: 46ch; font-size: 15.5px; }
.contact-info { display: grid; gap: 18px; }
.contact-info li { display: flex; align-items: center; gap: 14px; color: rgba(255,255,255,.82); font-size: 15px; }
.contact-info svg { width: 18px; height: 18px; color: var(--gold); flex: none; }
.contact-info a:hover { color: var(--gold); }

.contact-form {
  background: rgba(255,255,255,.04);
  border: 1px solid rgba(255,255,255,.12);
  border-radius: var(--r); padding: clamp(26px, 3.4vw, 40px);
  display: grid; gap: 20px;
}
.field { display: grid; gap: 8px; }
.field label { font-size: 13px; letter-spacing: .08em; color: rgba(255,255,255,.6); }
.field input, .field textarea {
  font: inherit; color: #fff; background: rgba(255,255,255,.05);
  border: 1px solid rgba(255,255,255,.16); border-radius: var(--r);
  padding: 12px 14px; transition: border-color .25s, background .25s;
  resize: vertical;
}
.field input::placeholder, .field textarea::placeholder { color: rgba(255,255,255,.35); }
.field input:focus, .field textarea:focus {
  outline: none; border-color: var(--gold); background: rgba(255,255,255,.08);
}
.form-note { font-size: 12.5px; color: rgba(255,255,255,.4); text-align: center; }

/* ============================================================
   Footer
   ============================================================ */
.site-footer { background: #070C16; color: rgba(255,255,255,.6); }
.footer-grid {
  display: grid; grid-template-columns: 1.4fr 1fr 1fr;
  gap: clamp(32px, 5vw, 80px); padding-block: clamp(52px, 6vw, 80px) 40px;
}
.footer-brand p { margin-top: 18px; font-size: 13.5px; max-width: 30ch; }
.footer-col { display: grid; gap: 10px; align-content: start; font-size: 14px; }
.footer-col h4 {
  color: #fff; font-size: 13px; letter-spacing: .16em; text-transform: uppercase;
  margin-bottom: 8px; font-weight: 600;
}
.footer-col a:hover { color: var(--gold); }
.footer-base {
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px;
  border-top: 1px solid rgba(255,255,255,.08);
  padding-block: 22px; font-size: 12.5px; color: rgba(255,255,255,.35);
}

/* ============================================================
   入场动效
   ============================================================ */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .8s var(--ease), transform .8s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation: none !important; }
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .section-head { grid-template-columns: 1fr; align-items: start; }
}
@media (max-width: 860px) {
  .site-nav {
    position: fixed; inset: 76px 0 auto 0; z-index: 99;
    flex-direction: column; align-items: stretch; gap: 0;
    background: rgba(11,18,32,.97); -webkit-backdrop-filter: blur(16px); backdrop-filter: blur(16px);
    padding: 10px var(--gutter) 26px;
    transform: translateY(-12px); opacity: 0; visibility: hidden;
    transition: transform .3s var(--ease), opacity .3s var(--ease), visibility .3s;
  }
  .site-nav.open { transform: none; opacity: 1; visibility: visible; }
  .site-nav > a { padding: 15px 0; border-bottom: 1px solid rgba(255,255,255,.08); font-size: 16px; }
  .nav-cta { margin-top: 18px; text-align: center; border-bottom: 0 !important; }
  .menu-toggle { display: block; }

  .case { grid-template-columns: 1fr; }
  .case-visual { min-height: 180px; }
  .about-grid, .contact-grid { grid-template-columns: 1fr; }
  .contact-grid { gap: 48px; }
}
@media (max-width: 640px) {
  .hero-stats { grid-template-columns: repeat(2, 1fr); row-gap: 4px; }
  .stat { padding-right: 0; }
  .stat:nth-child(odd) { padding-left: 0 !important; border-left: 0 !important; }
  .stat:nth-child(n+3) { padding-left: 28px !important; border-left: 1px solid rgba(255,255,255,.12) !important; }
  .grid-4 { grid-template-columns: 1fr; }
  .news-item { grid-template-columns: 1fr; gap: 6px; }
  .values { grid-template-columns: 1fr; }
  .values li:nth-child(odd) { border-right: 0; padding-right: 4px; }
  .values li:nth-child(even) { padding-left: 4px; }
  .footer-grid { grid-template-columns: 1fr; gap: 34px; }
}