/* ==========================================================================
   云大师官网 · 整站设计系统
   参考 siliconflow.cn 的版式语言（留白、层级、组件节奏），
   保留云大师自有调性（品牌蓝、宋体标题、克制的中性色）。
   —— 旧变量名全部保留并映射，内页无需改动即可继承新体系。
   ========================================================================== */

/* ==================== 1. Tokens ==================== */
:root {
  /* ---- 中性色 ---- */
  --bg: #FAFBFC;
  --bg-warm: #F2F7FD;
  --bg-warm-deep: #E4EFFB;
  --surface: #FFFFFF;
  --text: #0B1220;
  --text-secondary: rgba(11, 18, 32, 0.62);
  --text-tertiary: rgba(11, 18, 32, 0.42);

  /* ---- 品牌色（--gold 为历史命名，实为品牌蓝） ---- */
  --gold: #2563EB;
  --gold-light: #3B82F6;
  --gold-deep: #1D4ED8;
  --brand: #2563EB;
  --brand-deep: #1D4ED8;
  --brand-light: #3B82F6;
  --brand-soft: rgba(37, 99, 235, 0.07);
  --brand-line: rgba(37, 99, 235, 0.16);

  /* ---- 深色块 ---- */
  --brown: #1E293B;
  --brown-warm: #334155;
  --accent: #1E40AF;
  --ink: #0F172A;

  /* ---- 表面 ---- */
  --white: #FFFFFF;
  --white-soft: rgba(255, 255, 255, 0.72);
  --white-card: rgba(255, 255, 255, 0.52);

  /* ---- 线条 ---- */
  --border-soft: rgba(11, 18, 32, 0.07);
  --border-warm: rgba(37, 99, 235, 0.14);
  --line: rgba(11, 18, 32, 0.07);
  --line-strong: rgba(11, 18, 32, 0.13);

  /* ---- 阴影（比原版更轻、更收敛） ---- */
  --shadow-warm: 0 1px 2px rgba(11, 18, 32, 0.03);
  --shadow-card: 0 2px 8px rgba(11, 18, 32, 0.04), 0 12px 32px rgba(11, 18, 32, 0.05);
  --shadow-elevated: 0 8px 24px rgba(11, 18, 32, 0.07), 0 24px 64px rgba(11, 18, 32, 0.08);

  /* ---- 圆角 ---- */
  --r-sm: 10px;
  --r-md: 14px;
  --radius-lg: 16px;
  --radius-card: 20px;
  --r-xl: 28px;
  --radius-pill: 9999px;

  /* ---- 字体 ---- */
  --font-serif: 'Songti SC', 'STSong', 'Source Han Serif SC', 'Noto Serif SC', 'SimSun', serif;
  --font-sans: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', 'JetBrains Mono', Consolas, 'Courier New', monospace;

  /* ---- 字号刻度 ---- */
  --fs-hero: clamp(36px, 5vw, 60px);
  --fs-h2: clamp(28px, 3.4vw, 40px);
  --fs-h3: clamp(20px, 2.2vw, 24px);
  --fs-lead: clamp(16px, 1.6vw, 19px);
  --fs-body: 16px;
  --fs-sm: 14px;
  --fs-xs: 13px;

  /* ---- 节奏 ---- */
  --container-max: 1200px;
  --gutter: 24px;
  --section-y: clamp(72px, 8vw, 116px);
  --nav-h: 68px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==================== 2. Reset & Base ==================== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  font-size: var(--fs-body);
  line-height: 1.65;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
img, svg { max-width: 100%; display: block; }
ul, ol { list-style: none; }
::selection { background: rgba(37, 99, 235, 0.15); }
:focus-visible { outline: 2px solid var(--brand); outline-offset: 3px; border-radius: 4px; }

/* 强调工具类 */
.serif { font-family: var(--font-serif); }
.accent { color: var(--brand); }
.muted { color: var(--text-secondary); }

/* ==================== 3. Layout ==================== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* 板块：统一纵向节奏 + 交替底色 */
.section { padding: var(--section-y) 0; position: relative; }
.section--tint { background: var(--bg-warm); }
.section--plain { background: var(--surface); }

/* 页头小标签 */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: var(--fs-xs);
  font-weight: 600;
  color: var(--brand);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 14px;
}
.section-label::before {
  content: '';
  width: 16px;
  height: 1.5px;
  background: var(--brand);
  border-radius: 2px;
  opacity: 0.7;
}

.section-title {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  font-weight: 700;
  color: var(--text);
  line-height: 1.28;
  letter-spacing: -0.012em;
  margin-bottom: 16px;
}
.section-desc {
  font-size: var(--fs-lead);
  color: var(--text-secondary);
  line-height: 1.72;
  max-width: 640px;
}

/* 板块头（居中版，首页用） */
.sec-head { text-align: center; max-width: 780px; margin: 0 auto clamp(40px, 5vw, 64px); }
.sec-head h2 {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  font-weight: 700;
  color: var(--text);
  line-height: 1.28;
  letter-spacing: -0.012em;
  margin-bottom: 16px;
}
.sec-head p {
  font-size: var(--fs-lead);
  color: var(--text-secondary);
  line-height: 1.72;
  max-width: 700px;
  margin: 0 auto;
}
/* 左对齐版 */
.sec-head.left { text-align: left; margin-left: 0; }
.sec-head.left p { margin: 0; }

/* ==================== 4. Navigation ==================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 90;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  background: rgba(250, 251, 252, 0.78);
  backdrop-filter: blur(18px) saturate(1.6);
  -webkit-backdrop-filter: blur(18px) saturate(1.6);
  border-bottom: 1px solid var(--border-soft);
  transition: box-shadow 0.3s var(--ease), background 0.3s var(--ease);
}
.nav.scrolled {
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 1px 3px rgba(11, 18, 32, 0.04), 0 8px 24px rgba(11, 18, 32, 0.04);
}
.nav-inner {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
}
.nav-brand { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.nav-brand-logo { height: 28px; width: auto; display: block; filter: url(#logo-blue); }
.nav-links { display: flex; align-items: center; gap: 2px; flex: 1; margin-left: 24px; }
.nav-link {
  padding: 8px 14px;
  font-size: 15px;
  font-weight: 400;
  color: var(--text-secondary);
  border-radius: var(--radius-pill);
  transition: color 0.2s var(--ease), background 0.2s var(--ease);
  position: relative;
  white-space: nowrap;
}
.nav-link:hover { color: var(--text); background: var(--brand-soft); }
.nav-link.active { color: var(--text); font-weight: 500; }
.nav-right { display: flex; align-items: center; gap: 10px; }

/* ---------- 导航下拉 ---------- */
.nav-item { position: relative; display: flex; align-items: center; }
.nav-item .nav-link { display: inline-flex; align-items: center; gap: 5px; }
.nav-caret { opacity: 0.45; transition: transform 0.25s var(--ease), opacity 0.25s var(--ease); flex-shrink: 0; }
.nav-item:hover .nav-caret { transform: rotate(180deg); opacity: 0.8; }
.nav-dropdown {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  min-width: 220px;
  padding: 8px;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-elevated);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-6px);
  transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), visibility 0.22s;
  z-index: 95;
}
/* 悬停桥接，避免鼠标经过间隙时下拉消失 */
.nav-item::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  height: 12px;
}
.nav-item:hover .nav-dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.nav-dropdown a {
  display: block;
  padding: 9px 13px;
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  border-radius: var(--r-sm);
  white-space: nowrap;
  transition: background 0.18s, color 0.18s;
}
.nav-dropdown a:hover { background: var(--brand-soft); color: var(--text); }
.nav-dropdown a.dd-all { color: var(--brand-deep); font-weight: 500; }
.nav-dropdown a.dd-all:first-child { margin-bottom: 4px; }
.nav-dropdown a.dd-all:last-child { margin-top: 4px; }

/* ==================== 5. Buttons ==================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  border-radius: var(--radius-pill);
  font-size: 15px;
  font-weight: 500;
  font-family: var(--font-sans);
  line-height: 1.4;
  transition: transform 0.22s var(--ease), box-shadow 0.22s var(--ease),
              background 0.22s var(--ease), border-color 0.22s var(--ease), color 0.22s var(--ease);
  white-space: nowrap;
  cursor: pointer;
}
.btn-primary {
  background: var(--ink);
  color: var(--white);
  box-shadow: 0 1px 2px rgba(11, 18, 32, 0.16);
}
.btn-primary:hover {
  transform: translateY(-1px);
  background: #1B2536;
  box-shadow: 0 6px 20px rgba(11, 18, 32, 0.2);
}
.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--line-strong);
}
.btn-secondary:hover {
  transform: translateY(-1px);
  border-color: var(--brand-line);
  background: var(--surface);
  box-shadow: 0 4px 14px rgba(11, 18, 32, 0.06);
}
/* 品牌蓝按钮：用于重点转化 */
.btn-accent {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 1px 2px rgba(37, 99, 235, 0.24);
}
.btn-accent:hover {
  transform: translateY(-1px);
  background: var(--brand-deep);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.28);
}
/* 透明按钮：深色底上使用 */
.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line-strong);
}
.btn-ghost:hover { background: var(--brand-soft); border-color: var(--brand-line); color: var(--brand-deep); }
.btn-dark { background: var(--ink); color: #fff; }
.btn-dark:hover { background: #1B2536; transform: translateY(-1px); }
.btn-lg { padding: 15px 34px; font-size: 16px; }
.btn-sm { padding: 9px 20px; font-size: var(--fs-sm); }
.btn .arr { transition: transform 0.22s var(--ease); }
.btn:hover .arr { transform: translateX(3px); }

/* ==================== 6. Cards ==================== */
.card {
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-card);
  padding: 32px;
  box-shadow: var(--shadow-warm);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
  border-color: var(--line-strong);
}

/* ==================== 7. 内页页头 ==================== */
.page-main { min-height: calc(100vh - var(--nav-h) - 320px); padding: 0 0 88px; }
.page-header {
  padding: clamp(64px, 8vw, 104px) var(--gutter) clamp(48px, 6vw, 72px);
  text-align: center;
  position: relative;
  background:
    radial-gradient(58% 54% at 50% -8%, rgba(37, 99, 235, 0.09) 0%, transparent 68%),
    radial-gradient(38% 40% at 14% 22%, rgba(59, 130, 246, 0.06) 0%, transparent 64%),
    radial-gradient(34% 36% at 86% 12%, rgba(29, 78, 216, 0.05) 0%, transparent 62%);
  border-bottom: 1px solid var(--border-soft);
}
.page-header h1 {
  font-family: var(--font-serif);
  font-size: clamp(34px, 4.6vw, 52px);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.015em;
  line-height: 1.24;
  margin-bottom: 18px;
}
.page-header p {
  font-size: var(--fs-lead);
  color: var(--text-secondary);
  max-width: 660px;
  margin: 0 auto;
  line-height: 1.72;
}
.page-content {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ==================== 8. 数据指标带 ==================== */
.stats-band {
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
  background: var(--surface);
  padding: clamp(36px, 4vw, 52px) 0;
}
.stats-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat { position: relative; }
.stat + .stat::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 1px;
  height: 32px;
  background: var(--border-soft);
}
.stat-num {
  font-family: var(--font-serif);
  font-size: clamp(30px, 3.4vw, 42px);
  font-weight: 700;
  color: var(--text);
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.stat-label {
  margin-top: 8px;
  font-size: var(--fs-sm);
  color: var(--text-tertiary);
  letter-spacing: 0.02em;
}

/* ==================== 9. 产品矩阵（2×2） ==================== */
.prod-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.matrix-card {
  position: relative;
  padding: clamp(28px, 3vw, 40px);
  border-radius: var(--r-xl);
  border: 1px solid var(--border-soft);
  background: var(--surface);
  box-shadow: var(--shadow-warm);
  overflow: hidden;
  transition: transform 0.35s var(--ease), box-shadow 0.35s var(--ease), border-color 0.35s var(--ease);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-height: 240px;
}
.matrix-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: var(--brand-line);
}
.matrix-card h3 {
  font-family: var(--font-serif);
  font-size: clamp(21px, 2.2vw, 26px);
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
  margin-bottom: 12px;
}
.matrix-card p {
  font-size: 15px;
  line-height: 1.72;
  color: var(--text-secondary);
  max-width: 92%;
  margin-bottom: 24px;
}
.matrix-card .btn { margin-top: auto; }
/* 深色变体：保留一处强调块，但不做花哨装饰 */
.matrix-card.dark {
  background: linear-gradient(160deg, #16233A 0%, #0F172A 100%);
  border-color: rgba(255, 255, 255, 0.08);
}
.matrix-card.dark h3 { color: #fff; }
.matrix-card.dark p { color: rgba(255, 255, 255, 0.62); }
.matrix-card.dark .btn-secondary {
  background: #fff;
  border-color: transparent;
  color: var(--ink);
}
.matrix-card.dark .btn-secondary:hover { background: #F1F5F9; border-color: transparent; }
.matrix-card.dark .btn-ghost {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.22);
  color: #fff;
}
.matrix-card.dark .btn-ghost:hover { background: rgba(255, 255, 255, 0.16); color: #fff; }
.matrix-card.dark .btn-primary { background: #fff; color: var(--ink); }
.matrix-card.dark .btn-primary:hover { background: #F1F5F9; }
.matrix-card.light { background: var(--surface); }
/* 卡片角标：替代硅基流动的像素装饰，改为极简序号 */
.matrix-card::after {
  content: attr(data-idx);
  position: absolute;
  right: 26px;
  bottom: 18px;
  font-family: var(--font-serif);
  font-size: 54px;
  font-weight: 700;
  line-height: 1;
  color: var(--text);
  opacity: 0.045;
  pointer-events: none;
}
.matrix-card.dark::after { color: #fff; opacity: 0.07; }

/* ==================== 10. 优势区块 ==================== */
.why-big {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-bottom: 20px;
}
.why-card {
  position: relative;
  padding: clamp(28px, 3vw, 40px);
  border-radius: var(--r-xl);
  border: 1px solid var(--border-soft);
  background: var(--surface);
  overflow: hidden;
}
.why-card h3 {
  font-family: var(--font-serif);
  font-size: clamp(21px, 2.2vw, 26px);
  font-weight: 700;
  margin-bottom: 20px;
  letter-spacing: -0.01em;
  color: var(--text);
}
.why-card.dark { background: linear-gradient(160deg, #16233A 0%, #0F172A 100%); border-color: rgba(255, 255, 255, 0.08); }
.why-card.dark h3 { color: #fff; }
.why-card.dark .why-line { color: rgba(255, 255, 255, 0.6); }
.why-line {
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-secondary);
  margin-bottom: 12px;
}
.why-stat {
  font-family: var(--font-serif);
  font-size: 34px;
  font-weight: 700;
  line-height: 1;
  vertical-align: -4px;
  margin-right: 6px;
}
.hl-pri { color: var(--brand); font-weight: 600; }
.why-card.dark .hl-pri { color: #7DD3FC; }
.hl-gold { color: var(--brand); }
.why-card.dark .hl-gold { color: #7DD3FC; }

.why-small {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.why-mini {
  padding: 28px 24px;
  border-radius: var(--radius-card);
  border: 1px solid var(--border-soft);
  background: var(--surface);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}
.why-mini:hover { transform: translateY(-3px); box-shadow: var(--shadow-card); border-color: var(--brand-line); }
.why-mini-icon { margin-bottom: 16px; height: 44px; display: flex; align-items: center; }
.why-mini h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 12px;
}
.why-mini ul { display: flex; flex-direction: column; gap: 8px; }
.why-mini li {
  position: relative;
  padding-left: 14px;
  font-size: var(--fs-sm);
  line-height: 1.6;
  color: var(--text-secondary);
}
.why-mini li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 9px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--brand);
  opacity: 0.45;
}

/* ==================== 11. Hero（首页轮播） ==================== */
.hero {
  position: relative;
  min-height: clamp(520px, 68vh, 680px);
  display: flex;
  align-items: center;
  overflow: hidden;
  padding: clamp(56px, 7vw, 96px) 0 clamp(72px, 8vw, 104px);
  background:
    radial-gradient(56% 52% at 50% -10%, rgba(37, 99, 235, 0.1) 0%, transparent 68%),
    radial-gradient(36% 40% at 16% 18%, rgba(59, 130, 246, 0.07) 0%, transparent 64%),
    linear-gradient(180deg, var(--bg-warm) 0%, var(--bg) 62%, var(--surface) 100%);
  border-bottom: 1px solid var(--border-soft);
}
/* Hero 装饰：极简细环，替代模糊光斑 */
.hero-blob { display: none; }
.hero-ring {
  position: absolute;
  border: 1px solid var(--brand-line);
  border-radius: 50%;
  pointer-events: none;
  opacity: 0.5;
}
.hero-ring.r1 { width: 780px; height: 780px; right: -260px; top: -340px; }
.hero-ring.r2 { width: 520px; height: 520px; right: -80px; top: -180px; opacity: 0.35; }

.hero-inner { position: relative; z-index: 2; width: 100%; max-width: var(--container-max); margin: 0 auto; padding: 0 var(--gutter); }
.hero-slide { display: none; }
.hero-slide.active { display: block; animation: slideIn 0.6s var(--ease) both; }
@keyframes slideIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  background: var(--surface);
  border: 1px solid var(--brand-line);
  font-size: var(--fs-xs);
  color: var(--brand-deep);
  font-weight: 500;
  margin-bottom: 24px;
}
.hero-badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--brand);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.14);
}
.hero-title {
  font-family: var(--font-serif);
  font-size: var(--fs-hero);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text);
  max-width: 820px;
}
/* 强调文字：品牌蓝，不做渐变裁剪 */
.hero-title .grad { color: var(--brand); }
.hero-desc {
  margin-top: 22px;
  font-size: var(--fs-lead);
  line-height: 1.75;
  color: var(--text-secondary);
  max-width: 620px;
}
.hero-ctas { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 34px; }
.hero-dots {
  position: absolute;
  left: 50%;
  bottom: 36px;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  z-index: 3;
}
.hero-dot {
  width: 22px;
  height: 3px;
  border-radius: 3px;
  background: var(--line-strong);
  transition: background 0.3s var(--ease), width 0.3s var(--ease);
}
.hero-dot.active { background: var(--brand); width: 34px; }

/* ==================== 12. 行业方案手风琴 ==================== */
.acc {
  display: flex;
  gap: 12px;
  height: 420px;
}
.acc-item {
  position: relative;
  flex: 1;
  min-width: 0;
  border-radius: var(--radius-card);
  overflow: hidden;
  cursor: pointer;
  transition: flex 0.55s var(--ease);
  border: 1px solid var(--border-soft);
}
.acc-item.active { flex: 4.2; }
.acc-bg { position: absolute; inset: 0; opacity: 0.55; transition: opacity 0.5s var(--ease); }
.acc-item.active .acc-bg { opacity: 1; }
.acc-item .shade {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(11, 18, 32, 0.28) 0%, rgba(11, 18, 32, 0.62) 100%);
  transition: opacity 0.5s var(--ease);
}
.acc-item.active .shade {
  background: linear-gradient(180deg, rgba(11, 18, 32, 0) 0%, rgba(11, 18, 32, 0.55) 100%);
}
/* 竖排标签（收起态） */
.acc-label {
  position: absolute;
  left: 50%;
  bottom: 28px;
  transform: translateX(-50%);
  writing-mode: vertical-rl;
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  letter-spacing: 0.12em;
  white-space: nowrap;
  transition: opacity 0.3s var(--ease);
}
.acc-item.active .acc-label { opacity: 0; }
/* 展开内容 */
.acc-body {
  position: relative;
  z-index: 2;
  height: 100%;
  padding: clamp(24px, 2.6vw, 36px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  color: #fff;
  opacity: 0;
  transition: opacity 0.4s var(--ease) 0.12s;
}
.acc-item.active .acc-body { opacity: 1; }
.acc-body h3 {
  font-family: var(--font-serif);
  font-size: clamp(19px, 2vw, 24px);
  font-weight: 700;
  margin-bottom: 10px;
  white-space: nowrap;
}
.acc-desc {
  font-size: var(--fs-sm);
  line-height: 1.68;
  color: rgba(255, 255, 255, 0.76);
  max-width: 480px;
  margin-bottom: 16px;
}
.acc-body ul { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 18px; }
.acc-body li {
  padding: 5px 12px;
  font-size: var(--fs-xs);
  border-radius: var(--radius-pill);
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.16);
  white-space: nowrap;
}
.acc-link {
  align-self: flex-start;
  font-size: var(--fs-sm);
  font-weight: 500;
  color: #fff;
  border-bottom: 1px solid rgba(255, 255, 255, 0.4);
  padding-bottom: 2px;
  transition: border-color 0.2s;
}
.acc-link:hover { border-color: #fff; }

/* ==================== 13. 模型生态 ==================== */
.eco { background: var(--bg-warm); border-top: 1px solid var(--border-soft); }
.eco-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.eco-card {
  padding: 22px 20px;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-lg);
  transition: transform 0.28s var(--ease), box-shadow 0.28s var(--ease), border-color 0.28s var(--ease);
}
.eco-card:hover {
  transform: translateY(-2px);
  border-color: var(--brand-line);
  box-shadow: var(--shadow-card);
}
.eco-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
  letter-spacing: -0.01em;
}
.eco-tag { font-size: var(--fs-xs); color: var(--text-tertiary); }
.eco-card.more {
  background: var(--brand-soft);
  border-color: var(--brand-line);
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.eco-card.more .eco-name { color: var(--brand-deep); }
.eco-card.more .eco-tag { color: var(--brand); }

/* ==================== 14. 底部 CTA ==================== */
.cta-band {
  padding: clamp(64px, 7vw, 96px) 0;
  background: linear-gradient(160deg, #16233A 0%, #0F172A 100%);
  color: #fff;
}
.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}
.cta-inner h2 {
  font-family: var(--font-serif);
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.3;
  max-width: 620px;
}
.cta-right { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.cta-right .tip { font-size: var(--fs-sm); color: rgba(255, 255, 255, 0.5); margin-right: 4px; }
.cta-band .btn-primary { background: #fff; color: var(--ink); box-shadow: none; }
.cta-band .btn-primary:hover { background: #F1F5F9; }
.cta-band .btn-dark {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #fff;
}
.cta-band .btn-dark:hover { background: rgba(255, 255, 255, 0.16); }

/* ==================== 15. Footer ==================== */
.footer { background: var(--ink); color: rgba(255, 255, 255, 0.6); padding: 68px 0 32px; }
.footer-inner { max-width: var(--container-max); margin: 0 auto; padding: 0 var(--gutter); }
.footer-top {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}
.footer-brand { display: flex; flex-direction: column; gap: 16px; }
.footer-brand-name { display: flex; align-items: center; gap: 10px; }
.footer-brand-logo { height: 28px; width: auto; display: block; filter: brightness(0) invert(1); }
.footer-brand-desc { font-size: var(--fs-sm); line-height: 1.7; color: rgba(255, 255, 255, 0.4); max-width: 280px; }
.footer-col h4 { font-size: var(--fs-sm); font-weight: 600; color: rgba(255, 255, 255, 0.85); margin-bottom: 16px; }
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col a { font-size: var(--fs-sm); color: rgba(255, 255, 255, 0.45); transition: color 0.2s; }
.footer-col a:hover { color: rgba(255, 255, 255, 0.85); }
.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-copy { font-size: var(--fs-xs); color: rgba(255, 255, 255, 0.32); }
.footer-links { display: flex; gap: 20px; }
.footer-links a { font-size: var(--fs-xs); color: rgba(255, 255, 255, 0.32); transition: color 0.2s; }
.footer-links a:hover { color: rgba(255, 255, 255, 0.62); }

/* ==================== 16. 动画 ==================== */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.fade-in.visible { opacity: 1; transform: translateY(0); }
.fade-in-delay-1 { transition-delay: 0.08s; }
.fade-in-delay-2 { transition-delay: 0.16s; }
.fade-in-delay-3 { transition-delay: 0.24s; }
@media (prefers-reduced-motion: reduce) {
  .fade-in { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ==================== 17. 响应式 ==================== */
@media (max-width: 1024px) {
  .why-small { grid-template-columns: repeat(2, 1fr); }
  .eco-grid { grid-template-columns: repeat(3, 1fr); }
  .acc { height: 380px; }
}
@media (max-width: 900px) {
  .nav-links { display: none; }
  .footer-top { grid-template-columns: 1fr 1fr; gap: 32px; }
  .prod-grid { grid-template-columns: 1fr; }
  .why-big { grid-template-columns: 1fr; }
  .stats-inner { grid-template-columns: repeat(2, 1fr); gap: 28px 16px; }
  .stat:nth-child(3)::before { display: none; }
  .acc { flex-direction: column; height: auto; }
  .acc-item { height: 72px; transition: height 0.45s var(--ease); }
  .acc-item.active { height: 380px; }
  .acc-label { writing-mode: horizontal-tb; left: 24px; transform: none; bottom: auto; top: 50%; translate: 0 -50%; }
}
@media (max-width: 600px) {
  .hero { min-height: auto; padding: 48px 0 72px; }
  .hero-ctas .btn { flex: 1; }
  .eco-grid { grid-template-columns: repeat(2, 1fr); }
  .why-small { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .page-header { padding: 48px 20px 40px; }
  .card, .why-mini { padding: 24px; }
  .matrix-card { padding: 26px; min-height: auto; }
  .cta-inner { flex-direction: column; align-items: flex-start; }
}