/* ====================================================================
   魔之弦官网 V2 — 全站样式
   上海魔之弦智能科技有限公司 · AI技术服务官方网站
   ====================================================================
   结构：
     1. :root 设计令牌
     2. 基础重置 & 排版
     3. 通用布局 / 容器 / Section
     4. 顶部导航（含下拉菜单）
     5. Hero 首屏
     6. 按钮系统
     7. 通用卡片组件
     8. 服务入口卡片（首页）
     9. 案例卡片（首页预览 & 案例页完整版）
    10. 服务详情卡片（brand / consulting / dev 页面）
    11. 步骤条
    12. FAQ 手风琴
    13. 关于页
    14. 联系页
    15. 底部 Footer
    16. Sticky CTA 条
    17. Reveal 入场动画
    18. 响应式断点
   ==================================================================== */

/* ——————————————————————————————————————————————
   1. :root 设计令牌
   —————————————————————————————————————————————— */
:root {
  /* 背景层级 */
  --bg:      #05060d;
  --bg-2:    #0a0e1a;
  --bg-3:    #11162a;
  /* 表面 / 边框 */
  --surface:        rgba(255,255,255,.04);
  --surface-2:      rgba(255,255,255,.07);
  --border:         rgba(255,255,255,.08);
  --border-strong:  rgba(255,255,255,.16);
  /* 文字层级 */
  --text:     #e7eaf6;
  --text-dim: #9aa3bf;
  --text-mute:#6b7390;
  /* 品牌色 */
  --primary: #7b5cff;
  --accent:  #22d3ee;
  --gold:    #f5c674;
  /* 渐变 */
  --grad:      linear-gradient(135deg,#7b5cff 0%,#22d3ee 55%,#f5c674 100%);
  --grad-soft: linear-gradient(135deg,rgba(123,92,255,.18),rgba(34,211,238,.12));
  /* 阴影 */
  --shadow-glow: 0 0 24px rgba(123,92,255,.35), 0 0 60px rgba(34,211,238,.15);
  /* 尺寸 */
  --radius:    14px;
  --radius-lg: 22px;
  --container: 1180px;
  /* 动效 */
  --ease: cubic-bezier(.22,.61,.36,1);
  --t:    .35s;
  /* 字体栈 */
  --font-sans:    "Inter","Space Grotesk","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-display: "Space Grotesk","Inter","Noto Sans SC","PingFang SC",system-ui,sans-serif;
  --font-mono:    "JetBrains Mono","Fira Code",ui-monospace,SFMono-Regular,Menlo,monospace;
}

/* ——————————————————————————————————————————————
   2. 基础重置 & 排版
   —————————————————————————————————————————————— */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--text);
  background:
    radial-gradient(1200px 800px at 80% -10%, rgba(123,92,255,.15), transparent 60%),
    radial-gradient(900px 700px at -10% 30%,  rgba(34,211,238,.1),  transparent 60%),
    var(--bg);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
ul { list-style: none; margin: 0; padding: 0; }

h1,h2,h3,h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -.01em;
  line-height: 1.15;
  margin: 0;
}
h1 { font-size: clamp(36px,5.5vw,68px); }
h2 { font-size: clamp(26px,3.2vw,42px); }
h3 { font-size: 20px; }
h4 { font-size: 16px; }
p  { margin: 0 0 16px; color: var(--text-dim); }

/* AI 抓取友好：视觉隐藏但 DOM 可读 */
.sr-only {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* 渐变文字 */
.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ——————————————————————————————————————————————
   3. 通用布局 / 容器 / Section
   —————————————————————————————————————————————— */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}
.section {
  position: relative;
  padding: 100px 0;
}
.section-tight { padding: 72px 0; }
.section-head {
  margin-bottom: 52px;
  text-align: center;
}
.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .22em;
  color: var(--accent);
  padding: 5px 12px;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  background: var(--surface);
  margin-bottom: 16px;
}
.lead {
  font-size: clamp(15px,1.3vw,17px);
  color: var(--text-dim);
  max-width: 680px;
  margin: 12px auto 0;
}
/* 分隔线 */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 0;
}

/* ——————————————————————————————————————————————
   4. 顶部导航（含下拉菜单）
   —————————————————————————————————————————————— */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  background: rgba(5,6,13,.55);
  border-bottom: 1px solid transparent;
  transition: background var(--t) var(--ease), border-color var(--t) var(--ease);
}
.site-header.scrolled {
  background: rgba(5,6,13,.82);
  border-bottom-color: var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 66px;
}
/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  flex-shrink: 0;
}
.brand-icon {
  width: 32px; height: 32px;
  flex-shrink: 0;
}
.brand-name b {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 主导航链接 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
}
.nav-links > li { position: relative; }
.nav-links a, .nav-links button {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 7px 13px;
  font-size: 14px;
  color: var(--text-dim);
  border-radius: 10px;
  transition: color var(--t) var(--ease), background var(--t) var(--ease);
  white-space: nowrap;
}
.nav-links a:hover,
.nav-links button:hover,
.nav-links li.active > a,
.nav-links li.active > button {
  color: var(--text);
  background: var(--surface);
}
.nav-links a.active { color: var(--text); }

/* 下拉菜单触发箭头 */
.nav-dropdown-btn svg {
  width: 12px; height: 12px;
  transition: transform var(--t) var(--ease);
  flex-shrink: 0;
}
.nav-links li.open > .nav-dropdown-btn svg { transform: rotate(180deg); }

/* 下拉面板 */
.nav-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  min-width: 200px;
  background: rgba(10,14,26,.96);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  padding: 8px;
  backdrop-filter: blur(16px);
  opacity: 0;
  pointer-events: none;
  transform: translateX(-50%) translateY(-8px);
  transition: opacity var(--t) var(--ease), transform var(--t) var(--ease);
}
.nav-links li.open > .nav-dropdown {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}
.nav-dropdown a {
  display: block;
  padding: 9px 14px;
  font-size: 13.5px;
  color: var(--text-dim);
  border-radius: 8px;
  transition: color var(--t) var(--ease), background var(--t) var(--ease);
}
.nav-dropdown a:hover {
  color: var(--text);
  background: var(--surface-2);
}

/* 右侧 CTA */
.nav-cta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
/* 汉堡按钮 */
.menu-btn {
  display: none;
  width: 40px; height: 40px;
  border: 1px solid var(--border-strong) !important;
  background: var(--surface) !important;
  border-radius: 10px;
  align-items: center;
  justify-content: center;
  color: var(--text);
  padding: 0;
}
.menu-btn svg { width: 18px; height: 18px; pointer-events: none; }

/* ——————————————————————————————————————————————
   5. Hero 首屏
   —————————————————————————————————————————————— */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 140px 0 100px;
  overflow: hidden;
}
.hero-canvas {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  z-index: 0; opacity: .9;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background:
    radial-gradient(60% 50% at 50% 30%, rgba(123,92,255,.16), transparent 70%),
    linear-gradient(to bottom, transparent 0%, rgba(5,6,13,.3) 60%, var(--bg) 100%);
  pointer-events: none;
  z-index: 1;
}
.hero-inner {
  position: relative;
  z-index: 2;
  text-align: center;
}
.hero h1 {
  margin: 18px auto 22px;
  max-width: 16ch;
}
.hero h1 .line { display: block; }
.hero-sub {
  font-size: clamp(18px,2.4vw,30px);
  color: var(--text-dim);
  font-weight: 500;
  letter-spacing: 0;
  margin-top: 6px;
}
.hero p.lead { max-width: 640px; margin: 0 auto 36px; font-size: 17px; }
.hero-cta {
  display: inline-flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}
.hero-tags {
  margin-top: 28px;
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--text-dim);
}
.hero-tags span {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
}
/* 滚动提示 */
.scroll-cue {
  position: absolute; left: 50%; bottom: 28px;
  transform: translateX(-50%);
  z-index: 2;
  width: 22px; height: 36px;
  border: 1px solid var(--border-strong);
  border-radius: 14px;
  display: grid;
  place-items: start center;
  padding-top: 6px;
}
.scroll-cue::after {
  content: "";
  width: 3px; height: 8px;
  border-radius: 2px;
  background: var(--accent);
  animation: cue 1.6s var(--ease) infinite;
}
@keyframes cue {
  0%   { transform: translateY(0);    opacity: 1; }
  70%  { transform: translateY(12px); opacity: .2; }
  100% { opacity: 0; }
}

/* ——————————————————————————————————————————————
   6. 按钮系统
   —————————————————————————————————————————————— */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 22px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--text);
  font-weight: 500;
  font-size: 14px;
  cursor: pointer;
  transition: transform var(--t) var(--ease), box-shadow var(--t) var(--ease),
              background var(--t) var(--ease), border-color var(--t) var(--ease);
  white-space: nowrap;
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
  border-color: var(--accent);
}
.btn-primary {
  background: var(--grad);
  color: #0a0e1a;
  border-color: transparent;
  font-weight: 700;
}
.btn-primary:hover {
  box-shadow: 0 10px 40px rgba(123,92,255,.45);
  border-color: transparent;
}
.btn .arrow { transition: transform var(--t) var(--ease); }
.btn:hover .arrow { transform: translateX(4px); }
.btn-sm { padding: 8px 16px; font-size: 13px; }
.btn-lg { padding: 15px 28px; font-size: 16px; }

/* ——————————————————————————————————————————————
   7. 通用卡片基础样式
   —————————————————————————————————————————————— */
.card {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(180deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 28px;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.card::before {
  content: "";
  position: absolute; inset: 0;
  background: var(--grad-soft);
  opacity: 0;
  transition: opacity var(--t) var(--ease);
  pointer-events: none;
}
.card:hover { transform: translateY(-4px); border-color: var(--border-strong); }
.card:hover::before { opacity: 1; }
.card > * { position: relative; z-index: 1; }

/* 卡片图标徽章 */
.card-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: grid; place-items: center;
  background: var(--bg-3);
  border: 1px solid var(--border-strong);
  color: var(--accent);
  margin-bottom: 18px;
  font-size: 22px;
}
.card-icon svg { width: 24px; height: 24px; }

/* ——————————————————————————————————————————————
   8. 首页：核心服务入口卡片网格
   —————————————————————————————————————————————— */
.services-grid {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  gap: 18px;
}
.service-card {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 30px 26px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
  text-decoration: none;
}
.service-card::before {
  content: "";
  position: absolute; inset: 0;
  background: var(--grad-soft);
  opacity: 0;
  transition: opacity var(--t) var(--ease);
  pointer-events: none;
}
.service-card:hover { transform: translateY(-5px); border-color: var(--primary); }
.service-card:hover::before { opacity: 1; }
.service-card > * { position: relative; z-index: 1; }
.service-card .s-icon {
  font-size: 28px;
  line-height: 1;
}
.service-card h3 { font-size: 17px; color: var(--text); }
.service-card p { font-size: 13.5px; margin: 0; color: var(--text-dim); flex: 1; }
.service-card .s-link {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--accent);
  letter-spacing: .08em;
  margin-top: 4px;
}

/* ——————————————————————————————————————————————
   9a. 首页：案例预览卡片（2 列）
   —————————————————————————————————————————————— */
.preview-cases {
  display: grid;
  grid-template-columns: repeat(2,1fr);
  gap: 20px;
}
.preview-case {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 28px;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.preview-case:hover { transform: translateY(-4px); border-color: var(--accent); }
.preview-case .pc-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(123,92,255,.12);
  color: var(--primary);
  border: 1px solid rgba(123,92,255,.3);
  margin-bottom: 14px;
}
.preview-case h3 { font-size: 18px; margin-bottom: 8px; }
.preview-case p { font-size: 14px; color: var(--text-dim); }
.preview-case .pc-stats {
  display: flex;
  gap: 20px;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}
.preview-case .pc-stats .stat b {
  display: block;
  font-family: var(--font-display);
  font-size: 20px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.preview-case .pc-stats .stat span {
  font-size: 12px;
  color: var(--text-mute);
}

/* ——————————————————————————————————————————————
   9b. 案例页：完整案例卡片
   —————————————————————————————————————————————— */
.cases-full {
  display: grid;
  grid-template-columns: 1fr;
  gap: 28px;
}
.case-full {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.case-full:hover { transform: translateY(-3px); border-color: var(--border-strong); }
.case-full-header {
  padding: 28px 32px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: flex-start;
  gap: 16px;
}
.case-full-header .cf-num {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--grad);
  display: grid; place-items: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: #0a0e1a;
  flex-shrink: 0;
}
.case-full-header .cf-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 999px;
  background: rgba(245,198,116,.1);
  color: var(--gold);
  border: 1px solid rgba(245,198,116,.3);
  margin-bottom: 6px;
}
.case-full-header h3 { font-size: 20px; }
.case-full-body {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 0;
}
.cf-col {
  padding: 24px 28px;
  border-right: 1px solid var(--border);
}
.cf-col:last-child { border-right: none; }
.cf-col .cf-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 10px;
}
.cf-col ul { list-style: none; padding: 0; margin: 0; }
.cf-col ul li {
  font-size: 14px;
  color: var(--text-dim);
  padding: 4px 0;
  padding-left: 14px;
  position: relative;
}
.cf-col ul li::before {
  content: "·";
  position: absolute; left: 0;
  color: var(--accent);
}
.cf-col.effect ul li::before { color: var(--gold); }
.cf-result {
  padding: 16px 28px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
.cf-result .r-stat {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-mute);
}
.cf-result .r-stat b {
  display: block;
  font-family: var(--font-display);
  font-size: 22px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 2px;
}

/* ——————————————————————————————————————————————
   10a. 服务卡片（brand / consulting / dev）
   —————————————————————————————————————————————— */
.svc-grid {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 20px;
}
.svc-card {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 30px;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.svc-card::before {
  content: "";
  position: absolute; inset: 0;
  background: var(--grad-soft);
  opacity: 0;
  transition: opacity var(--t) var(--ease);
  pointer-events: none;
}
.svc-card:hover { transform: translateY(-4px); border-color: var(--border-strong); }
.svc-card:hover::before { opacity: 1; }
.svc-card > * { position: relative; z-index: 1; }
.svc-num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 16px;
}
.svc-card h3 { font-size: 18px; margin-bottom: 10px; }
.svc-card p { font-size: 14px; margin: 0; }

/* 定制开发页：分组标题 */
.dev-group { margin-bottom: 48px; }
.dev-group:last-child { margin-bottom: 0; }
.dev-group-title {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 20px;
}
.dev-group-title .dg-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .2em;
  text-transform: uppercase;
  padding: 5px 12px;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: var(--surface);
  color: var(--accent);
}
.dev-group-title h3 { font-size: 20px; }
.dev-grid {
  display: grid;
  grid-template-columns: repeat(2,1fr);
  gap: 16px;
}
.dev-card {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: linear-gradient(160deg, rgba(255,255,255,.04), rgba(255,255,255,.01));
  padding: 22px 24px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.dev-card:hover { transform: translateY(-3px); border-color: var(--border-strong); }
.dev-card .dc-icon {
  font-size: 24px;
  line-height: 1;
  flex-shrink: 0;
  margin-top: 2px;
}
.dev-card h4 { font-size: 15px; margin-bottom: 5px; color: var(--text); }
.dev-card p { font-size: 13px; margin: 0; color: var(--text-dim); }

/* ——————————————————————————————————————————————
   10b. 咨询页：3步服务条
   —————————————————————————————————————————————— */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 18px;
  position: relative;
}
.steps-grid::before {
  content: "";
  position: absolute;
  top: 38px; left: calc(33.33% + 10px); right: calc(33.33% + 10px);
  height: 1px;
  background: var(--grad);
  opacity: .3;
  pointer-events: none;
}
.step-card {
  position: relative;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 28px 26px;
  text-align: center;
  overflow: hidden;
  transition: transform var(--t) var(--ease), border-color var(--t) var(--ease);
}
.step-card:hover { transform: translateY(-4px); border-color: var(--accent); }
.step-card .step-num {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--grad);
  display: grid; place-items: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: #0a0e1a;
  margin: 0 auto 18px;
}
.step-card h3 { font-size: 17px; margin-bottom: 8px; }
.step-card p { font-size: 14px; margin: 0; }
.step-card .step-free {
  display: inline-block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--gold);
  background: rgba(245,198,116,.1);
  border: 1px solid rgba(245,198,116,.3);
  padding: 3px 10px;
  border-radius: 999px;
}

/* 信任背书横条 */
.trust-bar {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 22px 32px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(123,92,255,.08), rgba(34,211,238,.05));
  flex-wrap: wrap;
}
.trust-bar .trust-num {
  font-family: var(--font-display);
  font-size: 36px;
  font-weight: 700;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  white-space: nowrap;
}
.trust-bar .trust-text { font-size: 15px; color: var(--text-dim); }
.trust-bar .trust-divider {
  width: 1px; height: 40px;
  background: var(--border-strong);
  flex-shrink: 0;
}

/* ——————————————————————————————————————————————
   11. FAQ 手风琴
   —————————————————————————————————————————————— */
.faq-list {
  display: grid;
  gap: 12px;
  max-width: 820px;
  margin: 0 auto;
}
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  overflow: hidden;
  transition: border-color var(--t) var(--ease);
}
.faq-item.open { border-color: var(--border-strong); }
.faq-q {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 22px;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  color: var(--text);
  user-select: none;
}
.faq-q svg {
  width: 18px; height: 18px;
  flex-shrink: 0;
  color: var(--accent);
  transition: transform var(--t) var(--ease);
}
.faq-item.open .faq-q svg { transform: rotate(45deg); }
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height .4s var(--ease), padding .4s var(--ease);
  padding: 0 22px;
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.7;
}
.faq-item.open .faq-a {
  max-height: 200px;
  padding: 0 22px 18px;
}

/* ——————————————————————————————————————————————
   12. 关于页
   —————————————————————————————————————————————— */
.about-hero {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.about-copy h2 { margin-bottom: 20px; }
.about-copy .quote {
  margin-top: 24px;
  padding: 18px 22px;
  border-left: 2px solid var(--accent);
  background: var(--surface);
  border-radius: 0 12px 12px 0;
  color: var(--text);
  font-family: var(--font-display);
  font-size: 17px;
  line-height: 1.55;
}
.about-visual {
  aspect-ratio: 1/1;
  border-radius: var(--radius-lg);
  background:
    radial-gradient(60% 60% at 30% 30%, rgba(123,92,255,.35), transparent 60%),
    radial-gradient(60% 60% at 70% 70%, rgba(34,211,238,.25), transparent 60%),
    var(--bg-2);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.about-visual .av-inner {
  text-align: center;
  padding: 32px;
}
.about-visual .av-logo {
  font-family: var(--font-display);
  font-size: clamp(40px,6vw,80px);
  font-weight: 900;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1;
}
.about-visual .av-sub {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .18em;
  color: var(--text-mute);
  margin-top: 10px;
}

/* 故事卡片 */
.story-grid {
  display: grid;
  grid-template-columns: repeat(2,1fr);
  gap: 20px;
}
.story-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 28px;
}
.story-card .sc-icon { font-size: 28px; margin-bottom: 14px; }
.story-card h3 { font-size: 17px; margin-bottom: 10px; }
.story-card p { font-size: 14px; margin: 0; }

/* slogan 大字 */
.slogan-block {
  text-align: center;
  padding: 60px 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(80% 80% at 50% 50%, rgba(123,92,255,.1), transparent 70%),
    var(--surface);
}
.slogan-block .slogan-main {
  font-family: var(--font-display);
  font-size: clamp(24px,3.5vw,44px);
  font-weight: 700;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 12px;
}
.slogan-block .slogan-en {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: .2em;
  color: var(--text-mute);
  text-transform: uppercase;
}

/* ——————————————————————————————————————————————
   13. 联系页
   —————————————————————————————————————————————— */
.contact-layout {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 48px;
  align-items: start;
}
.contact-copy h2 { margin-bottom: 14px; }
.contact-copy p { font-size: 16px; }
.contact-info {
  display: grid;
  gap: 12px;
  margin-top: 28px;
}
.contact-row {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(255,255,255,.02);
  transition: border-color var(--t) var(--ease);
}
.contact-row:hover { border-color: var(--border-strong); }
.contact-row .cr-icon {
  width: 36px; height: 36px;
  border-radius: 8px;
  background: var(--bg-3);
  border: 1px solid var(--border-strong);
  display: grid; place-items: center;
  font-size: 16px;
  flex-shrink: 0;
}
.contact-row .cr-lbl {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 2px;
}
.contact-row .cr-val {
  font-size: 14px;
  color: var(--text);
}
.contact-row a.cr-val:hover { color: var(--accent); }

/* 微信二维码卡片 */
.wechat-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(160deg, rgba(255,255,255,.05), rgba(255,255,255,.01));
  padding: 32px;
  text-align: center;
}
.wechat-card .wc-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
  display: block;
}
.wechat-card img {
  width: min(200px,100%);
  height: auto;
  margin: 0 auto;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: #fff;
}
.wechat-card .wc-caption {
  margin-top: 14px;
  font-size: 14px;
  color: var(--text-dim);
}
.wechat-card .wc-id {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
}
/* 联系页 QR scan 动效：扫描线 */
.wechat-card {
  position: relative;
  overflow: hidden;
}
.wechat-card::after {
  content: "";
  position: absolute;
  left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  top: 40px;
  animation: scan 3s linear infinite;
  opacity: .6;
  pointer-events: none;
}
@keyframes scan {
  0%   { top: 40px;   opacity: 0; }
  10%  { opacity: .6; }
  90%  { opacity: .6; }
  100% { top: calc(100% - 40px); opacity: 0; }
}

/* ——————————————————————————————————————————————
   14. CTA 横幅
   —————————————————————————————————————————————— */
.cta-banner {
  text-align: center;
  padding: 64px 40px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(60% 60% at 80% 20%, rgba(123,92,255,.2), transparent 70%),
    radial-gradient(60% 60% at 20% 80%, rgba(34,211,238,.15), transparent 70%),
    var(--bg-2);
  position: relative;
  overflow: hidden;
}
.cta-banner::before {
  content: "";
  position: absolute; inset: 0;
  background: var(--grad-soft);
  opacity: .3;
  pointer-events: none;
}
.cta-banner > * { position: relative; z-index: 1; }
.cta-banner h2 { margin-bottom: 12px; }
.cta-banner p { margin-bottom: 28px; }
.cta-banner .cta-btns {
  display: inline-flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: center;
}

/* ——————————————————————————————————————————————
   15. Footer
   —————————————————————————————————————————————— */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 80px;
  padding: 28px 0 40px;
  text-align: center;
  color: var(--text-mute);
  font-size: 13px;
  font-family: var(--font-mono);
}
.footer-brand {
  font-weight: 600;
  color: var(--text-dim);
  margin-bottom: 6px;
}
.footer-links {
  display: inline-flex;
  gap: 20px;
  margin-top: 10px;
  flex-wrap: wrap;
  justify-content: center;
}
.footer-links a:hover { color: var(--accent); }
.footer-copy { margin-top: 8px; opacity: .65; }

/* ——————————————————————————————————————————————
   16. Sticky CTA 条
   —————————————————————————————————————————————— */
.sticky-cta {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  z-index: 90;
  background: rgba(10,14,26,.92);
  border-top: 1px solid var(--border-strong);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transform: translateY(100%);
  transition: transform .4s var(--ease);
  padding: 12px 0;
}
.sticky-cta.visible { transform: translateY(0); }
.sticky-cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.sticky-text {
  font-size: 14px;
  color: var(--text-dim);
}
.sticky-actions { display: flex; gap: 10px; }

/* ——————————————————————————————————————————————
   17. Reveal 滚动入场动画
   —————————————————————————————————————————————— */
.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .7s var(--ease), transform .7s var(--ease);
}
.reveal.in { opacity: 1; transform: none; }
.reveal-delay-1 { transition-delay: .1s; }
.reveal-delay-2 { transition-delay: .2s; }
.reveal-delay-3 { transition-delay: .3s; }

/* ——————————————————————————————————————————————
   18. 响应式断点
   —————————————————————————————————————————————— */
@media (max-width: 1060px) {
  .services-grid { grid-template-columns: repeat(2,1fr); }
  .case-full-body { grid-template-columns: 1fr; }
  .cf-col { border-right: none; border-bottom: 1px solid var(--border); }
  .cf-col:last-child { border-bottom: none; }
  .about-hero { grid-template-columns: 1fr; gap: 40px; }
  .about-visual { max-width: 400px; margin: 0 auto; }
  .contact-layout { grid-template-columns: 1fr; }
  .svc-grid { grid-template-columns: repeat(2,1fr); }
  .steps-grid { grid-template-columns: 1fr; }
  .steps-grid::before { display: none; }
}
@media (max-width: 720px) {
  .section { padding: 72px 0; }
  .nav-links { display: none; }
  .menu-btn { display: inline-flex !important; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 66px; left: 12px; right: 12px;
    background: rgba(5,6,13,.97);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 10px;
    backdrop-filter: blur(14px);
    z-index: 200;
  }
  .nav-links.open > li { width: 100%; }
  .nav-links.open a,
  .nav-links.open button { width: 100%; padding: 11px 14px; }
  .nav-dropdown {
    position: static;
    transform: none !important;
    opacity: 1 !important;
    pointer-events: auto !important;
    background: transparent;
    border: none;
    padding: 0 0 0 16px;
    display: none;
  }
  .nav-links.open li.open .nav-dropdown { display: block; }
  .services-grid { grid-template-columns: 1fr; }
  .preview-cases { grid-template-columns: 1fr; }
  .svc-grid { grid-template-columns: 1fr; }
  .dev-grid { grid-template-columns: 1fr; }
  .story-grid { grid-template-columns: 1fr; }
  .trust-bar { flex-direction: column; align-items: flex-start; gap: 10px; }
  .trust-bar .trust-divider { display: none; }
  .hero h1 { max-width: 90%; }
  .hero p.lead { font-size: 15px; }
  .cta-banner { padding: 40px 20px; }
  .contact-row { flex-wrap: wrap; }
  .sticky-cta-inner { flex-direction: column; align-items: stretch; }
  .sticky-actions { justify-content: center; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* ——————————————————————————————————————————————
   19. 补充组件
   —————————————————————————————————————————————— */

/* 联系页右侧二维码列 */
.contact-qr-side {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 4px;
}

/* wechat-card 补充子元素 */
.wechat-card .wc-hint {
  font-size: 12px;
  color: var(--text-mute);
  margin-top: 6px;
}
.wechat-card .wc-qr {
  width: 100%;
  display: flex;
  justify-content: center;
  margin: 14px 0;
}
.wechat-card .wc-qr img {
  width: 180px;
  height: 180px;
  object-fit: cover;
  border-radius: 10px;
}

/* 联系页信任提示列表 */
.trust-hints {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.th-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  color: var(--text-dim);
}
.th-icon {
  font-size: 16px;
  flex-shrink: 0;
}

/* reveal 延迟变体 */
.reveal-delay-3 { transition-delay: .45s; }

/* dev-card 4列 */
@media (min-width: 1060px) {
  .dev-grid { grid-template-columns: repeat(2, 1fr); }
}


/* ══════════════════════════════════════════════
   20. 电子名片（E-Card）组件
   ══════════════════════════════════════════════ */

/* 外层容器包裹 */
.ecard-wrap {
  display: flex;
  justify-content: center;
}

/* 外层容器：生成旋转渐变边框 */
.ecard-outer {
  position: relative;
  width: 100%;
  max-width: 480px;
  border-radius: calc(var(--radius-lg) + 2px);
  padding: 2px;
  overflow: hidden;
  box-shadow:
    0 0 0 0 rgba(123,92,255,.0),
    0 0 40px rgba(123,92,255,.22),
    0 0 80px rgba(34,211,238,.12);
  animation: ecard-pulse-glow 3s ease-in-out infinite;
}

@keyframes ecard-pulse-glow {
  0%,100% { box-shadow: 0 0 40px rgba(123,92,255,.22), 0 0 80px rgba(34,211,238,.12); }
  50%      { box-shadow: 0 0 60px rgba(123,92,255,.42), 0 0 120px rgba(34,211,238,.22); }
}

/* 旋转圆锥渐变：制造流动边框效果 */
.ecard-outer::before {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  width: 200%; height: 200%;
  background: conic-gradient(
    from 0deg,
    #7b5cff  0deg,
    #22d3ee  120deg,
    #f5c674  240deg,
    #7b5cff  360deg
  );
  animation: ecard-border-spin 6s linear infinite;
  z-index: 0;
}

@keyframes ecard-border-spin {
  0%   { transform: translate(-50%, -50%) rotate(0deg); }
  100% { transform: translate(-50%, -50%) rotate(360deg); }
}

/* 内层卡片正文区 */
.ecard-body {
  position: relative;
  z-index: 1;
  background: var(--bg-2);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  text-align: center;
}

/* 头部：Logo 徽章 + 公司名称 */
.ecard-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
  text-align: left;
}

.ecard-logo-m {
  width: 52px; height: 52px;
  border-radius: 14px;
  background: var(--grad);
  display: grid; place-items: center;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 900;
  color: #0a0e1a;
  flex-shrink: 0;
}

.ecard-brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  color: var(--text);
}

.ecard-brand-name b {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.ecard-company {
  font-size: 12px;
  color: var(--text-mute);
  margin-top: 3px;
  font-family: var(--font-mono);
  letter-spacing: .04em;
}

/* 职位标签 */
.ecard-role {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--accent);
  padding: 5px 14px;
  border: 1px solid rgba(34,211,238,.28);
  background: rgba(34,211,238,.06);
  border-radius: 999px;
  display: inline-block;
  margin-bottom: 24px;
}

/* 联系信息列表 */
.ecard-contacts {
  display: grid;
  gap: 10px;
  margin-bottom: 28px;
  text-align: left;
}

.ecard-citem {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: rgba(255,255,255,.02);
  transition: border-color var(--t) var(--ease), background var(--t) var(--ease);
}

.ecard-citem:hover {
  border-color: var(--border-strong);
  background: var(--surface);
}

.eci-icon { font-size: 15px; flex-shrink: 0; }

.eci-val {
  font-size: 14px;
  color: var(--text);
  font-family: var(--font-mono);
  letter-spacing: .02em;
}

a.eci-val:hover { color: var(--accent); }

/* 下载按钮 */
.ecard-save-btn {
  width: 100%;
  justify-content: center;
  font-size: 15px;
  padding: 14px 24px;
  margin-bottom: 12px;
  gap: 10px;
}

/* 注释文字 */
.ecard-note {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .06em;
  color: var(--text-mute);
  margin: 0;
  text-align: center;
}

/* 减少动效偏好：静止边框 */
@media (prefers-reduced-motion: reduce) {
  .ecard-outer::before { animation: none; }
  .ecard-outer { animation: none; }
}

/* 移动端紧凑 */
@media (max-width: 520px) {
  .ecard-body { padding: 24px 18px; }
  .ecard-logo-m { width: 44px; height: 44px; font-size: 20px; }
}

/* ——————————————————————————————————————————————
   19. 语言切换按钮
   —————————————————————————————————————————————— */
.lang-toggle {
  background: transparent;
  border: 1px solid rgba(255,255,255,0.2);
  color: var(--text-dim);
  border-radius: 6px;
  padding: 4px 11px;
  font-size: 12px;
  font-family: var(--font-mono);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
  flex-shrink: 0;
  line-height: 1.6;
  white-space: nowrap;
}
.lang-toggle:hover { border-color: var(--accent); color: var(--text); }