/* ============================================================
   海贝达科技 官网静态站样式
   纯 CSS,无任何外部依赖,可离线部署
   ============================================================ */

:root {
  --c-primary: #1667e0;
  --c-primary-deep: #0d4bb0;
  --c-teal: #0fb5a6;
  --c-ink: #12213d;
  --c-text: #3d4c66;
  --c-muted: #6f7d95;
  --c-line: #e3eaf4;
  --c-bg: #ffffff;
  --c-bg-soft: #f4f8fd;
  --c-bg-deep: #0a1f3c;
  --grad-brand: linear-gradient(120deg, #1667e0 0%, #0fb5a6 100%);
  --grad-hero: linear-gradient(135deg, #081f45 0%, #0c3a80 52%, #0c7f86 120%);
  --shadow-sm: 0 2px 10px rgba(18, 33, 61, 0.06);
  --shadow-md: 0 12px 32px rgba(18, 33, 61, 0.1);
  --shadow-lg: 0 24px 60px rgba(10, 31, 60, 0.22);
  --radius: 14px;
  --header-h: 68px;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC",
    system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

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

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { color: var(--c-ink); line-height: 1.35; font-weight: 700; }

a { color: var(--c-primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--c-primary-deep); }

img, svg { display: block; max-width: 100%; }

ul, ol { padding-left: 1.4em; }

.container { width: min(1160px, 100% - 48px); margin-inline: auto; }

::selection { background: rgba(22, 103, 224, 0.18); }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: #fff; /* 不用毛玻璃:backdrop-filter 在滚动时每帧重算,是卡顿主因 */
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s, box-shadow 0.25s;
}
.site-header.scrolled {
  border-bottom-color: var(--c-line);
  box-shadow: var(--shadow-sm);
}
.header-inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--c-ink);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: 0.5px;
  white-space: nowrap;
}
.brand:hover { color: var(--c-ink); }
.brand-mark { width: 34px; height: 34px; flex: none; }
.brand-name { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name small {
  font-size: 10.5px;
  font-weight: 500;
  color: var(--c-muted);
  letter-spacing: 2.5px;
}

/* 智教说品牌徽标(导航 Logo 旁) */
.brand-badge {
  margin-left: 4px;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--grad-brand);
  color: #fff;
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 1px;
  line-height: 1.4;
  align-self: flex-start;
}
.site-footer .brand-badge { align-self: center; }

.site-nav { display: flex; align-items: center; gap: 6px; }
.site-nav a {
  padding: 8px 18px;
  border-radius: 999px;
  color: var(--c-text);
  font-size: 15.5px;
  font-weight: 500;
}
.site-nav a:hover { color: var(--c-primary); background: rgba(22, 103, 224, 0.07); }
.site-nav a.active {
  color: var(--c-primary);
  background: rgba(22, 103, 224, 0.1);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px;
  height: 42px;
  padding: 10px;
  background: none;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--c-ink);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}
.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); }

/* ---------- 首页 Hero ---------- */
.hero {
  position: relative;
  background: var(--grad-hero);
  color: #fff;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, 0.14) 1px, transparent 1px);
  background-size: 26px 26px;
  opacity: 0.18; /* 静态低透明度,不用 mask-image(mask 在大面积上合成开销高) */
}
.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
  padding: 96px 0 140px;
}
.hero-eyebrow {
  display: inline-block;
  padding: 6px 16px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  font-size: 13.5px;
  letter-spacing: 3px;
  color: rgba(255, 255, 255, 0.92);
  margin-bottom: 22px;
}
.hero h1 {
  color: #fff;
  font-size: clamp(32px, 4.6vw, 50px);
  line-height: 1.28;
  letter-spacing: 1px;
  margin-bottom: 20px;
}
.hero h1 .grad {
  background: linear-gradient(100deg, #6ee7dd, #8fc1ff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-lead {
  font-size: 17px;
  color: rgba(255, 255, 255, 0.82);
  max-width: 34em;
  margin-bottom: 32px;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 44px; }

.hero-stats {
  display: flex;
  gap: 44px;
  flex-wrap: wrap;
}
.hero-stats .stat-value {
  font-size: 30px;
  font-weight: 700;
  color: #fff;
  line-height: 1.2;
}
.hero-stats .stat-label { font-size: 13.5px; color: rgba(255, 255, 255, 0.66); }

.hero-wave {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  width: 100%;
  height: 90px;
  color: var(--c-bg);
}

/* Hero 右侧悬浮卡片 */
.hero-art { position: relative; min-height: 320px; }
.glass-card {
  position: relative;
  background: rgba(255, 255, 255, 0.16);
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 18px;
  padding: 22px 24px;
  box-shadow: var(--shadow-lg);
  display: grid;
  gap: 18px;
}
.glass-row { display: flex; align-items: flex-start; gap: 14px; }
.glass-row .g-icon {
  flex: none;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, rgba(110, 231, 221, 0.9), rgba(96, 165, 250, 0.9));
  color: #06264f;
}
.glass-row strong { display: block; color: #fff; font-size: 15.5px; }
.glass-row small { color: rgba(255, 255, 255, 0.68); font-size: 12.5px; line-height: 1.5; display: block; }
.glass-chip {
  position: absolute;
  background: #fff;
  color: var(--c-ink);
  border-radius: 12px;
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 600;
  box-shadow: var(--shadow-md);
}
.glass-chip.c1 { top: -26px; right: -6px; color: var(--c-primary); }
.glass-chip.c2 { bottom: -24px; left: -14px; color: var(--c-teal); }

/* ---------- 通用 Section ---------- */
.section { padding: 88px 0; }
.section.soft { background: var(--c-bg-soft); }
.section-head { max-width: 720px; margin: 0 auto 52px; text-align: center; }
.section-head.left { text-align: left; margin-left: 0; }
.eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 3px;
  color: var(--c-teal);
  text-transform: uppercase;
  margin-bottom: 10px;
}
.section-head h2,
.section h2 {
  font-size: clamp(24px, 3.2vw, 34px);
  letter-spacing: 0.5px;
  margin-bottom: 14px;
}
.section-head p { color: var(--c-muted); font-size: 16px; }

/* ---------- 卡片网格 ---------- */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.card-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.card-grid.cols-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 28px 26px;
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: rgba(22, 103, 224, 0.35);
}
.card.soft { background: #fff; }
.icon-chip {
  width: 48px;
  height: 48px;
  border-radius: 13px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, rgba(22, 103, 224, 0.1), rgba(15, 181, 166, 0.12));
  color: var(--c-primary);
  margin-bottom: 18px;
}
.icon-chip svg { width: 24px; height: 24px; }
.card h3 { font-size: 18.5px; margin-bottom: 10px; }
.card p { font-size: 14.5px; color: var(--c-muted); flex: 1; }
.card .card-link {
  margin-top: 18px;
  font-size: 14px;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.card .card-link::after { content: "→"; transition: transform 0.2s; }
.card:hover .card-link::after { transform: translateX(4px); }
.card .card-tag {
  position: absolute;
  top: 22px;
  right: 22px;
  font-size: 11.5px;
  font-weight: 600;
  color: var(--c-teal);
  background: rgba(15, 181, 166, 0.1);
  padding: 3px 10px;
  border-radius: 999px;
}

/* ---------- 优势 / 特性列表 ---------- */
.feature-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.feature-item {
  display: flex;
  gap: 16px;
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 22px 24px;
}
.feature-item .icon-chip { margin-bottom: 0; flex: none; width: 44px; height: 44px; }
.feature-item h3 { font-size: 16.5px; margin-bottom: 6px; }
.feature-item p { font-size: 14px; color: var(--c-muted); }

/* ---------- 关于我们 ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 56px;
  align-items: center;
}
.about-copy p { margin-bottom: 14px; }
.vm-list { display: grid; gap: 16px; }
.vm-item {
  background: #fff;
  border: 1px solid var(--c-line);
  border-left: 4px solid var(--c-teal);
  border-radius: 12px;
  padding: 20px 24px;
}
.vm-item h3 { font-size: 16px; margin-bottom: 6px; }
.vm-item h3 span { color: var(--c-teal); margin-right: 8px; }
.vm-item p { font-size: 14.5px; color: var(--c-muted); }

/* ---------- CTA 横幅 ---------- */
.cta-band {
  position: relative;
  background: var(--grad-hero);
  border-radius: 20px;
  padding: 56px 48px;
  text-align: center;
  color: #fff;
  overflow: hidden;
}
.cta-band::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, 0.16) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.3;
}
.cta-band h2 { color: #fff; font-size: clamp(22px, 3vw, 30px); margin-bottom: 12px; position: relative; }
.cta-band p { color: rgba(255, 255, 255, 0.8); margin-bottom: 28px; position: relative; }
.cta-band .hero-actions { justify-content: center; margin-bottom: 0; position: relative; }

/* ---------- 页面 Hero(内页) ---------- */
.page-hero {
  position: relative;
  background: var(--grad-hero);
  color: #fff;
  padding: 72px 0 64px;
  overflow: hidden;
}
.page-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, 0.13) 1px, transparent 1px);
  background-size: 26px 26px;
  opacity: 0.3;
}
.page-hero .container { position: relative; }
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.62);
  margin-bottom: 20px;
}
.breadcrumb a { color: rgba(255, 255, 255, 0.78); }
.breadcrumb a:hover { color: #fff; }
.page-hero-eyebrow {
  display: inline-block;
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 3px;
  color: #6ee7dd;
  border: 1px solid rgba(110, 231, 221, 0.4);
  border-radius: 999px;
  padding: 4px 14px;
  margin-bottom: 16px;
}
.page-hero h1 {
  color: #fff;
  font-size: clamp(28px, 4vw, 40px);
  margin-bottom: 14px;
}
.page-hero .lead {
  color: rgba(255, 255, 255, 0.8);
  font-size: 16.5px;
  max-width: 46em;
}

/* ---------- 详情页内容 ---------- */
.doc { padding: 72px 0 88px; }
.doc-section { margin-bottom: 64px; }
.doc-section:last-child { margin-bottom: 0; }
.doc-section > h2 {
  font-size: 24px;
  padding-bottom: 14px;
  margin-bottom: 24px;
  border-bottom: 2px solid var(--c-line);
  position: relative;
}
.doc-section > h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 64px;
  height: 2px;
  background: var(--grad-brand);
}
.doc-section h3 {
  font-size: 18px;
  margin: 26px 0 12px;
}
.doc-section h3::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 2px;
  background: var(--c-teal);
  margin-right: 10px;
  vertical-align: 2px;
}
.doc-section p { margin-bottom: 12px; }
.doc-section > p:last-child { margin-bottom: 0; }

.doc-lead {
  font-size: 16.5px;
  color: var(--c-text);
  background: var(--c-bg-soft);
  border-left: 4px solid var(--c-primary);
  border-radius: 0 12px 12px 0;
  padding: 18px 24px;
  margin-bottom: 40px;
}

/* 内容卡片(小标题 + 描述) */
.doc-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.doc-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.doc-card {
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 24px;
  transition: transform 0.25s, box-shadow 0.25s;
}
.doc-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.doc-card h3 { font-size: 16.5px; margin: 0 0 8px; }
.doc-card h3::before { display: none; }
.doc-card h3 .num {
  display: inline-grid;
  place-items: center;
  width: 26px;
  height: 26px;
  margin-right: 10px;
  border-radius: 8px;
  background: rgba(22, 103, 224, 0.1);
  color: var(--c-primary);
  font-size: 13.5px;
  vertical-align: 3px;
}
.doc-card p { font-size: 14px; color: var(--c-muted); margin: 0; }

/* 步骤流程 */
.step-list { display: grid; gap: 0; counter-reset: step; }
.step-item {
  position: relative;
  display: flex;
  gap: 20px;
  padding: 20px 0;
}
.step-item .step-no {
  flex: none;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--grad-brand);
  color: #fff;
  font-weight: 700;
  font-size: 17px;
  box-shadow: 0 6px 14px rgba(22, 103, 224, 0.28);
  z-index: 1;
}
.step-item:not(:last-child)::before {
  content: "";
  position: absolute;
  left: 21.5px;
  top: 64px;
  bottom: -8px;
  width: 1px;
  background: var(--c-line);
}
.step-item h3 { font-size: 16.5px; margin: 8px 0 6px; }
.step-item p { font-size: 14.5px; color: var(--c-muted); }

/* 表格 */
.table-wrap { overflow-x: auto; border: 1px solid var(--c-line); border-radius: 12px; }
.table { width: 100%; border-collapse: collapse; font-size: 14.5px; background: #fff; }
.table th {
  background: var(--c-bg-soft);
  color: var(--c-ink);
  text-align: left;
  font-weight: 600;
  padding: 14px 18px;
  border-bottom: 1px solid var(--c-line);
  white-space: nowrap;
}
.table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--c-line);
  vertical-align: top;
}
.table tr:last-child td { border-bottom: 0; }
.table td:first-child { color: var(--c-ink); font-weight: 600; white-space: nowrap; }

/* 提示框 */
.callout {
  background: linear-gradient(120deg, rgba(22, 103, 224, 0.06), rgba(15, 181, 166, 0.08));
  border: 1px solid rgba(22, 103, 224, 0.18);
  border-radius: 12px;
  padding: 20px 26px;
  font-size: 15px;
}
.callout strong { color: var(--c-primary); }

/* 标签组 */
.tag-row { display: flex; flex-wrap: wrap; gap: 10px; }
.tag {
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: 999px;
  padding: 7px 16px;
  font-size: 13.5px;
  color: var(--c-text);
}

/* ---------- 服务/产品列表页条目 ---------- */
.service-block {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 48px;
  align-items: start;
  padding: 56px 0;
}
.service-block:first-of-type { padding-top: 0; }
.service-intro .service-no {
  font-size: 44px;
  font-weight: 800;
  line-height: 1;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 14px;
}
.service-intro h2 { font-size: clamp(22px, 2.8vw, 28px); margin-bottom: 14px; }
.service-intro > p { color: var(--c-muted); margin-bottom: 22px; }
.service-points { list-style: none; padding: 0; display: grid; gap: 12px; }
.service-points li {
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: 12px;
  padding: 15px 20px;
  font-size: 14px;
  color: var(--c-muted);
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.service-points li:hover { transform: translateX(4px); border-color: rgba(22, 103, 224, 0.35); box-shadow: var(--shadow-sm); }
.service-points li strong { display: block; color: var(--c-ink); font-size: 15px; margin-bottom: 2px; }

@media (max-width: 960px) {
  .service-block { grid-template-columns: 1fr; gap: 28px; padding: 44px 0; }
}

/* 相关推荐 */
.related { background: var(--c-bg-soft); }
.related .card-grid { margin-top: 0; }

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--c-bg-deep);
  color: rgba(255, 255, 255, 0.72);
  font-size: 14px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 0.7fr 1fr 1fr 0.9fr;
  gap: 32px;
  padding: 64px 0 48px;
}
.footer-brand .brand { color: #fff; margin-bottom: 16px; }
.footer-brand .brand-name small { color: rgba(255, 255, 255, 0.5); }
.footer-brand p { color: rgba(255, 255, 255, 0.6); line-height: 1.8; max-width: 26em; }
.footer-col h4 {
  color: #fff;
  font-size: 15px;
  letter-spacing: 1px;
  margin-bottom: 18px;
}
.footer-col a {
  display: block;
  color: rgba(255, 255, 255, 0.62);
  padding: 5px 0;
  font-size: 13.5px;
}
.footer-col a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255, 255, 255, 0.1); }
.footer-bottom-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px;
  padding: 20px 0;
  font-size: 12.5px;
  color: rgba(255, 255, 255, 0.45);
}
.footer-bottom a { color: rgba(255, 255, 255, 0.45); }
.footer-bottom a:hover { color: #fff; }

/* ---------- 404 ---------- */
.error-page {
  min-height: 72vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 80px 0;
}
.error-code {
  font-size: 88px;
  font-weight: 800;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.1;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s, background 0.2s, color 0.2s;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: var(--grad-brand);
  color: #fff;
  box-shadow: 0 8px 20px rgba(22, 103, 224, 0.35);
}
.btn-primary:hover { color: #fff; box-shadow: 0 12px 26px rgba(22, 103, 224, 0.42); }
.btn-light { background: #fff; color: var(--c-primary); box-shadow: 0 8px 20px rgba(4, 20, 48, 0.25); }
.btn-light:hover { color: var(--c-primary-deep); }
.btn-outline {
  border-color: rgba(255, 255, 255, 0.55);
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
}
.btn-outline:hover { color: #fff; border-color: #fff; background: rgba(255, 255, 255, 0.14); }
.btn-ghost {
  border-color: var(--c-line);
  color: var(--c-primary);
  background: #fff;
}
.btn-ghost:hover { border-color: var(--c-primary); color: var(--c-primary-deep); }

/* ---------- 滚动进入动画(仅淡入,避免 transform 触发的逐帧重排) ---------- */
.reveal { opacity: 0; transition: opacity 0.5s ease; }
.reveal.in { opacity: 1; }
.reveal.d1 { transition-delay: 0.06s; }
.reveal.d2 { transition-delay: 0.12s; }
.reveal.d3 { transition-delay: 0.18s; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transition: none; }
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; padding: 72px 0 120px; }
  .hero-art { display: none; }
  .card-grid, .card-grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; gap: 36px; }
  .feature-list { grid-template-columns: 1fr; }
  .doc-grid, .doc-grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 680px) {
  .container { width: min(1160px, 100% - 36px); }
  .nav-toggle { display: flex; }
  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 12px 18px 18px;
    background: #fff;
    border-bottom: 1px solid var(--c-line);
    box-shadow: var(--shadow-md);
    display: none;
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 12px 16px; border-radius: 10px; }
  .hero-stats { gap: 28px; }
  .section { padding: 64px 0; }
  .card-grid, .card-grid.cols-2, .doc-grid, .doc-grid.cols-3 { grid-template-columns: 1fr; }
  .doc-grid { grid-template-columns: 1fr; }
  .cta-band { padding: 44px 24px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; padding: 48px 0 36px; }
  .hero-wave { height: 48px; }
  .pain-grid { grid-template-columns: 1fr; }
  .pain-item h3 { font-size: 17px; }
  .position-grid { grid-template-columns: 1fr; gap: 36px; }
}

/* ---------- 三大共性难点 ---------- */
.pain-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.pain-item {
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: transform 0.25s, box-shadow 0.25s, border-color 0.25s;
}
.pain-item:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-color: rgba(22, 103, 224, 0.35); }
.pain-item .icon-chip { width: 52px; height: 52px; margin-bottom: 16px; }
.pain-item .icon-chip svg { width: 26px; height: 26px; }
.pain-item h3 { font-size: 19px; margin-bottom: 4px; }
.pain-item .pain-sub { color: var(--c-teal); font-size: 13px; font-weight: 600; letter-spacing: 1px; margin-bottom: 14px; }
.pain-item .pain-quote {
  font-size: 14.5px;
  color: var(--c-text);
  background: var(--c-bg-soft);
  border-left: 3px solid var(--c-teal);
  border-radius: 0 10px 10px 0;
  padding: 12px 16px;
  margin-bottom: 14px;
  font-style: italic;
}
.pain-item .pain-desc { font-size: 14px; color: var(--c-muted); }

/* ---------- 定位:三个不是 + 三句话 ---------- */
.position-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.position-grid .vm-item { border-left-color: var(--c-primary); }
.position-grid .vm-item h3 span { color: var(--c-primary); }
.no-list { display: grid; gap: 16px; }
.no-item {
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: 12px;
  padding: 20px 24px;
  display: flex;
  gap: 16px;
  align-items: flex-start;
}
.no-item .no-tag {
  flex: none;
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: rgba(18, 33, 61, 0.06);
  color: var(--c-muted);
  font-size: 20px;
  font-weight: 800;
  font-family: "PingFang SC", sans-serif;
}
.no-item h3 { font-size: 16px; margin-bottom: 4px; }
.no-item h3 del { color: var(--c-muted); text-decoration-thickness: 2px; text-decoration-color: rgba(220, 38, 38, 0.55); }
.no-item p { font-size: 14px; color: var(--c-muted); margin: 0; }

/* ---------- 动态/活动 ---------- */
.activity-list { display: grid; gap: 18px; }
.activity-card {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 24px;
  align-items: start;
  background: #fff;
  border: 1px solid var(--c-line);
  border-radius: var(--radius);
  padding: 26px 28px;
  transition: transform 0.25s, box-shadow 0.25s;
}
.activity-card:hover { transform: translateX(4px); box-shadow: var(--shadow-md); }
.activity-date { text-align: center; }
.activity-date .day { font-size: 34px; font-weight: 800; line-height: 1.1; background: var(--grad-brand); -webkit-background-clip: text; background-clip: text; color: transparent; }
.activity-date .ym { font-size: 13px; color: var(--c-muted); margin-top: 4px; }
.activity-card .tag { display: inline-block; margin-bottom: 10px; font-size: 12px; font-weight: 600; color: var(--c-primary); background: rgba(22, 103, 224, 0.08); border: 0; padding: 4px 12px; }
.activity-card h3 { font-size: 18px; margin-bottom: 8px; }
.activity-card p { font-size: 14.5px; color: var(--c-muted); margin: 0; }
.activity-meta { margin-top: 12px; display: flex; flex-wrap: wrap; gap: 8px; }
.activity-meta span { font-size: 12.5px; color: var(--c-muted); background: var(--c-bg-soft); border-radius: 999px; padding: 4px 12px; }

@media (max-width: 680px) {
  .activity-card { grid-template-columns: 1fr; gap: 14px; }
  .activity-date { display: flex; align-items: baseline; gap: 10px; }
  .activity-date .day { font-size: 28px; }
}