/* ==========================================================================
   乐知课官网 · 样式表
   上海知派数字科技有限公司
   纯静态 / 零外部依赖 / 移动优先响应式
   断点：968px(平板) / 768px(手机) / 480px(小屏)
   ========================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
  /* 主色板 */
  --amber: #f59e0b;
  --amber-d: #d97706;
  --amber-l: #fbbf24;
  --teal: #4ECDC4;
  --coral: #FF6B6B;
  --yellow: #FFD93D;
  --blue: #4d96ff;
  --purple: #9b59b6;
  --green: #6bcb77;

  /* 中性色 */
  --ink: #1a1d24;
  --ink-2: #3a4150;
  --ink-3: #6b7280;
  --line: #e8eaef;
  --bg: #ffffff;
  --bg-tint: #fbf9f5;
  --bg-dark: #16181f;

  /* 渐变 */
  --grad-brand: linear-gradient(135deg, var(--amber) 0%, var(--coral) 100%);
  --grad-teal: linear-gradient(135deg, var(--teal) 0%, var(--blue) 100%);

  /* 阴影 */
  --sh-sm: 0 2px 8px rgba(26, 29, 36, .06);
  --sh-md: 0 8px 24px rgba(26, 29, 36, .08);
  --sh-lg: 0 18px 48px rgba(26, 29, 36, .12);
  --sh-amber: 0 10px 28px rgba(245, 158, 11, .28);

  /* 尺寸 */
  --radius: 16px;
  --radius-lg: 24px;
  --radius-sm: 10px;
  --nav-h: 68px;
  --maxw: 1200px;

  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", "Noto Sans SC", "Helvetica Neue", Arial, sans-serif;
}

/* ---------- 2. 基础重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 12px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-2);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.no-scroll { overflow: hidden; }

h1, h2, h3, h4 { margin: 0; color: var(--ink); line-height: 1.3; font-weight: 800; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }
strong { color: var(--ink); font-weight: 700; }
em { font-style: normal; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- 3. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 700;
  white-space: nowrap;
  transition: transform .2s ease, box-shadow .2s ease, background .2s ease, color .2s ease;
}
.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--grad-brand);
  color: #fff;
  box-shadow: var(--sh-amber);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 34px rgba(245, 158, 11, .36); }

.btn-ghost {
  background: #fff;
  color: var(--ink);
  border: 2px solid var(--line);
}
.btn-ghost:hover { border-color: var(--amber); color: var(--amber-d); transform: translateY(-2px); }

.btn-sm { padding: 9px 18px; font-size: 14px; }
.btn-lg { padding: 15px 30px; font-size: 16px; }
.btn-block { width: 100%; }

/* ---------- 4. 导航 ---------- */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--nav-h);
  z-index: 200;
  background: rgba(255, 255, 255, .82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .25s ease, background .25s ease, border-color .25s ease;
}
.nav.scrolled {
  background: rgba(255, 255, 255, .96);
  box-shadow: var(--sh-sm);
  border-bottom-color: var(--line);
}

.nav-inner {
  max-width: var(--maxw);
  height: 100%;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.nav-brand { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.nav-logo { width: 40px; height: 40px; border-radius: 10px; object-fit: cover; }
.nav-brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.nav-brand-text strong { font-size: 18px; color: var(--ink); letter-spacing: .5px; }
.nav-brand-text em { font-size: 11px; color: var(--ink-3); }

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links > a {
  padding: 8px 13px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink-2);
  transition: background .2s ease, color .2s ease;
}
.nav-links > a:hover { background: rgba(245, 158, 11, .1); color: var(--amber-d); }
.nav-cta-mobile { display: none; }

.nav-right { display: flex; align-items: center; gap: 12px; }

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: #fff;
  padding: 11px 10px;
  flex-direction: column;
  justify-content: space-between;
}
.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 2px;
  background: var(--ink);
  transition: transform .28s ease, opacity .2s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(9px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-9px) rotate(-45deg); }

.nav-overlay {
  position: fixed;
  inset: 0;
  z-index: 150;
  background: rgba(16, 18, 24, .45);
  opacity: 0;
  transition: opacity .28s ease;
}
.nav-overlay.show { opacity: 1; }

/* ---------- 5. 区块通用 ---------- */
.section { padding: 96px 0; position: relative; }
.section-tint { background: var(--bg-tint); }
.section-dark { background: var(--bg-dark); color: rgba(255, 255, 255, .78); }
.section-dark h2, .section-dark h3 { color: #fff; }
.section-dark strong { color: #fff; }

.section-head { max-width: 780px; margin: 0 auto 52px; text-align: center; }
.section-tag {
  display: inline-block;
  padding: 6px 16px;
  margin-bottom: 16px;
  border-radius: 999px;
  background: rgba(245, 158, 11, .12);
  color: var(--amber-d);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .5px;
}
.section-tag.tag-light { background: rgba(245, 158, 11, .18); color: var(--amber-l); }
.section-title { font-size: 36px; margin-bottom: 16px; letter-spacing: -.5px; }
.section-desc { font-size: 17px; color: var(--ink-3); }

.grid { display: grid; gap: 22px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-5 { grid-template-columns: repeat(5, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  transition: transform .28s ease, box-shadow .28s ease, border-color .28s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--sh-md); border-color: rgba(245, 158, 11, .35); }

/* 勾选列表 */
.tick li {
  position: relative;
  padding-left: 24px;
  margin-top: 8px;
  font-size: 14.5px;
  line-height: 1.6;
}
.tick li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--teal);
  font-weight: 800;
}
.tick-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 4px 20px; }

/* 叉号列表 */
.xlist li {
  position: relative;
  padding-left: 24px;
  margin-top: 9px;
  font-size: 14.5px;
  line-height: 1.6;
}
.xlist li::before {
  content: "✕";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--coral);
  font-weight: 800;
}

/* 关键词 chips */
.kw { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.kw li {
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(26, 29, 36, .05);
  color: var(--ink-3);
  font-size: 12.5px;
  font-weight: 600;
}

/* 规划中 / 示例 徽标 */
.badge-soon {
  display: inline-block;
  padding: 2px 9px;
  margin-left: 4px;
  border-radius: 999px;
  background: rgba(155, 89, 182, .12);
  color: var(--purple);
  font-size: 11.5px;
  font-weight: 700;
  white-space: nowrap;
  vertical-align: middle;
}
.badge-demo {
  display: inline-block;
  padding: 2px 9px;
  margin-left: 6px;
  border-radius: 999px;
  background: rgba(107, 114, 128, .14);
  color: var(--ink-3);
  font-size: 11.5px;
  font-weight: 700;
  white-space: nowrap;
  vertical-align: middle;
}

/* 滚动揭示动画 */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .6s cubic-bezier(.22, .68, .36, 1), transform .6s cubic-bezier(.22, .68, .36, 1);
}
.reveal.in-view { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation-duration: .001ms !important; animation-iteration-count: 1 !important; }
}

/* ---------- 6. Hero ---------- */
.hero {
  position: relative;
  padding: calc(var(--nav-h) + 72px) 0 88px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: -1;
  background: radial-gradient(circle at 90% 10%, rgba(245, 158, 11, .08) 0%, transparent 35%),
              radial-gradient(circle at 10% 90%, rgba(78, 205, 196, .08) 0%, transparent 35%);
}
.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  opacity: .55;
}
.blob-a { width: 420px; height: 420px; background: rgba(245, 158, 11, .28); top: -120px; right: -80px; }
.blob-b { width: 360px; height: 360px; background: rgba(78, 205, 196, .24); bottom: -100px; left: -80px; }
.blob-c { width: 260px; height: 260px; background: rgba(255, 107, 107, .18); top: 40%; left: 55%; }

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 60px;
  align-items: center;
}
.hero-copy { max-width: 600px; }
.eyebrow {
  display: inline-block;
  padding: 6px 14px;
  margin-bottom: 18px;
  border-radius: 999px;
  background: rgba(245, 158, 11, .12);
  color: var(--amber-d);
  font-size: 13px;
  font-weight: 700;
}
.hero-title {
  font-size: 48px;
  line-height: 1.15;
  letter-spacing: -1px;
  margin-bottom: 20px;
}
.hero-sub { font-size: 17.5px; color: var(--ink-3); margin-bottom: 26px; }
.hero-sub strong { color: var(--ink); }

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}
.hero-tags li {
  padding: 8px 16px;
  border-radius: 999px;
  background: #fff;
  border: 1px solid var(--line);
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-2);
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 34px; }
.hero-stats { display: flex; gap: 40px; flex-wrap: wrap; }
.hero-stats div { display: flex; flex-direction: column; }
.hero-stats b {
  font-size: 30px;
  font-weight: 800;
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.2;
}
.hero-stats span { font-size: 13.5px; color: var(--ink-3); }

/* 手机 mockup */
.hero-visual { position: relative; display: flex; justify-content: center; }
.phone {
  position: relative;
  width: 320px;
  border-radius: 40px;
  padding: 12px;
  background: linear-gradient(160deg, #23262f 0%, #34394a 100%);
  box-shadow: var(--sh-lg), 0 0 0 1px rgba(255, 255, 255, .06) inset;
}
.phone-notch {
  position: absolute;
  top: 12px; left: 50%;
  transform: translateX(-50%);
  width: 110px; height: 20px;
  border-radius: 0 0 14px 14px;
  background: #23262f;
  z-index: 3;
}
.phone-screen {
  background: #fff;
  border-radius: 30px;
  padding: 0;
  overflow: hidden;
}
.phone-screen > img {
  display: block;
  width: 100%;
  border-radius: 30px;
}

/* 小尺寸手机框，用于功能截图 / 数据中心宽幅区 */
.phone-sm { width: 280px; }
.wide-visual .phone-screen { max-height: 520px; }
.wide-visual .phone-screen > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

/* ---------- 7. 痛点 ---------- */
/* 网格语义钩子：统一卡片等高对齐 */
.pain-grid, .feature-grid, .compare-grid, .code-grid, .contact-grid { align-items: stretch; }

.pain-card { position: relative; padding-top: 30px; }
.pain-num {
  position: absolute;
  top: 14px; right: 16px;
  font-size: 26px;
  font-weight: 800;
  color: rgba(26, 29, 36, .07);
}
.pain-icon { display: block; font-size: 30px; margin-bottom: 12px; }
.pain-card h3 { font-size: 17px; margin-bottom: 8px; }
.pain-card p { font-size: 14.5px; color: var(--ink-3); }

.pain-foot {
  margin-top: 36px;
  padding: 22px 26px;
  border-radius: var(--radius);
  background: #fff;
  border: 1px dashed rgba(245, 158, 11, .55);
  text-align: center;
  font-size: 16px;
  color: var(--ink-2);
}

/* ---------- 8. 价值主线 ---------- */
.value-card { position: relative; padding: 32px 26px; overflow: hidden; }
.value-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: var(--amber);
}
.value-card.v-amber::before { background: var(--amber); }
.value-card.v-teal::before { background: var(--teal); }
.value-card.v-coral::before { background: var(--coral); }
.value-en {
  display: block;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--ink-3);
  margin-bottom: 10px;
}
.value-icon { display: block; font-size: 36px; margin-bottom: 12px; }
.value-card h3 { font-size: 20px; margin-bottom: 10px; }
.value-card > p { font-size: 15px; color: var(--ink-3); margin-bottom: 16px; }

/* ---------- 9. 核心功能 ---------- */
.feature-card { position: relative; padding-top: 30px; }
.f-idx {
  position: absolute;
  top: 16px; right: 18px;
  font-size: 12px;
  font-weight: 800;
  color: var(--ink-3);
  opacity: .5;
}
.f-shot {
  position: relative;
  margin-bottom: 14px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--line);
  background: #f8f9fb;
}
.f-shot img {
  display: block;
  width: 100%;
  height: 170px;
  object-fit: cover;
  object-position: top center;
}
.f-icon {
  position: absolute;
  top: 10px;
  left: 10px;
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  font-size: 22px;
  background: rgba(245, 158, 11, .12);
  box-shadow: var(--sh-sm);
  border: 1px solid rgba(255, 255, 255, .35);
}
.f-amber .f-icon { background: rgba(245, 158, 11, .92); }
.f-teal .f-icon { background: rgba(78, 205, 196, .92); }
.f-coral .f-icon { background: rgba(255, 107, 107, .92); }
.f-blue .f-icon { background: rgba(77, 150, 255, .92); }
.f-yellow .f-icon { background: rgba(255, 217, 61, .92); }
.f-purple .f-icon { background: rgba(155, 89, 182, .92); }
.f-green .f-icon { background: rgba(107, 203, 119, .92); }
.feature-card h3 { font-size: 17.5px; margin-bottom: 8px; }
.feature-card p { font-size: 14.5px; color: var(--ink-3); }

/* 宽幅展示卡 */
.wide-card {
  margin-top: 34px;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 40px;
  align-items: center;
  padding: 40px;
  border-radius: var(--radius-lg);
  background: #fff;
  border: 1px solid var(--line);
  box-shadow: var(--sh-md);
}
.wc-alt { margin-top: 34px; background: var(--bg-tint); }
.wide-copy h3 { font-size: 26px; margin-bottom: 14px; }
.wide-copy > p { font-size: 15.5px; color: var(--ink-3); margin-bottom: 18px; }

.dc-views { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 18px; }
.dc-view {
  padding: 7px 15px;
  border-radius: 999px;
  background: #f4f5f8;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--ink-3);
}
.dc-view.on { background: var(--grad-teal); color: #fff; }

.wide-visual { display: flex; justify-content: center; }

/* ---------- 10. 完成率引擎（深色区） ---------- */
.engine-compare { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.engine-card {
  background: rgba(255, 255, 255, .05);
  border: 1px solid rgba(255, 255, 255, .1);
  padding: 30px 26px;
}
.engine-card:hover { background: rgba(255, 255, 255, .07); border-color: rgba(255, 255, 255, .18); box-shadow: none; }
.ec-tag {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 12px;
  border-radius: 999px;
  font-size: 12.5px;
  font-weight: 700;
}
.engine-card.bad .ec-tag { background: rgba(255, 107, 107, .18); color: #ff8f8f; }
.engine-card.good .ec-tag { background: rgba(78, 205, 196, .18); color: var(--teal); }
.engine-card h3 { font-size: 21px; margin-bottom: 14px; }
.engine-card .xlist li, .engine-card .tick li { color: rgba(255, 255, 255, .72); }
.engine-card.good { border-color: rgba(78, 205, 196, .35); }

.quote {
  margin: 40px 0 0;
  padding: 30px 34px;
  border-radius: var(--radius-lg);
  background: rgba(245, 158, 11, .1);
  border-left: 5px solid var(--amber);
}
.quote p { font-size: 19px; line-height: 1.75; color: rgba(255, 255, 255, .88); }
.quote em { color: var(--amber-l); font-weight: 700; }

.engine-flow {
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 10px;
  margin-top: 40px;
  flex-wrap: wrap;
}
.ef-step {
  flex: 1;
  min-width: 160px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 16px;
  border-radius: var(--radius);
  background: rgba(255, 255, 255, .05);
  border: 1px solid rgba(255, 255, 255, .1);
}
.ef-step span { font-size: 13px; color: var(--amber-l); font-weight: 800; }
.ef-step b { font-size: 16px; color: #fff; }
.ef-step em { font-size: 12.5px; color: rgba(255, 255, 255, .6); }
.ef-step.hi { background: rgba(78, 205, 196, .12); border-color: rgba(78, 205, 196, .4); }
.ef-step.hi em { color: var(--teal); }
.ef-arrow { display: grid; place-items: center; color: rgba(255, 255, 255, .35); font-size: 20px; }

/* ---------- 11. 竞品差异化 ---------- */
.compare-card { padding: 30px 26px; }
.cc-tag {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 12px;
  border-radius: 999px;
  font-size: 12.5px;
  font-weight: 700;
}
.cc-tag-direct { background: rgba(255, 107, 107, .12); color: var(--coral); }
.cc-tag-b { background: rgba(77, 150, 255, .12); color: var(--blue); }
.compare-card h3 { font-size: 20px; margin-bottom: 4px; }
.cc-sub { font-size: 13.5px; color: var(--ink-3); margin-bottom: 12px; }

.pos-band {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-top: 34px;
  padding: 28px 30px;
  border-radius: var(--radius-lg);
  background: var(--bg-tint);
  border: 1px solid var(--line);
}
.pos-item { flex: 1; display: flex; flex-direction: column; gap: 4px; }
.pos-emo { font-size: 28px; }
.pos-item b { font-size: 17px; color: var(--ink); }
.pos-item em { font-size: 14.5px; color: var(--ink-3); }
.pos-item.pos-hi {
  flex: 1.6;
  padding: 18px 22px;
  border-radius: var(--radius);
  background: #fff;
  border: 2px solid var(--amber);
  box-shadow: var(--sh-sm);
}
.pos-item.pos-hi em { color: var(--amber-d); font-weight: 600; }
.pos-vs { font-size: 14px; font-weight: 800; color: var(--ink-3); letter-spacing: 1px; }

/* ---------- 12. 定价 ---------- */
.anchor-note {
  max-width: 780px;
  margin: 0 auto 36px;
  padding: 16px 24px;
  border-radius: var(--radius);
  background: rgba(255, 217, 61, .18);
  border: 1px solid rgba(245, 158, 11, .3);
  text-align: center;
  font-size: 15.5px;
  color: var(--ink-2);
}

.price-grid { align-items: stretch; }
.price-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 32px 26px;
  text-align: center;
}
.pc-hot {
  border: 2px solid var(--amber);
  box-shadow: var(--sh-amber);
  transform: translateY(-8px);
}
.pc-hot:hover { transform: translateY(-12px); }
.pc-ribbon {
  position: absolute;
  top: -14px; left: 50%;
  transform: translateX(-50%);
  padding: 5px 18px;
  border-radius: 999px;
  background: var(--grad-brand);
  color: #fff;
  font-size: 12.5px;
  font-weight: 700;
  white-space: nowrap;
  box-shadow: var(--sh-sm);
}
.pc-name { font-size: 19px; margin-bottom: 4px; }
.pc-desc { font-size: 13.5px; color: var(--ink-3); margin-bottom: 14px; }
.pc-price { display: flex; align-items: baseline; justify-content: center; gap: 2px; margin-bottom: 4px; }
.pc-price .cur { font-size: 20px; font-weight: 700; color: var(--amber-d); }
.pc-price b { font-size: 46px; font-weight: 800; color: var(--ink); line-height: 1; }
.pc-price .per { font-size: 14px; color: var(--ink-3); margin-left: 4px; }
.pc-save { font-size: 12.5px; color: var(--teal); font-weight: 700; margin-bottom: 6px; }
.pc-list { text-align: left; margin: 14px 0 22px; flex: 1; }
.pc-foot { margin-top: 12px; font-size: 12px; color: var(--ink-3); }

.tier-compare { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; margin-top: 38px; }
.tier { padding: 28px 26px; border-radius: var(--radius-lg); border: 1px solid var(--line); background: #fff; }
.tier h3 { font-size: 19px; margin-bottom: 12px; }
.tier-free { border-color: rgba(78, 205, 196, .45); background: rgba(78, 205, 196, .05); }
.tier-vip { border-color: rgba(245, 158, 11, .45); background: rgba(245, 158, 11, .05); }
.tier-note { margin-top: 14px; font-size: 12.5px; color: var(--ink-3); line-height: 1.6; }

/* ---------- 13. 增长 / 三码 ---------- */
.code-card { padding: 30px 26px; }
.code-icon {
  display: grid;
  place-items: center;
  width: 54px; height: 54px;
  border-radius: 16px;
  font-size: 26px;
  margin-bottom: 14px;
}
.c-amber .code-icon { background: rgba(245, 158, 11, .13); }
.c-teal .code-icon { background: rgba(78, 205, 196, .16); }
.c-coral .code-icon { background: rgba(255, 107, 107, .13); }
.code-card h3 { font-size: 19px; margin-bottom: 8px; }
.code-card p { font-size: 14.5px; color: var(--ink-3); }

.isolate-note {
  margin-top: 24px;
  padding: 18px 24px;
  border-radius: var(--radius);
  background: var(--bg-tint);
  border: 1px dashed rgba(155, 89, 182, .45);
  font-size: 15px;
  color: var(--ink-2);
  text-align: center;
}

/* 机构合作示意 */
.coop {
  width: 100%;
  max-width: 380px;
  padding: 26px 20px;
  border-radius: var(--radius);
  background: #fff;
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}
.coop-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  width: 100%;
  padding: 14px 10px;
  border-radius: 14px;
  font-size: 26px;
}
.coop-node span { font-size: 13.5px; font-weight: 700; color: var(--ink); }
.n-org { background: rgba(77, 150, 255, .1); }
.n-app { background: var(--grad-brand); }
.n-app span { color: #fff; }
.n-fam { background: rgba(78, 205, 196, .13); }
.coop-line { width: 2px; height: 18px; background: var(--line); }
.coop-tips { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; margin-top: 16px; }
.coop-tips span {
  padding: 4px 11px;
  border-radius: 999px;
  background: #f4f5f8;
  font-size: 12px;
  font-weight: 700;
  color: var(--ink-3);
}

/* ---------- 14. 关于 ---------- */
.about-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.about-card { padding: 28px 24px; }
.about-icon { display: block; font-size: 30px; margin-bottom: 12px; }
.about-card h3 { font-size: 18px; margin-bottom: 8px; }
.about-card p { font-size: 14.5px; color: var(--ink-3); }

/* ---------- 15. 联系 ---------- */
.contact-card { padding: 30px 26px; text-align: center; }
.contact-icon { display: block; font-size: 32px; margin-bottom: 12px; }
.contact-card h3 { font-size: 19px; margin-bottom: 8px; }
.contact-card p { font-size: 14.5px; color: var(--ink-3); }
.contact-val { margin-top: 10px; font-weight: 700; color: var(--ink); word-break: break-all; }
.cc-cta { background: var(--bg-tint); border-color: rgba(245, 158, 11, .35); }
.cc-cta .btn { margin-top: 16px; }

/* ---------- 16. 页脚 ---------- */
.footer { background: var(--bg-dark); color: rgba(255, 255, 255, .6); padding: 56px 0 30px; }
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  flex-wrap: wrap;
  padding-bottom: 28px;
  border-bottom: 1px solid rgba(255, 255, 255, .1);
}
.footer-brand { display: flex; align-items: center; gap: 14px; }
.footer-logo { width: 44px; height: 44px; border-radius: 12px; object-fit: cover; }
.footer-brand strong { color: #fff; font-size: 18px; }
.footer-brand p { font-size: 13px; color: rgba(255, 255, 255, .55); }
.footer-links { display: flex; flex-wrap: wrap; gap: 6px 20px; }
.footer-links a { font-size: 14px; color: rgba(255, 255, 255, .6); transition: color .2s ease; }
.footer-links a:hover { color: var(--amber-l); }
.footer-bottom {
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  font-size: 13px;
  color: rgba(255, 255, 255, .45);
}

/* ---------- 17. 回到顶部 ---------- */
.to-top {
  position: fixed;
  right: 24px; bottom: 24px;
  /* 必须低于 .nav-overlay(150)，否则移动端菜单遮罩打开时按钮会浮在遮罩之上 */
  z-index: 140;
  width: 46px; height: 46px;
  border-radius: 50%;
  background: var(--grad-brand);
  color: #fff;
  font-size: 20px;
  font-weight: 800;
  box-shadow: var(--sh-amber);
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .28s ease, transform .28s ease;
}
.to-top.show { opacity: 1; transform: none; }

/* ---------- 18. 扫码弹窗 ---------- */
.modal { position: fixed; inset: 0; z-index: 300; display: grid; place-items: center; padding: 20px; }
/* [hidden] 必须战胜上面的 display:grid，否则弹窗初始即可见 */
.modal[hidden] { display: none; }
.nav-overlay[hidden], .to-top[hidden] { display: none; }
.modal-mask { position: absolute; inset: 0; background: rgba(16, 18, 24, .6); opacity: 0; transition: opacity .28s ease; }
.modal.show .modal-mask { opacity: 1; }
.modal-box {
  position: relative;
  width: 100%;
  max-width: 380px;
  padding: 34px 28px 28px;
  border-radius: var(--radius-lg);
  background: #fff;
  box-shadow: var(--sh-lg);
  text-align: center;
  opacity: 0;
  transform: translateY(18px) scale(.97);
  transition: opacity .28s ease, transform .28s ease;
}
.modal.show .modal-box { opacity: 1; transform: none; }
.modal-close {
  position: absolute;
  top: 12px; right: 14px;
  width: 32px; height: 32px;
  border-radius: 50%;
  font-size: 22px;
  line-height: 1;
  color: var(--ink-3);
  transition: background .2s ease, color .2s ease;
}
.modal-close:hover { background: #f2f3f6; color: var(--ink); }
.modal-logo { width: 56px; height: 56px; border-radius: 14px; margin: 0 auto 12px; object-fit: cover; }
.modal-box h3 { font-size: 19px; margin-bottom: 6px; }
.modal-sub { font-size: 13.5px; color: var(--ink-3); margin-bottom: 20px; }

.qr-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 200px;
  height: 200px;
  margin: 0 auto 18px;
  border-radius: var(--radius);
  border: 2px dashed rgba(245, 158, 11, .6);
  background: rgba(245, 158, 11, .05);
}
.qr-emo { font-size: 42px; opacity: .5; }
.qr-text { font-size: 14.5px; font-weight: 700; color: var(--amber-d); }
.qr-hint { font-size: 11.5px; color: var(--ink-3); padding: 0 16px; line-height: 1.5; }

.modal-tips { text-align: left; display: inline-block; }
.modal-tips li { font-size: 13.5px; color: var(--ink-3); margin-top: 6px; }

/* ==========================================================================
   19. 响应式
   ========================================================================== */

/* --- 平板 968px --- */
@media (max-width: 968px) {
  .section { padding: 72px 0; }
  .section-title { font-size: 30px; }
  .section-desc { font-size: 16px; }

  /* 导航折叠 */
  .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .nav-cta-mobile { display: inline-flex; margin-top: 10px; }

  .nav-links {
    position: fixed;
    top: 0; right: 0;
    z-index: 160;
    width: min(300px, 82vw);
    height: 100vh;
    padding: calc(var(--nav-h) + 20px) 22px 30px;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    background: #fff;
    box-shadow: -10px 0 40px rgba(16, 18, 24, .14);
    transform: translateX(105%);
    transition: transform .32s cubic-bezier(.3, .7, .3, 1);
    overflow-y: auto;
  }
  .nav-links.open { transform: none; }
  .nav-links > a { padding: 13px 14px; border-radius: 12px; font-size: 16px; }

  .hero { padding: calc(var(--nav-h) + 48px) 0 68px; }
  .hero-grid { grid-template-columns: 1fr; gap: 46px; }
  .hero-title { font-size: 38px; }
  .hero-sub { font-size: 16.5px; }
  .hero-copy { text-align: center; }
  .hero-sub { margin-left: auto; margin-right: auto; }
  .hero-tags, .hero-actions, .hero-stats { justify-content: center; }

  .grid-5 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: repeat(2, 1fr); }

  .wide-card { grid-template-columns: 1fr; gap: 30px; padding: 32px 26px; }
  .wide-copy h3 { font-size: 22px; }

  .engine-compare { grid-template-columns: 1fr; }
  .ef-arrow { display: none; }
  .ef-step { min-width: calc(50% - 6px); }
  .quote p { font-size: 17px; }

  .pos-band { flex-direction: column; align-items: stretch; text-align: center; }
  .pos-item { align-items: center; }
  .pos-vs { text-align: center; }

  .pc-hot { transform: none; }
  .pc-hot:hover { transform: translateY(-4px); }
  .tier-compare { grid-template-columns: 1fr; }
}

/* --- 手机 768px --- */
@media (max-width: 768px) {
  body { font-size: 15.5px; }
  .container { padding: 0 18px; }
  .nav-inner { padding: 0 18px; }
  .section { padding: 60px 0; }
  .section-head { margin-bottom: 38px; }
  .section-title { font-size: 26px; }
  .section-desc { font-size: 15px; }

  .nav-brand-text em { display: none; }

  .hero-title { font-size: 31px; }
  .hero-sub { font-size: 15.5px; }
  .hero-actions .btn { width: 100%; }
  .hero-stats { gap: 26px; }
  .hero-stats b { font-size: 25px; }
  .phone { width: 288px; }
  .phone-sm { width: 260px; }

  .grid { gap: 16px; }
  .grid-5, .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .tick-2 { grid-template-columns: 1fr; }

  .card { padding: 22px 20px; }
  .pain-foot { font-size: 15px; padding: 18px 20px; }
  .quote { padding: 22px 22px; }
  .quote p { font-size: 16px; }
  .ef-step { min-width: 100%; }

  .wide-visual .phone-screen { max-height: 460px; }

  .footer-inner { flex-direction: column; align-items: flex-start; }
  .footer-bottom { flex-direction: column; }

  .to-top { right: 16px; bottom: 16px; width: 42px; height: 42px; }
}

/* --- 小屏 480px --- */
@media (max-width: 480px) {
  .section-title { font-size: 23px; }
  .hero-title { font-size: 26px; }
  .hero-tags li { font-size: 13px; padding: 6px 13px; }
  .hero-stats { gap: 18px; }
  .hero-stats b { font-size: 22px; }
  .hero-stats span { font-size: 12px; }

  .phone { width: 100%; max-width: 300px; }
  .phone-sm { width: 100%; max-width: 260px; }
  .f-shot img { height: 150px; }

  .pc-price b { font-size: 38px; }
  .qr-placeholder { width: 170px; height: 170px; }
  .modal-box { padding: 30px 20px 24px; }
  .wide-visual .phone-screen { max-height: 420px; }
}