/* =========================================================
   Bubble 官网样式
   思路：页面从上往下，背景色从“浅水天蓝”逐渐变成“深海蓝”，
   模拟一次下潜。每个 section 负责自己那一段的渐变。
   ========================================================= */

/* ---------- 1. 设计变量（改这里就能统一换色） ---------- */
:root {
  --navy: #0b2540;          /* 深色文字 */
  --ink-soft: #3d5670;      /* 次要文字 */
  --blue: #2f7fd8;          /* 品牌蓝 */
  --white: #ffffff;
  /* 取自 App 图标的彩虹泡泡色 */
  --iridescent: linear-gradient(100deg, #6fd6ff 0%, #a99bff 45%, #ffb3d9 75%, #ffe39a 100%);

  --radius-lg: 28px;
  --radius-md: 18px;
  --shadow: 0 30px 60px -20px rgba(11, 37, 64, 0.35);
  --container: 1160px;
  --header-h: 68px;

  /* 中文优先用苹方，其次系统字体（不依赖外部字体，国内打开更快） */
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
          "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
}

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

html {
  scroll-behavior: smooth;
  /* 点击锚点时，给固定导航栏留出空间 */
  scroll-padding-top: calc(var(--header-h) + 12px);
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--navy);
  background: #020b1c;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
h1, h2, h3 { line-height: 1.2; margin: 0; letter-spacing: -0.01em; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }

.container {
  width: min(100% - 40px, var(--container));
  margin-inline: auto;
}
.narrow { max-width: 760px; }
.center { text-align: center; }
.muted { color: var(--ink-soft); }
.small { font-size: 0.85rem; }

/* ---------- 3. 通用组件 ---------- */
.eyebrow {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--blue);
  margin-bottom: 14px;
}
.lead { font-size: 1.15rem; color: var(--ink-soft); max-width: 34em; }
.center .lead { margin-inline: auto; }

.iridescent {
  background: var(--iridescent);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.2s, background 0.2s, box-shadow 0.2s;
}
.btn:hover { transform: translateY(-2px); }
.btn-small { padding: 8px 16px; font-size: 0.88rem; }
.btn-dark { background: var(--navy); color: var(--white); }
.btn-light { background: var(--white); color: var(--navy); }
.btn-ghost {
  border: 1.5px solid currentColor;
  background: transparent;
}

/* App Store 下载按钮 */
.appstore-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 10px 22px 10px 18px;
  border-radius: 14px;
  background: #000;
  color: #fff;
  transition: transform 0.2s, box-shadow 0.2s;
}
.appstore-badge:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 30px -10px rgba(0, 0, 0, 0.5);
}
.appstore-badge svg { width: 24px; height: 28px; }
.appstore-badge span { display: flex; flex-direction: column; font-size: 1.15rem; font-weight: 600; line-height: 1.15; }
.appstore-badge small { font-size: 0.7rem; font-weight: 400; opacity: 0.85; }
.appstore-badge.light { background: #fff; color: #000; }

/* 毛玻璃卡片，呼应 App 的玻璃质感 */
.glass-card {
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 20px 50px -25px rgba(11, 37, 64, 0.3);
}

/* App 截图（截图本身带浅蓝背景，这里只加圆角和阴影） */
.shot {
  height: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  /* 真实截图都是 473×1024，固定同一个比例，并排时两张一样高 */
  aspect-ratio: 473 / 1024;
  object-fit: cover;
  object-position: center top;
  background: #dcecfa;
}

/* ---------- 4. 顶部导航 ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--header-h);
  z-index: 50;
  transition: background 0.3s, box-shadow 0.3s;
}
/* 滚动后变成毛玻璃（JS 会加上 .scrolled） */
.site-header.scrolled {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  box-shadow: 0 1px 0 rgba(11, 37, 64, 0.08);
}
.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.2rem; }
.logo img { border-radius: 10px; }

.site-nav { display: flex; align-items: center; gap: 26px; font-size: 0.93rem; }
.site-nav a:not(.btn) { color: var(--ink-soft); transition: color 0.2s; }
.site-nav a:not(.btn):hover,
.site-nav a.active { color: var(--navy); }

.nav-toggle { display: none; }

/* ---------- 5. 深度计 ---------- */
.depth-meter {
  position: fixed;
  right: 22px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 40;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  font-size: 0.78rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: var(--blue);
  /* 半透明胶囊底色：深浅背景上都看得清 */
  padding: 14px 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.depth-track {
  width: 3px;
  height: 160px;
  border-radius: 3px;
  background: rgba(47, 127, 216, 0.25);
  overflow: hidden;
}
.depth-fill { width: 100%; height: 0%; background: var(--blue); }

/* ---------- 6. Section 通用 + 深度渐变 ---------- */
.section {
  position: relative;
  padding: 120px 0;
  overflow: hidden;
}
.section-head { margin-bottom: 56px; }
.section h2 { font-size: clamp(2rem, 4vw, 3rem); margin-bottom: 24px; }

/* 每一段从上一段的结尾颜色开始，连成一条完整的“下潜”渐变 */
.hero        { background: linear-gradient(#f4fbff, #e0f1fd); }
.s-training  { background: linear-gradient(#e0f1fd, #c6e3fa); }
.s-coach     { background: linear-gradient(#c6e3fa, #a2d0f3); }
.s-log       { background: linear-gradient(#a2d0f3, #5fa6e0); }
.s-ai        { background: linear-gradient(#5fa6e0, #1f5f9f); }
.s-tools     { background: linear-gradient(#1f5f9f, #10427c); }
.s-safety    { background: linear-gradient(#10427c, #0b2f5c); }
.s-pricing   { background: linear-gradient(#0b2f5c, #08224a); }
.s-faq       { background: linear-gradient(#08224a, #051735); }
.s-cta       { background: linear-gradient(#051735, #020b1c); }

/* 深色区域：文字反白 */
.on-dark { color: #eaf4ff; }
.on-dark .eyebrow { color: #8fd0ff; }
.on-dark .lead,
.on-dark .muted,
.on-dark p { color: rgba(234, 244, 255, 0.75); }
.on-dark .glass-card {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.12);
}

/* ---------- 7. Hero ---------- */
.hero { padding-top: calc(var(--header-h) + 60px); }
.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  align-items: center;
  gap: 40px;
}
.hero h1 {
  font-size: clamp(2.4rem, 5.2vw, 4rem);
  font-weight: 800;
  margin-bottom: 22px;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 34px 0 26px; }
.tagline { font-style: italic; color: var(--ink-soft); letter-spacing: 0.02em; }

.hero-visual { position: relative; height: 660px; }
.hero-visual .shot { position: absolute; width: 270px; }
.shot-front { left: 18%; top: 0; z-index: 2; }
.shot-back  { left: 50%; top: 60px; transform: rotate(6deg); opacity: 0.95; }

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 70px;
}
.stats li {
  padding: 22px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid rgba(255, 255, 255, 0.8);
}
.stats strong { display: block; font-size: 1.8rem; color: var(--blue); }
.stats span { color: var(--ink-soft); font-size: 0.92rem; }

/* 上浮的气泡（JS 动态生成 span） */
.bubbles { position: absolute; inset: 0; pointer-events: none; z-index: 0; }
.bubbles span {
  position: absolute;
  bottom: -40px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0.15) 60%, rgba(111, 214, 255, 0.25));
  border: 1px solid rgba(255, 255, 255, 0.6);
  animation: rise linear infinite;
}
@keyframes rise {
  0%   { transform: translate(0, 0); opacity: 0; }
  10%  { opacity: 1; }
  100% { transform: translate(var(--drift, 20px), -110vh); opacity: 0; }
}
.hero .container,
.s-cta .container { position: relative; z-index: 1; }

/* ---------- 8. 左右分栏的功能模块 ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 70px;
}
/* reverse：图片放左边，文字放右边 */
.split.reverse .split-copy { order: 2; }

.feature-list { display: grid; gap: 26px; margin-top: 10px; }
.feature-list h3 { font-size: 1.15rem; margin-bottom: 6px; }
.feature-list p { color: var(--ink-soft); }

.feature-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 10px;
}
.feature-grid li {
  padding: 20px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.75);
}
.feature-grid h3 { font-size: 1.02rem; margin-bottom: 6px; }
.feature-grid p { font-size: 0.92rem; color: var(--ink-soft); }
.on-dark .feature-grid li { background: rgba(255, 255, 255, 0.07); border-color: rgba(255, 255, 255, 0.12); }
.on-dark .feature-grid p { color: rgba(234, 244, 255, 0.75); }

/* 两张截图并排，宽度和比例相同，所以高度也相同 */
.duo { display: flex; align-items: flex-start; justify-content: center; gap: 22px; }
.duo .shot { width: 46%; max-width: 260px; }
.shot-single { width: 72%; max-width: 300px; margin-inline: auto; }

.pb-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.pb-chips span {
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  background: rgba(255, 255, 255, 0.7);
  color: var(--blue);
}

/* ---------- 9. CO₂ 训练表生成器 ---------- */
.co2-card { margin-top: 90px; padding: 40px; }
.co2-head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-end;
  gap: 24px;
  margin-bottom: 30px;
}
.co2-head h3 { font-size: 1.6rem; margin-bottom: 8px; }
.co2-head .muted { max-width: 30em; }
.co2-form { display: flex; flex-wrap: wrap; gap: 20px; }
.co2-form label { display: flex; flex-direction: column; gap: 6px; font-size: 0.85rem; font-weight: 600; color: var(--ink-soft); }
.time-input { display: flex; align-items: center; gap: 6px; color: var(--navy); }
.co2-form input,
.co2-form select {
  font: inherit;
  font-size: 1rem;
  font-weight: 600;
  color: var(--navy);
  padding: 10px 12px;
  border: 1px solid rgba(11, 37, 64, 0.15);
  border-radius: 12px;
  background: #fff;
}
.co2-form input { width: 64px; text-align: center; }

.co2-table { display: grid; gap: 8px; counter-reset: round; }
.co2-row {
  display: grid;
  grid-template-columns: 34px 1fr 72px 72px;
  align-items: center;
  gap: 14px;
  font-variant-numeric: tabular-nums;
  font-size: 0.92rem;
}
.co2-row .no {
  width: 28px; height: 28px;
  display: grid; place-items: center;
  border-radius: 50%;
  background: rgba(47, 127, 216, 0.12);
  color: var(--blue);
  font-weight: 700; font-size: 0.8rem;
}
/* 进度条：浅色=休息，深色=闭气 */
.co2-bar { display: flex; height: 12px; border-radius: 6px; overflow: hidden; background: rgba(11, 37, 64, 0.06); }
.co2-bar .rest { background: #9fd3ff; }
.co2-bar .hold { background: var(--blue); }
.co2-row .label { color: var(--ink-soft); }
.co2-row .label b { color: var(--navy); }
.co2-foot {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-top: 28px;
}

/* ---------- 10. AI 对话气泡 ---------- */
.chat { display: grid; gap: 12px; margin: 10px 0 24px; }
.msg {
  max-width: 88%;
  padding: 14px 18px;
  border-radius: 20px;
  font-size: 0.95rem;
}
.on-dark .msg.user {
  justify-self: end;
  background: #fff;
  color: var(--navy);
  border-bottom-right-radius: 6px;
}
.on-dark .msg.bot {
  background: rgba(255, 255, 255, 0.1);
  color: #eaf4ff;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-bottom-left-radius: 6px;
}
.feature-grid.two { margin-bottom: 14px; }

/* ---------- 11. 工具网格 ---------- */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}
.tools-grid li { padding: 28px; }
.tools-grid svg {
  width: 40px; height: 40px;
  padding: 8px;
  margin-bottom: 18px;
  border-radius: 12px;
  background: rgba(143, 208, 255, 0.15);
  fill: none;
  stroke: #8fd0ff;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.tools-grid h3 { font-size: 1.1rem; margin-bottom: 6px; }
.tools-grid p { font-size: 0.93rem; }

/* ---------- 12. 安全理念 ---------- */
.big-quote {
  font-size: clamp(2.2rem, 5vw, 3.6rem) !important;
  font-style: italic;
  background: var(--iridescent);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.safety-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 46px;
  text-align: left;
}
.safety-list li {
  padding: 22px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.12);
  color: rgba(234, 244, 255, 0.75);
  font-size: 0.93rem;
}
.safety-list strong { display: block; color: #fff; font-size: 1.05rem; margin-bottom: 6px; }

/* ---------- 13. 价格 ---------- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  align-items: stretch;
}
.price-card {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 34px 30px;
}
.price-card h3 { font-size: 1.1rem; }
.price { font-size: 2.6rem; font-weight: 800; color: #fff !important; margin: 14px 0 20px; }
.price small { font-size: 1rem; font-weight: 500; opacity: 0.7; margin-left: 4px; }
.price-card ul { display: grid; gap: 10px; margin-bottom: 30px; flex: 1; }
.price-card li { color: rgba(234, 244, 255, 0.75); padding-left: 22px; position: relative; }
.price-card li::before { content: "✓"; position: absolute; left: 0; color: #8fd0ff; }
.price-card.featured {
  background: linear-gradient(160deg, rgba(111, 214, 255, 0.22), rgba(169, 155, 255, 0.18));
  border-color: rgba(143, 208, 255, 0.45);
}
.badge {
  position: absolute;
  top: 20px; right: 20px;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--navy);
  background: var(--iridescent);
}

/* ---------- 14. FAQ ---------- */
.faq-list { display: grid; gap: 12px; }
.faq-list details {
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.04);
  padding: 0 24px;
}
.faq-list summary {
  cursor: pointer;
  list-style: none;
  padding: 20px 0;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  gap: 16px;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; font-size: 1.3rem; line-height: 1; transition: transform 0.2s; }
.faq-list details[open] summary::after { transform: rotate(45deg); }
.faq-list details p { padding-bottom: 20px; }

/* ---------- 15. 结尾 CTA ---------- */
.s-cta { padding: 140px 0 160px; }
.cta-icon { margin: 0 auto 28px; border-radius: 22px; box-shadow: 0 0 80px rgba(143, 208, 255, 0.35); }
.s-cta .lead { margin-bottom: 36px; }

/* ---------- 16. 页脚 ---------- */
.site-footer {
  background: #020b1c;
  color: rgba(234, 244, 255, 0.6);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 34px 0;
  font-size: 0.9rem;
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}
.footer-brand { display: flex; align-items: center; gap: 10px; color: #fff; font-weight: 600; }
.footer-brand img { border-radius: 7px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 24px; }
.footer-links a:hover { color: #fff; }

/* ---------- 17. 滚动出现动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}
.reveal.visible { opacity: 1; transform: none; }

/* 用户系统设置了“减少动态效果”时，关闭动画 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .bubbles { display: none; }
  .article-cover img { transition: none; }
  .article-card:hover .article-cover img { transform: none; }
}

/* =========================================================
   文章页（articles/）
   ========================================================= */
.page-articles { background: linear-gradient(#f4fbff 0, #e0f1fd 480px, #f4fbff 100%); }
.page-articles main { padding: calc(var(--header-h) + 60px) 0 100px; min-height: 80vh; }
.page-articles .site-header { background: rgba(255, 255, 255, 0.72); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); }
.page-articles h1 { font-size: clamp(2rem, 4vw, 2.8rem); margin-bottom: 14px; }

.article-list {
  display: grid;
  /* 桌面固定一行 4 篇；窄屏再减列，避免卡片被挤到没法读 */
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 22px;
  margin-top: 46px;
  scroll-margin-top: calc(var(--header-h) + 24px);
}
/* 脚本算好当前页之前，先藏起第 41 篇及以后，避免一下子铺满整页 */
.article-list:not(.is-ready) .article-card:nth-child(n + 41) { display: none; }
.article-card { display: flex; flex-direction: column; padding: 0; overflow: hidden; transition: transform 0.2s; }
.article-card:hover { transform: translateY(-4px); }
.article-cover {
  display: block;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #d7eefc;
}
.article-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 32%;
  transition: transform 0.45s ease;
}
.article-card:hover .article-cover img { transform: scale(1.04); }
.article-cover-empty {
  background:
    linear-gradient(145deg, rgba(111, 214, 255, 0.45), rgba(169, 155, 255, 0.32) 52%, rgba(255, 227, 154, 0.42));
}
.article-card-body {
  display: flex;
  flex-direction: column;
  flex: 1;
  padding: 18px 20px 22px;
}
.article-card .meta { font-size: 0.82rem; color: var(--blue); font-weight: 600; margin-bottom: 10px; }
.article-card h2 { font-size: 1.12rem; margin-bottom: 10px; }
.article-card p { color: var(--ink-soft); font-size: 0.94rem; flex: 1; }
.article-card .more { margin-top: 18px; font-weight: 600; color: var(--blue); }
.article-card.placeholder { border-style: dashed; opacity: 0.7; }
.article-card[hidden] { display: none; }

.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 40px;
}
.pagination[hidden] { display: none; }
.page-btn {
  min-width: 40px;
  height: 40px;
  padding: 0 12px;
  border: 1px solid rgba(11, 37, 64, 0.12);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  color: var(--navy);
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
}
.page-btn:hover:not(:disabled):not(.is-current) { border-color: var(--blue); color: var(--blue); }
.page-btn.is-current {
  background: var(--navy);
  color: #fff;
  border-color: transparent;
  cursor: default;
}
.page-btn:disabled { opacity: 0.35; cursor: default; }
.page-ellipsis { min-width: 24px; text-align: center; color: var(--ink-soft); letter-spacing: 0.08em; }

/* 单篇文章正文排版 */
.article { max-width: 720px; margin-inline: auto; }
.breadcrumb { font-size: 0.85rem; color: var(--ink-soft); margin-bottom: 22px; }
.breadcrumb a { color: var(--blue); }
.article .meta { color: var(--ink-soft); font-size: 0.9rem; margin-bottom: 36px; }
.article-body { font-size: 1.06rem; line-height: 1.9; }
.article-body h2 { font-size: 1.5rem; margin: 44px 0 14px; }
.article-body p { margin-bottom: 18px; }
.article-body ul,
.article-body ol { margin: 0 0 18px 1.3em; list-style: disc; }
.article-body ol { list-style: decimal; }
.article-body li { margin-bottom: 6px; }
.article-body table { width: 100%; border-collapse: collapse; margin-bottom: 22px; font-variant-numeric: tabular-nums; }
.article-body th,
.article-body td { padding: 10px 12px; border-bottom: 1px solid rgba(11, 37, 64, 0.1); text-align: left; }
.article-body blockquote {
  margin: 0 0 18px;
  padding: 16px 20px;
  border-left: 4px solid var(--blue);
  background: rgba(47, 127, 216, 0.07);
  border-radius: 0 12px 12px 0;
}
.article-cta { margin-top: 56px; padding: 32px; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 18px; }
.article-cta h2 { font-size: 1.2rem; margin: 0 0 4px; }

/* =========================================================
   响应式：平板和手机
   ========================================================= */
@media (max-width: 1080px) {
  .depth-meter { display: none; }
  .site-nav { gap: 18px; }
}

@media (max-width: 960px) {
  /* 手机端导航：收进汉堡菜单 */
  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 6px;
    width: 40px; height: 40px;
    border: 0;
    background: transparent;
    cursor: pointer;
  }
  .nav-toggle span { display: block; height: 2px; width: 22px; margin-inline: auto; background: var(--navy); transition: transform 0.25s; }
  .nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(4px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:last-child { transform: translateY(-4px) rotate(-45deg); }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 20px 24px;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(20px);
    box-shadow: 0 20px 40px -20px rgba(11, 37, 64, 0.3);
    transform: translateY(-120%);
    transition: transform 0.3s;
  }
  .site-nav.open { transform: none; }
  .site-nav a:not(.btn) { padding: 14px 4px; border-bottom: 1px solid rgba(11, 37, 64, 0.06); font-size: 1rem; }
  .site-nav .btn { margin-top: 16px; }
  /* 菜单打开时导航栏也要有底色 */
  .site-header:has(.site-nav.open) { background: rgba(255, 255, 255, 0.96); }

  .section { padding: 90px 0; }
  .hero-grid,
  .split { grid-template-columns: 1fr; gap: 50px; }
  .split.reverse .split-copy { order: 0; }
  .hero-visual { height: 560px; max-width: 460px; margin-inline: auto; width: 100%; }
  .hero-visual .shot { width: 220px; }
  .shot-front { left: 6%; }
  .shot-back { left: auto; right: 4%; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .article-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tools-grid { grid-template-columns: 1fr 1fr; }
  .pricing-grid { grid-template-columns: 1fr; max-width: 460px; margin-inline: auto; }
}

@media (max-width: 600px) {
  .hero-visual { height: 470px; }
  .hero-visual .shot { width: 180px; }
  .feature-grid,
  .tools-grid,
  .pricing-grid,
  .safety-list,
  .article-list { grid-template-columns: 1fr; }
  .co2-card { padding: 26px 20px; }
  .co2-row { grid-template-columns: 28px 1fr 60px 60px; gap: 8px; font-size: 0.84rem; }
  .footer-inner { flex-direction: column; text-align: center; }
}