/* ==========================================================================
   动力云学堂 · AI实战 —— 产品官网样式
   浅色体系；主色取自品牌 Logo（藏青 #1A3A6B / 明黄 #EFA92F）
   零第三方依赖
   ========================================================================== */

/* ---------- 1. 设计令牌 ---------- */
:root {
  /* 藏青（主色） */
  --navy: #1A3A6B;
  --navy-dark: #12305C;
  --navy-mid: #2C5490;
  --navy-100: #E2E9F4;
  --navy-50: #F2F6FB;

  /* 明黄（强调色） */
  --gold: #EFA92F;
  --gold-dark: #C98A1B;
  --gold-50: #FDF7EA;

  /* 文字 */
  --ink: #1C2733;
  --ink-2: #56626E;
  --ink-3: #8B96A2;

  /* 面 */
  --white: #FFFFFF;
  --paper: #F7F8FA;
  --paper-2: #FBFCFD;
  --line: #E5E8EC;
  --line-2: #D5DAE1;

  /* 状态 */
  --ok: #1F8A54;
  --ok-bg: #EAF6EF;

  /* 圆角 */
  --r-sm: 6px;
  --r: 10px;
  --r-lg: 14px;

  --wrap: 1180px;
  --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

/* ---------- 2. 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--ink);
  background: var(--white);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; border: 0; }
a { color: var(--navy-mid); text-decoration: none; }
a:hover { color: var(--navy); text-decoration: underline; text-underline-offset: 3px; }
h1, h2, h3, h4 { margin: 0 0 .6em; line-height: 1.32; font-weight: 700; color: var(--ink); letter-spacing: -.01em; }
h1 { font-size: 40px; }
h2 { font-size: 27px; }
h3 { font-size: 17.5px; font-weight: 600; }
p { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.15em; }
li { margin: .3em 0; }
hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }
:focus-visible { outline: 2px solid var(--navy-mid); outline-offset: 2px; border-radius: 3px; }

/* ---------- 3. 布局 ---------- */
.container { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 24px; }
.section { padding: 68px 0; }
.section--tight { padding: 44px 0; }
.section--paper { background: var(--paper); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section--navy { background: var(--navy-50); border-top: 1px solid var(--navy-100); border-bottom: 1px solid var(--navy-100); }

/* 区块标题：左对齐（不使用居中 + 装饰线） */
.sec-head { margin-bottom: 34px; max-width: 760px; }
.sec-head h2 { margin-bottom: 8px; }
.sec-head p { color: var(--ink-2); margin: 0; }
.sec-head--split {
  display: flex; align-items: flex-end; justify-content: space-between;
  gap: 24px; max-width: none; flex-wrap: wrap;
}
.sec-head--split .sec-head__text { max-width: 700px; }
.kicker {
  display: block; font-size: 13px; font-weight: 700;
  color: var(--navy-mid); margin-bottom: 8px;
}

/* ---------- 4. 顶部导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .94);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; gap: 28px; min-height: 64px; }
.brand {
  display: flex; align-items: center; gap: 9px;
  color: var(--navy); font-weight: 700; font-size: 17px; letter-spacing: -.01em;
  flex-shrink: 0;
}
.brand:hover { color: var(--navy); text-decoration: none; }
.brand img { width: 30px; height: 30px; }
.brand span { white-space: nowrap; }
.brand em { font-style: normal; color: var(--ink-3); font-weight: 500; font-size: 14px; margin-left: 2px; }
.nav-links {
  display: flex; align-items: center; gap: 24px;
  list-style: none; margin: 0; padding: 0; flex: 1;
}
.nav-links a { color: var(--ink-2); font-size: 14.5px; }
.nav-links a:hover { color: var(--navy); text-decoration: none; }
.nav-links a[aria-current="page"] { color: var(--navy); font-weight: 600; }
.nav-cta { flex-shrink: 0; }
.nav-toggle {
  display: none; background: var(--white); border: 1px solid var(--line-2);
  color: var(--navy); border-radius: var(--r-sm); padding: 6px 11px;
  font-size: 16px; line-height: 1; cursor: pointer;
}

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 11px 22px;
  border-radius: var(--r-sm);
  font-weight: 600; font-size: 14.5px; font-family: inherit;
  border: 1px solid transparent;
  cursor: pointer; white-space: nowrap;
  transition: background .15s ease, border-color .15s ease, color .15s ease;
}
.btn:hover { text-decoration: none; }
.btn--primary { background: var(--navy); color: #fff; }
.btn--primary:hover { background: var(--navy-dark); color: #fff; }
.btn--gold { background: var(--gold); color: #3A2A05; }
.btn--gold:hover { background: #E39E22; color: #3A2A05; }
.btn--ghost { background: var(--white); border-color: var(--line-2); color: var(--navy); }
.btn--ghost:hover { border-color: var(--navy); color: var(--navy); }
.btn--quiet { background: transparent; color: var(--navy); padding-left: 0; padding-right: 0; }
.btn--quiet:hover { color: var(--navy-dark); }
.btn--sm { padding: 8px 16px; font-size: 14px; }
.btn--block { width: 100%; }
.btn[aria-disabled="true"] { opacity: .5; pointer-events: none; }
.link-arrow { font-weight: 600; font-size: 14.5px; }
.link-arrow::after { content: " →"; }

/* ---------- 6. 首页 Hero ---------- */
.hero {
  background: linear-gradient(180deg, var(--navy-50) 0%, var(--white) 100%);
  border-bottom: 1px solid var(--line);
  padding: 64px 0 60px;
}
.hero__inner { display: grid; grid-template-columns: 1.15fr .85fr; gap: 56px; align-items: center; }
.hero__label {
  display: inline-block; font-size: 13px; font-weight: 600;
  color: var(--navy-mid); background: var(--white);
  border: 1px solid var(--navy-100); border-radius: var(--r-sm);
  padding: 5px 12px; margin-bottom: 20px;
}
.hero h1 { margin-bottom: 14px; }
.hero__sub { font-size: 19px; color: var(--navy); font-weight: 600; margin: 0 0 16px; }
.hero__desc { color: var(--ink-2); font-size: 16px; max-width: 600px; }
.hero__actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.hero__meta { margin: 22px 0 0; font-size: 13.5px; color: var(--ink-3); }
.hero__shot { display: flex; justify-content: center; }
.hero__shot img {
  width: 100%; max-width: 300px; height: auto;
  border: 1px solid var(--line-2); border-radius: 20px;
  box-shadow: 0 18px 40px -18px rgba(26, 58, 107, .35);
}

/* ---------- 7. 数据条 ---------- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; border: 1px solid var(--line); border-radius: var(--r); overflow: hidden; }
.stats .stat { padding: 24px 20px; border-right: 1px solid var(--line); background: var(--white); }
.stats .stat:last-child { border-right: 0; }
.stats .num { font-size: 26px; font-weight: 700; color: var(--navy); line-height: 1.25; letter-spacing: -.02em; }
.stats .lab { font-size: 13.5px; color: var(--ink-3); margin-top: 2px; }

/* ---------- 8. 卡片与栅格 ---------- */
.grid { display: grid; gap: 20px; }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--r);
  overflow: hidden;
  display: flex; flex-direction: column;
  transition: border-color .15s ease, transform .15s ease;
}
.card:hover { border-color: var(--line-2); transform: translateY(-2px); }
.card__media { background: var(--paper); border-bottom: 1px solid var(--line); padding: 18px; display: flex; justify-content: center; }
.card__media img {
  width: auto; max-width: 190px; height: auto;
  border: 1px solid var(--line-2); border-radius: 12px;
}
.card__body { padding: 20px 22px 22px; flex: 1; display: flex; flex-direction: column; }
.card__body h3 { margin-bottom: 7px; }
.card__body p { color: var(--ink-2); font-size: 14.5px; margin-bottom: 14px; }
.card__body .link-arrow { margin-top: auto; }

/* 纯文字条目（用于人群、下载等不需要配图的场合） */
.item-list { border-top: 1px solid var(--line); }
.item {
  display: grid; grid-template-columns: 220px 1fr auto;
  gap: 24px; align-items: baseline;
  padding: 22px 0; border-bottom: 1px solid var(--line);
}
.item h3 { margin: 0; }
.item p { margin: 0; color: var(--ink-2); font-size: 14.5px; }
.item .link-arrow { white-space: nowrap; }

/* ---------- 9. 标签 ---------- */
.tag {
  display: inline-block; font-size: 12px; font-weight: 600;
  padding: 2px 9px; border-radius: 4px; margin-bottom: 10px;
  align-self: flex-start; letter-spacing: .01em;
}
.tag--free { background: var(--ok-bg); color: var(--ok); }
.tag--vip { background: var(--gold-50); color: var(--gold-dark); }
.tag--info { background: var(--navy-50); color: var(--navy-mid); }
.tag--mute { background: var(--paper); color: var(--ink-3); }

/* ---------- 10. 功能详情（图文左右） ---------- */
.feature-row {
  display: grid; grid-template-columns: 1fr 320px; gap: 56px;
  align-items: start; padding: 44px 0; border-bottom: 1px solid var(--line);
}
.feature-row:last-child { border-bottom: 0; }
.feature-row:nth-child(even) { grid-template-columns: 320px 1fr; }
.feature-row:nth-child(even) .feature-row__body { order: 2; }
.feature-row:nth-child(even) .feature-row__media { order: 1; }
.feature-row h3 { font-size: 21px; margin-bottom: 10px; }
.feature-row p { color: var(--ink-2); }
.feature-row ul { color: var(--ink-2); font-size: 14.5px; margin-bottom: 16px; }
.feature-row ul li::marker { color: var(--navy-mid); }
.feature-row__no {
  display: block; font-size: 13px; font-weight: 700;
  color: var(--ink-3); margin-bottom: 6px; letter-spacing: .04em;
}
.feature-row__media { display: flex; justify-content: center; }
.feature-row__media img {
  width: 100%; max-width: 300px; height: auto;
  border: 1px solid var(--line-2); border-radius: 18px;
  box-shadow: 0 16px 36px -20px rgba(26, 58, 107, .4);
}
/* 桌面端截图：左右等宽 */
.feature-row--wide, .feature-row--wide:nth-child(even) { grid-template-columns: 1fr 1fr; }
.feature-row--wide .feature-row__media img { max-width: 100%; border-radius: 12px; }
/* 无配图的纯文字条目 */
.feature-row--plain, .feature-row--plain:nth-child(even) { grid-template-columns: 1fr; }

/* ---------- 11. 截图区（仅移动端） ---------- */
.shot-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px 22px; }
.shot-grid figure { margin: 0; }
.shot-grid img {
  width: 100%; height: auto; border-radius: 16px;
  border: 1px solid var(--line-2); background: var(--paper);
  box-shadow: 0 12px 28px -18px rgba(26, 58, 107, .45);
}
.shot-grid figcaption { font-size: 13px; color: var(--ink-3); text-align: center; padding-top: 9px; }

/* ---------- 12. 多端下载 ---------- */
.dl-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.dl-card {
  background: var(--white); border: 1px solid var(--line);
  border-radius: var(--r); padding: 22px;
  display: flex; flex-direction: column; gap: 10px;
  transition: border-color .15s ease;
}
.dl-card:hover { border-color: var(--navy-100); }
.dl-card--ready { border-color: var(--navy); }
.dl-card__icon { width: 30px; height: 30px; color: var(--navy); }
.dl-card__icon svg { width: 100%; height: 100%; }
.dl-card h3 { margin: 0; font-size: 16.5px; }
.dl-card__meta { font-size: 13.5px; color: var(--ink-2); margin: 0; min-height: 42px; }
.dl-card__status { font-size: 12px; font-weight: 600; align-self: flex-start; padding: 2px 8px; border-radius: 4px; }
.dl-card__status--on { background: var(--ok-bg); color: var(--ok); }
.dl-card__status--soon { background: var(--paper); color: var(--ink-3); }
.dl-card .btn { margin-top: auto; }

/* ---------- 13. 表格 ---------- */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--r); background: var(--white); }
table.data { width: 100%; border-collapse: collapse; min-width: 620px; font-size: 14.5px; }
table.data caption { text-align: left; padding: 16px 20px 0; color: var(--ink-3); font-size: 13.5px; }
table.data th, table.data td { padding: 13px 20px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
table.data thead th { background: var(--paper); font-size: 13.5px; color: var(--ink-2); font-weight: 600; white-space: nowrap; }
table.data tbody tr:last-child th, table.data tbody tr:last-child td { border-bottom: 0; }
table.data tbody th { font-weight: 600; color: var(--ink); white-space: nowrap; }
table.data td.yes { color: var(--ok); font-weight: 600; }
table.data td.no { color: var(--ink-3); }

/* ---------- 14. 定价 ---------- */
.price-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; align-items: start; }
.price-card {
  background: var(--white); border: 1px solid var(--line);
  border-radius: var(--r); padding: 28px 24px;
  display: flex; flex-direction: column;
}
.price-card--pick { border-color: var(--navy); border-width: 2px; }
.price-card h3 { font-size: 17px; margin-bottom: 12px; }
.price-card .price { font-size: 34px; font-weight: 700; color: var(--navy); line-height: 1.15; letter-spacing: -.02em; }
.price-card .price small { font-size: 14px; font-weight: 500; color: var(--ink-3); }
.price-card .price-old { color: var(--ink-3); text-decoration: line-through; margin-left: 8px; font-size: 14px; font-weight: 500; }
.price-card .price-note-in { color: var(--ink-2); font-size: 13.5px; margin: 6px 0 0; }
.price-card ul { list-style: none; padding: 0; margin: 20px 0 24px; font-size: 14.5px; }
.price-card ul li { padding: 5px 0 5px 20px; position: relative; color: var(--ink-2); }
.price-card ul li::before { content: "✓"; position: absolute; left: 0; color: var(--navy-mid); font-weight: 700; }
.price-card .btn { margin-top: auto; }
.price-foot { color: var(--ink-3); font-size: 13.5px; margin: 24px 0 0; }

/* ---------- 15. FAQ ---------- */
.faq { max-width: 820px; border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  cursor: pointer; padding: 17px 0; font-weight: 600; font-size: 15.5px;
  list-style: none; display: flex; justify-content: space-between; gap: 16px; align-items: baseline;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "＋"; color: var(--ink-3); font-size: 15px; font-weight: 400; }
.faq details[open] summary::after { content: "－"; color: var(--navy-mid); }
.faq details p { margin: 0 0 18px; color: var(--ink-2); font-size: 14.5px; max-width: 700px; }

/* ---------- 16. 页面头 + 面包屑 ---------- */
.page-head { background: var(--navy-50); border-bottom: 1px solid var(--navy-100); padding: 34px 0 42px; }
.breadcrumb { font-size: 13.5px; color: var(--ink-3); margin-bottom: 16px; }
.breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 0; }
.breadcrumb li::after { content: "/"; margin-left: 8px; color: var(--line-2); }
.breadcrumb li:last-child::after { content: ""; }
.breadcrumb a { color: var(--ink-3); }
.breadcrumb [aria-current="page"] { color: var(--navy); font-weight: 600; }
.page-head h1 { font-size: 32px; margin-bottom: 10px; }
.page-head .lead { color: var(--ink-2); max-width: 780px; font-size: 16px; margin: 0; }

/* ---------- 17. 通用内容块 ---------- */
.prose { max-width: 820px; }
.prose h2 { margin-top: 44px; }
.prose h2:first-child { margin-top: 0; }
.prose h3 { margin-top: 28px; }
.prose p, .prose li { color: var(--ink-2); }
.panel { background: var(--white); border: 1px solid var(--line); border-radius: var(--r); padding: 26px; }
.panel h3 { margin-bottom: 8px; }
.panel p:last-child { margin-bottom: 0; }
.panel p { color: var(--ink-2); font-size: 14.5px; }
.callout { border-left: 3px solid var(--navy-mid); background: var(--navy-50); padding: 18px 22px; margin: 24px 0; border-radius: 0 var(--r) var(--r) 0; }
.callout p { margin: 0; color: var(--ink-2); font-size: 14.5px; }
.callout strong { color: var(--ink); }
.checklist { list-style: none; padding: 0; }
.checklist li { padding-left: 22px; position: relative; color: var(--ink-2); }
.checklist li::before { content: ""; position: absolute; left: 2px; top: .68em; width: 6px; height: 6px; border-radius: 50%; background: var(--navy-mid); }
.checklist strong { color: var(--ink); }

/* 结尾行动区（每页一个，品牌色块） */
.cta-band {
  background: var(--navy); border-radius: var(--r-lg);
  padding: 40px 36px; display: flex; align-items: center;
  justify-content: space-between; gap: 28px; flex-wrap: wrap;
}
.cta-band__text { max-width: 620px; }
.cta-band h2 { color: #fff; font-size: 23px; margin-bottom: 6px; }
.cta-band p { color: #BFD0E6; margin: 0; font-size: 15px; }
.cta-band__actions { display: flex; gap: 12px; flex-wrap: wrap; }

/* ---------- 18. 页脚 ---------- */
.site-footer { background: var(--paper); border-top: 1px solid var(--line); padding: 48px 0 24px; font-size: 14px; }
.footer-grid { display: grid; grid-template-columns: 1.7fr 1fr 1fr 1.3fr; gap: 36px; }
.site-footer h3 { font-size: 14px; color: var(--ink); margin-bottom: 12px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid ul li { margin: 7px 0; }
.footer-grid a { color: var(--ink-2); }
.footer-grid a:hover { color: var(--navy); }
.footer-grid p { color: var(--ink-2); font-size: 14px; }
.footer-brand { display: flex; align-items: center; gap: 9px; color: var(--navy); font-weight: 700; font-size: 16px; margin-bottom: 10px; }
.footer-brand img { width: 28px; height: 28px; }
.footer-brand em { font-style: normal; color: var(--ink-3); font-weight: 500; font-size: 13.5px; }
.footer-bottom {
  border-top: 1px solid var(--line); margin-top: 34px; padding-top: 20px;
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px;
  font-size: 13px; color: var(--ink-3);
}
.footer-bottom p { margin: 0; }

/* ---------- 19. 无障碍 ---------- */
.visually-hidden {
  position: absolute !important; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--navy); color: #fff; padding: 10px 18px; font-weight: 600;
}
.skip-link:focus { left: 0; }

/* ---------- 20. 响应式 ---------- */
@media (max-width: 1100px) {
  .dl-grid { grid-template-columns: repeat(3, 1fr); }
  .footer-grid { grid-template-columns: 1.6fr 1fr 1.2fr; }
}

@media (max-width: 900px) {
  h1 { font-size: 32px; }
  h2 { font-size: 23px; }
  .section { padding: 52px 0; }
  .nav { gap: 16px; }
  .nav-toggle { display: block; margin-left: auto; }
  .nav-links {
    display: none; position: absolute; left: 0; right: 0; top: 100%;
    flex-direction: column; align-items: stretch; gap: 0; flex: none;
    background: var(--white); border-bottom: 1px solid var(--line);
    padding: 6px 24px 14px;
  }
  .nav-links.is-open { display: flex; }
  .nav-links li { border-bottom: 1px solid var(--line); }
  .nav-links li:last-child { border-bottom: 0; }
  .nav-links a { display: block; padding: 12px 0; font-size: 15.5px; }
  .nav-cta { display: none; }
  .hero { padding: 44px 0 46px; }
  .hero__inner { grid-template-columns: 1fr; gap: 34px; }
  .hero__sub { font-size: 17px; }
  .hero__shot { order: -1; }
  .hero__shot img { max-width: 230px; }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stats .stat:nth-child(2) { border-right: 0; }
  .stats .stat:nth-child(1), .stats .stat:nth-child(2) { border-bottom: 1px solid var(--line); }
  .grid--3, .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .dl-grid { grid-template-columns: repeat(2, 1fr); }
  .price-grid { grid-template-columns: 1fr; }
  .feature-row, .feature-row:nth-child(even), .feature-row--wide, .feature-row--wide:nth-child(even) { grid-template-columns: 1fr; gap: 26px; }
  .feature-row:nth-child(even) .feature-row__body { order: 1; }
  .feature-row:nth-child(even) .feature-row__media { order: 2; }
  .feature-row--wide .feature-row__media img { max-width: 300px; border-radius: 18px; }
  .item { grid-template-columns: 1fr; gap: 6px; }
  .page-head h1 { font-size: 26px; }
  .cta-band { padding: 32px 26px; flex-direction: column; align-items: flex-start; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 28px; }
  .shot-grid { grid-template-columns: repeat(3, 1fr); gap: 20px 18px; }
}

@media (max-width: 600px) {
  body { font-size: 15px; }
  h1 { font-size: 27px; }
  h2 { font-size: 21px; }
  .section { padding: 42px 0; }
  .hero__actions .btn { width: 100%; }
  .grid--2, .grid--3, .grid--4, .dl-grid { grid-template-columns: 1fr; }
  .card__media img { max-width: 160px; }
  .footer-grid { grid-template-columns: 1fr; }
  .cta-band__actions { width: 100%; }
  .cta-band__actions .btn { width: 100%; }
  .shot-grid { grid-template-columns: repeat(2, 1fr); gap: 18px 14px; }
  .stats .num { font-size: 22px; }
}

/* ---------- 21. 动效降级 / 打印 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .001ms !important; animation-duration: .001ms !important; }
}
@media print {
  .site-header, .cta-band, .site-footer, .skip-link { display: none; }
  body { background: #fff; }
}