/* 思源宋体（Noto Serif SC，与 Adobe 的 Source Han Serif SC 同一套字形）：本机装了就用本机的，
   没装就由浏览器下载页面自带的子集。子集只含页面用到的字，改了文案要重新切：
   python tools/subset_font.py <NotoSerifSC[wght].ttf> index.html fonts/ */
@font-face {
  font-family: "XGJ Serif SC";
  src: local("Source Han Serif SC"), local("Noto Serif CJK SC"), url("fonts/serif-sc-400.woff2") format("woff2");
  font-weight: 400;
  font-display: swap;
  unicode-range: U+2018-201D, U+2026, U+2E80-2EFF, U+3000-303F, U+3400-4DBF, U+4E00-9FFF, U+F900-FAFF, U+FE30-FE4F, U+FF00-FFEF;
}
@font-face {
  font-family: "XGJ Serif SC";
  src: local("Source Han Serif SC SemiBold"), local("Noto Serif CJK SC SemiBold"), url("fonts/serif-sc-600.woff2") format("woff2");
  font-weight: 500 700;
  font-display: swap;
  unicode-range: U+2018-201D, U+2026, U+2E80-2EFF, U+3000-303F, U+3400-4DBF, U+4E00-9FFF, U+F900-FAFF, U+FE30-FE4F, U+FF00-FFEF;
}

:root {
  --paper: #f5f4ed;
  --ivory: #fbfaf6;
  --sand: #ebe8dd;
  --line: #d9d5c8;
  --line-faint: #e9e6db;

  --ink: #2f2d2a;
  --text: #4b4944;
  --muted: #77756d;

  --brand: #1f4f8f;
  --brand-hover: #173d70;

  --serif: Charter, Georgia, "XGJ Serif SC", "Songti SC", "STSong", serif;
  --ui: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;

  --max: 1120px;
  --gap: 96px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--text);
  font: 17px/1.75 var(--serif);
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; height: auto; }
a { color: var(--brand); text-decoration: none; }
h1, h2, h3 { color: var(--ink); font-weight: 600; margin: 0; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 32px; }
.block { padding-top: var(--gap); }
.block > h2 { font-size: 32px; letter-spacing: .01em; line-height: 1.3; }
.sub { margin: 10px 0 36px; color: var(--muted); font-size: 16px; }

/* 顶栏：三层叠出玻璃感
   ① 整宽的纸色帘子（::before）：胶囊处是实色，往下 22px 渐隐成透明，内容滚到顶栏下面时是"溶"进纸里，不是硬切
   ② 胶囊本身 80% 象牙白 + 14px 背景模糊，透出底下内容的颜色
   ③ 一根发丝边框，不加阴影 */
.nav { position: sticky; top: 16px; z-index: 10; margin-top: 16px; padding: 0 16px; }
.nav::before {
  content: ""; position: absolute; left: 50%; top: -40px; transform: translateX(-50%);
  width: 100vw; height: calc(100% + 40px + 22px);
  background: linear-gradient(180deg, var(--paper) 0%, var(--paper) 72%, transparent 100%);
  z-index: -1; pointer-events: none;
}
.nav-in {
  max-width: calc(var(--max) - 36px); margin: 0 auto; display: flex; align-items: center; gap: 28px;
  min-height: 56px; padding: 8px 10px 8px 18px; border-radius: 999px;
  background: color-mix(in srgb, var(--ivory) 80%, transparent);
  -webkit-backdrop-filter: blur(14px); backdrop-filter: blur(14px);
  border: 1px solid color-mix(in srgb, var(--line-faint) 80%, transparent);
}
.brand { display: flex; align-items: center; gap: 8px; color: var(--ink); font-weight: 600; font-size: 18px; }
.brand-mark {
  width: 26px; height: 26px; border-radius: 8px; display: grid; place-items: center;
  background: var(--brand); color: #fff; font-size: 14px; font-weight: 600; line-height: 1;
}
.nav-links { display: flex; gap: 26px; margin-right: auto; font-size: 16px; }
.nav-links a { color: var(--ink); }
.nav-links a:hover { color: var(--brand); }
/* 首屏按钮还在视野里时，顶栏不重复放购买按钮；滚过去才出现 */
.nav .btn { transition: opacity .2s, background .15s, transform .15s; }
.nav.hide-cta .btn { opacity: 0; pointer-events: none; }

/* 按钮：和正文同一套宋体 */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-width: 158px; padding: 12px 28px; border-radius: 999px;
  border: 1px solid var(--brand); background: var(--brand); color: var(--ivory);
  font-family: var(--serif); font-size: 16px; font-weight: 500; line-height: 1.55; letter-spacing: .04em;
  transition: background .15s, border-color .15s, transform .15s;
}
.btn:hover { background: var(--brand-hover); border-color: var(--brand-hover); transform: translateY(-1px); }
.btn-sm { min-width: 0; padding: 6px 18px; font-size: 15px; }
.btn-ghost { background: var(--ivory); color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { background: var(--sand); border-color: var(--line); }

/* 首屏 */
.hero { padding-top: 64px; padding-bottom: 8px; }
.hero h1 { font-size: 76px; line-height: 1.1; letter-spacing: .02em; }
.lede { max-width: 760px; margin: 22px 0 0; font-size: 21px; line-height: 1.7; color: var(--text); }
.meta { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 12px; margin: 18px 0 0; color: var(--muted); font-size: 15px; }
.meta i { width: 3px; height: 3px; border-radius: 50%; background: var(--line); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 32px; }

/* 标签切换截图 */
.stage { margin: 0; padding: 28px; border-radius: 18px; background: var(--sand); }
.stage-frame {
  border-radius: 10px; overflow: hidden; background: #fff;
  box-shadow: 0 1px 2px rgba(40, 36, 28, .06), 0 18px 40px -16px rgba(40, 36, 28, .22);
}
.stage-frame img { transition: opacity .25s ease; }
.stage-frame img.fading { opacity: 0; }
.stage-bar { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-top: 16px; }
.stage-cap { margin: 0; font-size: 15px; color: var(--muted); }
.stage-cap b { color: var(--brand); font-weight: 600; margin-right: 12px; }
.tabs { display: flex; gap: 4px; flex-shrink: 0; }
.tabs button {
  border: 0; background: transparent; cursor: pointer;
  padding: 5px 13px; border-radius: 999px;
  font-family: var(--serif); font-size: 15px; color: var(--text);
}
.tabs button:hover { background: var(--sand); }
.tabs button[aria-selected="true"] { background: var(--brand); color: #fff; }

/* 六组能力 */
.feat {
  display: grid; grid-template-columns: 5fr 6fr; gap: 56px; align-items: center;
  padding: 40px 0; border-top: 1px solid var(--line-faint);
}
.feat:first-of-type { border-top: 0; padding-top: 0; }
.feat.flip { grid-template-columns: 6fr 5fr; }
.feat.flip .feat-text { order: 2; }
.feat h3 { font-size: 24px; margin-bottom: 14px; }
.feat ul { margin: 0; padding: 0; list-style: none; }
.feat li { position: relative; padding-left: 18px; margin: 10px 0; font-size: 16px; line-height: 1.7; }
.feat li::before {
  content: ""; position: absolute; left: 2px; top: .78em;
  width: 5px; height: 5px; border-radius: 50%; background: var(--muted);
}
.feat-shot {
  border-radius: 12px; overflow: hidden; background: #fff;
  border: 1px solid var(--line-faint);
  box-shadow: 0 14px 32px -18px rgba(40, 36, 28, .25);
}

/* 细节墙 */
.wall { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--line-faint); border: 1px solid var(--line-faint); border-radius: 14px; overflow: hidden; }
.wall li { background: var(--ivory); padding: 22px 20px 20px; }
.wall svg { width: 24px; height: 24px; fill: none; stroke: var(--brand); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.wall b { display: block; margin-top: 12px; color: var(--ink); font-size: 16px; font-weight: 600; }
.wall span { display: block; margin-top: 2px; color: var(--muted); font-size: 14px; line-height: 1.6; }

/* 数字 */
.nums { display: grid; grid-template-columns: repeat(5, 1fr); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.nums div { padding: 28px 8px 26px; text-align: center; }
.nums div + div { border-left: 1px solid var(--line-faint); }
.nums b { display: block; color: var(--ink); font-size: 40px; font-weight: 500; line-height: 1.2; font-variant-numeric: tabular-nums; }
.nums span { color: var(--muted); font-size: 15px; }

/* 购买 */
.buy {
  display: grid; grid-template-columns: 1fr 260px; gap: 40px; align-items: center;
  padding: 36px 40px; border-radius: 18px; background: var(--ivory); border: 1px solid var(--line-faint);
}
.price { margin: 0 0 14px; font-size: 15px; color: var(--muted); }
.price span { display: block; margin-top: 4px; color: var(--ink); font-size: 30px; font-weight: 600; }
.buy ul { margin: 0; padding: 0; list-style: none; }
.buy li { position: relative; padding-left: 26px; margin: 8px 0; font-size: 16px; }
.buy li::before {
  content: ""; position: absolute; left: 2px; top: .55em; width: 12px; height: 6px;
  border-left: 1.8px solid var(--brand); border-bottom: 1.8px solid var(--brand); transform: rotate(-45deg);
}
.buy-contact { text-align: center; }
.qr {
  width: 168px; height: 168px; margin: 0 auto; display: grid; place-items: center;
  border: 1px dashed var(--line); border-radius: 12px; color: var(--muted); font-size: 14px; line-height: 1.6;
}
.buy-contact p { margin: 14px 0 0; font-size: 15px; color: var(--muted); }
.buy-contact p b { margin-left: 8px; color: var(--ink); }

/* 常见问题 */
.faq { margin-top: 32px; border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  list-style: none; cursor: pointer; position: relative;
  padding: 20px 40px 20px 0; color: var(--ink); font-size: 18px; font-weight: 600;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+"; position: absolute; right: 6px; top: 50%; transform: translateY(-50%);
  color: var(--muted); font-size: 24px; font-weight: 300; transition: transform .2s;
}
.faq details[open] summary::after { transform: translateY(-50%) rotate(45deg); }
.faq details p { margin: 0 0 22px; max-width: 820px; font-size: 16px; }

/* 页脚 */
.foot { margin-top: var(--gap); padding: 40px 0 48px; border-top: 1px solid var(--line); }
.foot-in p { margin: 0; color: var(--text); font-size: 15px; }
.foot-in b { color: var(--ink); }
.foot-in .small { margin-top: 6px; color: var(--muted); font-size: 13px; }

/* 平板 */
@media (max-width: 980px) {
  .stage-bar { flex-direction: column; align-items: flex-start; }
  .tabs { flex-wrap: wrap; }
  .feat, .feat.flip { grid-template-columns: 1fr; gap: 24px; }
  .feat.flip .feat-text { order: 0; }
  .wall { grid-template-columns: repeat(3, 1fr); }
  .nums { grid-template-columns: repeat(3, 1fr); }
  .nums div:nth-child(4) { border-left: 0; }
  .nums div:nth-child(n+4) { border-top: 1px solid var(--line-faint); }
}

/* 手机 */
@media (max-width: 640px) {
  :root { --gap: 64px; }
  body { font-size: 16px; }
  .wrap { padding-left: 16px; padding-right: 16px; }
  .nav { top: 8px; margin-top: 8px; padding: 0 8px; }
  .nav-in { gap: 12px; min-height: 0; padding: 6px 6px 6px 14px; }
  .btn { min-width: 0; padding: 10px 20px; }
  .btn-sm { padding: 6px 14px; font-size: 14px; }
  .nav-links { display: none; }
  .brand { margin-right: auto; }
  .hero { padding-top: 48px; }
  .hero h1 { font-size: 48px; }
  .lede { font-size: 18px; }
  .block > h2 { font-size: 26px; }
  .stage { padding: 10px; border-radius: 12px; }
  .stage-frame { border-radius: 6px; }
  .tabs { flex-wrap: nowrap; overflow-x: auto; max-width: 100%; scrollbar-width: none; }
  .tabs::-webkit-scrollbar { display: none; }
  .tabs button { flex-shrink: 0; }
  .wall { grid-template-columns: repeat(2, 1fr); }
  .wall li { padding: 18px 14px; }
  .nums { grid-template-columns: repeat(2, 1fr); }
  .nums div:nth-child(4) { border-left: 1px solid var(--line-faint); }
  .nums div:nth-child(odd) { border-left: 0; }
  .nums div:nth-child(n+3) { border-top: 1px solid var(--line-faint); }
  .nums div:last-child { grid-column: 1 / -1; }
  .nums b { font-size: 32px; }
  .buy { grid-template-columns: 1fr; padding: 24px 20px; gap: 28px; }
}