/* ============================================================================
   SEO 落地页共用样式（2026-09-11 新增）
   /lunwen-jiangchong  /dabian-ppt  /cankao-wenxian  /jisuanji-biyesheji 四页共用。

   为什么不复用 index.html 那套：首页的样式是跟七万个粒子的 WebGL 场景绑在一起
   的，整段抄过来会连带一堆用不上的动画与滚动观察器。落地页要的是「点开立刻出
   字」——它是给从搜索结果点进来的人看的第一屏，慢一秒就跳走。所以这里从零写一
   套纯静态的，无脚本、无动画、无 WebGL，只借首页的配色（黑底 / 淡紫 #6156eb /
   同一套字体栈），让人点进来不觉得换了个站。

   走外链 .css 而不是四份内联：改一处四页生效。它不在 site_common.conf 的图片
   正则里，所以走 location / 正常返回，且已在 gzip_types 里。
   ========================================================================== */

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

html {
  background: #000;
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body {
  background: #000;
  color: #fff;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  overflow-x: hidden;
  line-height: 1.9;
  /* 首页顶部那层淡紫辉光的静态版，不用 WebGL 也能接上同一个视觉基调 */
  background-image: radial-gradient(ellipse at 50% -10%, rgba(97,86,235,0.2), transparent 55%);
  background-repeat: no-repeat;
  background-size: 100% 900px;
}

::selection { background: rgba(97,86,235,0.6); }

.mono { font-family: "JetBrains Mono", Consolas, monospace; }

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 6vw;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.topbar .brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 15px;
  color: #fff;
  text-decoration: none;
  letter-spacing: 0.02em;
}
.topbar .brand img { height: 26px; width: auto; border-radius: 6px; }
.topbar .back {
  font-size: 13px;
  color: rgba(169,155,255,0.85);
  text-decoration: none;
  white-space: nowrap;
}

/* ---------- 主体 ---------- */
main {
  max-width: 860px;
  margin: 0 auto;
  padding: 7vh 6vw 4vh;
}

/* 面包屑：给搜索引擎一条层级线索，也让人知道自己在哪一层 */
.crumb {
  font-size: 12px;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.04em;
}
.crumb a {
  color: rgba(255,255,255,0.5);
  text-decoration: none;
}

h1 {
  margin-top: 14px;
  font-size: clamp(26px, 5.2vw, 40px);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.01em;
}
h1 .hot { color: rgba(169,155,255,0.95); }

.lede {
  margin-top: 20px;
  font-size: 15px;
  line-height: 2;
  color: rgba(255,255,255,0.6);
}

h2 {
  margin-top: 54px;
  padding-top: 26px;
  border-top: 1px solid rgba(255,255,255,0.08);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: rgba(255,255,255,0.92);
}

h3 {
  margin-top: 30px;
  font-size: 15px;
  font-weight: 600;
  color: rgba(255,255,255,0.85);
}

p {
  margin-top: 14px;
  font-size: 14px;
  line-height: 2.1;
  color: rgba(255,255,255,0.52);
}

b, strong { color: rgba(255,255,255,0.8); font-weight: 600; }

a { color: rgba(169,155,255,0.85); }

main a {
  text-decoration: none;
  border-bottom: 1px solid rgba(169,155,255,0.35);
}

ul, ol { margin-top: 14px; padding-left: 20px; }
li {
  margin-top: 9px;
  font-size: 14px;
  line-height: 2;
  color: rgba(255,255,255,0.52);
}
li::marker { color: rgba(169,155,255,0.6); }

/* ---------- 步骤条 ---------- */
.steps { counter-reset: s; list-style: none; padding-left: 0; }
.steps li {
  counter-increment: s;
  position: relative;
  padding-left: 38px;
  margin-top: 14px;
}
.steps li::before {
  content: counter(s);
  position: absolute;
  left: 0;
  top: 2px;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: rgba(97,86,235,0.22);
  border: 1px solid rgba(169,155,255,0.4);
  color: rgba(199,190,255,0.95);
  font-family: "JetBrains Mono", Consolas, monospace;
  font-size: 12px;
  line-height: 22px;
  text-align: center;
}

/* ---------- 要点卡 ---------- */
.cards {
  margin-top: 22px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
}
.card {
  padding: 20px 20px 22px;
  border: 1px solid rgba(255,255,255,0.09);
  border-radius: 14px;
  background: rgba(255,255,255,0.03);
}
.card b { display: block; font-size: 14px; margin-bottom: 6px; }
.card p { margin-top: 0; font-size: 13px; line-height: 1.95; }

/* ---------- 提示条 ---------- */
.note {
  margin-top: 22px;
  padding: 16px 18px;
  border-left: 2px solid rgba(169,155,255,0.5);
  border-radius: 0 10px 10px 0;
  background: rgba(97,86,235,0.08);
}
.note p { margin-top: 0; color: rgba(255,255,255,0.6); }
.note p + p { margin-top: 10px; }

/* ---------- 问答 ---------- */
.qa { margin-top: 26px; }
.qa dt {
  margin-top: 22px;
  font-size: 14px;
  font-weight: 600;
  color: rgba(255,255,255,0.85);
}
.qa dd {
  margin-top: 8px;
  margin-left: 0;
  font-size: 14px;
  line-height: 2.05;
  color: rgba(255,255,255,0.52);
}

/* ---------- 行动按钮 ---------- */
.cta {
  margin-top: 44px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px 14px;
  align-items: center;
}
.cta a {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  border: none;
}
.cta .primary { background: rgba(97,86,235,0.9); color: #fff; }
.cta .ghost {
  border: 1px solid rgba(255,255,255,0.2);
  color: rgba(255,255,255,0.8);
}

/* ---------- 相邻页互链 ---------- */
.sibling {
  margin-top: 56px;
  padding-top: 26px;
  border-top: 1px solid rgba(255,255,255,0.08);
}
.sibling h2 {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
  font-size: 14px;
  color: rgba(255,255,255,0.6);
}
.sibling ul {
  margin-top: 16px;
  padding-left: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 10px 22px;
}
.sibling li { margin-top: 0; }
.sibling a { font-size: 13px; }

/* ---------- 页脚 ---------- */
footer {
  margin-top: 20px;
  padding: 30px 6vw 40px;
  border-top: 1px solid rgba(255,255,255,0.08);
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: rgba(255,255,255,0.35);
}
footer a { color: rgba(255,255,255,0.45); text-decoration: none; }

@media (max-width: 620px) {
  main { padding-top: 5vh; }
  h2 { margin-top: 42px; }
  .cta a { width: 100%; text-align: center; }
}