/* 设计系统 v3 — OpenAI 官网风格：纯白底 + 渐变色块卡片 + 玻璃 mockup + 黑胶囊 CTA */
:root {
  --ink: #0d0d12;
  --ink2: #55555f;
  --ink3: #8a8a94;
  --edge: #e8e8ee;
  --edge2: #d8d8e0;
  --accent: #2563eb;
  --mono: ui-monospace, "Cascadia Code", Consolas, "SF Mono", Menlo, monospace;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #fff; color: var(--ink); line-height: 1.75;
  -webkit-font-smoothing: antialiased; overflow-x: hidden;
}
::selection { background: #dbe7ff; color: #0d0d12; }
a { color: var(--accent); text-decoration: none; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 28px; }

/* ===== 导航 ===== */
.topnav { position: sticky; top: 0; z-index: 20; background: rgba(255, 255, 255, 0.85); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); border-bottom: 1px solid var(--edge); }
.navrow { display: flex; align-items: center; justify-content: space-between; height: 58px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 9px; font-family: var(--mono); font-weight: 700; font-size: 15px; color: var(--ink); }
.brand .orb { width: 11px; height: 11px; border-radius: 50%; background: radial-gradient(circle at 32% 30%, #9db4ff, #2563eb 70%); }
.brand-dim { color: var(--ink3); font-weight: 400; }
.navlinks { display: flex; gap: 4px; }
.navlinks a { color: var(--ink2); font-size: 14px; padding: 6px 14px; border-radius: 999px; transition: all .15s; }
.navlinks a:hover { color: var(--ink); background: #f2f2f5; }
.navlinks a.on { color: var(--ink); background: #ececf1; }
.navcta {
  display: inline-flex; align-items: center; gap: 6px; background: #0d0d12; color: #fff;
  font-size: 13.5px; font-weight: 500; border-radius: 999px; padding: 8px 18px; transition: all .15s; white-space: nowrap;
}
.navcta:hover { background: #2a2a33; transform: translateY(-1px); }

/* ===== Hero（OpenAI 式一句话居中） ===== */
.ohero { text-align: center; padding: 58px 0 40px; }
.ohero p { font-size: 17px; color: var(--ink2); }
.ohero .ohero-sub { font-size: 13.5px; color: var(--ink3); font-family: var(--mono); margin-top: 8px; }

/* ===== 卡片网格 ===== */
.ogrid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 26px 22px; padding-bottom: 30px; }
.ocard { display: block; color: var(--ink); }
.othumb {
  position: relative; height: 176px; border-radius: 12px; overflow: hidden;
  transition: filter .2s, transform .25s;
}
.ocard:hover .othumb { filter: brightness(1.07); transform: translateY(-2px); }
.art { position: absolute; inset: 0; width: 100%; height: 100%; padding: 8px 10px; transition: transform .25s; }
.ocard:hover .art { transform: translateY(-2px) scale(1.03); }
.t-blue { background: linear-gradient(135deg, #60a5fa, #2563eb); }
.t-cyan { background: linear-gradient(135deg, #67e8f9, #0e9fd8); }
.t-purple { background: linear-gradient(135deg, #a78bfa, #7c3aed); }
.t-indigo { background: linear-gradient(135deg, #818cf8, #4f46e5); }
.t-sky { background: linear-gradient(135deg, #7dd3fc, #0284c7); }

/* 色块内的玻璃 mockup 窗口 */
.mock { position: absolute; inset: 20px 22px; background: rgba(255, 255, 255, 0.18); border: 1px solid rgba(255, 255, 255, 0.35); border-radius: 12px; backdrop-filter: blur(5px); -webkit-backdrop-filter: blur(5px); padding: 11px 14px; }
.mbar { display: flex; gap: 6px; align-items: center; padding-bottom: 9px; border-bottom: 1px solid rgba(255, 255, 255, 0.25); }
.mbar i { width: 7px; height: 7px; border-radius: 50%; background: rgba(255, 255, 255, 0.55); }
.mbar .mtitle { margin-left: 6px; font-family: var(--mono); font-size: 10px; color: rgba(255, 255, 255, 0.65); }
.mline { height: 6px; border-radius: 3px; background: rgba(255, 255, 255, 0.42); margin-top: 11px; }
.mline.short { width: 55%; }
.mchip {
  position: absolute; left: 14px; bottom: 13px; background: rgba(255, 255, 255, 0.92); color: #1f2430;
  font-family: var(--mono); font-size: 11px; padding: 3.5px 12px; border-radius: 999px;
  display: inline-flex; align-items: center; gap: 6px; box-shadow: 0 4px 14px rgba(20, 30, 80, 0.25);
}
.mchip svg { flex-shrink: 0; }
.mico {
  position: absolute; right: 13px; bottom: 12px; width: 32px; height: 32px; border-radius: 9px;
  background: rgba(255, 255, 255, 0.25); border: 1px solid rgba(255, 255, 255, 0.45);
  display: flex; align-items: center; justify-content: center; color: #fff;
}
.ocard h3 { font-size: 15.5px; font-weight: 600; letter-spacing: -.2px; margin: 14px 0 4px; }
.ocard > p { font-size: 13.5px; color: var(--ink2); line-height: 1.6; }
.otags { display: flex; gap: 14px; margin-top: 10px; flex-wrap: wrap; }
.otags span { font-size: 12px; color: var(--ink3); }
.otags span.cat { color: var(--ink2); font-weight: 500; }

/* ===== 区块标题 ===== */
.sec { padding: 30px 0 6px; }
.sec-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 20px; }
.sec-head h2 { font-size: 20px; font-weight: 600; letter-spacing: -.3px; }
.sec-head a { font-size: 13.5px; color: var(--ink2); }
.sec-head a:hover { color: var(--ink); }

/* ===== 详情页（文档风） ===== */
.detailwrap { max-width: 800px; margin: 0 auto; padding: 40px 28px 60px; }
.crumb { font-family: var(--mono); font-size: 12.5px; color: var(--ink3); margin-bottom: 22px; }
.crumb a { color: var(--ink2); }
.crumb a:hover { color: var(--ink); }
.dhead h1 { font-size: 32px; font-weight: 700; letter-spacing: -.8px; margin-bottom: 10px; line-height: 1.3; }
.d-desc { font-size: 15.5px; color: var(--ink2); margin-bottom: 18px; }
.d-actions { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; padding-bottom: 22px; border-bottom: 1px solid var(--edge); margin-bottom: 10px; }
.btn {
  font-family: var(--mono); font-size: 12.5px; cursor: pointer; display: inline-flex; align-items: center; gap: 7px;
  border-radius: 999px; padding: 8px 18px; transition: all .15s; text-decoration: none;
  background: #fff; color: var(--ink); border: 1px solid var(--edge2);
}
.btn:hover { border-color: #b9b9c4; }
.btn.primary { background: #0d0d12; color: #fff; border-color: #0d0d12; }
.btn.primary:hover { background: #2a2a33; }
.btn.ok { background: #e7f6ee; border-color: #b5e2cc; color: #177a58; }
.d-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; }
.d-tags span { font-family: var(--mono); font-size: 11.5px; color: var(--ink2); background: #f2f2f5; border-radius: 999px; padding: 3px 12px; }

/* markdown 正文 */
.mdbody { font-size: 15px; color: #303038; }
.mdbody strong { color: var(--ink); font-weight: 600; }
.mdbody .md-h { font-size: 19px; font-weight: 650; color: var(--ink); letter-spacing: -.3px; margin: 30px 0 10px; }
.mdbody h3.md-h { font-size: 16px; }
.mdbody p { margin: 10px 0; }
.mdbody ul, .mdbody ol { margin: 10px 0 10px 22px; }
.mdbody li { margin: 5px 0; }
.mdbody li::marker { color: var(--accent); }
.mdbody blockquote { border-left: 2px solid var(--accent); background: #f6f8ff; border-radius: 0 10px 10px 0; padding: 10px 18px; margin: 14px 0; color: var(--ink); }
.mdbody code { font-family: var(--mono); font-size: 12.8px; background: #f2f2f5; border: 1px solid var(--edge); border-radius: 6px; padding: 1px 7px; color: #1f2430; }
.mdbody .code { position: relative; background: #16181f; border: 1px solid #2a2d38; border-radius: 12px; padding: 18px 20px; margin: 14px 0; overflow-x: auto; }
.mdbody .code code { background: none; border: none; padding: 0; font-size: 12.8px; color: #d6dae6; line-height: 1.7; white-space: pre; }
.mdbody .code .lang { position: absolute; top: 8px; right: 14px; font-family: var(--mono); font-size: 10.5px; color: #6a6e7c; }
.mdbody .tblwrap { overflow-x: auto; margin: 14px 0; border: 1px solid var(--edge); border-radius: 10px; }
.mdbody table { border-collapse: collapse; width: 100%; font-size: 13.5px; }
.mdbody th { text-align: left; color: var(--ink); font-weight: 600; padding: 9px 14px; background: #f7f7f9; border-bottom: 1px solid var(--edge); white-space: nowrap; }
.mdbody td { padding: 9px 14px; border-bottom: 1px solid var(--edge); }
.mdbody td:last-child, .mdbody th:last-child { border-right: none; }
.mdbody a { border-bottom: 1px solid rgba(37, 99, 235, 0.35); }
.mdbody a:hover { border-bottom-color: var(--accent); }

/* ===== AI 通道页 ===== */
.aihero { text-align: center; padding: 58px 0 30px; }
.aihero h1 { font-size: clamp(30px, 4.5vw, 44px); font-weight: 700; letter-spacing: -1px; margin-bottom: 12px; }
.aihero p { font-size: 16px; color: var(--ink2); max-width: 620px; margin: 0 auto; }
.ailist { max-width: 780px; margin: 0 auto; padding-bottom: 40px; }
.aicard { background: #fff; border: 1px solid var(--edge); border-radius: 16px; padding: 26px 30px; margin-bottom: 14px; transition: border-color .2s, box-shadow .2s; }
.aicard:hover { border-color: var(--edge2); box-shadow: 0 8px 24px rgba(20, 24, 50, 0.06); }
.aicard .ai-no { font-family: var(--mono); font-size: 12px; color: var(--accent); letter-spacing: 2px; display: block; margin-bottom: 10px; }
.aicard h3 { font-size: 17px; font-weight: 600; margin-bottom: 6px; }
.aicard p { font-size: 14px; color: var(--ink2); }
.aicard p code { font-family: var(--mono); font-size: 12px; background: #f2f2f5; border: 1px solid var(--edge); border-radius: 6px; padding: 1px 7px; }
.aicard .btn { margin-top: 12px; }

/* ===== 页脚 ===== */
footer { border-top: 1px solid var(--edge); margin-top: 30px; padding: 26px 0 44px; }
.footrow { display: flex; align-items: center; justify-content: center; gap: 9px; font-family: var(--mono); font-size: 12.5px; color: var(--ink3); flex-wrap: wrap; }
.footrow .orb { width: 9px; height: 9px; border-radius: 50%; background: radial-gradient(circle at 32% 30%, #9db4ff, #2563eb 70%); }
.footrow a { color: var(--ink2); border-bottom: 1px dashed #c9c9d2; }

/* ===== 动效 ===== */
.rv { opacity: 0; transform: translateY(14px); transition: opacity .5s ease, transform .5s ease; }
.rv.in { opacity: 1; transform: none; }

@media (max-width: 880px) {
  .ogrid { grid-template-columns: 1fr; }
  .navlinks { display: none; }
  .ohero { padding: 40px 0 30px; }
  .detailwrap { padding: 28px 22px 50px; }
}
@media (prefers-reduced-motion: reduce) {
  .rv { opacity: 1; transform: none; transition: none; }
}