/* =========================================================
   全站统一主题（亮蓝）
   ========================================================= */
:root{
  --bg:#f6f8fc;
  --bg-glow-1:rgba(59,130,246,.06);
  --bg-glow-2:rgba(96,165,250,.05);
  --card:#fff;
  --line:#e8edf5;
  --line-2:#eef2f8;

  --ink:#0f172a;
  --text:#334155;
  --text-2:#475569;
  --muted:#94a3b8;
  --muted-lt:#a9b4c5;
  --dot:#cbd5e1;

  --accent:#1d4ed8;
  --accent-2:#3b82f6;
  --accent-3:#60a5fa;
  --accent-soft:#eff5ff;
  --accent-glow:rgba(37,99,235,.18);
  --accent-grad:linear-gradient(135deg,#1d4ed8,#3b82f6);
  --top-line:linear-gradient(90deg,#1d4ed8,#3b82f6,#60a5fa,#93c5fd);
  --h1-grad:linear-gradient(135deg,#0f172a 0%,#1e3a8a 100%);
  --mark:#dbeafe;
  --selection-bg:#bfdbfe;
  --selection-color:#0f172a;

  --header-bg:
    radial-gradient(900px 300px at 15% -60%, rgba(255,255,255,.28), transparent 60%),
    radial-gradient(700px 300px at 90% 130%, rgba(147,197,253,.45), transparent 60%),
    linear-gradient(120deg,#1e3a8a 0%,#2563eb 58%,#3b82f6 100%);
  --header-grid:rgba(255,255,255,.06);
  --header-glow:rgba(255,255,255,.28);
  --header-tip-bg:rgba(255,255,255,.14);
  --header-tip-border:rgba(255,255,255,.24);
  --header-tip-dot:#4ade80;

  --nav-hover-bg:#f1f5fb;
  --nav-active-bg:linear-gradient(135deg,#eff6ff,#dbeafe);
  --nav-active-ring:#dbeafe;
  --search-focus-border:#bfdbfe;
  --search-focus-ring:rgba(59,130,246,.1);

  --comment-bg:#fbfcfe;
  --comment-bg-hover:#f7faff;
  --comment-hover-border:#c7dbff;

  --rank-bg:#f1f5fb;
  --rank-color:#94a3b8;
  --rank-1:linear-gradient(135deg,#f97316,#fb923c);
  --rank-1-shadow:rgba(249,115,22,.6);
  --rank-2:linear-gradient(135deg,#1d4ed8,#3b82f6);
  --rank-2-shadow:rgba(29,78,216,.6);
  --rank-3:linear-gradient(135deg,#0ea5e9,#38bdf8);
  --rank-3-shadow:rgba(14,165,233,.55);

  --footer-bg:linear-gradient(180deg,#fff 0%,#fafbff 100%);
  --footer-nav-bg:#f4f7fc;
  --footer-nav-hover:linear-gradient(135deg,#eff6ff,#dbeafe);

  --shadow-md:0 4px 16px rgba(15,23,42,.06),0 1px 3px rgba(15,23,42,.04);
  --shadow-lg:0 20px 40px -18px rgba(15,23,42,.18),0 4px 12px rgba(15,23,42,.05);
}

/* 基础重置 */
*{margin:0;padding:0;box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body{
  font-family:system-ui,-apple-system,"SF Pro Text","Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:var(--bg); color:var(--text);
  font-size:16px; line-height:1.8;
  -webkit-font-smoothing:antialiased; -moz-osx-font-smoothing:grayscale;
  padding-bottom:0;
  background-image:
    radial-gradient(1200px 500px at 50% -200px, var(--bg-glow-1), transparent 70%),
    radial-gradient(800px 400px at 100% 0%, var(--bg-glow-2), transparent 60%);
  background-attachment:fixed;
}
a{color:inherit;}
img{max-width:100%;display:block;}
ul{list-style:none;}
::selection{background:var(--selection-bg);color:var(--selection-color);}
.container{width:100%;max-width:1180px;margin:0 auto;padding:0 20px;}

/* 头部 */
.header{
  position:relative;overflow:hidden;padding:26px 0;color:#fff;
  background:var(--header-bg); isolation:isolate;
}
.header::before{
  content:"";position:absolute;inset:0;
  background-image:
    linear-gradient(var(--header-grid) 1px,transparent 1px),
    linear-gradient(90deg,var(--header-grid) 1px,transparent 1px);
  background-size:32px 32px;
  mask-image:radial-gradient(600px 200px at 50% 0%,#000 20%,transparent 90%);
  -webkit-mask-image:radial-gradient(600px 200px at 50% 0%,#000 20%,transparent 90%);
  z-index:-1;opacity:.9;
}
.header::after{
  content:"";position:absolute;left:50%;top:-140px;transform:translateX(-50%);
  width:680px;height:320px;
  background:radial-gradient(closest-side, var(--header-glow), transparent 70%);
  filter:blur(30px);z-index:-1;pointer-events:none;
}
.header-inner{
  display:flex;align-items:center;justify-content:space-between;
  gap:18px;flex-wrap:wrap;
}
.header-left{display:flex;align-items:center;gap:20px;min-width:0;flex-wrap:wrap;}

.brand{display:flex;align-items:center;gap:14px;text-decoration:none;flex-shrink:0;}
.brand-mark{
  width:48px;height:48px;flex-shrink:0;border-radius:14px;
  display:grid;place-items:center;font-size:21px;font-weight:800;color:#fff;
  background:rgba(255,255,255,.18);border:1px solid rgba(255,255,255,.3);
  backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);
  box-shadow:inset 0 1px 0 rgba(255,255,255,.35);letter-spacing:-1px;
}
.logo-text{font-size:22px;font-weight:700;letter-spacing:-.4px;line-height:1.2;color:#fff;}
.site-branding{display:block;font-size:12.5px;font-weight:400;opacity:.85;line-height:1.5;letter-spacing:.2px;margin-top:2px;}

.header-slogan{
  position:relative;
  padding-left:20px;
  font-size:13.5px;
  color:rgba(255,255,255,.9);
  letter-spacing:.3px;
  line-height:1.5;
  white-space:nowrap;
}
.header-slogan::before{
  content:"";
  position:absolute;
  left:0;top:50%;transform:translateY(-50%);
  width:1px;height:26px;
  background:rgba(255,255,255,.28);
}

.header-tip{
  display:inline-flex;align-items:center;gap:8px;font-size:12.5px;
  padding:8px 16px;border-radius:999px;
  background:var(--header-tip-bg);border:1px solid var(--header-tip-border);
  color:#fff;white-space:nowrap;flex-shrink:0;
  backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);
}
.header-tip::before{
  content:"";width:6px;height:6px;border-radius:50%;
  background:var(--header-tip-dot);box-shadow:0 0 8px var(--header-tip-dot);
  animation:pulse 2s infinite;
}
@keyframes pulse{0%,100%{opacity:1;}50%{opacity:.5;}}

.platform-desc{
  text-align:center;color:var(--muted);font-size:13px;line-height:1.75;
  margin:22px auto 20px;max-width:820px;padding:0 10px;
}

.search-section{margin-bottom:26px;}
.search-form{
  display:flex;gap:0;align-items:center;max-width:600px;margin:0 auto;
  background:var(--card);padding:6px;border-radius:999px;
  border:1px solid var(--line);
  box-shadow:0 1px 2px rgba(15,23,42,.04),0 12px 32px -12px rgba(15,23,42,.12);
  transition:box-shadow .3s,border-color .3s,transform .3s;
}
.search-form:focus-within{
  border-color:var(--search-focus-border);
  box-shadow:0 0 0 4px var(--search-focus-ring),0 16px 40px -14px var(--accent-glow);
  transform:translateY(-1px);
}
.search-input{
  flex:1;min-width:0;height:44px;border:none;background:transparent;
  padding:0 20px;font-size:15px;color:var(--ink);outline:none;font-family:inherit;
}
.search-input::placeholder{color:var(--muted-lt);}
.search-btn{
  height:44px;padding:0 28px;border:none;border-radius:999px;
  background:var(--accent-grad);color:#fff;font-size:14.5px;font-weight:600;
  cursor:pointer;transition:all .25s;font-family:inherit;letter-spacing:.3px;
  box-shadow:0 6px 16px -6px var(--accent-glow);
}
.search-btn:hover{transform:translateY(-1px);box-shadow:0 10px 22px -8px var(--accent-glow);}
.search-btn:active{transform:translateY(0);}

.nav-wrap{
  position:sticky;top:0;z-index:60;
  background:rgba(255,255,255,.82);
  backdrop-filter:saturate(180%) blur(14px);
  -webkit-backdrop-filter:saturate(180%) blur(14px);
  border-top:1px solid var(--line-2);
  border-bottom:1px solid var(--line);
  margin-bottom:30px;
}
.nav ul{display:flex;justify-content:center;gap:2px;padding:8px 0;}
.nav a{
  display:flex;align-items:center;gap:7px;padding:9px 16px;border-radius:10px;
  font-size:14.5px;color:var(--text-2);text-decoration:none;white-space:nowrap;
  transition:all .2s;font-weight:500;
}
.nav a i{font-size:13px;opacity:.75;}
.nav a:hover{background:var(--nav-hover-bg);color:var(--ink);}
.nav a.active{
  background:var(--nav-active-bg);color:var(--accent);font-weight:600;
  box-shadow:inset 0 0 0 1px var(--nav-active-ring);
}
.nav a.active i{opacity:1;}

.main{margin:0 auto 12px;}
.row{display:flex;gap:24px;align-items:flex-start;}

.article{
  flex:1;min-width:0;background:var(--card);
  padding:44px 48px 40px;border-radius:0;
  border:1px solid var(--line);box-shadow:var(--shadow-lg);
  overflow:hidden;
}
.breadcrumb{font-size:12.5px;color:var(--muted);margin-bottom:20px;line-height:1.9;letter-spacing:.2px;}
.breadcrumb a{color:var(--muted);text-decoration:none;transition:color .2s;}
.breadcrumb a:hover{color:var(--accent);}

.article h1{
  font-size:32px;line-height:1.4;font-weight:800;letter-spacing:-.6px;
  color:var(--ink);margin-bottom:18px;
  background:var(--h1-grad);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;
}
.article .info{
  display:flex;flex-wrap:wrap;gap:8px 24px;font-size:13px;color:var(--muted);
  padding-bottom:22px;margin-bottom:30px;
  border-bottom:1px solid var(--line-2);position:relative;
}
.article .info::after{
  content:"";position:absolute;bottom:-1px;left:0;width:72px;height:2px;
  background:var(--accent-grad);border-radius:2px;
}
.article .info span{display:inline-flex;align-items:center;gap:7px;}
.article .info span i{font-size:11px;color:var(--accent-3);}

.article .content{font-size:17px;line-height:1.95;color:var(--text);letter-spacing:.1px;}
.article .content p{margin:0 0 1.2em;}
.article .content h2{
  position:relative;font-size:21px;font-weight:800;color:var(--ink);
  margin:40px 0 18px;padding-left:18px;line-height:1.5;letter-spacing:-.3px;
}
.article .content h2::before{
  content:"";position:absolute;left:0;top:.3em;width:5px;height:1.05em;
  border-radius:3px;background:var(--accent-grad);
  box-shadow:0 0 12px var(--accent-glow);
}
.article .content strong{
  font-weight:700;color:var(--ink);
  padding:0 3px;border-radius:3px;
}
.article .content ul,.article .content ol{margin:12px 0 20px 22px;}
.article .content li{margin-bottom:8px;}
.article .content li::marker{color:var(--accent-3);}

.article .content img{
  display:block;
  margin:24px auto;
  border-radius:10px;
  box-shadow:0 6px 22px rgba(15,23,42,.1);
  max-width:100%;
  height:auto;
}
.article .content p img{margin:12px auto;}
.article .content img + em,
.article .content img + i{
  display:block;
  text-align:center;
  font-size:13px;
  color:var(--muted);
  margin-top:-16px;
  margin-bottom:20px;
  font-style:normal;
}

.comment-section{margin-top:44px;}
.comment-title{
  display:flex;align-items:center;gap:10px;font-size:18px;font-weight:800;
  color:var(--ink);margin-bottom:20px;padding-bottom:14px;
  border-bottom:1px solid var(--line-2);letter-spacing:-.2px;
}
.comment-title i{
  color:var(--accent);font-size:16px;padding:7px;border-radius:9px;
  background:var(--accent-soft);
}
.comment-item{
  position:relative;background:var(--comment-bg);border:1px solid var(--line-2);
  border-radius:14px;padding:16px 18px;margin-bottom:12px;
  transition:all .25s;
}
.comment-item:hover{
  border-color:var(--comment-hover-border);background:var(--comment-bg-hover);
  transform:translateX(2px);
  box-shadow:0 8px 20px -12px var(--accent-glow);
}
.comment-author{
  display:flex;align-items:center;gap:10px;margin-bottom:8px;
  font-size:14.5px;font-weight:600;color:var(--ink);
}
.avatar-letter{
  display:inline-flex;align-items:center;justify-content:center;
  width:34px;height:34px;flex-shrink:0;border-radius:50%;
  color:#fff;font-size:14px;font-weight:700;background:#795548;
  box-shadow:0 2px 6px rgba(15,23,42,.15);letter-spacing:0;
}
.comment-time{margin-left:auto;font-size:12px;font-weight:400;color:var(--muted-lt);letter-spacing:.2px;}
.comment-text{font-size:14.5px;line-height:1.8;color:var(--text-2);padding-left:44px;}
.comment-text strong{color:var(--accent);font-weight:600;}

.related{
  background:transparent;
  border:none;
  border-radius:0;
  box-shadow:none;
  padding:0;
  margin-top:44px;
}
.related h3{
  display:flex;
  align-items:center;
  gap:10px;
  font-size:18px;
  font-weight:800;
  color:var(--ink);
  margin:0 0 20px;
  padding:0 0 14px 0;
  border-bottom:1px solid var(--line-2);
  letter-spacing:-.2px;
  position:static;
}
.related h3::before{content:none;}
.related h3 i{
  color:var(--accent);
  font-size:16px;
  padding:7px;
  border-radius:9px;
  background:var(--accent-soft);
  flex-shrink:0;
}
.related ul li{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:11px 0;
  border-bottom:1px dashed var(--line-2);
}
.related ul li:last-child{border-bottom:none;}
.related ul li a{
  position:relative;
  color:var(--text-2);
  font-size:15px;
  text-decoration:none;
  line-height:1.6;
  padding-left:18px;
  transition:color .2s,padding .25s;
}
.related ul li a::before{
  content:"";
  position:absolute;
  left:0;top:50%;
  width:6px;height:6px;
  border-radius:50%;
  background:var(--dot);
  transform:translateY(-50%);
  transition:background .2s,box-shadow .2s;
}
.related ul li a:hover{color:var(--accent);padding-left:22px;}
.related ul li a:hover::before{
  background:var(--accent);
  box-shadow:0 0 10px var(--accent-glow);
}
.related ul li span{
  flex-shrink:0;
  font-size:12.5px;
  color:var(--muted-lt);
  font-variant-numeric:tabular-nums;
  letter-spacing:.3px;
}

.sidebar{width:312px;flex-shrink:0;}
.sidebar .box{
  background:var(--card);border:1px solid var(--line);
  border-radius:20px;padding:24px 22px 12px;
  margin-bottom:20px;box-shadow:var(--shadow-md);
}
.sidebar h4{
  position:relative;font-size:15px;font-weight:800;color:var(--ink);
  margin-bottom:10px;padding-left:16px;letter-spacing:-.2px;
}
.sidebar h4::before{
  content:"";position:absolute;left:0;top:50%;transform:translateY(-50%);
  width:5px;height:16px;border-radius:3px;background:var(--accent-grad);
  box-shadow:0 0 10px var(--accent-glow);
}
.sidebar .box ul{counter-reset:rank;}
.sidebar .box ul li{
  counter-increment:rank;display:flex;align-items:flex-start;gap:11px;
  padding:11px 0;border-bottom:1px dashed var(--line-2);
  font-size:14.5px;line-height:1.65;
}
.sidebar .box ul li:last-child{border-bottom:none;}
.sidebar .box ul li::before{
  content:counter(rank,decimal);flex-shrink:0;
  width:20px;height:20px;margin-top:3px;border-radius:7px;
  display:grid;place-items:center;font-size:11px;font-weight:800;
  color:var(--rank-color);background:var(--rank-bg);
  font-variant-numeric:tabular-nums;letter-spacing:-.3px;
  transition:all .25s;
}
.sidebar .box ul li:nth-child(1)::before{background:var(--rank-1);color:#fff;box-shadow:0 4px 12px -4px var(--rank-1-shadow);}
.sidebar .box ul li:nth-child(2)::before{background:var(--rank-2);color:#fff;box-shadow:0 4px 12px -4px var(--rank-2-shadow);}
.sidebar .box ul li:nth-child(3)::before{background:var(--rank-3);color:#fff;box-shadow:0 4px 12px -4px var(--rank-3-shadow);}
.sidebar .box ul li a{color:var(--text-2);text-decoration:none;transition:color .2s;}
.sidebar .box ul li:hover a{color:var(--accent);}
.sidebar .box ul li:hover::before{transform:scale(1.08);}

/* =========================================================
   页脚（通栏）
   ========================================================= */
.footer{
  margin-top:56px;
  padding:40px 0 32px;
  text-align:center;
  font-size:13.5px;
  color:var(--muted);
  background:var(--footer-bg);
  border-top:1px solid var(--line);
  border-radius:0;
  box-shadow:0 -4px 12px rgba(15,23,42,.03);
}
.footer-nav{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 10px;margin-bottom:18px;}
.footer-nav a{
  color:var(--text-2);text-decoration:none;font-size:13.5px;
  padding:7px 15px;border-radius:999px;background:var(--footer-nav-bg);
  transition:all .25s;font-weight:500;
}
.footer-nav a:hover{
  background:var(--footer-nav-hover);color:var(--accent);transform:translateY(-1px);
}
.footer p{margin:8px 0;line-height:1.85;}
.footer p a{text-decoration:none;color:var(--muted);transition:color .2s;}
.footer p a:hover{color:var(--accent);}
.footer .copyright{
  padding-top:16px;margin-top:16px;border-top:1px solid var(--line-2);
  font-size:13px;color:var(--text-2);font-weight:500;
}
.footer .disclaimer{font-size:12px;color:var(--muted-lt);max-width:900px;margin:14px auto 0 !important;line-height:1.8;}

/* 返回顶部 */
.back-top{
  position:fixed;right:24px;bottom:24px;z-index:99;
  width:44px;height:44px;border-radius:50%;
  background:var(--accent-grad);color:#fff;
  display:grid;place-items:center;
  font-size:16px;
  box-shadow:0 8px 22px -6px var(--accent-glow);
  cursor:pointer;
  opacity:0;visibility:hidden;
  transform:translateY(10px);
  transition:opacity .28s,visibility .28s,transform .28s,box-shadow .25s;
  border:none;
}
.back-top.show{opacity:1;visibility:visible;transform:translateY(0);}
.back-top:hover{transform:translateY(-3px);box-shadow:0 12px 28px -8px var(--accent-glow);}
.back-top:active{transform:translateY(-1px);}

@media (max-width:960px){
  .row{flex-direction:column;}
  .sidebar{width:100%;}
  .article{padding:30px 26px 28px;}
  .article h1{font-size:24px;}
  .article .content{font-size:16.5px;}
  .comment-text{padding-left:0;}
}
@media (max-width:768px){
  .container{padding:0 16px;}
  .header{padding:20px 0;}
  .header-tip{display:none;}
  .header-slogan{display:none;}
  .logo-text{font-size:19px;}
  .brand-mark{width:42px;height:42px;border-radius:12px;font-size:18px;}
  .site-branding{font-size:12px;}
  .platform-desc{font-size:12.5px;margin:16px auto 16px;}
  .search-form{padding:5px;}
  .search-input{height:42px;font-size:14.5px;padding:0 16px;}
  .search-btn{height:42px;padding:0 22px;font-size:14px;}
  .nav ul{justify-content:flex-start;flex-wrap:nowrap;overflow-x:auto;padding:8px 0;scrollbar-width:none;}
  .nav ul::-webkit-scrollbar{display:none;}
  .nav a{padding:8px 14px;font-size:14px;}
  .article h1{font-size:22px;letter-spacing:-.4px;}
  .related ul li{flex-direction:column;align-items:flex-start;gap:3px;}
  .related ul li span{font-size:12px;}
  .footer{padding:32px 0 24px;margin-top:40px;}
  .footer-nav{gap:8px;}
  .back-top{right:16px;bottom:16px;width:40px;height:40px;font-size:15px;}
}