:root{
  --bg:#f7f8fa; --panel:#ffffff; --text:#1f2933; --muted:#6b7280;
  --line:#e5e7eb; --accent:#2563eb; --accent-soft:#eff6ff;
  --code-bg:#f1f5f9; --table-head:#f8fafc;
}
*{box-sizing:border-box;}
body{
  margin:0; background:var(--bg); color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  line-height:1.7; font-size:16px;
}
.site-header{
  background:var(--panel); border-bottom:1px solid var(--line);
  padding:14px 20px; display:flex; align-items:center; justify-content:space-between;
  flex-wrap:wrap; gap:8px; position:sticky; top:0; z-index:10;
}
.brand{font-size:20px; font-weight:700; color:var(--accent);}
.site-nav{font-size:14px; color:var(--muted); display:flex; gap:18px; align-items:center; flex-wrap:wrap;}
.site-nav a{color:var(--muted); text-decoration:none; padding:4px 2px; position:relative; transition:color .15s;}
.site-nav a:hover{color:var(--accent);}
.site-nav a.active{color:var(--accent); font-weight:700;}
.site-nav a.active::after{content:""; position:absolute; left:0; right:0; bottom:-6px; height:2px; background:var(--accent); border-radius:2px;}
.nav-toggle{display:none; background:var(--panel); border:1px solid var(--line); border-radius:8px; font-size:18px; line-height:1; padding:6px 12px; cursor:pointer; color:var(--text);}
.container{max-width:900px; margin:24px auto; padding:0 18px;}
.content{
  background:var(--panel); border:1px solid var(--line); border-radius:12px;
  padding:24px 28px; box-shadow:0 1px 3px rgba(0,0,0,.04);
}
.page-title{margin:0 0 6px; font-size:26px;}
.meta-line{color:var(--muted); font-size:13px; margin-bottom:18px;}
.markdown-body h1,.markdown-body h2,.markdown-body h3{
  margin:22px 0 10px; line-height:1.3;
}
.markdown-body h2{border-left:4px solid var(--accent); padding-left:10px;}
.markdown-body p{margin:10px 0;}
.markdown-body ul,.markdown-body ol{padding-left:22px; margin:10px 0;}
.markdown-body li{margin:4px 0;}
.markdown-body code{
  background:var(--code-bg); padding:2px 6px; border-radius:5px;
  font-family:Consolas,Menlo,monospace; font-size:14px;
}
.markdown-body strong{color:var(--accent);}
.md-table{
  border-collapse:collapse; width:100%; margin:14px 0; font-size:14px;
  background:var(--panel);
}
.md-table th,.md-table td{
  border:1px solid var(--line); padding:8px 10px; text-align:left;
}
.md-table thead th{background:var(--table-head); font-weight:600;}
.md-table tbody tr:nth-child(even){background:#fafbfc;}
img{max-width:100%; height:auto;}
.cat{margin-bottom:28px;}
.cat h2{border-left:4px solid var(--accent); padding-left:10px; margin-bottom:10px;}
.post-list{list-style:none; padding:0; margin:0;}
.post-list li{
  padding:12px 14px; border:1px solid var(--line); border-radius:10px;
  margin-bottom:10px; background:var(--panel);
}
.post-list a{font-size:17px; font-weight:600; color:var(--accent); text-decoration:none;}
.post-list .date{color:var(--muted); font-size:13px; margin-left:8px;}
.post-list .summary{display:block; color:var(--muted); font-size:14px; margin-top:4px;}
.empty{color:var(--muted); padding:20px; text-align:center;}
.site-footer{
  text-align:center; color:var(--muted); font-size:13px;
  padding:20px; border-top:1px solid var(--line); margin-top:30px;
}
/* ===== 首页 Hero ===== */
.hero{
  background:linear-gradient(135deg,#2563eb 0%,#1e40af 100%);
  color:#fff; border-radius:16px; padding:34px 30px; margin-bottom:26px;
  box-shadow:0 10px 28px rgba(37,99,235,.20);
}
.hero h1{margin:0; font-size:32px; letter-spacing:1px; color:#fff; line-height:1.25;}
.hero .hero-sub{margin:10px 0 0; font-size:16px; opacity:.92;}
.hero .hero-desc{margin:14px 0 0; font-size:14px; opacity:.85; max-width:680px; line-height:1.8;}

/* ===== 快速入口卡片 ===== */
.quicknav{display:grid; grid-template-columns:repeat(4,1fr); gap:16px; margin-bottom:30px;}
.qcard{
  display:flex; flex-direction:column; gap:6px; background:var(--panel);
  border:1px solid var(--line); border-radius:14px; padding:20px 18px;
  text-decoration:none; color:var(--text);
  transition:transform .15s, box-shadow .15s, border-color .15s;
}
.qcard:hover{transform:translateY(-3px); box-shadow:0 10px 22px rgba(0,0,0,.08); border-color:var(--accent);}
.qicon{font-size:26px; line-height:1;}
.qtitle{font-size:18px; font-weight:700; color:var(--accent);}
.qdesc{font-size:13px; color:var(--muted); line-height:1.6;}
.qgo{margin-top:6px; font-size:13px; color:var(--accent); font-weight:600;}
.qcard.featured{background:linear-gradient(135deg,#eff6ff,#dbeafe); border-color:#bfdbfe;}
.qcard.featured .qtitle{color:#1d4ed8;}
.qcard.featured .qgo{color:#1d4ed8;}

/* ===== 工具区入口 ===== */
.tool-link{
  display:inline-block; margin-top:6px; background:linear-gradient(135deg,#2563eb,#1e40af);
  color:#fff; text-decoration:none; padding:14px 22px; border-radius:12px;
  font-weight:600; font-size:15px; box-shadow:0 6px 16px rgba(37,99,235,.20);
  transition:filter .15s, transform .15s;
}
.tool-link:hover{filter:brightness(1.06); transform:translateY(-2px);}

/* ===== 响应式 ===== */
/* 大屏桌面：更宽容器、更大 Hero */
@media (min-width:1200px){
  .container{max-width:1120px;}
  .hero{padding:44px 42px;}
  .hero h1{font-size:36px;}
  .quicknav{gap:20px;}
}
/* 笔记本/小平板：容器略收窄 */
@media (max-width:1080px){
  .container{max-width:960px;}
}
/* 平板：快捷卡片两列 */
@media (max-width:900px){
  .quicknav{grid-template-columns:repeat(2,1fr);}
}
/* 手机：汉堡菜单 + 容器收窄 + Hero 缩小 */
@media (max-width:640px){
  .nav-toggle{display:block;}
  .site-nav{display:none; width:100%; flex-direction:column; align-items:flex-start; gap:10px; margin-top:10px;}
  .site-header.nav-open .site-nav{display:flex;}
  .site-nav a.active::after{display:none;}
  .container{padding:0 14px;}
  .content{padding:18px 16px;}
  .hero{padding:26px 20px;}
  .hero h1{font-size:26px;}
  .page-title{font-size:22px;}
}
/* 超窄手机：快捷卡片单列 */
@media (max-width:520px){
  .quicknav{grid-template-columns:1fr;}
}
/* 手机表格横向滚动，避免溢出 */
@media (max-width:600px){
  .md-table{font-size:13px;}
  .markdown-body table{display:block; overflow-x:auto; white-space:nowrap; -webkit-overflow-scrolling:touch;}
}