:root {
  --bg: #faf9f7;
  --card: #ffffff;
  --ink: #2b2b2b;
  --muted: #7a7a7a;
  --line: #e7e4df;
  --accent: #4a6fa5;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
}

.wrap { max-width: 760px; margin: 0 auto; padding: 0 20px; }

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--card);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 56px; }
.brand { font-weight: 700; text-decoration: none; color: var(--ink); }
.site-header nav a { color: var(--muted); text-decoration: none; }
.site-header nav a.active { color: var(--accent); }

.filters { padding: 24px 0 8px; }
.filter-group { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }
.filter-label { color: var(--muted); font-size: 14px; width: 36px; }
.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
  padding: 5px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  cursor: pointer;
  font-size: 14px;
  color: var(--ink);
}
.chip[data-active] { background: var(--accent); border-color: var(--accent); color: #fff; }
.result-count { color: var(--muted); font-size: 13px; margin: 4px 0 0; }

.post-list { padding: 12px 0 40px; }
.post-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  margin-bottom: 14px;
  transition: box-shadow .15s;
}
.post-card:hover { box-shadow: 0 3px 12px rgba(0,0,0,.06); }
.post-link { display: block; padding: 18px 20px; text-decoration: none; color: inherit; }
.post-title { font-size: 19px; margin: 8px 0 4px; }
.post-date { color: var(--muted); font-size: 13px; }
.post-summary { color: var(--muted); font-size: 14px; margin: 8px 0 0; }

.badge {
  display: inline-block; padding: 2px 8px; border-radius: 6px;
  font-size: 12px; color: #fff; margin-right: 6px;
}
.genre { background: var(--accent); }
.theme { background: #8a8a8a; }
.tag { background: #8a8aa0; }

.empty-msg { color: var(--muted); text-align: center; padding: 40px 0; }

.article { padding: 28px 0 60px; }
.crumb { margin-bottom: 20px; }
.crumb a { color: var(--accent); text-decoration: none; }
.post-meta { margin-bottom: 8px; }
.article-body { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 28px 30px; }
.article-body h1 { font-size: 22px; }
.article-body h1:first-child { margin-top: 0; }
.article-body pre { background: #f2f1ee; padding: 14px; border-radius: 8px; overflow-x: auto; }
.article-body code { background: #f2f1ee; padding: 2px 5px; border-radius: 4px; font-size: 14px; }
.article-body pre code { background: none; padding: 0; }

/* 数学公式：长公式横向滚动，编号引用可点击 */
.article-body .arithmatex,
.article-body .equation {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 0;
}
a.eqref { color: var(--accent); text-decoration: none; }

.pager { display: flex; justify-content: space-between; gap: 20px; margin-top: 24px; }
.pager a { color: var(--accent); text-decoration: none; font-size: 14px; }
.pager .next { margin-left: auto; }