/* ============================================================
   QuickGainsHub — 轻量静态博客样式
   设计目标：极快加载、Tier1 阅读体验、移动端优先
   ============================================================ */
:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --ink: #1c2430;
  --muted: #5b6b7f;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --line: #e5eaf1;
  --accent: #f59e0b;
  --ok: #16a34a;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(16, 24, 40, .08), 0 8px 24px rgba(16, 24, 40, .06);
  --maxw: 860px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font: 16px/1.7 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; }

/* 顶部导航 */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 20;
}
.nav-wrap {
  max-width: var(--maxw); margin: 0 auto; padding: 14px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand { font-weight: 800; font-size: 1.15rem; color: var(--ink); letter-spacing: -.01em; }
.brand span { color: var(--brand); }
.nav-links { display: flex; gap: 18px; font-size: .95rem; flex-wrap: wrap; }
.nav-links a { color: var(--muted); font-weight: 600; }
.nav-links a:hover { color: var(--brand); text-decoration: none; }
.nav-links a.active { color: var(--brand); }

/* 主体 */
main { max-width: var(--maxw); margin: 0 auto; padding: 28px 20px 60px; }
.page { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 32px 34px; }

/* 首页 hero */
.hero { background: linear-gradient(135deg, #1d4ed8 0%, #2563eb 55%, #3b82f6 100%); color: #fff; border-radius: var(--radius); padding: 40px 34px; margin-bottom: 26px; }
.hero h1 { margin: 0 0 10px; font-size: 2rem; line-height: 1.2; }
.hero p { margin: 0; opacity: .92; font-size: 1.05rem; max-width: 640px; }
.hero .badges { margin-top: 18px; display: flex; gap: 10px; flex-wrap: wrap; }
.badge { background: rgba(255,255,255,.16); border: 1px solid rgba(255,255,255,.28); padding: 4px 12px; border-radius: 999px; font-size: .82rem; }

/* 文章卡片 */
.post-grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
@media (min-width: 640px) { .post-grid { grid-template-columns: 1fr 1fr; } }
.post-card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px 24px; box-shadow: var(--shadow); transition: transform .15s ease, box-shadow .15s ease; display: flex; flex-direction: column; }
.post-card:hover { transform: translateY(-2px); box-shadow: 0 4px 6px rgba(16,24,40,.06), 0 14px 34px rgba(16,24,40,.1); }
.post-card h3 { margin: 0 0 8px; font-size: 1.12rem; line-height: 1.35; }
.post-card h3 a { color: var(--ink); }
.post-card h3 a:hover { color: var(--brand); text-decoration: none; }
.post-card .meta { font-size: .8rem; color: var(--muted); margin-bottom: 10px; }
.post-card p { margin: 0 0 14px; color: var(--muted); font-size: .95rem; flex: 1; }
.tag { display: inline-block; background: #eef4ff; color: var(--brand-dark); font-size: .75rem; font-weight: 700; padding: 2px 10px; border-radius: 999px; margin-right: 6px; }

/* 文章正文 */
.post h1 { font-size: 1.85rem; line-height: 1.25; margin: 0 0 6px; }
.post .post-meta { color: var(--muted); font-size: .88rem; margin-bottom: 24px; padding-bottom: 18px; border-bottom: 1px solid var(--line); }
.post h2 { font-size: 1.35rem; margin: 34px 0 12px; padding-top: 6px; }
.post h3 { font-size: 1.1rem; margin: 24px 0 8px; }
.post p, .post li { color: #2b3648; }
.post ul, .post ol { padding-left: 22px; }
.post li { margin: 6px 0; }
.post blockquote { margin: 18px 0; padding: 12px 18px; border-left: 4px solid var(--brand); background: #f0f5ff; border-radius: 0 8px 8px 0; color: #33466b; }
.post .toc { background: #f7f9fc; border: 1px solid var(--line); border-radius: 10px; padding: 14px 20px; margin: 18px 0 26px; font-size: .92rem; }
.post .toc b { display: block; margin-bottom: 6px; }
.post .toc a { display: inline-block; margin: 2px 14px 2px 0; }

/* 提示框 */
.callout { border-radius: 10px; padding: 14px 18px; margin: 18px 0; font-size: .95rem; }
.callout.tip { background: #ecfdf5; border: 1px solid #a7f3d0; color: #065f46; }
.callout.warn { background: #fffbeb; border: 1px solid #fde68a; color: #92400e; }
.callout.info { background: #eff6ff; border: 1px solid #bfdbfe; color: #1e40af; }

/* 表格 */
.table-wrap { overflow-x: auto; margin: 18px 0; }
table { border-collapse: collapse; width: 100%; font-size: .92rem; }
th, td { border: 1px solid var(--line); padding: 9px 12px; text-align: left; }
th { background: #f4f7fb; font-weight: 700; }

/* 底部 */
.site-footer { border-top: 1px solid var(--line); background: var(--card); margin-top: 20px; }
.footer-wrap { max-width: var(--maxw); margin: 0 auto; padding: 22px 20px 34px; font-size: .84rem; color: var(--muted); text-align: center; }
.footer-wrap a { color: var(--muted); text-decoration: underline; }

/* 404 */
.notfound { text-align: center; padding: 70px 20px; }
.notfound h1 { font-size: 4rem; margin: 0; color: var(--brand); }
.notfound p { color: var(--muted); margin: 10px 0 24px; }

/* 打印与无障碍 */
:focus-visible { outline: 3px solid #93c5fd; outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto; } }