* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.75; color: #2c3e50; background: #f5f7fa;
}
a { color: #4a6fa5; text-decoration: none; }
a:hover { text-decoration: underline; }

.topbar { background: #fff; border-bottom: 1px solid #eaeef3; position: sticky; top: 0; z-index: 10; }
.topbar .inner {
  max-width: 900px; margin: 0 auto; padding: 14px 20px;
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 8px;
}
.topbar .brand { font-weight: 600; color: #2c3e50; }
.topbar .nav a { margin-left: 16px; font-size: .9rem; color: #4a6fa5; }

header.hero { background: linear-gradient(135deg, #4a6fa5 0%, #2c3e50 100%); color: #fff; padding: 56px 20px; text-align: center; }
header.hero h1 { font-size: 2rem; font-weight: 600; letter-spacing: 1px; }
header.hero p { margin-top: 12px; opacity: .9; }

.container { max-width: 900px; margin: 0 auto; padding: 0 20px; }
section { margin: 40px 0; }
h2.section-title { font-size: 1.35rem; border-left: 4px solid #4a6fa5; padding-left: 12px; margin-bottom: 18px; }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }
.card {
  display: block; background: #fff; border-radius: 10px; padding: 20px;
  box-shadow: 0 2px 12px rgba(0,0,0,.05); transition: transform .15s ease, box-shadow .15s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: 0 6px 18px rgba(0,0,0,.08); text-decoration: none; }
.card h3 { font-size: 1.05rem; color: #4a6fa5; margin-bottom: 8px; }
.card p { font-size: .9rem; color: #777; }
.card .tag { display: inline-block; margin-top: 10px; font-size: .75rem; color: #4a6fa5; background: #eef2f8; padding: 3px 10px; border-radius: 20px; }
.card .more { display: block; margin-top: 12px; font-size: .85rem; color: #4a6fa5; }

.intro, .about, .note { background: #fff; border-radius: 10px; padding: 24px; box-shadow: 0 2px 12px rgba(0,0,0,.05); }
.intro p { color: #555; }

.page-title { margin: 28px 0 6px; font-size: 1.6rem; color: #2c3e50; }
.page-desc { color: #888; margin-bottom: 8px; }
.back { display: inline-block; margin: 24px 0 8px; font-size: .9rem; }

.note { margin-bottom: 18px; }
.note h3 { font-size: 1.12rem; color: #2c3e50; margin-bottom: 4px; }
.note .meta { font-size: .78rem; color: #aab; margin-bottom: 10px; }
.note p { color: #555; margin: 8px 0; }

pre {
  background: #1e2a38; color: #d6e2f0; padding: 14px 16px; border-radius: 8px;
  overflow-x: auto; font-size: .85rem; line-height: 1.65;
  font-family: Consolas, Monaco, "Courier New", monospace; margin: 10px 0;
}
code.inline { background: #eef2f8; color: #4a6fa5; padding: 1px 6px; border-radius: 4px; font-size: .88em; font-family: Consolas, Monaco, monospace; }

ul.dot { margin: 8px 0 0 22px; color: #555; }
ul.dot li { margin: 6px 0; }

footer { text-align: center; padding: 28px 20px; color: #888; font-size: .85rem; background: #fff; border-top: 1px solid #eee; margin-top: 40px; }
footer a { color: #4a6fa5; }