:root {
  --bg: #f5f8fb;
  --card: #ffffff;
  --text: #1f2d3d;
  --muted: #5b6b7a;
  --brand: #0b7ad1;
  --line: #dbe5ef;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px 16px 48px;
}

header {
  background: linear-gradient(120deg, #e8f5ff, #f7fbff);
  border-bottom: 1px solid var(--line);
}

h1,
h2,
h3 {
  line-height: 1.35;
  margin: 0 0 12px;
}

h1 {
  font-size: 32px;
}

h2 {
  font-size: 24px;
  margin-top: 28px;
}

h3 {
  font-size: 18px;
  margin-top: 20px;
}

p,
li {
  color: var(--text);
}

.intro {
  color: var(--muted);
  margin-top: 6px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px;
}

.card h3 {
  margin-top: 0;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

ul {
  padding-left: 20px;
}

.meta {
  color: var(--muted);
  font-size: 14px;
}

.tag {
  display: inline-block;
  font-size: 12px;
  background: #e8f4ff;
  color: #0d62a5;
  border: 1px solid #c8e4fb;
  border-radius: 999px;
  padding: 2px 10px;
  margin-right: 8px;
}

.notice {
  margin-top: 24px;
  padding: 12px 14px;
  background: #fff9e6;
  border: 1px solid #ffe6a8;
  border-radius: 8px;
  color: #775b00;
  font-size: 14px;
}

footer {
  margin-top: 34px;
  padding-top: 16px;
  border-top: 1px dashed var(--line);
  color: var(--muted);
  font-size: 13px;
}