:root {
  --ink: #1b2430;
  --muted: #66727f;
  --line: #e3e9e8;
  --brand: #0e9c8a;
  --brand-dark: #0a7a6c;
  --brand-pale: #eef8f6;
  --warn: #b45309;
  --warn-pale: #fff8ec;
  --bg: #f7f9f9;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.75 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}

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

.topbar {
  background: #fff;
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 10;
}

.topbar-in {
  max-width: 880px;
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.brand {
  font-weight: 700;
  font-size: 17px;
  letter-spacing: .3px;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand::before {
  content: "";
  width: 20px;
  height: 20px;
  border-radius: 6px;
  background: linear-gradient(135deg, var(--brand), #34c7a0);
}

.topnav { margin-left: auto; display: flex; gap: 18px; font-size: 14px; }
.topnav a { color: var(--muted); }
.topnav a:hover { color: var(--brand-dark); }

.wrap { max-width: 880px; margin: 0 auto; padding: 0 20px 72px; }

.crumb { font-size: 13px; color: var(--muted); padding: 20px 0 6px; }
.crumb a { color: var(--muted); }

article {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 34px 32px 40px;
  margin-top: 8px;
}

h1 {
  font-size: 27px;
  line-height: 1.45;
  margin: 0 0 14px;
  letter-spacing: -.2px;
}

.lead {
  font-size: 16px;
  color: var(--muted);
  margin: 0 0 22px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

h2 {
  font-size: 20px;
  margin: 38px 0 12px;
  padding-left: 12px;
  border-left: 4px solid var(--brand);
  line-height: 1.5;
}

h3 { font-size: 16.5px; margin: 24px 0 8px; }

p { margin: 12px 0; }
ul, ol { margin: 12px 0; padding-left: 22px; }
li { margin: 6px 0; }

.answer {
  background: var(--brand-pale);
  border: 1px solid #cfeae4;
  border-radius: 10px;
  padding: 16px 18px;
  margin: 18px 0 22px;
}

.answer strong { color: var(--brand-dark); }

.warn {
  background: var(--warn-pale);
  border: 1px solid #f3ddb7;
  border-radius: 10px;
  padding: 14px 18px;
  margin: 18px 0;
  font-size: 15px;
}

.warn b { color: var(--warn); }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 18px 0;
  font-size: 14.5px;
}

th, td {
  border: 1px solid var(--line);
  padding: 9px 12px;
  text-align: left;
  vertical-align: top;
}

th { background: #f2f7f6; font-weight: 600; }
tbody tr:nth-child(even) { background: #fbfcfc; }

code {
  background: #f1f4f4;
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 1px 6px;
  font-size: 13.5px;
  font-family: ui-monospace, Consolas, "Courier New", monospace;
}

pre {
  background: #1f2a33;
  color: #e6edf3;
  padding: 14px 16px;
  border-radius: 10px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.6;
}

pre code { background: none; border: 0; color: inherit; padding: 0; }

.faq { margin-top: 32px; }
.faq-item {
  border-top: 1px solid var(--line);
  padding: 16px 0;
}
.faq-item h3 { margin: 0 0 6px; font-size: 15.5px; }
.faq-item p { margin: 0; color: #3d4a56; font-size: 15px; }

.next {
  margin-top: 34px;
  padding: 18px 20px;
  background: #f4f8f7;
  border-radius: 12px;
  font-size: 15px;
}
.next b { display: block; margin-bottom: 8px; }
.next a { display: inline-block; margin: 3px 14px 3px 0; }

footer {
  max-width: 880px;
  margin: 0 auto;
  padding: 26px 20px 40px;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.9;
}
footer a { color: var(--muted); }

/* 指南索引页 */
.cards { display: grid; gap: 14px; margin: 22px 0 8px; }

.card {
  display: block;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px 20px;
  transition: border-color .15s, transform .15s;
}
.card:hover { border-color: #bfe3dc; text-decoration: none; transform: translateY(-1px); }
.card h2 { border: 0; padding: 0; margin: 0 0 6px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 14.5px; }

@media (max-width: 640px) {
  article { padding: 22px 18px 28px; border-radius: 12px; }
  h1 { font-size: 22px; }
  h2 { font-size: 18px; margin-top: 30px; }
  .topnav { gap: 12px; font-size: 13px; }
  table { font-size: 13px; }
  th, td { padding: 7px 8px; }
}