:root {
  --bg: #f6f7fb;
  --card: #fff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --primary: #2563eb;
  --primary-soft: #eff4ff;
  --ok: #059669;
  --err: #dc2626;
  --radius: 14px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --card: #181b22;
    --text: #e5e7eb;
    --muted: #9ca3af;
    --line: #2a2f3a;
    --primary: #60a5fa;
    --primary-soft: #1c2638;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 16px; }

.site-header { background: var(--card); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 10; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 56px; gap: 12px; }
.logo { font-weight: 700; font-size: 18px; color: var(--text); white-space: nowrap; }
.site-header nav { display: flex; gap: 16px; overflow-x: auto; }
.site-header nav a { color: var(--muted); white-space: nowrap; }

main { padding: 24px 16px 48px; }
h1 { font-size: 28px; margin: 8px 0; }
h2 { font-size: 20px; margin: 0 0 12px; }
h2.sub { font-size: 17px; margin: 20px 0 10px; }
.lead { color: var(--muted); margin-top: 0; }
.breadcrumb { font-size: 14px; color: var(--muted); }

.hero { text-align: center; padding: 32px 0 16px; }
.hero h1 { font-size: 36px; }
.hero p { color: var(--muted); }
#search { width: 100%; max-width: 520px; font-size: 17px; padding: 12px 18px; border-radius: 999px; }

section[id] { margin-top: 28px; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 12px; }
.tool-card {
  display: flex; flex-direction: column; gap: 4px; padding: 16px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  color: var(--text); transition: transform .15s, border-color .15s, box-shadow .15s;
}
.tool-card:hover { text-decoration: none; transform: translateY(-2px); border-color: var(--primary); box-shadow: 0 6px 20px rgb(37 99 235 / .12); }
.tool-card span:last-child { color: var(--muted); font-size: 14px; }
.tool-icon { font-size: 26px; }
.tool-card[hidden], section[hidden] { display: none; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; margin: 20px 0; }
.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 14px; margin-bottom: 14px; }
label { display: flex; flex-direction: column; gap: 6px; font-size: 14px; color: var(--muted); }
label.inline { flex-direction: row; align-items: center; gap: 6px; color: var(--text); }
input, select, textarea {
  font: inherit; color: var(--text); background: var(--bg);
  border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; width: 100%;
}
input[type="checkbox"] { width: auto; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--primary); outline-offset: -1px; }
textarea { resize: vertical; margin: 8px 0; }
.mono { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 14px; }

.btn {
  font: inherit; font-weight: 600; cursor: pointer; border: 0; border-radius: 10px;
  padding: 10px 20px; background: var(--primary); color: #fff;
}
.btn:hover { filter: brightness(1.08); }
.btn-ghost { background: var(--primary-soft); color: var(--primary); }
.btn-sm { padding: 4px 10px; font-size: 13px; }
.btn-row { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin: 10px 0; }
.btn-row select { width: auto; }

.result:empty { display: none; }
.result { margin-top: 16px; }
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 10px; }
.stat { background: var(--primary-soft); border-radius: 12px; padding: 12px 14px; }
.stat span { display: block; font-size: 13px; color: var(--muted); }
.stat strong { font-size: 20px; word-break: break-all; }
.output-row { display: flex; gap: 10px; align-items: center; margin-top: 14px; }
.big-output { flex: 1; font-size: 22px; font-weight: 600; background: var(--primary-soft); padding: 14px; border-radius: 12px; min-height: 60px; }
.hint { font-size: 14px; color: var(--muted); }
.hint.ok { color: var(--ok); }
.hint.err { color: var(--err); }

details { margin-top: 14px; }
summary { cursor: pointer; font-weight: 600; }
.table-scroll { overflow: auto; max-height: 480px; margin-top: 10px; }
table { width: 100%; border-collapse: collapse; font-size: 14px; font-variant-numeric: tabular-nums; }
th, td { padding: 8px 10px; text-align: right; border-bottom: 1px solid var(--line); white-space: nowrap; }
th:first-child, td:first-child { text-align: left; }
thead th { position: sticky; top: 0; background: var(--card); }

.faq details { border-top: 1px solid var(--line); padding-top: 12px; }
.faq p { color: var(--muted); margin: 8px 0 0; }

.affiliate { border-left: 4px solid var(--primary); }
.affiliate h2 { margin-bottom: 8px; }
.affiliate ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.affiliate a {
  display: flex; flex-direction: column; gap: 4px; padding: 14px 16px; border-radius: 12px;
  background: var(--primary-soft); color: var(--text); border: 1px solid transparent;
  transition: border-color .15s, transform .15s;
}
.affiliate a:hover { text-decoration: none; border-color: var(--primary); transform: translateY(-1px); }
.affiliate a strong { font-size: 16px; }
.affiliate a span { font-size: 13px; color: var(--muted); }
.affiliate-prominent {
  border-left-color: #d97706;
  background: linear-gradient(180deg, rgb(245 158 11 / .14), var(--card) 78px);
}
.sponsor-note { margin: 0 0 12px; font-size: 13px; color: var(--muted); }
.post-calc-finance .related {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 16px 8px;
}
.hero-note { color: var(--muted); margin: -4px 0 14px; }
.guide p { color: var(--muted); margin: 0 0 10px; }
.prose code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: var(--bg);
  padding: 1px 6px;
  border-radius: 6px;
}
.checklist { padding-left: 18px; }
.checklist li { margin: 12px 0; }
.owner-line { margin-top: 2px; }
.owner-link { color: var(--muted); font-size: 13px; }

.donate { text-align: center; }
.donate-codes { display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; }
.donate figure { margin: 0; }
.donate img { border-radius: 10px; }

.ad { margin: 20px 0; min-height: 90px; }
.prose h2 { margin-top: 20px; }

.related { margin-top: 28px; }

.site-footer { border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; text-align: center; padding: 20px 0; }
.site-footer p { margin: 4px 0; }

@media (prefers-color-scheme: dark) {
  .affiliate-prominent { border-left-color: #fbbf24; background: linear-gradient(180deg, rgb(245 158 11 / .16), var(--card) 78px); }
}
@media (max-width: 600px) {
  h1 { font-size: 24px; }
  .hero h1 { font-size: 28px; }
  .site-header nav { gap: 12px; font-size: 14px; }
}