:root {
  --bg: #ffffff;
  --bg-soft: #f6f8fb;
  --bg-sunk: #eef2f7;
  --border: #e2e8f0;
  --text: #16202e;
  --text-soft: #5a6b80;
  --text-mute: #8695a8;
  --brand: #1f6feb;
  --brand-soft: #e8f1ff;
  --good: #0f9d58;
  --good-soft: #e6f5ec;
  --warn: #b7791f;
  --warn-soft: #fdf3e0;
  --bad: #c5221f;
  --bad-soft: #fdeceb;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(16, 24, 40, .05), 0 4px 16px rgba(16, 24, 40, .06);
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px; }

/* ---------- header ---------- */
.site-header {
  border-bottom: 1px solid var(--border);
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 20;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 60px;
}
.brand {
  font-weight: 700;
  font-size: 17px;
  color: var(--text);
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.brand span { color: var(--brand); }
.site-nav { display: flex; gap: 18px; font-size: 14px; overflow-x: auto; }
.site-nav a { color: var(--text-soft); white-space: nowrap; }
.site-nav a:hover { color: var(--brand); text-decoration: none; }

/* ---------- hero ---------- */
.hero { padding: 44px 0 28px; }
.hero h1 {
  font-size: 34px;
  line-height: 1.25;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
  font-weight: 700;
}
.hero p.lede { font-size: 17px; color: var(--text-soft); margin: 0 0 24px; max-width: 640px; }

/* ---------- cards ---------- */
.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
}
.grid { display: grid; gap: 16px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 760px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 26px; }
}

.tool-card h3 { margin: 0 0 6px; font-size: 16px; }
.tool-card p { margin: 0; font-size: 14px; color: var(--text-soft); }

/* ---------- clock pair ---------- */
.clock-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 640px) { .clock-pair { grid-template-columns: 1fr; } }
.clock-box {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  background: var(--bg-soft);
}
.clock-box .city { font-size: 13px; color: var(--text-mute); text-transform: uppercase; letter-spacing: .06em; }
.clock-box .time {
  font-family: var(--mono);
  font-size: 38px;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 4px 0 2px;
  font-variant-numeric: tabular-nums;
}
.clock-box .date { font-size: 14px; color: var(--text-soft); }
.clock-box .off { font-size: 12px; color: var(--text-mute); margin-top: 6px; }

.diff-banner {
  margin: 16px 0;
  padding: 14px 18px;
  border-radius: var(--radius);
  background: var(--brand-soft);
  border: 1px solid #cfe0fb;
  font-weight: 600;
  font-size: 15px;
}

/* ---------- table ---------- */
.tbl-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius); }
table { border-collapse: collapse; width: 100%; font-size: 14px; background: #fff; }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); white-space: nowrap; }
th { background: var(--bg-sunk); font-weight: 600; font-size: 13px; color: var(--text-soft); }
tbody tr:last-child td { border-bottom: none; }
td.mono { font-family: var(--mono); font-variant-numeric: tabular-nums; }

.pill {
  display: inline-block;
  padding: 2px 9px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}
.pill.good { background: var(--good-soft); color: var(--good); }
.pill.ok   { background: var(--warn-soft); color: var(--warn); }
.pill.bad  { background: var(--bad-soft);  color: var(--bad); }

/* ---------- forms ---------- */
.field { display: flex; flex-direction: column; gap: 6px; font-size: 14px; }
.field label { font-weight: 600; font-size: 13px; color: var(--text-soft); }
select, input[type="text"], input[type="number"], input[type="time"] {
  font: inherit;
  padding: 9px 11px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: #fff;
  color: var(--text);
  width: 100%;
}
select:focus, input:focus { outline: 2px solid var(--brand-soft); border-color: var(--brand); }
.form-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 14px; }
.swap-btn {
  align-self: end;
  padding: 9px 14px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  border-radius: 9px;
  cursor: pointer;
  font: inherit;
  font-size: 14px;
  white-space: nowrap;
}
.swap-btn:hover { background: var(--bg-sunk); }

/* ---------- links / misc ---------- */
.link-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 6px 18px; font-size: 14px; }
.muted { color: var(--text-mute); }
.small { font-size: 13px; }
h2 { font-size: 22px; margin: 36px 0 14px; letter-spacing: -0.01em; }
h3 { font-size: 17px; margin: 24px 0 10px; }
p { margin: 0 0 14px; }
ul.seo-list { columns: 2; column-gap: 24px; font-size: 14px; padding-left: 18px; }
@media (max-width: 640px) { ul.seo-list { columns: 1; } }

.site-footer {
  margin-top: 56px;
  border-top: 1px solid var(--border);
  padding: 26px 0 40px;
  font-size: 13px;
  color: var(--text-mute);
}
.site-footer a { color: var(--text-soft); }

.ad-slot {
  margin: 24px 0;
  border: 1px dashed #cbd5e1;
  border-radius: var(--radius);
  background: var(--bg-soft);
  color: var(--text-mute);
  font-size: 12px;
  text-align: center;
  padding: 14px;
}

.breadcrumb { font-size: 13px; color: var(--text-mute); margin: 20px 0 8px; }
.breadcrumb a { color: var(--text-soft); }