:root {
  --bg: #f5f7fa;
  --card: #ffffff;
  --ink: #1f2733;
  --muted: #64748b;
  --line: #e2e8f0;
  --accent: #0e7490;
  --accent-ink: #ffffff;
  --pop: #0f172a;
  --shadow: 0 1px 2px rgba(15,23,42,.06), 0 8px 24px rgba(15,23,42,.06);
  --radius: 14px;
  --ok: #15803d; --okbg: #ecfdf3;
  --warn: #b45309; --warnbg: #fffbeb;
  --bad: #b91c1c; --badbg: #fef2f2;
  --under: #0369a1; --underbg: #eff6ff;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.55;
  font-size: 17px;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 820px; margin: 0 auto; padding: 0 18px; }

/* header / footer / crumbs */
.site-head { border-bottom: 1px solid var(--line); background: var(--card); }
.site-head .wrap { display: flex; align-items: center; justify-content: space-between; height: 58px; }
.brand { font-weight: 800; font-size: 19px; color: var(--pop); letter-spacing: -.02em; }
.brand:hover { text-decoration: none; }
.nav a { color: var(--muted); font-size: 15px; margin-left: 18px; }
.crumbs { font-size: 13px; color: var(--muted); margin: 18px 0 4px; }
.crumbs a { color: var(--muted); }
h1 { font-size: 28px; line-height: 1.2; letter-spacing: -.02em; margin: 10px 0 14px; }
.lead { color: var(--muted); margin: 0 0 20px; }
h2 { font-size: 20px; margin: 30px 0 12px; letter-spacing: -.01em; }
.group-blurb { color: var(--muted); margin: 0 0 12px; font-size: 15px; }
.site-foot { border-top: 1px solid var(--line); margin-top: 40px; padding: 22px 0 50px; color: var(--muted); font-size: 14px; background: var(--card); }
.site-foot a { color: var(--muted); }
.site-foot .wrap { display: flex; flex-wrap: wrap; gap: 8px 18px; }

/* calculator form */
.calc { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 18px; margin: 8px 0 0; }
.fields { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.field { min-width: 0; }
.field-unit, .field-wide { grid-column: 1 / -1; }
.field label { display: block; font-size: 13px; color: var(--muted); margin: 0 0 5px; font-weight: 600; }
.field .sfx { font-weight: 400; text-transform: none; }
input, select { width: 100%; max-width: 100%; padding: 10px 12px; font-size: 16px; border: 1px solid var(--line); border-radius: 10px; background: #fff; color: var(--ink); }
input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: 0; border-color: var(--accent); }

/* number-with-unit-label + height composite */
.numsuffix { display: flex; align-items: stretch; }
.numsuffix input { border-top-right-radius: 0; border-bottom-right-radius: 0; }
.u-lbl { display: inline-flex; align-items: center; padding: 0 12px; font-size: 14px; color: var(--muted); background: #f8fafc; border: 1px solid var(--line); border-left: 0; border-radius: 0 10px 10px 0; white-space: nowrap; }
.uf { display: flex; align-items: stretch; gap: 8px; }
.uf .u-in { width: 100%; }
.uf .u-lbl { border-left: 1px solid var(--line); border-radius: 10px; padding: 0 10px; }
.uf .u-in { border-radius: 10px; }
.uf .u-lbl { margin-left: -4px; }
.calc[data-unit="metric"] .uf-imperial { display: none; }
.calc[data-unit="imperial"] .uf-metric { display: none; }

/* unit toggle */
.unit-toggle { display: inline-flex; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; background: #f8fafc; }
.unit-toggle button { font: inherit; font-size: 15px; font-weight: 600; cursor: pointer; border: 0; background: transparent; color: var(--muted); padding: 9px 20px; }
.unit-toggle button.active { background: var(--accent); color: var(--accent-ink); }

/* result */
.result-wrap { margin: 16px 0 0; }
.result { background: var(--card); border: 1px solid var(--line); border-left: 5px solid var(--accent); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px 22px; }
.rp { display: flex; flex-direction: column; }
.rp-num { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.rp-val { font-size: 40px; font-weight: 800; letter-spacing: -.02em; color: var(--pop); line-height: 1.05; }
.rp-unit { font-size: 18px; color: var(--muted); font-weight: 600; }
.rp-label { font-size: 14px; color: var(--muted); font-weight: 600; margin-top: 2px; }
.badge { display: inline-block; margin: 12px 0 0; padding: 5px 12px; border-radius: 999px; font-size: 14px; font-weight: 700; }
.badge-ok { background: var(--okbg); color: var(--ok); }
.badge-warn { background: var(--warnbg); color: var(--warn); }
.badge-bad { background: var(--badbg); color: var(--bad); }
.badge-under { background: var(--underbg); color: var(--under); }
.rrows { width: 100%; border-collapse: collapse; margin: 14px 0 0; }
.rrows th, .rrows td { text-align: left; padding: 9px 0; border-top: 1px solid var(--line); font-size: 15px; }
.rrows th { font-weight: 500; color: var(--muted); }
.rrows td { text-align: right; font-weight: 700; color: var(--ink); font-variant-numeric: tabular-nums; }
.rnote { font-size: 13.5px; color: var(--muted); margin: 14px 0 0; line-height: 1.5; }

/* disclaimer */
.disclaimer { font-size: 13.5px; color: var(--muted); background: #fffbeb; border: 1px solid #fde68a; border-radius: 10px; padding: 11px 14px; margin: 16px 0 0; }

/* link grids */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 8px; margin-bottom: 10px; }
.grid a { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; color: var(--ink); font-size: 15px; display: flex; align-items: center; }
.grid a:hover { border-color: var(--accent); text-decoration: none; }
.chip-emoji { margin-right: 8px; font-size: 18px; }

/* prose + ads */
.prose { margin: 22px 0; }
.prose p { margin: 0 0 14px; }
.prose h2 { margin-top: 22px; }
.prose h3 { font-size: 16px; margin: 20px 0 6px; letter-spacing: -.01em; }
.ad-slot {
  margin: 22px 0;
  min-height: 90px;
  display: flex; align-items: center; justify-content: center;
  background: repeating-linear-gradient(45deg, #eef2f6, #eef2f6 10px, #f4f7fa 10px, #f4f7fa 20px);
  border: 1px dashed #cbd5e1;
  border-radius: 10px;
  color: #94a3b8; font-size: 12px; letter-spacing: .1em; text-transform: uppercase;
}

@media (max-width: 560px) {
  h1 { font-size: 23px; }
  .fields { grid-template-columns: 1fr; }
  .rp-val { font-size: 34px; }
}