:root {
  --bg: #faf8f4;
  --surface: #ffffff;
  --text: #1f2421;
  --muted: #5b635d;
  --accent: #2f6b4f;
  --accent-ink: #ffffff;
  --border: #e2ddd2;
  --result: #eef4ef;
  --error: #9b2c2c;
  --radius: 10px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141815;
    --surface: #1c211d;
    --text: #ecefe9;
    --muted: #a3aba2;
    --accent: #6fbf94;
    --accent-ink: #0e1a13;
    --border: #2c352e;
    --result: #1d2a22;
    --error: #f0a0a0;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); }
.wrap { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header.site { border-bottom: 1px solid var(--border); background: var(--surface); }
header.site .wrap { display: flex; justify-content: space-between; align-items: center; padding-top: 14px; padding-bottom: 14px; }
.brand { font-weight: 700; font-size: 1.1rem; text-decoration: none; color: var(--text); letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
nav a { margin-left: 16px; font-size: 0.95rem; text-decoration: none; }
main { padding: 28px 0 48px; }
h1 { font-size: clamp(1.8rem, 5vw, 2.4rem); line-height: 1.15; margin: 0 0 8px; letter-spacing: -0.02em; }
h2 { font-size: 1.4rem; margin: 40px 0 8px; letter-spacing: -0.01em; }
h3 { font-size: 1.1rem; margin: 24px 0 4px; }
.lede { color: var(--muted); font-size: 1.1rem; margin: 0 0 24px; }
p, ul, ol { margin: 0 0 14px; }
li { margin-bottom: 4px; }

.calc { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; }
.calc fieldset { border: 0; padding: 0; margin: 0 0 18px; }
.calc legend, .calc label.lbl { font-weight: 600; font-size: 0.95rem; margin-bottom: 6px; display: block; padding: 0; }
.row { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 12px; }
.field { flex: 1 1 140px; min-width: 0; }
.field small { display: block; color: var(--muted); font-size: 0.82rem; margin-top: 4px; }
input[type=number], select {
  width: 100%; font: inherit; color: var(--text); background: var(--bg);
  border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; min-height: 44px;
}
input:focus-visible, select:focus-visible, button:focus-visible, .seg label:focus-within {
  outline: 3px solid var(--accent); outline-offset: 1px;
}
.seg { display: inline-flex; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.seg input { position: absolute; opacity: 0; pointer-events: none; }
.seg label { padding: 9px 16px; cursor: pointer; font-size: 0.95rem; background: var(--bg); min-height: 44px; display: flex; align-items: center; }
.seg input:checked + label { background: var(--accent); color: var(--accent-ink); font-weight: 600; }
.area-row { border: 1px dashed var(--border); border-radius: 8px; padding: 12px; margin-bottom: 10px; }
.area-row .row { margin-bottom: 0; align-items: end; }
button { font: inherit; cursor: pointer; border-radius: 8px; min-height: 44px; padding: 0 16px; }
button.ghost { background: transparent; color: var(--accent); border: 1px solid var(--accent); }
button.remove { background: transparent; border: 1px solid var(--border); color: var(--muted); }
.errors { color: var(--error); margin: 0 0 12px; padding-left: 18px; }
.results { background: var(--result); border-radius: var(--radius); padding: 18px; margin-top: 8px; }
.results .big { display: flex; flex-wrap: wrap; gap: 20px 32px; }
.results .big div { min-width: 120px; }
.results .num { font-size: 2rem; font-weight: 700; line-height: 1.1; letter-spacing: -0.02em; }
.results .unit { color: var(--muted); font-size: 0.9rem; }
.results table { width: 100%; border-collapse: collapse; margin-top: 14px; font-size: 0.95rem; }
.results td { padding: 5px 0; border-top: 1px solid var(--border); }
.results td:last-child { text-align: right; font-variant-numeric: tabular-nums; }
.note { color: var(--muted); font-size: 0.88rem; margin-top: 10px; }
table.data { width: 100%; border-collapse: collapse; margin-bottom: 14px; font-size: 0.95rem; }
table.data th, table.data td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--border); vertical-align: top; }
.example { background: var(--surface); border-left: 4px solid var(--accent); padding: 12px 16px; border-radius: 0 8px 8px 0; }
details { border-bottom: 1px solid var(--border); padding: 10px 0; }
summary { cursor: pointer; font-weight: 600; }
details p { margin: 8px 0 0; }
.cards { display: grid; gap: 12px; }
.card { display: block; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; text-decoration: none; color: var(--text); }
.card strong { display: block; color: var(--accent); font-size: 1.1rem; }
footer.site { border-top: 1px solid var(--border); padding: 24px 0 40px; color: var(--muted); font-size: 0.9rem; }
footer.site a { margin-right: 14px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
@media (min-width: 640px) { .cards { grid-template-columns: 1fr 1fr; } }

.neg { color: var(--error); }
.results tr.strong td { font-weight: 700; }
.results h3 { margin: 18px 0 4px; font-size: 1rem; }