:root {
  --bg: #f4f7fa; --card: #fff; --text: #1b2733; --muted: #5a6b7b;
  --primary: #1d4e89; --border: #cfd9e3; --row: #eaf1f8; --note: #8a4b00; --note-bg: #fff4e0;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11181f; --card: #1a242e; --text: #e6edf3; --muted: #9aabbb;
    --primary: #7db4ee; --border: #33434f; --row: #202d39; --note: #f3c37a; --note-bg: #35290f;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.6;
}
main { max-width: 640px; margin: 0 auto; padding: 20px 16px 32px; }
h1 { font-size: 1.4rem; margin: 4px 0 4px; color: var(--primary); }
h2 { font-size: 1.05rem; margin: 28px 0 10px; color: var(--primary); }
.lead { margin: 0 0 14px; color: var(--muted); font-size: .92rem; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

.card { background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 16px; }
.fields { display: grid; gap: 14px; }
@media (min-width: 560px) { .fields { grid-template-columns: 1fr 1fr; } }
label { display: block; font-weight: 600; font-size: .95rem; margin-bottom: 6px; }
.input-wrap { display: flex; align-items: center; gap: 8px; }
input {
  width: 100%; min-width: 0; font: inherit; font-size: 2rem; font-weight: 700;
  padding: 8px 12px; border: 2px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font-variant-numeric: tabular-nums;
}
input:focus { outline: none; border-color: var(--primary); }
input::placeholder { color: var(--muted); font-weight: 400; opacity: .6; }
.unit { font-size: 1.4rem; font-weight: 700; color: var(--muted); }
.approx { margin: 12px 0 0; font-size: .85rem; color: var(--muted); }
.note { margin: 10px 0 0; padding: 8px 10px; border-radius: 6px; background: var(--note-bg); color: var(--note); font-size: .88rem; }
[hidden] { display: none !important; }

.formula { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin-bottom: 8px; }
.dir { font-size: .8rem; color: var(--muted); font-weight: 600; min-width: 6.5em; }
.eq { font-size: 1.05rem; font-weight: 700; }

table { width: 100%; border-collapse: collapse; background: var(--card); border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
th { background: var(--primary); color: var(--card); padding: 10px; font-size: .95rem; }
td { text-align: center; font-size: 1.3rem; font-weight: 700; padding: 8px; border-top: 1px solid var(--border); font-variant-numeric: tabular-nums; }
tbody tr:nth-child(odd) td { background: var(--row); }
.small { font-size: .8rem; color: var(--muted); margin: 6px 0 0; }

.notes ul { margin: 0; padding-left: 1.2em; font-size: .9rem; }
.notes li { margin-bottom: 4px; }
.ref { font-size: .85rem; color: var(--muted); margin: 10px 0 0; }
footer { margin-top: 36px; padding-top: 14px; border-top: 1px solid var(--border); text-align: center; font-size: .75rem; color: var(--muted); }