:root {
  --bg: #f6f7f9; --card: #fff; --text: #16181d; --muted: #5d6470; --line: #dde1e7;
  --accent: #2458d6; --accent-ink: #fff; --field: #fff; --soft: #eef2fb;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #111317; --card: #1a1d23; --text: #e8eaee; --muted: #9aa2ae; --line: #2e333b; --accent: #7aa2ff; --accent-ink: #0d1330; --field: #13161b; --soft: #1f2636; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { max-width: 760px; margin: 0 auto; padding: 16px 16px 40px; }
h1 { font-size: 1.6rem; line-height: 1.2; margin: 4px 0 2px; }
.lede { margin: 0 0 12px; color: var(--muted); font-size: .95rem; }
.tool { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px; }
form { display: grid; gap: 10px; }
.field { display: grid; gap: 4px; font-size: .85rem; color: var(--muted); }
select, input { font: inherit; color: var(--text); background: var(--field); border: 1px solid var(--line); border-radius: 9px; min-height: 44px; padding: 8px 10px; width: 100%; min-width: 0; }
input:focus, select:focus, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
input.calc { background: var(--soft); }
fieldset.pair { border: 0; margin: 0; padding: 0; display: grid; grid-template-columns: 1fr auto 1fr; gap: 6px; align-items: center; }
fieldset.pair legend { font-size: .85rem; color: var(--muted); padding: 0; margin-bottom: 4px; }
legend small { opacity: .8; }
.x { color: var(--muted); }
.opts { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.result { margin-top: 14px; border-top: 1px solid var(--line); padding-top: 12px; }
.big { margin: 0 0 8px; display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; }
#ratio { font-size: 2rem; font-weight: 700; letter-spacing: -.01em; overflow-wrap: anywhere; }
.muted { color: var(--muted); }
.tag:not(:empty) { font-size: .8rem; background: var(--soft); border-radius: 999px; padding: 2px 10px; }
.hint { color: var(--muted); margin: 0; }
dl { margin: 0; display: grid; gap: 6px; }
dl > div { display: grid; grid-template-columns: 9.5rem 1fr; gap: 8px; align-items: baseline; }
dt { color: var(--muted); font-size: .9rem; }
dd { margin: 0; overflow-wrap: anywhere; }
.fit dd { display: grid; gap: 6px; }
.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
button { font: inherit; min-height: 44px; padding: 8px 16px; border-radius: 9px; border: 1px solid var(--line); background: var(--field); color: var(--text); cursor: pointer; }
button.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); font-weight: 600; }
.doc { margin-top: 28px; }
.doc h2 { font-size: 1.25rem; margin: 28px 0 8px; }
.doc h3 { font-size: 1rem; margin: 18px 0 4px; }
.doc p, .doc li { color: var(--text); }
.scroll { overflow-x: auto; border: 1px solid var(--line); border-radius: 10px; }
table { border-collapse: collapse; width: 100%; font-size: .9rem; background: var(--card); }
th, td { text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; }
td:first-child, td:nth-child(2) { white-space: nowrap; }
td:last-child { min-width: 15rem; }
footer { margin-top: 32px; color: var(--muted); font-size: .85rem; }
@media (max-width: 480px) {
  main { padding: 10px 12px 32px; }
  h1 { font-size: 1.35rem; }
  .lede { margin-bottom: 8px; }
  .tool { padding: 12px; }
  form { gap: 8px; }
  dl > div { grid-template-columns: 7.5rem 1fr; }
  #ratio { font-size: 1.7rem; }
}
footer a, .doc a, .page a { color: var(--accent); }
.site { max-width: 760px; margin: 0 auto; padding: 14px 16px 0; font-weight: 700; }
.site a { color: var(--text); text-decoration: none; }
.page { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 8px 20px 20px; }
.page h1 { margin-top: 12px; }
.page h2 { font-size: 1.15rem; margin: 22px 0 6px; }