:root {
  color-scheme: light dark;
  --bg: #f7f4ec;
  --surface: #ffffff;
  --ink: #1f2423;
  --muted: #55605e;
  --line: #d6d1c4;
  --accent: #1f6f6b;
  --accent-ink: #ffffff;
  --answer: #e6f1ef;
  --error: #a3211b;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161a19;
    --surface: #212726;
    --ink: #eff0ec;
    --muted: #b3bbb8;
    --line: #3a4240;
    --accent: #6fc5bd;
    --accent-ink: #12211f;
    --answer: #1c3431;
    --error: #ff9a92;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.55 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
a { color: var(--accent); }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 16px; }

.site-header { padding: 10px 0 0; }
.logo { color: var(--ink); font-weight: 750; text-decoration: none; display: inline-flex; gap: 8px; align-items: center; min-height: 44px; }
h1 { font-size: clamp(26px, 6vw, 38px); line-height: 1.15; letter-spacing: -0.02em; margin: 4px 0 12px; }
h2 { font-size: 23px; line-height: 1.25; margin: 36px 0 8px; }
h3 { font-size: 18px; margin: 20px 0 2px; }
p { margin: 0 0 10px; }
main > section p, main > section li { max-width: 66ch; }

.tool { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 14px; }
.segmented { border: 0; padding: 0; margin: 0 0 12px; display: flex; flex-wrap: wrap; gap: 6px; }
.segmented legend { font-size: 15px; font-weight: 600; margin-bottom: 4px; padding: 0; }
.segmented label { display: block; }
.segmented input { position: absolute; opacity: 0; }
.segmented span { display: flex; min-height: 44px; padding: 6px 12px; align-items: center; border: 1px solid var(--line); border-radius: 6px; font-weight: 600; font-size: 15px; cursor: pointer; }
.segmented input:checked + span { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.segmented input:focus-visible + span { outline: 3px solid var(--ink); outline-offset: 1px; }

.columns { display: grid; gap: 16px; }
.fields { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin-bottom: 12px; }
.field label { display: block; font-size: 15px; font-weight: 600; margin-bottom: 4px; }
.ctl { display: flex; align-items: center; gap: 6px; }
.ctl input, select, .packs input { width: 100%; min-height: 44px; padding: 8px 10px; font: inherit; color: var(--ink); background: var(--bg); border: 1px solid var(--line); border-radius: 6px; font-variant-numeric: tabular-nums; }
.unit { color: var(--muted); font-size: 15px; }
input[aria-invalid="true"] { border-color: var(--error); }
input:focus-visible, select:focus-visible, button:focus-visible, summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 1px; }
.err, .alert { color: var(--error); font-size: 15px; margin: 4px 0 0; }
.chips { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 6px; }
button { font: inherit; min-height: 44px; padding: 6px 12px; border-radius: 6px; border: 1px solid var(--line); background: var(--bg); color: var(--ink); cursor: pointer; }
.chips button { font-size: 14px; padding: 4px 8px; }
button.link { border: 0; background: none; color: var(--accent); text-decoration: underline; padding: 6px 2px; }
.check { display: flex; align-items: center; gap: 10px; min-height: 44px; font-weight: 600; font-size: 15px; }
.check input { width: 22px; height: 22px; }

.packs { width: 100%; border-collapse: collapse; margin-bottom: 6px; font-size: 15px; }
.packs th { text-align: left; font-weight: 600; padding: 2px; }
.packs td { padding: 2px; }

.output { background: var(--answer); border-radius: 8px; padding: 14px; align-self: start; }
.big { font-size: clamp(28px, 7vw, 36px); line-height: 1.15; font-weight: 800; margin: 0 0 6px; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.big-sub { font-size: 20px; font-weight: 650; margin: 0 0 8px; }
.hint { color: var(--muted); margin: 0; }
details { margin: 10px 0; }
summary { cursor: pointer; font-weight: 600; min-height: 44px; display: flex; align-items: center; }
details ul { margin: 0; padding-left: 20px; }
.note { color: var(--muted); font-size: 15px; margin: 6px 0 0; }
.site-free { color: var(--muted); font-size: 15px; margin: 10px 0 0; }
.js-off { color: var(--error); font-weight: 600; }

.site-footer { margin-top: 48px; padding: 18px 0 28px; border-top: 1px solid var(--line); color: var(--muted); font-size: 15px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 4px 16px; }
.site-footer a { display: inline-flex; align-items: center; min-height: 44px; }

@media (min-width: 760px) {
  .columns { grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); }
  .output { position: sticky; top: 12px; }
  .tool { padding: 20px; }
}