:root {
  color-scheme: light;
  --bg: #f3f6f5;
  --surface: #ffffff;
  --surface-muted: #eef5f2;
  --text: #17211e;
  --muted: #5f6f69;
  --primary: #0f766e;
  --primary-dark: #0b5f59;
  --border: #cbd8d3;
  --danger: #b42318;
  --warning: #9a6700;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(20, 45, 38, 0.08);
  font-family: Inter, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
body { min-width: 320px; margin: 0; background: var(--bg); color: var(--text); }
main { width: min(1180px, calc(100% - 24px)); margin: 0 auto 48px; }
.page-header { padding-top: 28px; }
h1, h2, h3, p { margin-top: 0; }
h1 { font-size: clamp(1.65rem, 7vw, 2.4rem); }
h2 { font-size: 1.2rem; }
.page-header p, #status-message, .result-row dt { color: var(--muted); }

.card { padding: 18px; margin-top: 16px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); box-shadow: var(--shadow); }
.field-grid { display: grid; grid-template-columns: 1fr; gap: 14px; }
.field { display: grid; min-width: 0; gap: 7px; }
.field-label, legend { font-weight: 600; }
.input-with-unit { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: stretch; }
input, select, button { min-height: 44px; font: inherit; }
input, select { width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: 10px; color: var(--text); background: #fff; }
.input-with-unit input { border-radius: 10px 0 0 10px; }
.unit { display: grid; min-width: 52px; padding: 0 10px; border: 1px solid var(--border); border-left: 0; border-radius: 0 10px 10px 0; place-items: center; color: var(--muted); background: var(--surface-muted); }
button { padding: 10px 16px; border: 0; border-radius: 10px; color: var(--text); background: var(--surface-muted); cursor: pointer; }
.button-primary, #calculate-theory, #calculate-actual, #copy-results, #confirm-reset { color: #fff; background: var(--primary); }
.button-primary:hover, #calculate-theory:hover, #calculate-actual:hover, #copy-results:hover, #confirm-reset:hover { background: var(--primary-dark); }
button:disabled { cursor: not-allowed; opacity: 0.55; }
button:focus-visible, input:focus-visible, select:focus-visible { outline: 3px solid rgba(15, 118, 110, 0.25); outline-offset: 2px; }
[aria-invalid="true"] { border-color: var(--danger); }
[data-stale="true"] { border-color: var(--warning); opacity: 0.62; }

.toggle-row, .actions { display: grid; gap: 12px; margin-top: 14px; }
.toggle-row label { display: grid; gap: 7px; }
.toggle-row input[type="checkbox"] { width: 20px; min-height: 20px; }
.actions button, #copy-results { width: 100%; }
.part-fields { min-width: 0; margin: 16px 0 0; padding: 14px; border: 1px solid var(--border); border-radius: 10px; }
.material-card { min-width: 0; padding: 16px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface-muted); }
.result-grid { display: grid; gap: 14px; }
.result-card { min-width: 0; padding: 16px; border: 1px solid var(--border); border-radius: 10px; background: var(--surface-muted); }
.result-list { margin: 0; }
.result-row { display: flex; justify-content: space-between; gap: 14px; padding: 7px 0; border-bottom: 1px solid var(--border); }
.result-row:last-child { border-bottom: 0; }
.result-row dd { margin: 0; text-align: right; font-weight: 600; }
.status-message, #status-message { min-height: 1.5em; margin: 16px 0 0; }
.app-dialog, dialog { width: min(calc(100% - 24px), 28rem); padding: 20px; border: 1px solid var(--border); border-radius: var(--radius); color: var(--text); background: var(--surface); box-shadow: var(--shadow); }
.app-dialog::backdrop, dialog::backdrop { background: rgb(23 33 30 / 55%); }
.copy-fallback { position: fixed; inset-inline-start: -10000px; top: 0; }
[hidden] { display: none !important; }

@media (min-width: 720px) {
  main { width: min(1180px, calc(100% - 40px)); }
  .field-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .dimensions-grid, #geometry-fields .field-grid, #actual-fields .field-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .toggle-row, .actions { grid-auto-flow: column; grid-auto-columns: max-content; align-items: end; }
  .actions button, #copy-results { width: auto; }
}
@media (min-width: 1040px) { .materials-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; } }