/* FitSense — styles. Own CSS only, no frameworks. Light + dark, accessible, responsive. */

:root {
  --bg: #f6f7fb;
  --surface: #ffffff;
  --surface-2: #f1f3f9;
  --ink: #1a1f2e;
  --ink-soft: #4a5167;
  --ink-faint: #717892;
  --line: #e2e6f0;
  --brand: #4f46e5;
  --brand-ink: #ffffff;
  --brand-soft: #eef0fe;
  --good: #0f9d6b;
  --ok: #2f7de1;
  --warn: #d98517;
  --bad: #d6453d;
  --good-soft: #e6f6ef;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 1px 2px rgba(20, 25, 45, 0.05), 0 8px 28px rgba(20, 25, 45, 0.07);
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1018;
    --surface: #171a24;
    --surface-2: #1f2331;
    --ink: #eef0f7;
    --ink-soft: #b6bcd0;
    --ink-faint: #888fa6;
    --line: #2a2f40;
    --brand: #8b85ff;
    --brand-ink: #0e1018;
    --brand-soft: #21223a;
    --good: #34d399;
    --ok: #6bb0ff;
    --warn: #f0b057;
    --bad: #f87171;
    --good-soft: #14271f;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 10px 30px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.55;
  font-size: 16px;
}

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

.sr-only {
  position: absolute !important;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0);
  white-space: nowrap; border: 0;
}

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--brand); color: var(--brand-ink);
  padding: 10px 16px; border-radius: 0 0 8px 0; z-index: 100;
}
.skip-link:focus { left: 0; }

a { color: var(--brand); }

/* Focus visibility for accessibility */
:focus-visible {
  outline: 3px solid var(--brand);
  outline-offset: 2px;
  border-radius: 6px;
}

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 10;
}
.header-inner { display: flex; align-items: center; justify-content: space-between; padding-top: 14px; padding-bottom: 14px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark { font-size: 28px; }
.brand-name { display: block; font-weight: 700; font-size: 19px; letter-spacing: -0.01em; }
.brand-tag { display: block; font-size: 12.5px; color: var(--ink-faint); }

.backend-badge {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; color: var(--ink-soft);
  background: var(--surface-2); border: 1px solid var(--line);
  padding: 7px 12px; border-radius: 999px;
}
.backend-badge .dot { width: 9px; height: 9px; border-radius: 50%; background: var(--ink-faint); }
.backend-badge .dot.webgpu { background: var(--good); }
.backend-badge .dot.wasm { background: var(--ok); }
.backend-badge .dot.cpu { background: var(--warn); }

/* Privacy banner */
.privacy-banner { background: var(--good-soft); border-bottom: 1px solid var(--line); }
.privacy-inner { display: flex; gap: 12px; align-items: center; padding: 12px 20px; }
.privacy-inner .lock { font-size: 20px; }
.privacy-inner p { margin: 0; font-size: 14px; color: var(--ink-soft); }
.privacy-inner strong { color: var(--ink); }

/* Hero */
.hero { padding: 36px 0 8px; }
.hero h1 { font-size: clamp(26px, 4vw, 38px); line-height: 1.12; letter-spacing: -0.02em; margin: 0 0 12px; }
.lede { font-size: 17px; color: var(--ink-soft); max-width: 62ch; margin: 0; }

/* Layout grid */
.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin-top: 24px; }
@media (max-width: 860px) { .grid { grid-template-columns: 1fr; } }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 22px;
}
.card h2 { margin: 0 0 18px; font-size: 18px; letter-spacing: -0.01em; }
.card h3 { font-size: 15px; margin: 18px 0 6px; }

/* Dropzone */
.dropzone {
  position: relative;
  border: 2px dashed var(--line);
  border-radius: var(--radius-sm);
  min-height: 190px;
  display: flex; align-items: center; justify-content: center;
  text-align: center; padding: 18px; cursor: pointer;
  background: var(--surface-2);
  transition: border-color 0.15s, background 0.15s;
  overflow: hidden;
}
.dropzone:hover, .dropzone.drag { border-color: var(--brand); background: var(--brand-soft); }
.dz-text { color: var(--ink-faint); font-size: 14.5px; max-width: 32ch; }
.dz-text.has-image { position: absolute; bottom: 8px; left: 8px; right: 8px; background: rgba(0,0,0,0.55); color:#fff; border-radius: 8px; padding: 4px 8px; font-size: 12px; }
.dropzone img.preview { max-height: 280px; max-width: 100%; border-radius: 8px; display: block; }

.field { margin-top: 18px; }
.field label { display: block; font-weight: 600; font-size: 14px; margin-bottom: 6px; }
.field-hint { color: var(--ink-faint); font-size: 12.5px; margin: 6px 0 0; }
input[type="number"] {
  width: 100%; padding: 11px 13px; font-size: 16px;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--surface); color: var(--ink);
}
input[type="number"][aria-invalid="true"] { border-color: var(--bad); }

/* Consent */
.consent {
  margin-top: 18px; padding: 14px;
  background: var(--brand-soft); border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  display: grid; grid-template-columns: auto 1fr; gap: 10px; align-items: start;
}
.consent label { font-size: 13.5px; color: var(--ink-soft); }
.consent input { margin-top: 3px; width: 18px; height: 18px; accent-color: var(--brand); }
.consent.flash { animation: flash 0.8s ease; }
@keyframes flash { 0%,100% { box-shadow: none; } 30% { box-shadow: 0 0 0 3px var(--brand); } }

/* Buttons */
.actions { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }
.btn {
  appearance: none; cursor: pointer; font: inherit; font-weight: 600;
  padding: 11px 18px; border-radius: var(--radius-sm);
  border: 1px solid var(--line); background: var(--surface); color: var(--ink);
  transition: transform 0.05s, background 0.15s, opacity 0.15s;
}
.btn:hover { background: var(--surface-2); }
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--brand); color: var(--brand-ink); border-color: var(--brand); }
.btn.primary:hover { filter: brightness(1.07); background: var(--brand); }
.btn.ghost { background: transparent; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn.busy { position: relative; color: transparent; }
.btn.busy::after {
  content: ""; position: absolute; inset: 0; margin: auto;
  width: 16px; height: 16px; border: 2px solid currentColor; border-top-color: transparent;
  border-radius: 50%; animation: spin 0.7s linear infinite; color: var(--brand-ink);
}
@keyframes spin { to { transform: rotate(360deg); } }

.sep { border: none; border-top: 1px solid var(--line); margin: 22px 0; }

.samples summary { cursor: pointer; font-weight: 600; font-size: 14px; }
.sample-row { display: flex; gap: 10px; margin-top: 12px; }
select {
  flex: 1; padding: 10px 12px; font-size: 14px;
  border: 1px solid var(--line); border-radius: var(--radius-sm);
  background: var(--surface); color: var(--ink);
}

/* Result */
.result { min-height: 200px; }
.placeholder { color: var(--ink-faint); font-size: 14.5px; }
.result[aria-busy="true"] { opacity: 0.5; }

.result-head { display: grid; gap: 16px; }
.size-badge {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  background: var(--surface-2); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 14px 16px;
}
.size-label { font-size: 12px; color: var(--ink-faint); text-transform: uppercase; letter-spacing: 0.05em; }
.size-badge .size { font-size: 40px; font-weight: 800; line-height: 1; color: var(--brand); letter-spacing: -0.02em; }
.adj { font-size: 12.5px; padding: 4px 9px; border-radius: 999px; background: var(--good-soft); color: var(--good); font-weight: 600; }
.adj.subtle { background: var(--surface); color: var(--ink-faint); border: 1px solid var(--line); }
.pose-chip { font-size: 11.5px; padding: 4px 9px; border-radius: 999px; background: var(--brand-soft); color: var(--brand); font-weight: 600; }

.confidence .lbl { display: flex; justify-content: space-between; font-size: 13px; font-weight: 600; margin-bottom: 6px; }
.confidence .bar { height: 10px; background: var(--surface-2); border-radius: 999px; overflow: hidden; border: 1px solid var(--line); }
.confidence .bar span { display: block; height: 100%; border-radius: 999px; background: var(--ok); transition: width 0.4s ease; }
.confidence.good .bar span { background: var(--good); }
.confidence.ok .bar span { background: var(--ok); }
.confidence.warn .bar span { background: var(--warn); }
.confidence.bad .bar span { background: var(--bad); }
.conf-note { font-size: 12.5px; color: var(--ink-faint); margin: 8px 0 0; }

.dist { margin-top: 20px; }
.dist-list { display: grid; gap: 8px; margin-top: 6px; }
.dist-row { display: grid; grid-template-columns: 36px 1fr 44px; gap: 10px; align-items: center; }
.dist-row.is-pick .dist-size { color: var(--brand); }
.dist-size { font-weight: 700; font-size: 14px; }
.dist-bar { height: 14px; background: var(--surface-2); border: 1px solid var(--line); border-radius: 999px; overflow: hidden; }
.dist-bar span { display: block; height: 100%; background: var(--brand); border-radius: 999px; }
.dist-row:not(.is-pick) .dist-bar span { background: var(--ink-faint); opacity: 0.6; }
.dist-pct { font-size: 13px; color: var(--ink-soft); text-align: right; }

table.metrics { width: 100%; border-collapse: collapse; margin-top: 20px; font-size: 14px; }
table.metrics th, table.metrics td { text-align: left; padding: 9px 8px; border-bottom: 1px solid var(--line); }
table.metrics thead th { font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-faint); }
table.metrics tbody th { font-weight: 600; }
table.metrics .val { font-variant-numeric: tabular-nums; font-weight: 700; }
table.metrics .range { font-variant-numeric: tabular-nums; color: var(--ink-soft); }
table.metrics .range .pm { color: var(--ink-faint); font-size: 12px; }
table.metrics .note { color: var(--ink-faint); font-size: 12px; }

.why { margin-top: 20px; background: var(--surface-2); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 14px 16px; }
.why h3 { margin-top: 0; }
.why p { margin: 0; font-size: 14px; color: var(--ink-soft); }

.flags { margin-top: 16px; }
.flags ul { margin: 0; padding-left: 0; list-style: none; display: grid; gap: 8px; }
.flags li {
  font-size: 13px; color: var(--ink-soft);
  background: color-mix(in srgb, var(--warn) 12%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--warn) 35%, var(--line));
  border-radius: var(--radius-sm); padding: 9px 12px;
}

/* Alert (graceful errors) */
.alert {
  display: flex; gap: 12px; align-items: flex-start;
  background: color-mix(in srgb, var(--bad) 10%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--bad) 40%, var(--line));
  border-radius: var(--radius-sm); padding: 16px;
}
.alert-icon {
  flex: none; width: 26px; height: 26px; border-radius: 50%;
  background: var(--bad); color: #fff; font-weight: 800;
  display: grid; place-items: center;
}
.alert strong { display: block; margin-bottom: 4px; }
.alert p { margin: 0; font-size: 13.5px; color: var(--ink-soft); }
.alert .alert-note { margin-top: 8px; font-size: 12.5px; color: var(--ink-faint); }

/* Learning */
.learn-intro { color: var(--ink-soft); max-width: 70ch; margin: 0 0 18px; }
.learn-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; }
@media (max-width: 720px) { .learn-grid { grid-template-columns: 1fr; } }
.learn-state { font-size: 14px; margin-bottom: 14px; }
.learn-state .muted, .muted { color: var(--ink-faint); }
.learn-result { background: var(--surface-2); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 16px; min-height: 80px; }
.learn-metric { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.learn-metric .big { font-size: 30px; font-weight: 800; display: block; line-height: 1; font-variant-numeric: tabular-nums; }
.learn-metric .big.good { color: var(--good); }
.learn-metric .cap { font-size: 12px; color: var(--ink-faint); }
.learn-metric .arrow { font-size: 24px; color: var(--ink-faint); }
.learn-metric .delta { margin-left: auto; font-weight: 700; color: var(--ink-faint); }
.learn-metric .delta.good { color: var(--good); }

/* Trust */
.trust-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
@media (max-width: 760px) { .trust-grid { grid-template-columns: 1fr; } }
.trust-grid h3 { margin-top: 0; }
.trust-grid p { font-size: 13.5px; color: var(--ink-soft); margin: 0 0 8px; }
.model-meta { font-size: 12px; color: var(--ink-faint); word-break: break-word; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); margin-top: 8px; padding: 24px 0; }
.site-footer p { margin: 0; font-size: 13px; color: var(--ink-faint); text-align: center; }

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}