:root {
  --accent: #7c3aed;
  --pale: #f7f5ff;
  --ink: #1e1b4b;
  --muted: #54627a;
  --card: #ffffff;
  --line: #e4e0f5;
  --line-strong: #d9d4ef;
  --danger: #9f1239;
  --radius: 14px;
  --max: 1100px;
  --pad: 18px;
  --control: 48px;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html { background: var(--pale); }

body {
  margin: 0;
  background: var(--pale);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  padding-top: env(safe-area-inset-top);
  padding-right: env(safe-area-inset-right);
  padding-bottom: env(safe-area-inset-bottom);
  padding-left: env(safe-area-inset-left);
}

img, svg { max-width: 100%; }

input, select, textarea { min-width: 0; }

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

a:hover { text-decoration: none; }

h1, h2, h3 { line-height: 1.2; margin: 0; }

h1 { font-size: 1.75rem; }

h2 { font-size: 1.35rem; }

h3 { font-size: 1.05rem; }

p { margin: 0; }

.skip {
  position: absolute;
  left: 12px;
  top: -48px;
  background: var(--card);
  color: var(--ink);
  padding: 12px 16px;
  border-radius: var(--radius);
  z-index: 10;
}

.skip:focus { top: calc(8px + env(safe-area-inset-top)); }

.wrap {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--pad);
}

.site-header {
  position: relative;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}

.header-bar {
  max-width: var(--max);
  margin: 0 auto;
  min-height: 56px;
  padding: 0 var(--pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  min-height: var(--control);
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.brand svg { width: 28px; height: 28px; flex: 0 0 auto; }

.nav-toggle {
  width: var(--control);
  height: var(--control);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.bars, .bars::before, .bars::after {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--ink);
  position: relative;
  content: "";
}

.bars::before { position: absolute; top: -6px; }

.bars::after { position: absolute; top: 6px; }

.site-nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.site-nav a {
  display: flex;
  align-items: center;
  min-height: var(--control);
  padding: 0 12px;
  border-radius: var(--radius);
  color: var(--ink);
  text-decoration: none;
  text-align: left;
}

.site-nav a[aria-current="page"] {
  background: var(--pale);
  color: var(--accent);
  font-weight: 700;
}

.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 12px;
  margin-bottom: 16px;
}

.lead { color: var(--muted); max-width: 42rem; }

.actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  width: 100%;
}

.tool-stack, .page-stack, .groups, #result, #result-card {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.tool-stack, .page-stack { gap: 16px; }

#tool { margin-bottom: 16px; }

.groups, #result, #result-card { gap: 16px; }

.groups { gap: 20px; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--pad);
  min-width: 0;
}

fieldset {
  border: 0;
  margin: 0;
  padding: 0;
  min-width: 0;
}

legend {
  font-weight: 700;
  padding: 0;
  margin: 0 0 8px;
}

.choices {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.choice {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 12px;
  min-height: var(--control);
  padding: 8px 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--card);
  text-align: left;
}

.choice input {
  width: 20px;
  height: 20px;
  margin: 0;
  flex: 0 0 auto;
  accent-color: var(--accent);
}

.choice span { min-width: 0; overflow-wrap: anywhere; }

.choice:has(input:checked) {
  border-color: var(--accent);
  background: var(--pale);
}

.field {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 8px;
  min-width: 0;
  text-align: left;
}

.field label, .choice, legend { text-align: left; }

.hint, .note { color: var(--muted); }

.field-error { color: var(--danger); font-weight: 700; }

.error-title { font-weight: 700; color: var(--danger); }

#form-errors {
  border: 1px solid #fecdd3;
  background: #fff1f2;
  border-radius: var(--radius);
  padding: 12px;
}

#form-errors ul { margin: 8px 0 0; padding-left: 1.2rem; }

#unit-note {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px;
}

input[type="text"], select {
  width: 100%;
  height: var(--control);
  min-height: var(--control);
  padding: 0 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--ink);
  font: inherit;
  font-size: 16px;
}

input[aria-invalid="true"], select[aria-invalid="true"] { border-color: var(--danger); }

.pair {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.button, button.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--control);
  padding: 0 18px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  background: var(--accent);
  color: #ffffff;
  font: inherit;
  font-size: 16px;
  font-weight: 700;
  text-decoration: none;
  text-align: center;
}

.button.secondary, button.secondary {
  background: var(--card);
  color: var(--ink);
  border-color: var(--line-strong);
}

.form-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

#calc-btn, #reset-btn {
  scroll-margin-bottom: calc(80px + env(safe-area-inset-bottom));
}

.form-actions .button { flex: 1 1 160px; }

.assumption {
  background: var(--pale);
  border-radius: var(--radius);
  padding: 12px;
}

.assumption a, .prose a, .source-list a { overflow-wrap: anywhere; }

.bag-count {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.metric {
  background: var(--pale);
  border-radius: var(--radius);
  padding: 12px;
  min-width: 0;
}

.metrics {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.metric-label { color: var(--muted); font-size: 0.95rem; }

.metric-value {
  font-size: 1.25rem;
  font-weight: 700;
  overflow-wrap: anywhere;
}

.prose { display: flex; flex-direction: column; gap: 12px; }

.source-list { margin: 0; padding-left: 1.2rem; display: flex; flex-direction: column; gap: 8px; }

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--card);
}

.site-footer .wrap {
  display: flex;
  flex-direction: column;
  gap: 8px;
  color: var(--muted);
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
}

.footer-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-sizing: border-box;
  min-width: 44px;
  min-height: 48px;
  color: var(--ink);
  text-decoration: none;
}
.site-footer p a {
  display: inline-flex;
  align-items: center;
  box-sizing: border-box;
  min-width: 44px;
  min-height: 48px;
}

summary {
  min-height: 48px;
  display: flex;
  align-items: center;
  cursor: pointer;
  font-weight: 700;
}

details.card .details-body {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-top: 12px;
}

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

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.choice input:focus { outline: none; }

.choice:focus-within {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

@media (max-width: 800px) {
  body { padding-bottom: calc(80px + env(safe-area-inset-bottom)); }
  .hero, .hero h1, .hero .lead, .hero .actions { text-align: center; }
  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 5;
    background: var(--card);
    border-bottom: 1px solid var(--line);
    padding: 8px var(--pad) var(--pad);
  }
}

@media (min-width: 801px) {
  h1 { font-size: 2.25rem; }
  .hero { align-items: flex-start; text-align: left; }
  .hero .actions { justify-content: flex-start; }
  .nav-toggle { display: none; }
  .header-bar { gap: 16px; }
  .site-nav {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 8px;
  }
  .choices.wide { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
  .choices.split { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
  .pair { flex-direction: row; align-items: flex-end; }
  .pair .field { flex: 1 1 0; }
  .metrics { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .site-footer .wrap { flex-direction: row; justify-content: space-between; align-items: center; }
}

/* Release polish: keep long values readable on narrow screens. */
.metric-value, dd { overflow-wrap: anywhere; }
.related-tools { margin-block: 2rem; }
details.card > summary { cursor: pointer; font-weight: 650; padding: .75rem 0; min-height: 44px; box-sizing: border-box; }