:root {
  --color-text-primary: #f8f6f9;
  --color-text-secondary: #e7d9e4;
  --color-text-tertiary: #c8b6c4;
  --color-background-primary: #202020;
  --color-background-secondary: #25242c;
  --color-panel: #ef7cac;
  --color-panel-muted: #f7c7d9;
  --color-card-border: rgba(255,255,255,0.12);
  --color-accent: #ef7cac;
  --color-border-tertiary: rgba(255,255,255,0.12);
  --color-border-secondary: rgba(255,255,255,0.18);
  --border-radius-sm: 10px;
  --border-radius-md: 16px;
  --border-radius-lg: 22px;
  --shadow-soft: 0 18px 40px rgba(22, 28, 40, 0.06);
  --font-sans: Inter, system-ui, sans-serif;
  --font-mono: ui-monospace, monospace;
}
@media (prefers-color-scheme: dark) {
  :root {
    --shadow-soft: 0 18px 40px rgba(0, 0, 0, 0.35);
  }
}
* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  font-family: var(--font-sans);
  color: var(--color-text-primary);
  background: var(--color-background-primary);
  padding: 30px 24px 40px;
  max-width: 980px;
  margin: 0 auto;
}
body > * + * {
  margin-top: 22px;
}
h1 {
  font-size: clamp(1.8rem, 2.2vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
}
.subtitle {
  font-size: 0.96rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-width: 760px;
}
.controls,
.results-grid,
.panels {
  display: grid;
  gap: 16px;
}
.controls {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.ctrl-row {
  background: rgba(239, 124, 172, 0.18);
  border: 1px solid rgba(239, 124, 172, 0.35);
  border-radius: var(--border-radius-md);
  padding: 14px 14px 12px;
  gap: 8px;
  display: grid;
}
.ctrl-row.ctrl-action {
  grid-column: span 2;
  align-items: center;
  justify-items: center;
}
.ctrl-label {
  font-size: 0.86rem;
  color: var(--color-text-secondary);
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
.ctrl-label span {
  font-weight: 600;
  color: var(--color-text-primary);
  white-space: nowrap;
}
input[type=range] {
  width: 100%;
  accent-color: var(--color-accent);
  height: 24px;
}
button {
  width: 100%;
  background: #202020;
  color: #ffffff;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.18s ease, background 0.18s ease;
}
button:hover {
  background: #111111;
  transform: translateY(-1px);
}
.results-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.metric {
  background: rgba(239, 124, 172, 0.16);
  border-radius: var(--border-radius-md);
  padding: 16px 14px;
  border: 1px solid rgba(239, 124, 172, 0.30);
  box-shadow: var(--shadow-soft);
}
.metric-label {
  font-size: 0.78rem;
  color: var(--color-text-secondary);
  margin-bottom: 8px;
}
.metric-value {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-text-primary);
}
.metric-unit {
  font-size: 0.82rem;
  color: var(--color-text-tertiary);
  margin-left: 4px;
}
.panels {
  grid-template-columns: 1.4fr 1fr;
}
.panel,
.formulae {
  background: var(--color-panel);
  border-radius: var(--border-radius-lg);
  padding: 18px;
  border: 1px solid rgba(255,255,255,0.18);
  box-shadow: var(--shadow-soft);
}
.panel-title {
  font-size: 0.72rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.formula-row {
  display: grid;
  grid-template-columns: minmax(120px, 1fr) minmax(140px, 1.5fr) auto;
  gap: 10px;
  align-items: baseline;
  padding: 10px 0;
  border-bottom: 1px solid rgba(255,255,255,0.18);
}
.formula-row:last-child {
  border-bottom: none;
}
.f-name {
  color: var(--color-text-secondary);
  font-size: 0.78rem;
}
.f-eq {
  color: var(--color-text-primary);
  font-family: var(--font-mono);
  font-size: 0.86rem;
}
.f-val {
  color: #ffffff;
  font-weight: 700;
  font-size: 0.88rem;
  text-align: right;
}
.chapter-tag {
  display: inline-flex;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 999px;
  margin-left: 6px;
  vertical-align: middle;
}
.c0 { background: #fdf3e5; color: #774b1d; }
.c1 { background: #fae3f0; color: #8b2a58; }
.c2 { background: #f7d7e6; color: #8b2a58; }
.c3 { background: #fbe2ec; color: #8b2a58; }
.c7 { background: #fcd9e9; color: #8b2a58; }
.note {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  margin-top: 4px;
  line-height: 1.7;
  padding-top: 14px;
  border-top: 1px solid var(--color-border-tertiary);
}
@media (max-width: 860px) {
  .controls,
  .results-grid,
  .panels {
    grid-template-columns: 1fr;
  }
  .formula-row {
    grid-template-columns: 1fr;
  }
  .f-val {
    text-align: left;
  }
}