:root {
  --color-bg: #fdf8f0;
  --color-surface: #ffffff;
  --color-primary: #6b5a2e;
  --color-primary-dark: #4a3e1e;
  --color-accent: #8b6914;
  --color-text: #2c2416;
  --color-muted: #7a6a4a;
  --color-border: #d4c49a;
  --color-numeral: #6b5a2e;
  --color-numeral-hover: #4a3e1e;
  --shadow: 0 2px 12px rgba(107, 90, 46, 0.12);
  --radius: 12px;
  --breakpoint-mobile: 600px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: 'Georgia', serif;
  line-height: 1.7;
}

/* ── Header ─────────────────────────────────────────────── */
header {
  background-color: var(--color-primary-dark);
  color: #fff;
  padding: 2.5rem 1.5rem 2rem;
  text-align: center;
}

header h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 0.4rem;
}

header p {
  font-size: 1.05rem;
  opacity: 0.85;
  max-width: 640px;
  margin: 0 auto;
}

/* ── Main ────────────────────────────────────────────────── */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

/* ── About section ───────────────────────────────────────── */
.about {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem 2.5rem;
  margin-bottom: 3rem;
  box-shadow: var(--shadow);
}

.about h2 {
  color: var(--color-primary-dark);
  font-size: 1.6rem;
  margin-bottom: 1rem;
}

.about p {
  color: var(--color-muted);
  margin-bottom: 0.8rem;
}

.about p:last-child {
  margin-bottom: 0;
}

.about a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.about a:hover {
  color: var(--color-primary-dark);
}

/* ── System info ─────────────────────────────────────────── */
.system-info {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1.4rem;
}

.badge {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 0.35rem 0.9rem;
  font-size: 0.88rem;
  color: var(--color-primary);
  font-family: 'Georgia', serif;
}

/* ── Section headings ────────────────────────────────────── */
.section-heading {
  font-size: 1.5rem;
  color: var(--color-primary-dark);
  margin-bottom: 1.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
}

/* ── Legend ──────────────────────────────────────────────── */
.legend {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
  align-items: flex-end;
}

.legend-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.legend-item span {
  font-size: 0.8rem;
  color: var(--color-muted);
  text-align: center;
}

/* ── Numerals grid ───────────────────────────────────────── */
.numerals-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 1.2rem;
  margin-bottom: 3rem;
}

.numeral-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.2rem 0.8rem 0.8rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.8rem;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  cursor: default;
}

.numeral-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(107, 90, 46, 0.18);
}

.numeral-card svg {
  display: block;
}

.numeral-label {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--color-primary-dark);
  line-height: 1;
}

/* ── Converter section ───────────────────────────────────── */
.converter {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem 2.5rem;
  box-shadow: var(--shadow);
  margin-bottom: 3rem;
}

.converter h2 {
  color: var(--color-primary-dark);
  font-size: 1.6rem;
  margin-bottom: 1.2rem;
}

.converter-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.converter-controls label {
  font-size: 1rem;
  color: var(--color-primary);
}

.converter-controls input[type="number"] {
  width: 120px;
  padding: 0.5rem 0.8rem;
  border: 1.5px solid var(--color-border);
  border-radius: 8px;
  font-size: 1.1rem;
  color: var(--color-text);
  background: var(--color-bg);
  outline: none;
  transition: border-color 0.2s;
}

.converter-controls input[type="number"]:focus {
  border-color: var(--color-primary);
}

.converter-output {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  align-items: flex-end;
  min-height: 80px;
}

.converter-output .numeral-card {
  min-width: 100px;
}

.converter-note {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin-top: 0.8rem;
}

/* ── Footer ──────────────────────────────────────────────── */
footer {
  background: var(--color-primary-dark);
  color: rgba(255, 255, 255, 0.75);
  text-align: center;
  padding: 1.5rem 1rem;
  font-size: 0.9rem;
}

footer a {
  color: rgba(255, 255, 255, 0.9);
}

.position-multiplier {
  font-size: 0.75rem;
  color: var(--color-muted);
}

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 600px) { /* --breakpoint-mobile */
  .about,
  .converter {
    padding: 1.4rem 1.2rem;
  }

  .numerals-grid {
    grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  }
}