@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

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

:root {
  --bg:      #f4f4f5;
  --surface: #ffffff;
  --border:  #e4e4e7;
  --text:    #18181b;
  --muted:   #71717a;
  --accent:  #2563eb;
  --radius:  10px;
}

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  padding: 2.5rem 1rem 5rem;
  font-size: 15px;
  line-height: 1.6;
}

header {
  max-width: 680px;
  margin: 0 auto 2.5rem;
}

header h1 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

header .subtitle {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.25rem;
}

main {
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  position: relative;
}

.card-label {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}

.card h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

/* Output rows */
#dateOutput {
  font-size: 1.05rem;
  font-weight: 500;
}

#numberConversionOutput p,
#mathOutput p {
  font-size: 0.875rem;
  padding: 0.6rem 0.85rem;
  background: var(--bg);
  border-radius: 6px;
  margin-bottom: 0.5rem;
}

#numberConversionOutput p:last-child,
#mathOutput p:last-child {
  margin-bottom: 0;
}

#mathOutput p strong {
  font-weight: 600;
}