/* Dark theme */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-bg-secondary: #1e293b;
  --color-bg-tertiary: #334155;
  --color-surface: #1e293b;
  --color-surface-hover: #334155;
  --color-border: #334155;
  --color-border-strong: #475569;

  --color-text: #f8fafc;
  --color-text-secondary: #cbd5e1;
  --color-text-tertiary: #64748b;

  --color-primary: #3b82f6;
  --color-primary-hover: #60a5fa;
  --color-primary-light: #1e3a5f;
  --color-primary-text: #ffffff;

  --color-accent: #a78bfa;
  --color-accent-light: #2e1065;

  --color-success: #22c55e;
  --color-error: #f87171;
  --color-error-bg: #450a0a;

  --color-calc-btn: #334155;
  --color-calc-btn-hover: #475569;
  --color-calc-btn-active: #64748b;
  --color-calc-btn-operator: #1e3a5f;
  --color-calc-btn-function: #2e1065;
  --color-calc-btn-equals: #3b82f6;
  --color-calc-btn-equals-text: #ffffff;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}