:root {
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;

    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.07);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.1);
    --shadow-xl: 0 16px 48px rgba(0,0,0,0.14);

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', monospace;
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;

    /* Colors - Brand */
    --color-primary: #1D4ED8;
    --color-secondary: #3B82F6;
    --color-soft: #93C5FD;
    --color-info: #06B6D4;

    /* Colors - Neutral (Slate scale) */
    --gray-50: #F8FAFC;
    --gray-100: #F1F5F9;
    --gray-200: #E2E8F0;
    --gray-300: #CBD5E1;
    --gray-400: #94A3B8;
    --gray-500: #64748B;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1E293B;
    --gray-900: #0F172A;

    /* Surfaces */
    --bg-primary: #ffffff;
    --bg-secondary: #F8FAFC;
    --bg-tertiary: #F1F5F9;
    --text-primary: #0F172A;
    --text-secondary: #64748B;
    --text-muted: #94A3B8;
    --border-color: #E2E8F0;

    /* Status colors (defaults, overridden by JS from settings) */
    --color-ok: #22C55E;
    --color-warning: #F59E0B;
    --color-critical: #EF4444;
    --color-expired: #991b1b;
    --color-paused: var(--gray-400);

    /* Accent (primary blue) */
    --color-accent: #1D4ED8;
    --color-accent-hover: #1E40AF;
    --color-accent-light: #93C5FD;

    /* Segment colors (purple → blue → teal for max contrast) */
    --seg-year: #7C3AED;
    --seg-year-light: #8B5CF6;
    --seg-month: #1D4ED8;
    --seg-month-light: #3B82F6;
    --seg-day: #0891B2;
    --seg-day-light: #06B6D4;

    /* Calendar heat map */
    --color-calendar-heat: #3B82F6;

    /* Touch target */
    --touch-min: 44px;

    /* Transitions */
    --ease-out: cubic-bezier(0.4, 0, 0.2, 1);
    --ease-bounce: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 150ms;
    --duration-normal: 300ms;
    --duration-slow: 500ms;
}