:root {
    /* Primary Colors */
    --color-navy-900: #0a192f;
    --color-navy-800: #112240;
    --color-navy-700: #1d3461;
    --color-navy-600: #233554;
    
    /* Medical Teal */
    --color-teal-700: #0e7490;
    --color-teal-600: #0891b2;
    --color-teal-500: #06b6d4;
    --color-teal-400: #22d3ee;
    --color-teal-100: #cffafe;
    --color-teal-50: #ecfeff;
    
    /* Neutrals */
    --color-white: #ffffff;
    --color-grey-50: #f8fafc;
    --color-grey-100: #f1f5f9;
    --color-grey-200: #e2e8f0;
    --color-grey-300: #cbd5e1;
    --color-grey-400: #94a3b8;
    --color-grey-500: #64748b;
    --color-grey-600: #475569;
    --color-grey-700: #334155;
    --color-grey-800: #1e293b;
    --color-grey-900: #0f172a;
    
    /* Semantic Colors */
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-info: #3b82f6;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-family-heading: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --line-height-tight: 1.2;
    --line-height-normal: 1.6;
    --line-height-relaxed: 1.75;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    --space-32: 8rem;
    
    /* Container */
    --container-max: 1280px;
    --container-narrow: 1024px;
    --container-wide: 1440px;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(10, 25, 47, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(10, 25, 47, 0.1), 0 2px 4px -2px rgba(10, 25, 47, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(10, 25, 47, 0.1), 0 4px 6px -4px rgba(10, 25, 47, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(10, 25, 47, 0.1), 0 8px 10px -6px rgba(10, 25, 47, 0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Z-index */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-overlay: 300;
    --z-modal: 400;
    --z-toast: 500;
    
    /* Header */
    --header-height: 72px;
    --header-top-height: 36px;
    
    /* Breakpoints (for reference in JS/CSS) */
    --bp-sm: 640px;
    --bp-md: 768px;
    --bp-lg: 1024px;
    --bp-xl: 1280px;
}