:root {
    /* Colour tokens */
    --ink-primary: #102A43;
    --ink-secondary: #243B53;
    --ink-muted: #627D98;
    --ink-light: #9FB3C8;
    
    --action-primary: #007C7A;
    --action-primary-hover: #006B69;
    --action-pale: #E6F5F4;
    --action-focus: #005F5D;
    
    --bg-page: #F7FAFC;
    --bg-card: #FFFFFF;
    --bg-border: #D9E2EC;
    --bg-subtle: #EDF2F7;
    
    --success: #0E8345;
    --success-pale: #E6F9ED;
    --warning: #B45309;
    --warning-pale: #FEF3C7;
    --error: #C53030;
    --error-pale: #FED7D7;
    --info: #2B6CB0;
    --info-pale: #E2E8F0;
    
    /* Typography */
    --font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", "DejaVu Sans", Ubuntu, 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;
    
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.625;
    
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* Spacing (4px base) */
    --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;
    
    /* Layout */
    --max-width: 1200px;
    --reading-width: 760px;
    --content-padding: 1.5rem;
    
    /* Borders */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 9999px;
    
    --border-width: 1px;
    --border-color: var(--bg-border);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(16, 42, 67, 0.05);
    --shadow-md: 0 4px 6px rgba(16, 42, 67, 0.07);
    --shadow-lg: 0 10px 15px rgba(16, 42, 67, 0.1);
    
    /* Focus */
    --focus-ring: 0 0 0 3px rgba(0, 124, 122, 0.3);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
    
    /* Z-index */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 300;
    --z-toast: 400;
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}