/* ==========================================================================
   CSS Custom Properties (Variables)
   Centralized design tokens for consistent theming
   ========================================================================== */

:root {
    /* -------------------------
       Color Palette
       ------------------------- */
    --color-background: #0a0a0a;
    --color-surface: #111111;
    --color-surface-elevated: #1a1a1a;

    /* Accent colors (green for sustainability) */
    --color-accent: #4ade80;
    --color-accent-light: #86efac;
    --color-accent-dark: #22c55e;

    /* Text colors */
    --color-text-primary: #ffffff;
    --color-text-secondary: #a0a0a0;
    --color-text-muted: #666666;

    /* Border colors */
    --color-border: #2a2a2a;
    --color-border-light: #333333;

    /* -------------------------
       Typography
       ------------------------- */
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-family-mono: 'SF Mono', 'Fira Code', 'Consolas', monospace;

    --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: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3rem;

    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    --line-height-tight: 1.25;
    --line-height-base: 1.6;
    --line-height-relaxed: 1.75;

    /* -------------------------
       Spacing Scale
       ------------------------- */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;

    /* -------------------------
       Layout
       ------------------------- */
    --container-max-width: 1100px;
    --container-padding: var(--spacing-lg);
    --section-spacing: var(--spacing-4xl);

    /* -------------------------
       Border Radius
       ------------------------- */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;

    /* -------------------------
       Transitions
       ------------------------- */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* -------------------------
       Shadows
       ------------------------- */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.6);
    --shadow-accent: 0 4px 20px rgba(74, 222, 128, 0.3);
}