/* ========================================
   Base CSS - Variables, Reset, Typography
   ======================================== */

/* CSS Variables & Design Tokens */
:root {
    /* Color Palette - Light Mode */
    --color-primary: #6366f1;
    --color-primary-dark: #4f46e5;
    --color-primary-light: #818cf8;
    --color-secondary: #8b5cf6;
    --color-accent: #ec4899;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-info: #3b82f6;

    /* Neutrals */
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f9fafb;
    --color-bg-tertiary: #f3f4f6;
    --color-surface: #ffffff;
    --color-surface-elevated: #ffffff;

    --color-text-primary: #111827;
    --color-text-secondary: #6b7280;
    --color-text-tertiary: #9ca3af;
    --color-text-inverse: #ffffff;

    --color-border: #e5e7eb;
    --color-border-light: #f3f4f6;
    --color-border-dark: #d1d5db;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

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

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-mono: 'Fira Code', 'Courier New', 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: 1.875rem;
    --font-size-4xl: 2.25rem;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* Dark Mode */
[data-theme="dark"] {
    --color-bg-primary: #121212;
    --color-bg-secondary: #1c1c1c;
    --color-bg-tertiary: #2d2d2d;
    --color-surface: #1e1e1e;
    --color-surface-elevated: #2d2d2d;

    --color-text-primary: #f3f4f6;
    --color-text-secondary: #d1d5db;
    --color-text-tertiary: #9ca3af;

    --color-border: #333333;
    --color-border-light: #404040;
    --color-border-dark: #1f1f1f;

    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
}

/* Base Styles & Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-text-primary);
    margin-bottom: var(--space-md);
}

h1 {
    font-size: var(--font-size-4xl);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: var(--font-size-3xl);
}

h3 {
    font-size: var(--font-size-2xl);
}