@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Plus+Jakarta+Sans:wght@300;400;500;600;700;800&display=swap');

/* ============================================================================
   GLOBAL RESET & BASE STYLES
   ============================================================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  height: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-dark-80);
  background-color: var(--color-dark-10);
  overflow-x: hidden; /* Prevent horizontal scroll */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  height: 100%;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: var(--font-weight-bold);
  color: var(--color-dark-100);
  line-height: var(--leading-tight);
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-fast);
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  display: block;
}

button, input, select, textarea {
  font: inherit;
  outline: none;
}

:root {
  /* --- Core Brand Colors --- */
  --color-primary: #6366f1;
  --color-primary-hover: #4f46e5;
  --color-primary-light: #818cf8;
  --color-primary-dark: #4338ca;
  
  --color-secondary: #a855f7;
  --color-secondary-hover: #9333ea;
  --color-secondary-light: #c084fc;
  
  --color-accent: #3b82f6;
  --color-accent-hover: #2563eb;
  
  /* --- Semantic Colors --- */
  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-success-dark: #065f46;
  
  --color-danger: #ef4444;
  --color-danger-light: #fee2e2;
  --color-danger-dark: #991b1b;
  
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;
  --color-warning-dark: #92400e;
  
  --color-info: #0ea5e9;
  --color-info-light: #e0f2fe;
  --color-info-dark: #0369a1;
  
  /* --- Neutral / Gray Scale --- */
  --color-dark-100: #0f172a;
  --color-dark-90: #1e293b;
  --color-dark-80: #334155;
  --color-dark-70: #475569;
  --color-dark-60: #64748b;
  --color-dark-50: #94a3b8;
  --color-dark-40: #cbd5e1;
  --color-dark-30: #e2e8f0;
  --color-dark-20: #f1f5f9;
  --color-dark-10: #f8fafc;
  
  --color-light: #ffffff;
  --color-black: #000000;
  
  /* --- Gradients --- */
  --grad-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  --grad-primary-reverse: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-primary) 100%);
  --grad-dark: linear-gradient(135deg, var(--color-dark-100) 0%, var(--color-dark-90) 60%, var(--color-dark-100) 100%);
  --grad-dark-subtle: linear-gradient(135deg, rgba(15, 23, 42, 0.9) 0%, rgba(30, 41, 59, 0.9) 100%);
  --grad-surface: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0) 100%);
  --grad-glass: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0) 100%);
  
  /* --- Role Colors --- */
  --role-admin: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  --role-instructor: linear-gradient(135deg, #0ea5e9, var(--color-primary));
  --role-student: linear-gradient(135deg, #10b981, var(--color-accent));
  
  /* ============================================================================
   2. TYPOGRAPHY SYSTEM
   ============================================================================ */
  
  /* Font Families */
  --font-display: 'Plus Jakarta Sans', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', monospace;
  
  /* Font Weights */
  --font-weight-thin: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  --font-weight-black: 900;
  
  /* Font Sizes - Modular Scale */
  --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;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 3.75rem;
  --text-7xl: 4.5rem;
  
  /* Line Heights */
  --leading-none: 1;
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  --leading-loose: 2;
  
  /* Letter Spacing */
  --tracking-tighter: -0.05em;
  --tracking-tight: -0.025em;
  --tracking-normal: 0;
  --tracking-wide: 0.025em;
  --tracking-wider: 0.05em;
  --tracking-widest: 0.1em;
  
  /* ============================================================================
   3. SPACING SYSTEM - 4px base unit
   ============================================================================ */
  
  --space-0: 0;
  --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 Padding */
  --container-padding: 1.5rem;
  --container-max-width: 1280px;
  --container-dashboard-max-width: 1400px;
  
  /* ============================================================================
   4. BORDER RADIUS SYSTEM
   ============================================================================ */
  
  --radius-xs: 0.25rem;
  --radius-sm: 0.375rem;
  --radius-base: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.25rem;
  --radius-2xl: 1.5rem;
  --radius-3xl: 2rem;
  --radius-full: 9999px;
  --radius-circle: 50%;
  
  /* ============================================================================
   5. SHADOW SYSTEM
   ============================================================================ */
  
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  
  /* Colored Shadows */
  --shadow-primary: 0 10px 15px -3px rgba(99, 102, 241, 0.3);
  --shadow-secondary: 0 10px 15px -3px rgba(168, 85, 247, 0.3);
  --shadow-success: 0 10px 15px -3px rgba(16, 185, 129, 0.3);
  --shadow-danger: 0 10px 15px -3px rgba(239, 68, 68, 0.3);
  
  /* Inner Shadows */
  --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
  --shadow-inset: inset 0 0 0 1px rgba(0, 0, 0, 0.05);
  
  /* ============================================================================
   6. TRANSITIONS & ANIMATIONS
   ============================================================================ */
  
  --ease-linear: cubic-bezier(0, 0, 1, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  
  --duration-75: 75ms;
  --duration-100: 100ms;
  --duration-150: 150ms;
  --duration-200: 200ms;
  --duration-300: 300ms;
  --duration-500: 500ms;
  --duration-700: 700ms;
  --duration-1000: 1000ms;
  
  --transition-fast: all var(--duration-150) var(--ease-in-out);
  --transition-base: all var(--duration-200) var(--ease-in-out);
  --transition-md: all var(--duration-300) var(--ease-in-out);
  --transition-slow: all var(--duration-500) var(--ease-in-out);
  
  /* ============================================================================
   7. LAYOUT & BREAKPOINTS
   ============================================================================ */
  
  /* Sidebar Width */
  --sidebar-width: 270px;
  --sidebar-width-collapsed: 80px;
  
  /* Header Height */
  --header-height: 64px;
  --topbar-height: 64px;
  
  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
  
  /* Breakpoints */
  --breakpoint-xs: 0;
  --breakpoint-sm: 576px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1200px;
  --breakpoint-2xl: 1400px;
  
  /* ============================================================================
   8. COMPONENT SPECIFIC TOKENS
   ============================================================================ */
  
  /* Buttons */
  --btn-border-width: 2px;
  --btn-border-radius: var(--radius-md);
  --btn-padding-x: 1.5rem;
  --btn-padding-y: 0.75rem;
  --btn-font-weight: var(--font-weight-semibold);
  --btn-transition: var(--transition-base);
  
  /* Cards */
  --card-border-radius: var(--radius-xl);
  --card-border-width: 1px;
  --card-shadow: var(--shadow-md);
  --card-shadow-hover: var(--shadow-xl);
  --card-padding: var(--space-6);
  
  /* Inputs */
  --input-height: 2.75rem;
  --input-padding-x: 1rem;
  --input-padding-y: 0.65rem;
  --input-border-width: 1.5px;
  --input-border-radius: var(--radius-md);
  --input-transition: var(--transition-base);
  
  /* Avatars */
  --avatar-size-sm: 2rem;
  --avatar-size-base: 2.5rem;
  --avatar-size-lg: 3rem;
  --avatar-size-xl: 4rem;
  --avatar-border-radius: var(--radius-full);
  
  /* Navigation */
  --nav-item-padding-x: 0.875rem;
  --nav-item-padding-y: 0.75rem;
  --nav-item-border-radius: var(--radius-md);
  
  /* ============================================================================
   9. UTILITY CLASSES - Generated from tokens
   ============================================================================ */

  /* Shorthand aliases used by view inline styles */
  --primary: var(--color-primary);
  --secondary: var(--color-secondary);
  --success: var(--color-success);
  --danger: var(--color-danger);
  --warning: var(--color-warning);
  --info: var(--color-info);
  --dark: var(--color-dark-100);
  --light: var(--color-light);

  /* Gray scale aliases */
  --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;
  --dark-900: #0f172a;
  --dark-800: #1e293b;
  --dark-700: #334155;

  /* RGB values for rgba() usage */
  --color-primary-rgb: 99, 102, 241;
  --color-secondary-rgb: 168, 85, 247;
  --color-success-rgb: 16, 185, 129;
  --color-danger-rgb: 239, 68, 68;
  --color-warning-rgb: 245, 158, 11;
}

/* Note: Dashboard shell layout is defined in layout.css */
/* Note: Glass utility is defined in layout.css */
/* Note: Form controls and buttons are defined in components.css */