/* =============================================================================
   Nexus Tracker Design System
   Stripe/Vercel inspired, Professional Blue
   ============================================================================= */

/* CSS Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* Light Mode Variables (Default) */
:root {
  /* Backgrounds */
  --bg-primary: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-tertiary: #f1f5f9;
  --bg-hover: #f8fafc;
  
  /* Text */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #64748b;
  --text-placeholder: #94a3b8;
  
  /* Brand Blue */
  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --blue-700: #1d4ed8;
  
  /* Borders */
  --border-light: #e2e8f0;
  --border-default: #cbd5e1;
  --border-focus: #3b82f6;
  
  /* Semantic */
  --success: #10b981;
  --success-bg: #ecfdf5;
  --warning: #f59e0b;
  --warning-bg: #fffbeb;
  --error: #ef4444;
  --error-bg: #fef2f2;
  --info: #3b82f6;
  --info-bg: #eff6ff;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
  --shadow-focus: 0 0 0 3px rgba(59,130,246,0.15);
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", Menlo, monospace;
  
  /* Font Sizes */
  --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: 2rem;
  
  /* Font Weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;
  
  /* 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;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 300ms ease;
}

/* Dark Mode Variables */
[data-theme="dark"] {
  --bg-primary: #0a0a0b;
  --bg-secondary: #111113;
  --bg-tertiary: #18181b;
  --bg-hover: #1f1f23;
  
  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;
  --text-placeholder: #52525b;
  
  --border-light: #27272a;
  --border-default: #3f3f46;
  
  --success-bg: rgba(16, 185, 129, 0.1);
  --warning-bg: rgba(245, 158, 11, 0.1);
  --error-bg: rgba(239, 68, 68, 0.1);
  --info-bg: rgba(59, 130, 246, 0.1);
  
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5);
}

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

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-semibold);
  line-height: 1.25;
  color: var(--text-primary);
}

h1 { font-size: var(--text-3xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5 { font-size: var(--text-base); }
h6 { font-size: var(--text-sm); }

p {
  color: var(--text-secondary);
  line-height: 1.6;
}

a {
  color: var(--blue-500);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--blue-600);
}

/* Focus States */
:focus-visible {
  outline: 2px solid var(--blue-500);
  outline-offset: 2px;
}

/* Selection */
::selection {
  background-color: var(--blue-100);
  color: var(--blue-700);
}

[data-theme="dark"] ::selection {
  background-color: rgba(59, 130, 246, 0.3);
  color: var(--text-primary);
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }

.text-success { color: var(--success); }
.text-warning { color: var(--warning); }
.text-error { color: var(--error); }

.font-normal { font-weight: var(--font-normal); }
.font-medium { font-weight: var(--font-medium); }
.font-semibold { font-weight: var(--font-semibold); }
.font-bold { font-weight: var(--font-bold); }

.hidden { display: none !important; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}