/* ============================================
   VARIABLES
   ============================================ */
:root {
  /* Corporate Tech Palette */
  --color-navy: #0a192f;
  --color-graphite: #2d3748;
  --color-white: #ffffff;
  --color-electric-blue: #00d4ff;
  --color-silver: #c0c0c0;
  --color-silver-light: #e2e8f0;
  
  /* Semantic Colors */
  --color-background: var(--color-white);
  --color-background-alt: #f8fafc;
  --color-text: var(--color-graphite);
  --color-text-muted: #64748b;
  --color-primary: var(--color-navy);
  --color-accent: var(--color-electric-blue);
  --color-border: var(--color-silver-light);
  
  /* Status Colors */
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-neutral: #94a3b8;
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
  
  --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;
  
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.75;
  
  /* Spacing Scale (0-96px) */
  --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;
  
  /* Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Shadows - Sophisticated Navy Tint */
  --shadow-sm: 0 1px 2px 0 rgba(10, 25, 47, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(10, 25, 47, 0.1), 0 2px 4px -1px rgba(10, 25, 47, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(10, 25, 47, 0.1), 0 4px 6px -2px rgba(10, 25, 47, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(10, 25, 47, 0.1), 0 10px 10px -5px rgba(10, 25, 47, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
}

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

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

input, button, textarea, select {
  font: inherit;
  color: inherit;
}

ul, ol {
  list-style: none;
}

/* ============================================
   BASE STYLES
   ============================================ */
body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text);
  background-color: var(--color-background);
}

h1, h2, h3, h4, h5, h6 {
  color: var(--color-primary);
  line-height: var(--leading-tight);
  font-weight: 700;
  letter-spacing: -0.025em;
}

h1 { font-size: var(--text-4xl); margin-bottom: var(--space-6); }
h2 { font-size: var(--text-3xl); margin-bottom: var(--space-4); }
h3 { font-size: var(--text-2xl); margin-bottom: var(--space-3); }
h4 { font-size: var(--text-xl); margin-bottom: var(--space-2); }
h5 { font-size: var(--text-lg); margin-bottom: var(--space-2); }
h6 { font-size: var(--text-base); margin-bottom: var(--space-2); }

p {
  margin-bottom: var(--space-4);
  }

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

a:hover {
  color: var(--color-primary);
}

/* ============================================
   UTILITIES
   ============================================ */
.container {
  width: 100%;
  max-width: 1280px;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

@media (min-width: 640px) {
  .container {
    padding-left: var(--space-6);
    padding-right: var(--space-6);
  }
}

.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.items-center {
  align-items: center;
}

.justify-between {
  justify-content: space-between;
}

.gap-4 {
  gap: var(--space-4);
}

.grid {
  display: grid;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ============================================
   COMPONENTS
   ============================================ */

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-base);
  font-weight: 600;
  line-height: 1;
  color: var(--color-white);
  background-color: var(--color-primary);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
}

.btn:hover {
  background-color: var(--color-graphite);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn--accent {
  background-color: var(--color-accent);
  color: var(--color-navy);
}

.btn--accent:hover {
  background-color: #00bcd4;
}

.btn--outline {
  background-color: var(--color-silver);
  border-color: var(--color-silver);
  color: var(--color-primary);
}

.btn--outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: rgba(0, 212, 255, 0.05);
}

/* Inputs */
.input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.15);
}

.input::placeholder {
  color: var(--color-text-muted);
}

.input:disabled {
  background-color: var(--color-background-alt);
  cursor: not-allowed;
}

/* Cards */
.card {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-border);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* ============================================
   ACCESSIBILITY
   ============================================ */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  .btn, .card, .input {
    transition: none;
  }
}