/* Variables */
:root {
  /* Colors */
  --color-background: #ffffff; /* Cool white */
  --color-text: #2c2c2c; /* Dark graphite */
  --color-primary: #003366; /* Midnight blue */
  --color-secondary: #c0c0c0; /* Chrome silver */
  --color-accent: #00ffff; /* Electric cyan */
  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-danger: #dc3545;
  --color-gray-100: #f8f9fa;
  --color-gray-200: #e9ecef;
  --color-gray-300: #dee2e6;
  --color-gray-400: #ced4da;
  --color-gray-500: #adb5bd;
  --color-gray-600: #6c757d;
  --color-gray-700: #495057;
  --color-gray-800: #343a40;
  --color-gray-900: #212529;

  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-heading: 'Poppins', sans-serif;
  --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;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  /* Spacing */
  --spacing-0: 0;
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-3: 0.75rem;
  --spacing-4: 1rem;
  --spacing-5: 1.25rem;
  --spacing-6: 1.5rem;
  --spacing-8: 2rem;
  --spacing-10: 2.5rem;
  --spacing-12: 3rem;
  --spacing-16: 4rem;
  --spacing-20: 5rem;
  --spacing-24: 6rem;
  --spacing-32: 8rem;
  --spacing-40: 10rem;
  --spacing-48: 12rem;
  --spacing-64: 16rem;
  --spacing-96: 24rem;

  /* Other */
  --border-radius-sm: 0.25rem;
  --border-radius: 0.375rem;
  --border-radius-lg: 0.5rem;
  --border-radius-xl: 0.75rem;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 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);
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
}

/* Reset / Normalize */
*, *::before, *::after {
  box-sizing: border-box;
}

* {
  margin: 0;
}

html, body {
  height: 100%;
}

html {
  scroll-behavior: smooth;
}

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

input, button, select, optgroup, textarea {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
}

/* Base */
body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  background-color: var(--color-background);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-heading);
  font-weight: 600;
  line-height: var(--line-height-tight);
  margin-bottom: var(--spacing-4);
}

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

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

a:hover, a:focus {
  color: var(--color-accent);
}

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

/* Utilities */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding-left: var(--spacing-4);
  padding-right: var(--spacing-4);
}

@media (min-width: 768px) {
  .container {
    padding-left: var(--spacing-6);
    padding-right: var(--spacing-6);
  }
}

.flex {
  display: flex;
}

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

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

.justify-center {
  justify-content: center;
}

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

.grid {
  display: grid;
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
  align-items: center;
  gap: var(--spacing-6);
}

@media (max-width: 767px) {
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

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

/* Components */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-3) var(--spacing-6);
  border: none;
  border-radius: var(--border-radius);
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  background-color: var(--color-primary);
  color: var(--color-background);
}

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

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

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn--secondary {
  background-color: var(--color-secondary);
  color: var(--color-text);
}

.btn--secondary:hover {
  background-color: var(--color-gray-300);
}

.input {
  display: block;
  width: 100%;
  padding: var(--spacing-3);
  border: 1px solid var(--color-gray-300);
  border-radius: var(--border-radius);
  font-size: var(--font-size-base);
  transition: border-color var(--transition-fast);
}

.input:focus {
  border-color: var(--color-accent);
  outline: none;
}

.card {
  background-color: var(--color-background);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow);
  padding: var(--spacing-6);
}

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

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