/* Variables */
:root {
  /* Colors */
  --color-background: #ffffff; /* Clean white */
  --color-text: #333333; /* Graphite gray */
  --color-primary: #00ffff; /* Electric cyan */
  --color-success: #00ff80; /* Soft green */
  --color-warning: #ffa500; /* Orange for warning */
  --color-danger: #ff0000; /* Red for danger */
  --color-neutral-100: #f5f5f5; /* Light gray */
  --color-neutral-200: #e0e0e0;
  --color-neutral-300: #cccccc;
  --color-neutral-400: #999999;
  --color-neutral-500: #666666;
  --color-neutral-600: #4d4d4d;
  --color-neutral-700: #333333;
  --color-neutral-800: #1a1a1a;
  --color-neutral-900: #000033; /* Deep navy blue */

  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem; /* 12px */
  --font-size-sm: 0.875rem; /* 14px */
  --font-size-base: 1rem; /* 16px */
  --font-size-lg: 1.125rem; /* 18px */
  --font-size-xl: 1.25rem; /* 20px */
  --font-size-2xl: 1.5rem; /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem; /* 36px */
  --font-size-5xl: 3rem; /* 48px */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Spacing */
  --spacing-0: 0;
  --spacing-1: 0.25rem; /* 4px */
  --spacing-2: 0.5rem; /* 8px */
  --spacing-3: 0.75rem; /* 12px */
  --spacing-4: 1rem; /* 16px */
  --spacing-5: 1.25rem; /* 20px */
  --spacing-6: 1.5rem; /* 24px */
  --spacing-8: 2rem; /* 32px */
  --spacing-10: 2.5rem; /* 40px */
  --spacing-12: 3rem; /* 48px */
  --spacing-16: 4rem; /* 64px */
  --spacing-20: 5rem; /* 80px */
  --spacing-24: 6rem; /* 96px */

  /* Other */
  --radius-sm: 0.125rem; /* 2px */
  --radius: 0.25rem; /* 4px */
  --radius-md: 0.375rem; /* 6px */
  --radius-lg: 0.5rem; /* 8px */
  --radius-xl: 0.75rem; /* 12px */
  --radius-full: 9999px;
  --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-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);
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
}

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

* {
  margin: 0;
}

html {
  line-height: 1.15;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-background);
}

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

input, button, select, optgroup, textarea {
  margin: 0;
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
}

button, input {
  overflow: visible;
}

button, select {
  text-transform: none;
}

button, [type="button"], [type="reset"], [type="submit"] {
  -webkit-appearance: button;
}

button::-moz-focus-inner, [type="button"]::-moz-focus-inner, [type="reset"]::-moz-focus-inner, [type="submit"]::-moz-focus-inner {
  border-style: none;
  padding: 0;
}

textarea {
  overflow: auto;
  resize: vertical;
}

/* Base Styles */
body {
  font-family: var(--font-family-primary);
  background-color: var(--color-background);
  color: var(--color-text);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-heading);
  margin: 0 0 var(--spacing-4) 0;
  line-height: var(--line-height-tight);
}

h1 { font-size: var(--font-size-5xl); }
h2 { font-size: var(--font-size-4xl); }
h3 { font-size: var(--font-size-3xl); }
h4 { font-size: var(--font-size-2xl); }
h5 { font-size: var(--font-size-xl); }
h6 { font-size: var(--font-size-lg); }

p {
  margin: 0 0 var(--spacing-4) 0;
  }

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

a:hover, a:focus {
  color: var(--color-primary);
  text-decoration: underline;
}

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

.flex {
  display: flex;
}

.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: 0;
}

/* Components */
.btn {
  display: inline-block;
  padding: var(--spacing-3) var(--spacing-6);
  font-size: var(--font-size-sm);
  font-weight: 500;
  text-align: center;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius);
  background-color: var(--color-primary);
  color: var(--color-background);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn:hover {
  background-color: var(--color-neutral-800);
}

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

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.input {
  display: block;
  width: 100%;
  padding: var(--spacing-3) var(--spacing-4);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-background);
  border: 1px solid var(--color-neutral-300);
  border-radius: var(--radius);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 255, 255, 0.1);
}

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

.card:hover {
  box-shadow: var(--shadow-md);
}

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

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