/* ==========================================================================
   CSS Examples - Shared Styles
   A clean, modern design system for educational CSS demonstrations
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Custom Properties (Variables)
   Using CSS variables for consistent theming and easy maintenance
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette */
  --color-primary: #6366f1;
  --color-primary-dark: #4f46e5;
  --color-secondary: #f59e0b;
  --color-accent: #10b981;
  
  /* Neutral Colors */
  --color-white: #ffffff;
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-600: #4b5563;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;
  
  /* Typography */
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: ui-monospace, 'Cascadia Code', 'Source Code Pro', Menlo, monospace;
  
  /* Spacing Scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  
  /* Shadows */
  --shadow-sm: 0 0.0625rem 0.125rem 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 0.25rem 0.375rem -0.0625rem rgb(0 0 0 / 0.1), 0 0.125rem 0.25rem -0.125rem rgb(0 0 0 / 0.1);
  --shadow-lg: 0 0.625rem 0.9375rem -0.1875rem rgb(0 0 0 / 0.1), 0 0.25rem 0.375rem -0.25rem rgb(0 0 0 / 0.1);
  --shadow-xl: 0 1.25rem 1.5625rem -0.3125rem rgb(0 0 0 / 0.1), 0 0.5rem 0.625rem -0.375rem rgb(0 0 0 / 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
}

/* --------------------------------------------------------------------------
   CSS Reset & Base Styles
   Modern reset for consistent cross-browser rendering
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  /* Smooth scrolling for anchor links */
  scroll-behavior: smooth;
  /* Prevent font size inflation on mobile */
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-gray-800);
  background-color: var(--color-gray-50);
  /* Improve text rendering */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --------------------------------------------------------------------------
   Typography
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  font-weight: 700;
  color: var(--color-gray-900);
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
}

h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
}

h3 {
  font-size: clamp(1.25rem, 3vw, 1.5rem);
}

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

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

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

/* Focus styles for accessibility */
a:focus-visible,
button:focus-visible {
  outline: 0.125rem solid var(--color-primary);
  outline-offset: 0.125rem;
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--color-gray-100);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
}

/* --------------------------------------------------------------------------
   Layout Components
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: 75rem;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* --------------------------------------------------------------------------
   Page Header
   Consistent header styling across all example pages
   -------------------------------------------------------------------------- */
.page-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-white);
  padding: var(--space-2xl) 0;
  margin-bottom: var(--space-2xl);
}

.page-header h1 {
  color: var(--color-white);
  margin-bottom: var(--space-sm);
}

.page-header p {
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.125rem;
  margin-bottom: 0;
  max-width: 37.5rem;
}

/* Back link in header */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.875rem;
  margin-bottom: var(--space-md);
  transition: color var(--transition-fast);
}

.back-link:hover {
  color: var(--color-white);
}

.back-link::before {
  content: '←';
  font-size: 1.25em;
}

/* --------------------------------------------------------------------------
   Section Styling
   -------------------------------------------------------------------------- */
.section {
  margin-bottom: var(--space-3xl);
}

.section-title {
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 0.125rem solid var(--color-gray-200);
}

.section-description {
  color: var(--color-gray-600);
  margin-bottom: var(--space-xl);
}

/* --------------------------------------------------------------------------
   Demo Grid
   Flexible grid for showcasing examples
   -------------------------------------------------------------------------- */
.demo-grid {
  display: grid;
  /* Responsive grid: auto-fit creates as many columns as fit */
  grid-template-columns: repeat(auto-fit, minmax(17.5rem, 1fr));
  gap: var(--space-xl);
}

/* --------------------------------------------------------------------------
   Demo Card
   Individual example card with label
   -------------------------------------------------------------------------- */
.demo-card {
  background: var(--color-white);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.demo-card:hover {
  transform: translateY(-0.25rem);
  box-shadow: var(--shadow-xl);
}

.demo-card__label {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--color-gray-600);
  margin-bottom: var(--space-md);
  display: block;
}

.demo-card__preview {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 9.375rem;
  background: var(--color-gray-50);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.demo-card__description {
  margin-top: var(--space-md);
  font-size: 0.875rem;
  color: var(--color-gray-600);
}

/* --------------------------------------------------------------------------
   Code Block
   For displaying CSS code snippets with copy functionality
   -------------------------------------------------------------------------- */
.code-block {
  position: relative;
  background: var(--color-gray-900);
  border-radius: var(--radius-lg);
  margin: var(--space-lg) 0;
}

.code-block pre {
  margin: 0;
  padding: var(--space-lg);
  padding-right: 3.75rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--color-gray-100);
}

.code-block code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

/* Copy Button */
.code-block__copy {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
  background: var(--color-gray-800);
  border: 0.0625rem solid var(--color-gray-600);
  color: var(--color-gray-300);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-family: var(--font-family);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.code-block__copy:hover {
  background: var(--color-gray-600);
  color: var(--color-white);
}

.code-block__copy--copied {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-white);
}

/* Syntax highlighting classes */
.code-property {
  color: #a5d6ff;
}

.code-value {
  color: #7ee787;
}

.code-comment {
  color: #8b949e;
}

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

.mt-lg {
  margin-top: var(--space-lg);
}

.mb-lg {
  margin-bottom: var(--space-lg);
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */
.page-footer {
  background: var(--color-gray-100);
  padding: var(--space-xl) 0;
  margin-top: var(--space-3xl);
  text-align: center;
  color: var(--color-gray-600);
  font-size: 0.875rem;
}

/* --------------------------------------------------------------------------
   Responsive Adjustments
   -------------------------------------------------------------------------- */
@media (max-width: 48rem) {
  .container {
    padding: 0 var(--space-md);
  }
  
  .page-header {
    padding: var(--space-xl) 0;
  }
  
  .demo-grid {
    grid-template-columns: 1fr;
  }
}