Modern CSS Accessibility Features

/* Default: animations enabled */
.slide-in {
  animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
  from { 
    transform: translateY(20px); 
    opacity: 0; 
  }
  to { 
    transform: translateY(0); 
    opacity: 1; 
  }
}

/* Reduced motion: instant appearance */
@media (prefers-reduced-motion: reduce) {
  .slide-in {
    animation: none;
    /* Maintain end state without animation */
    transform: translateY(0);
    opacity: 1;
  }
  
  /* Reduce all animations and transitions */
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Safe alternative: crossfade instead of slide */
@media (prefers-reduced-motion: reduce) {
  .modal {
    animation: fadeIn 0.15s ease-in;
  }
  
  @keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
  }
}

:root {
  /* Light mode (default) */
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f5;
  --text-primary: #1a1a1a;
  --text-secondary: #666666;
  --accent: #0066cc;
  --border: #e0e0e0;
  --focus-ring: #0066cc;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #1e1e1e;
    --bg-secondary: #2d2d2d;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --accent: #66b3ff;
    --border: #404040;
    --focus-ring: #66b3ff;
  }
  
  /* Adjust images for dark mode */
  img:not([src*=".svg"]) {
    filter: brightness(0.9);
  }
  
  /* Invert logos that need it */
  .logo {
    filter: invert(1);
  }
}

body {
  background: var(--bg-primary);
  color: var(--text-primary);
}

a {
  color: var(--accent);
  text-decoration: underline;
}

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

/* Standard contrast (default) */
.button {
  background: #0066cc;
  color: #ffffff;
  border: 1px solid #0052a3;
}

/* High contrast mode */
@media (prefers-contrast: more) {
  .button {
    background: #003d7a; /* Darker for more contrast */
    color: #ffffff;
    border: 2px solid #000000; /* Thicker, stronger border */
    font-weight: 600;
  }
  
  /* Ensure all UI components meet 7:1 ratio */
  body {
    --contrast-ratio: 7;
  }
  
  /* Stronger focus indicators */
  :focus-visible {
    outline: 3px solid #000000;
    outline-offset: 3px;
  }
}

/* Low contrast mode (light sensitivity) */
@media (prefers-contrast: less) {
  .button {
    background: #3385d6; /* Lighter blue */
    color: #f5f5f5;
    border: 1px solid #5c9dd9;
  }
  
  /* Reduce harsh contrasts */
  body {
    background: #f8f8f8;
    color: #3a3a3a;
  }
}

/* Windows High Contrast Mode detection */
@media (prefers-contrast: more) and (prefers-color-scheme: dark) {
  /* User is in Windows High Contrast Dark theme */
  .card {
    border: 2px solid ButtonText;
    background: Canvas;
    color: CanvasText;
  }
}

/* Enable container queries */
.card-container {
  container-type: inline-size;
  container-name: card;
}

/* Default: narrow card */
.card {
  padding: 16px;
  font-size: 14px;
}

.card h2 {
  font-size: 18px;
}

.card button {
  min-height: 44px;
  padding: 8px 16px;
}

/* Medium container: increase spacing and text */
@container card (min-width: 400px) {
  .card {
    padding: 24px;
    font-size: 16px;
  }
  
  .card h2 {
    font-size: 24px;
    line-height: 1.3;
  }
  
  .card button {
    min-height: 48px;
    padding: 12px 24px;
    font-size: 16px;
  }
}

/* Large container: optimal reading layout */
@container card (min-width: 600px) {
  .card {
    padding: 32px;
    max-width: 65ch; /* Optimal line length */
  }
  
  .card p {
    font-size: 18px;
    line-height: 1.6;
    margin-bottom: 1.5em;
  }
}

/* Container query for zoom support */
@container (max-width: 320px) {
  /* When container is narrow (e.g., at 200% zoom) */
  .card {
    /* Stack elements vertically */
    flex-direction: column;
  }
  
  .card button {
    width: 100%;
  }
}

/* Remove default focus outline (be careful!) */
*:focus {
  outline: none;
}

/* Custom focus-visible for keyboard navigation */
*:focus-visible {
  outline: 2px solid #0066cc;
  outline-offset: 2px;
  border-radius: 2px;
}

/* Button: show focus only for keyboard */
.button {
  border: 2px solid transparent;
  transition: border-color 0.15s;
}

.button:focus-visible {
  border-color: #0066cc;
  box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.2);
}

/* Input: always show focus (user is typing) */
input,
textarea,
select {
  border: 1px solid #d0d0d0;
}

input:focus,
textarea:focus,
select:focus {
  outline: 2px solid #0066cc;
  outline-offset: 0;
  border-color: #0066cc;
}

/* Focus-within: highlight form section when any field focused */
.form-section:focus-within {
  background: #f5f9ff;
  border-color: #0066cc;
}

/* High contrast mode: ensure focus is visible */
@media (prefers-contrast: more) {
  *:focus-visible {
    outline: 3px solid currentColor;
    outline-offset: 3px;
  }
}

/* Dark mode focus adjustment */
@media (prefers-color-scheme: dark) {
  *:focus-visible {
    outline-color: #66b3ff;
  }
}

/* Enable smooth scrolling (with reduced motion respect) */
html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

/* Sticky header with scroll compensation */
header {
  position: sticky;
  top: 0;
  height: 60px;
  background: white;
  z-index: 100;
}

/* Ensure anchored content visible below sticky header */
:target {
  scroll-margin-top: 80px; /* Header height + spacing */
}

/* Alternative: all headings (for skip links) */
h1, h2, h3, h4, h5, h6 {
  scroll-margin-top: 80px;
}

/* Focus visibility with sticky elements */
html {
  scroll-padding-top: 80px;
}

/* Accessible carousel with snap scrolling */
.carousel {
  display: flex;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
}

@media (prefers-reduced-motion: reduce) {
  .carousel {
    scroll-snap-type: none;
    scroll-behavior: auto;
  }
}

.carousel-item {
  scroll-snap-align: start;
  scroll-snap-stop: always;
  flex-shrink: 0;
  width: 100%;
}

/* Modal: prevent background scrolling */
.modal {
  overscroll-behavior: contain;
}

body.modal-open {
  overflow: hidden;
}

/* Smooth scroll for skip links */
.skip-link:focus {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  .skip-link:focus {
    scroll-behavior: auto;
  }
}