/**
 * Reveal.js A11y - RevealJS Accessibility Plugin Styles
 * Provides styling for skip navigation, focus indicators,
 * high contrast mode, reduced motion, link highlight,
 * alt text warnings, local font picker, and slide change indicator.
 *
 * @license MIT License
 * @copyright 2026 Mickaël Canouil
 * @author Mickaël Canouil
 */

:root {
  --a11y-accent: #4a90d9;
}

/* =========================================================================
   Skip Navigation Link
   ========================================================================= */

.revealjs-a11y-skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  padding: 0.75em 1.5em;
  background: #000;
  color: #fff;
  font-size: 1rem;
  font-weight: bold;
  text-decoration: none;
  border-radius: 0 0 0.5em 0.5em;
  transition: top 0.2s ease;
}

.revealjs-a11y-skip-link:focus {
  top: 0;
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

/* =========================================================================
   Enhanced Focus Indicators
   ========================================================================= */

.revealjs-a11y-focus-indicators *:focus-visible {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 4px;
  border-radius: 2px;
}

.revealjs-a11y-focus-indicators a:focus-visible {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
  text-decoration: underline;
}

.revealjs-a11y-focus-indicators button:focus-visible,
.revealjs-a11y-focus-indicators input:focus-visible,
.revealjs-a11y-focus-indicators select:focus-visible,
.revealjs-a11y-focus-indicators textarea:focus-visible {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
  box-shadow: 0 0 0 1px var(--a11y-accent);
}

/* =========================================================================
   High Contrast Mode
   ========================================================================= */

.revealjs-a11y-high-contrast .slides {
  color: #000 !important;
  background: #fff !important;
}

.revealjs-a11y-high-contrast .slides h1,
.revealjs-a11y-high-contrast .slides h2,
.revealjs-a11y-high-contrast .slides h3,
.revealjs-a11y-high-contrast .slides h4,
.revealjs-a11y-high-contrast .slides h5,
.revealjs-a11y-high-contrast .slides h6 {
  color: #000 !important;
}

.revealjs-a11y-high-contrast .slides a {
  color: #0000ee !important;
  text-decoration: underline !important;
}

.revealjs-a11y-high-contrast .slides a:visited {
  color: #551a8b !important;
}

.revealjs-a11y-high-contrast .slides code {
  color: #000 !important;
  background: #e8e8e8 !important;
  border: 1px solid #666 !important;
}

.revealjs-a11y-high-contrast .slides pre {
  background: #f5f5f5 !important;
  border: 2px solid #000 !important;
}

.revealjs-a11y-high-contrast .slides pre code {
  border: none !important;
}

.revealjs-a11y-high-contrast .slides blockquote {
  border-left: 4px solid #000 !important;
  color: #000 !important;
}

.revealjs-a11y-high-contrast .slides table th {
  background: #000 !important;
  color: #fff !important;
}

.revealjs-a11y-high-contrast .slides table td {
  border: 1px solid #000 !important;
}

.revealjs-a11y-high-contrast .slides img {
  outline: 2px solid #000;
}

.revealjs-a11y-high-contrast .reveal-viewport {
  background: #fff !important;
}

/* =========================================================================
   Reduced Motion
   ========================================================================= */

.revealjs-a11y-reduced-motion .slides section {
  transition: none !important;
}

.revealjs-a11y-reduced-motion .slides section .fragment {
  transition: none !important;
}

.revealjs-a11y-reduced-motion .backgrounds .slide-background {
  transition: none !important;
}

.revealjs-a11y-reduced-motion .progress span {
  transition: none !important;
}

/* =========================================================================
   Link Highlight (underline all links for non-colour distinction)
   ========================================================================= */

.revealjs-a11y-link-highlight .slides a {
  text-decoration: underline !important;
  text-underline-offset: 3px;
}

.revealjs-a11y-link-highlight .slides a:hover,
.revealjs-a11y-link-highlight .slides a:focus {
  text-decoration-thickness: 2px !important;
}

/* =========================================================================
   Alt Text Warnings
   ========================================================================= */

.revealjs-a11y-missing-alt {
  outline: 4px dashed #cc0000 !important;
  outline-offset: 4px;
}

.revealjs-a11y-missing-alt-label {
  display: block;
  padding: 0.25em 0.5em;
  background: #cc0000;
  color: #fff;
  font-size: 0.75rem;
  font-weight: bold;
  border-radius: 0.25em;
  width: fit-content;
  margin-top: 0.25em;
  pointer-events: none;
}

/* =========================================================================
   Slide Change Indicator
   ========================================================================= */

.revealjs-a11y-slide-change-indicator {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  z-index: 100;
  background: var(--a11y-accent);
  transform: scaleX(0);
  transform-origin: left center;
  pointer-events: none;
}

.revealjs-a11y-slide-change-active {
  animation: revealjs-a11y-indicator-sweep 0.4s ease-out forwards;
}

@keyframes revealjs-a11y-indicator-sweep {
  0% {
    transform: scaleX(0);
    opacity: 1;
  }
  50% {
    transform: scaleX(1);
    opacity: 1;
  }
  100% {
    transform: scaleX(1);
    opacity: 0;
  }
}

/* =========================================================================
   Font Override (applies to all elements including headings)
   ========================================================================= */

.revealjs-a11y-font-override .slides,
.revealjs-a11y-font-override .slides h1,
.revealjs-a11y-font-override .slides h2,
.revealjs-a11y-font-override .slides h3,
.revealjs-a11y-font-override .slides h4,
.revealjs-a11y-font-override .slides h5,
.revealjs-a11y-font-override .slides h6,
.revealjs-a11y-font-override .slides p,
.revealjs-a11y-font-override .slides li,
.revealjs-a11y-font-override .slides blockquote {
  font-family: var(--a11y-font-override) !important;
}

/* =========================================================================
   Text Spacing Override (line height and letter spacing)
   ========================================================================= */

.revealjs-a11y-line-height-override .slides,
.revealjs-a11y-line-height-override .slides section,
.revealjs-a11y-line-height-override .slides h1,
.revealjs-a11y-line-height-override .slides h2,
.revealjs-a11y-line-height-override .slides h3,
.revealjs-a11y-line-height-override .slides h4,
.revealjs-a11y-line-height-override .slides h5,
.revealjs-a11y-line-height-override .slides h6,
.revealjs-a11y-line-height-override .slides p,
.revealjs-a11y-line-height-override .slides li,
.revealjs-a11y-line-height-override .slides blockquote {
  line-height: var(--a11y-line-height) !important;
}

.revealjs-a11y-letter-spacing-override .slides,
.revealjs-a11y-letter-spacing-override .slides section,
.revealjs-a11y-letter-spacing-override .slides h1,
.revealjs-a11y-letter-spacing-override .slides h2,
.revealjs-a11y-letter-spacing-override .slides h3,
.revealjs-a11y-letter-spacing-override .slides h4,
.revealjs-a11y-letter-spacing-override .slides h5,
.revealjs-a11y-letter-spacing-override .slides h6,
.revealjs-a11y-letter-spacing-override .slides p,
.revealjs-a11y-letter-spacing-override .slides li,
.revealjs-a11y-letter-spacing-override .slides blockquote {
  letter-spacing: var(--a11y-letter-spacing) !important;
}

.revealjs-a11y-word-spacing-override .slides,
.revealjs-a11y-word-spacing-override .slides section,
.revealjs-a11y-word-spacing-override .slides h1,
.revealjs-a11y-word-spacing-override .slides h2,
.revealjs-a11y-word-spacing-override .slides h3,
.revealjs-a11y-word-spacing-override .slides h4,
.revealjs-a11y-word-spacing-override .slides h5,
.revealjs-a11y-word-spacing-override .slides h6,
.revealjs-a11y-word-spacing-override .slides p,
.revealjs-a11y-word-spacing-override .slides li,
.revealjs-a11y-word-spacing-override .slides blockquote {
  word-spacing: var(--a11y-word-spacing) !important;
}

/* =========================================================================
   Colour Overlay (reading aid)
   ========================================================================= */

.revealjs-a11y-colour-overlay .slides::after {
  content: "";
  position: fixed;
  inset: 0;
  background: var(--a11y-overlay-colour, transparent);
  pointer-events: none;
  z-index: 99;
}

/* =========================================================================
   Local Font Picker Dialog
   ========================================================================= */

.revealjs-a11y-font-dialog {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 200;
  width: min(500px, 90vw);
  max-height: 70vh;
  padding: 1.5em;
  background: #fff;
  color: #222;
  border: 2px solid var(--a11y-accent);
  border-radius: 0.5em;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  font-family: system-ui, sans-serif;
  font-size: 14px;
  display: flex;
  flex-direction: column;
}

.revealjs-a11y-font-dialog::backdrop {
  background: rgba(0, 0, 0, 0.5);
}

.revealjs-a11y-font-dialog h3 {
  margin: 0 0 0.75em;
  font-size: 1.2em;
  color: #222;
}

.revealjs-a11y-font-search {
  width: 100%;
  padding: 0.5em 0.75em;
  margin-bottom: 0.75em;
  border: 1px solid #999;
  border-radius: 0.25em;
  font-size: 1em;
  box-sizing: border-box;
}

.revealjs-a11y-font-search:focus {
  outline: 2px solid var(--a11y-accent);
  outline-offset: 1px;
}

.revealjs-a11y-font-list {
  list-style: none;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  flex: 1;
  min-height: 0;
}

.revealjs-a11y-font-list li {
  padding: 0.5em 0.75em;
  cursor: pointer;
  border-radius: 0.25em;
  transition: background 0.15s;
}

.revealjs-a11y-font-list li:hover,
.revealjs-a11y-font-list li:focus {
  background: #e8f0fe;
  outline: none;
}

.revealjs-a11y-font-dialog-close {
  margin-top: 0.75em;
  padding: 0.5em 1.5em;
  align-self: flex-end;
  background: var(--a11y-accent);
  color: #fff;
  border: none;
  border-radius: 0.25em;
  font-size: 1em;
  cursor: pointer;
}

.revealjs-a11y-font-dialog-close:hover {
  background: color-mix(in srgb, var(--a11y-accent) 85%, #000);
}

.revealjs-a11y-font-dialog-close:focus {
  outline: 2px solid #222;
  outline-offset: 2px;
}

/* =========================================================================
   Screen Reader Status Region
   ========================================================================= */

.revealjs-a11y-status {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

@media print {
  .revealjs-a11y-menu,
  .revealjs-a11y-menu-backdrop {
    display: none !important;
  }
}

/* =========================================================================
   Accessibility Settings Menu - Backdrop
   ========================================================================= */

.revealjs-a11y-menu-backdrop {
  position: fixed;
  inset: 0;
  z-index: 199;
  background: rgba(0, 0, 0, 0.4);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.revealjs-a11y-menu-backdrop[aria-hidden="false"] {
  opacity: 1;
  pointer-events: auto;
}

/* =========================================================================
   Accessibility Settings Menu - Panel
   ========================================================================= */

.revealjs-a11y-menu {
  position: fixed;
  top: 0;
  right: 0;
  width: min(380px, 85vw);
  height: 100vh;
  height: 100dvh;
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  background: #fff;
  color: #222;
  font-family: system-ui, -apple-system, sans-serif;
  font-size: 14px;
  line-height: 1.4;
  letter-spacing: normal;
  box-shadow: -4px 0 16px rgba(0, 0, 0, 0.2);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.revealjs-a11y-menu--left {
  right: auto;
  left: 0;
  transform: translateX(-100%);
  box-shadow: 4px 0 16px rgba(0, 0, 0, 0.2);
}

.revealjs-a11y-menu[aria-hidden="false"] {
  transform: translateX(0);
}

/* =========================================================================
   Accessibility Settings Menu - Header
   ========================================================================= */

.revealjs-a11y-menu-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid #e0e0e0;
  flex-shrink: 0;
}

.revealjs-a11y-menu-header h2 {
  margin: 0;
  font-size: 1.125rem;
  font-weight: 700;
  color: #222;
}

.revealjs-a11y-menu-close {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  font-size: 1.5rem;
  line-height: 1;
  color: #555;
  cursor: pointer;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
}

.revealjs-a11y-menu-close:hover {
  background: #f0f0f0;
  color: #222;
}

.revealjs-a11y-menu-close:focus {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

/* =========================================================================
   Accessibility Settings Menu - Body and Groups
   ========================================================================= */

.revealjs-a11y-menu-body {
  flex: 1;
  overflow-y: auto;
  padding: 0.75rem 1.25rem;
}

.revealjs-a11y-menu-group {
  border: none;
  padding: 0;
  margin: 0 0 1.25rem;
}

.revealjs-a11y-menu-group legend {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #666;
  padding: 0;
  margin-bottom: 0.5rem;
}

/* =========================================================================
   Accessibility Settings Menu - Controls
   ========================================================================= */

.revealjs-a11y-menu-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.5rem 0;
  border-bottom: 1px solid #f0f0f0;
}

.revealjs-a11y-menu-row:last-child {
  border-bottom: none;
}

.revealjs-a11y-menu-label {
  flex: 1;
  font-size: 0.875rem;
  color: #333;
}

.revealjs-a11y-menu-value {
  font-size: 0.8125rem;
  color: #666;
  min-width: 4em;
  text-align: right;
}

/* Toggle switch */

.revealjs-a11y-menu-switch {
  position: relative;
  width: 44px;
  height: 24px;
  border: none;
  border-radius: 12px;
  background: #ccc;
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
  transition: background 0.2s ease;
}

.revealjs-a11y-menu-switch[aria-checked="true"] {
  background: var(--a11y-accent);
}

.revealjs-a11y-menu-switch:focus {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

.revealjs-a11y-menu-switch-track {
  display: block;
  width: 100%;
  height: 100%;
  position: relative;
}

.revealjs-a11y-menu-switch-thumb {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 20px;
  height: 20px;
  background: #fff;
  border-radius: 50%;
  transition: transform 0.2s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
}

.revealjs-a11y-menu-switch[aria-checked="true"] .revealjs-a11y-menu-switch-thumb {
  transform: translateX(20px);
}

/* Range slider */

.revealjs-a11y-menu-range {
  width: 100%;
  height: 6px;
  appearance: none;
  -webkit-appearance: none;
  background: #e0e0e0;
  border-radius: 3px;
  outline: none;
  cursor: pointer;
  accent-color: var(--a11y-accent);
  margin: 0.25rem 0;
}

.revealjs-a11y-menu-range::-webkit-slider-thumb {
  appearance: none;
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  background: var(--a11y-accent);
  border-radius: 50%;
  border: 2px solid #fff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  cursor: pointer;
}

.revealjs-a11y-menu-range::-moz-range-thumb {
  width: 18px;
  height: 18px;
  background: var(--a11y-accent);
  border-radius: 50%;
  border: 2px solid #fff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
  cursor: pointer;
}

.revealjs-a11y-menu-range:focus {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

/* Select dropdown */

.revealjs-a11y-menu-select {
  width: 100%;
  padding: 0.375rem 0.5rem;
  font-size: 0.875rem;
  font-family: inherit;
  border: 1px solid #ccc;
  border-radius: 4px;
  background: #fff;
  color: #222;
  cursor: pointer;
  appearance: auto;
}

.revealjs-a11y-menu-select:focus {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

/* Local font picker button */

.revealjs-a11y-menu-local-font {
  width: 100%;
  padding: 0.375rem 0.5rem;
  font-size: 0.875rem;
  font-family: inherit;
  border: 1px dashed var(--a11y-accent);
  border-radius: 4px;
  background: #f8faff;
  color: var(--a11y-accent);
  cursor: pointer;
  text-align: center;
  transition: background 0.2s ease;
}

.revealjs-a11y-menu-local-font:hover {
  background: #e8f0fe;
}

.revealjs-a11y-menu-local-font:focus {
  outline: 3px solid var(--a11y-accent);
  outline-offset: 2px;
}

/* =========================================================================
   Accessibility Settings Menu - Footer
   ========================================================================= */

.revealjs-a11y-menu-footer {
  padding: 0.75rem 1.25rem;
  border-top: 1px solid #e0e0e0;
  flex-shrink: 0;
}

.revealjs-a11y-menu-reset {
  width: 100%;
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-family: inherit;
  font-weight: 600;
  border: 2px solid #c0392b;
  border-radius: 4px;
  background: #fff;
  color: #c0392b;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.revealjs-a11y-menu-reset:hover {
  background: #c0392b;
  color: #fff;
}

.revealjs-a11y-menu-reset:focus {
  outline: 3px solid #c0392b;
  outline-offset: 2px;
}

/* =========================================================================
   Accessibility Settings Menu - Reduced Motion
   ========================================================================= */

@media (prefers-reduced-motion: reduce) {
  .revealjs-a11y-skip-link,
  .revealjs-a11y-font-list li,
  .revealjs-a11y-menu,
  .revealjs-a11y-menu-backdrop,
  .revealjs-a11y-menu-switch,
  .revealjs-a11y-menu-switch-thumb,
  .revealjs-a11y-menu-local-font,
  .revealjs-a11y-menu-reset {
    transition: none;
  }
}

/* =========================================================================
   Accessibility Settings Menu - High Contrast Override
   ========================================================================= */

.revealjs-a11y-high-contrast .revealjs-a11y-menu {
  background: #fff;
  color: #000;
  border-left: 2px solid #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu--left {
  border-left: none;
  border-right: 2px solid #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-header {
  border-bottom-color: #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-footer {
  border-top-color: #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-switch {
  border: 2px solid #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-switch[aria-checked="true"] {
  background: #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-range {
  accent-color: #000;
}

.revealjs-a11y-high-contrast .revealjs-a11y-menu-select {
  border-color: #000;
}