feat(a11y): make the deck keyboard and screen-reader navigable

assets/components.css

@@ -75,6 +75,8 @@ html, body {
   z-index: 100; display: flex; flex-direction: column; gap: 6px;
 }
 .slide-nav-dot {
+  /* Reset the native button so the <button> dot matches the old <div> dot. */
+  appearance: none; -webkit-appearance: none; border: 0; padding: 0; margin: 0;
   width: 6px; height: 6px; border-radius: 50%;
   background: rgba(255,255,255,0.15); cursor: pointer; transition: all 0.3s ease;
 }
@@ -83,6 +85,14 @@ html, body {
   box-shadow: 0 0 8px var(--accent-blue);
 }
 .slide-nav-dot:hover { background: rgba(255,255,255,0.4); transform: scale(1.3); }
+/* Keyboard-only focus ring, suppressed for pointer users. */
+.slide-nav-dot:focus-visible { outline: 2px solid var(--accent-blue); outline-offset: 3px; }
+
+/* Visually hidden, still read by screen readers. Used for the live region. */
+.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;
+}
 
 /* -- Typography -- */
 .slide-tag {

assets/slides-runtime.js

@@ -27,24 +27,54 @@ let current = 0;
 const total = slides.length;
 
 slides.forEach((_, i) => {
-  const dot = document.createElement('div');
+  // Buttons give keyboard focus and Enter/Space activation for free.
+  const dot = document.createElement('button');
+  dot.type = 'button';
   dot.className = 'slide-nav-dot' + (i===0?' active':'');
+  dot.setAttribute('aria-label', 'Go to slide ' + (i+1) + ' of ' + total);
+  if (i===0) dot.setAttribute('aria-current', 'true');
   dot.addEventListener('click', () => goTo(i));
   slideNav.appendChild(dot);
 });
 
+// Visually hidden region that announces slide changes to screen readers.
+const liveRegion = document.createElement('div');
+liveRegion.className = 'sr-only';
+liveRegion.setAttribute('aria-live', 'polite');
+document.body.appendChild(liveRegion);
+
+// Inactive slides start outside the accessibility tree and tab order.
+slides.forEach((s, i) => {
+  s.setAttribute('tabindex', '-1');
+  if (i !== current) {
+    s.setAttribute('inert', '');
+    s.setAttribute('aria-hidden', 'true');
+  }
+});
+
 function updateUI() {
   progress.style.width = ((current+1)/total*100)+'%';
   counter.textContent = `${current+1} / ${total}`;
-  document.querySelectorAll('.slide-nav-dot').forEach((d,i) => d.classList.toggle('active', i===current));
+  document.querySelectorAll('.slide-nav-dot').forEach((d,i) => {
+    d.classList.toggle('active', i===current);
+    if (i===current) d.setAttribute('aria-current', 'true');
+    else d.removeAttribute('aria-current');
+  });
 }
 
 function goTo(index) {
   if (index<0 || index>=total || index===current) return;
   const prev = current;
   current = index;
-  slides.forEach((s,i) => s.classList.toggle('active', i===current));
+  slides.forEach((s,i) => {
+    s.classList.toggle('active', i===current);
+    // Keep inactive slides out of the reading order and tab order.
+    if (i===current) { s.removeAttribute('inert'); s.removeAttribute('aria-hidden'); }
+    else { s.setAttribute('inert', ''); s.setAttribute('aria-hidden', 'true'); }
+  });
   updateUI();
+  slides[current].focus();
+  liveRegion.textContent = 'Slide ' + (current+1) + ' of ' + total;
   showSpeakerNotes(current);
 
   // Chart lifecycle: destroy on exit, create on entry

references/html-template.md

@@ -94,6 +94,21 @@ Every generated HTML file **must** comply with these rules:
         .reveal:nth-child(3) { transition-delay: 0.3s; }
         .reveal:nth-child(4) { transition-delay: 0.4s; }
 
+        /* ===========================================
+           ACCESSIBILITY
+           =========================================== */
+        /* Reset the native button so the <button> dot matches the old <div> dot. */
+        .slide-nav-dot { appearance: none; -webkit-appearance: none; border: 0; padding: 0; margin: 0; }
+
+        /* Keyboard-only focus ring, suppressed for pointer users. */
+        .slide-nav-dot:focus-visible { outline: 2px solid var(--accent-blue); outline-offset: 3px; }
+
+        /* Visually hidden, still read by screen readers. Used for the live region. */
+        .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;
+        }
+
         /* ... preset-specific styles ... */
     </style>
 </head>
@@ -131,9 +146,14 @@ Every generated HTML file **must** comply with these rules:
             current = index;
             slides.forEach(function(s, i) {
                 s.classList.toggle('active', i === current);
+                // Keep inactive slides out of the reading order and tab order.
+                if (i === current) { s.removeAttribute('inert'); s.removeAttribute('aria-hidden'); }
+                else { s.setAttribute('inert', ''); s.setAttribute('aria-hidden', 'true'); }
             });
             slides[current].scrollIntoView({ behavior: 'smooth' });
             updateUI();
+            slides[current].focus();
+            liveRegion.textContent = 'Slide ' + (current + 1) + ' of ' + total;
             showSpeakerNotes(current);
         }
 
@@ -152,6 +172,8 @@ Every generated HTML file **must** comply with these rules:
             // Nav dots
             document.querySelectorAll('.slide-nav-dot').forEach(function(d, i) {
                 d.classList.toggle('active', i === current);
+                if (i === current) d.setAttribute('aria-current', 'true');
+                else d.removeAttribute('aria-current');
             });
         }
 
@@ -183,13 +205,32 @@ Every generated HTML file **must** comply with these rules:
         var slideNav = document.getElementById('slideNav');
         if (slideNav) {
             slides.forEach(function(_, i) {
-                var dot = document.createElement('div');
+                // Buttons give keyboard focus and Enter/Space activation for free.
+                var dot = document.createElement('button');
+                dot.type = 'button';
                 dot.className = 'slide-nav-dot' + (i === 0 ? ' active' : '');
+                dot.setAttribute('aria-label', 'Go to slide ' + (i + 1) + ' of ' + total);
+                if (i === 0) dot.setAttribute('aria-current', 'true');
                 dot.addEventListener('click', function() { goTo(i); });
                 slideNav.appendChild(dot);
             });
         }
 
+        // Visually hidden region that announces slide changes to screen readers.
+        var liveRegion = document.createElement('div');
+        liveRegion.className = 'sr-only';
+        liveRegion.setAttribute('aria-live', 'polite');
+        document.body.appendChild(liveRegion);
+
+        // Inactive slides start outside the accessibility tree and tab order.
+        slides.forEach(function(s, i) {
+            s.setAttribute('tabindex', '-1');
+            if (i !== current) {
+                s.setAttribute('inert', '');
+                s.setAttribute('aria-hidden', 'true');
+            }
+        });
+
         updateUI();
 
         /* ===========================================

references/presentation-layer.md

@@ -95,6 +95,15 @@ The presentation must support:
 
 Build navigation inline following the pattern in [html-template.md](html-template.md). Generate `goTo()`, `next()`, `prev()` as global functions, plus speaker notes console logging on each slide change.
 
+## Accessibility Contract
+
+The navigation runtime holds to the following contract so keyboard and screen-reader users can drive the deck:
+
+- Nav dots are `<button type="button">` elements, so each dot is reachable by Tab and activates on Enter or Space. Every dot carries an `aria-label` of the form "Go to slide N of M".
+- The active dot carries `aria-current="true"`, and the others carry none. `updateUI()` keeps this in sync on every slide change.
+- Only the active slide is in the accessibility tree. Inactive slides carry `inert` and `aria-hidden="true"`, so a screen reader reads just the current slide and Tab skips controls inside hidden slides. Each slide also carries `tabindex="-1"` so it can receive focus.
+- On every slide change, focus moves to the active slide, and a visually hidden `aria-live="polite"` region announces "Slide N of M". The region is created once at startup and uses the `.sr-only` utility.
+
 ## Generator Meta Tag
 
 Every presentation must include in `<head>`: