Keep the slider moving in Safari and draw real dots in 1.11.2

Safari cancels a smooth scroll on a snapping container and snaps back to
the slide it came from, so arrows and autoplay stuttered on the iPhone. The
slider switches snapping off for the ride and restores it on arrival. The
control dots are drawn as dots with the active one filled.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

public/assets/site.css

@@ -203,7 +203,7 @@ body.consent-open{padding-bottom:260px}
 .slider-dots{position:relative}
 @supports selector(::scroll-marker){.slider-dots:not(.slider-controlled){scroll-marker-group:after;scroll-behavior:smooth;padding-bottom:0;scrollbar-width:none;scrollbar-gutter:auto}.slider-dots:not(.slider-controlled)::-webkit-scrollbar{display:none}.slider-dots:not(.slider-controlled)>*::scroll-marker{content:'';width:12px;height:12px;border-radius:50%;background:color-mix(in srgb,currentColor 30%,transparent);margin:0 6px;cursor:pointer}.slider-dots>*::scroll-marker:target-current{background:var(--accent)}.slider-dots::scroll-marker-group{display:flex;justify-content:center;align-items:center;padding:14px 0 2px}}
 .slider-controlled{scrollbar-width:none;scrollbar-gutter:auto}.slider-controlled::-webkit-scrollbar{display:none}
-.slider-controls{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:8px;min-height:48px;margin-top:8px;padding:4px;font:14px/1.4 system-ui,sans-serif}.slider-controls button{display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:40px;padding:8px 12px;border:1px solid #b2c2b8;border-radius:7px;background:#fff;color:#193c2d;cursor:pointer;font:inherit}.slider-controls button:focus-visible{outline:3px solid #b55b12;outline-offset:3px}.slider-controls button:hover{background:#e4efe7}.slider-controls button:disabled{opacity:.6;cursor:default}.slider-position{font-variant-numeric:tabular-nums;min-width:44px;text-align:center}.slider-control-dots{display:flex;flex-wrap:wrap;gap:3px}.slider-control-dots button{min-width:30px;padding:5px;border:0;background:transparent;color:inherit;opacity:.5}.slider-control-dots button[aria-pressed=true]{opacity:1;outline:1px solid currentColor;outline-offset:-5px}.slider-controls[hidden]{display:none}
+.slider-controls{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:8px;min-height:48px;margin-top:8px;padding:4px;font:14px/1.4 system-ui,sans-serif}.slider-controls button{display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:40px;padding:8px 12px;border:1px solid #b2c2b8;border-radius:7px;background:#fff;color:#193c2d;cursor:pointer;font:inherit}.slider-controls button:focus-visible{outline:3px solid #b55b12;outline-offset:3px}.slider-controls button:hover{background:#e4efe7}.slider-controls button:disabled{opacity:.6;cursor:default}.slider-position{font-variant-numeric:tabular-nums;min-width:44px;text-align:center}.slider-control-dots{display:flex;flex-wrap:wrap;gap:3px}.slider-control-dots button{min-width:32px;padding:0;border:0;background:transparent;color:inherit;font-size:0}.slider-control-dots button::before{content:'';width:10px;height:10px;border-radius:50%;border:2px solid currentColor;background:transparent;transition:background-color .2s}.slider-control-dots button[aria-pressed=true]::before{background:currentColor}.slider-control-dots button:hover::before{background:color-mix(in srgb,currentColor 50%,transparent)}.slider-controls[hidden]{display:none}
 @media(max-width:650px){.slider-controls button{min-height:44px;min-width:44px}}
 
 .slide-desktop-1{grid-auto-columns:100%}.slide-desktop-2{grid-auto-columns:calc(50% - 10px)}

public/assets/slider.js

@@ -28,9 +28,25 @@ export function initSliders(doc = document) {
       available().forEach(i => { const delta = Math.abs(left(slides[i]) - slider.scrollLeft); if (delta < distance) { distance = delta; index = i; } });
       return index;
     };
+    let settle = null;
     const go = index => {
       if (!available().includes(index)) return;
-      slider.scrollTo({ left: Math.max(0, Math.min(slider.scrollWidth - slider.clientWidth, left(slides[index]))), behavior: reduced() ? 'instant' : 'smooth' });
+      const target = Math.max(0, Math.min(slider.scrollWidth - slider.clientWidth, left(slides[index])));
+      if (reduced()) { slider.scrollTo({ left: target, behavior: 'instant' }); return; }
+      // Safari cancels a smooth scroll on a snapping container and snaps back to the slide it
+      // came from - the slider stutters instead of moving on. Snapping is switched off for the
+      // ride and put back once the movement has settled, on the exact start of a slide, so
+      // restoring it moves nothing.
+      clearInterval(settle);
+      const snap = slider.style.scrollSnapType;
+      slider.style.scrollSnapType = 'none';
+      slider.scrollTo({ left: target, behavior: 'smooth' });
+      // Restored on arrival, or after two seconds if the ride was interrupted - a background tab
+      // pauses smooth scrolling, and snapping must not come back halfway.
+      let ticks = 0;
+      settle = setInterval(() => {
+        if (Math.abs(slider.scrollLeft - target) < 1 || ++ticks > 25) { clearInterval(settle); settle = null; slider.style.scrollSnapType = snap; }
+      }, 80);
     };
     const step = direction => {
       const visible = available(), position = visible.indexOf(active());
@@ -82,7 +98,7 @@ export function initSliders(doc = document) {
     const resize = new view.ResizeObserver(update); resize.observe(slider);
     preference.addEventListener('change', () => { if (reduced()) pause(); update(); }, { signal });
     schedule();
-    cleanups.push(() => { clearTimeout(timer); events.abort(); observer.disconnect(); resize.disconnect(); controls.remove(); slider.classList.remove('slider-controlled'); delete slider.dataset.enhanced; });
+    cleanups.push(() => { clearTimeout(timer); clearInterval(settle); slider.style.scrollSnapType = ''; events.abort(); observer.disconnect(); resize.disconnect(); controls.remove(); slider.classList.remove('slider-controlled'); delete slider.dataset.enhanced; });
   });
   return () => cleanups.forEach(cleanup => cleanup());
 }