@@ -65,7 +65,14 @@ export class GiottoPlayer extends Base {
     this.schemes.addEventListener('change', this.retheme);
     this.themeWatch = new MutationObserver(this.retheme);
     this.themeWatch.observe(document.documentElement, { attributes: true, attributeFilter: ['data-theme', 'class', 'style'] });
-    this.sizeWatch = new ResizeObserver(() => this.fit());
+    // Only a new width needs a refit: fit() sets the figure's height, which resizes this element, and
+    // refitting on that too (in the same callback) made the browser report a ResizeObserver loop.
+    // The refit waits a frame so it never resizes anything while the observer is still delivering.
+    this.sizeWatch = new ResizeObserver(([e]) => {
+      if (e.contentRect.width === this.watchedWidth) return;
+      this.watchedWidth = e.contentRect.width;
+      requestAnimationFrame(() => this.fit());
+    });
     this.sizeWatch.observe(this);
     // Off screen, nothing plays (a docs page can hold many figures).
     this.seenWatch = new IntersectionObserver(([e]) => { this.state.seen = e.isIntersecting; this.loop(); });