diff --git a/src/app/components/MediaManager.tsx b/src/app/components/MediaManager.tsx
index fd9027a..d92f03f 100644
--- a/src/app/components/MediaManager.tsx
+++ b/src/app/components/MediaManager.tsx
@@ -1,4 +1,4 @@
-import { lazy, Suspense, useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react';
+import { lazy, Suspense, useCallback, useEffect, useRef, useState } from 'react';
 import {
   AlignLeft,
   ArrowLeft,
@@ -128,45 +128,69 @@ function ViewerModeIcon({ mode, className }: { mode: ViewMode; className?: strin
 
 // ─── MarqueeText ──────────────────────────────────────────────────────────────
 // Scrolls text left→right when it overflows its container, then back — ping-pong.
-// Uses a CSS variable for the per-instance scroll distance so a single keyframe
-// declaration covers every instance.
+// Injects a unique per-instance @keyframes rule with the exact pixel offset so
+// no CSS variables are needed (more reliable inside Radix portals).
 
-if (typeof document !== 'undefined' && !document.getElementById('mm-marquee-kf')) {
-  const s = document.createElement('style');
-  s.id = 'mm-marquee-kf';
-  s.textContent = `@keyframes mm-scroll {
-    0%,12%  { transform: translateX(0) }
-    88%,100%{ transform: translateX(var(--mm-dx,0px)) }
-  }`;
-  document.head.appendChild(s);
-}
+let _mmSeq = 0;
 
 function MarqueeText({ children, className }: { children?: string; className?: string }) {
   const wrapRef = useRef<HTMLSpanElement>(null);
-  const textRef = useRef<HTMLSpanElement>(null);
-  const [dx, setDx] = useState(0);
+  const idRef   = useRef(`mm${++_mmSeq}`);
+  const [animCSS, setAnimCSS] = useState('');
 
-  useLayoutEffect(() => {
+  useEffect(() => {
+    let cancelled = false;
+    const id   = idRef.current;
     const wrap = wrapRef.current;
-    const text = textRef.current;
-    if (!wrap || !text) return;
-    const measure = () => setDx(Math.max(0, text.scrollWidth - wrap.offsetWidth));
-    measure();
+    if (!wrap) return;
+
+    const measure = () => {
+      if (cancelled) return;
+      const ov = wrap.scrollWidth - wrap.clientWidth;
+      if (ov <= 0) { setAnimCSS(''); return; }
+
+      // Inject / update the keyframe with the exact measured pixel offset.
+      let el = document.getElementById(`kf-${id}`) as HTMLStyleElement | null;
+      if (!el) {
+        el = document.createElement('style');
+        el.id = `kf-${id}`;
+        document.head.appendChild(el);
+      }
+      el.textContent = `@keyframes ${id}{0%,12%{transform:translateX(0)}88%,100%{transform:translateX(-${ov}px)}}`;
+
+      const secs = (Math.max(2000, ov * 20) / 1000).toFixed(2);
+      setAnimCSS(`${id} ${secs}s ease-in-out 0.8s infinite alternate`);
+    };
+
+    // Two nested RAFs ensure the portal element has a stable layout before we
+    // measure (one RAF fires before browser layout; two guarantees post-layout).
+    const r1 = requestAnimationFrame(() => {
+      const r2 = requestAnimationFrame(measure);
+      return () => cancelAnimationFrame(r2);
+    });
+
     const ro = new ResizeObserver(measure);
     ro.observe(wrap);
-    return () => ro.disconnect();
+
+    return () => {
+      cancelled = true;
+      cancelAnimationFrame(r1);
+      ro.disconnect();
+      document.getElementById(`kf-${id}`)?.remove();
+      setAnimCSS('');
+    };
   }, [children]);
 
   return (
-    <span ref={wrapRef} className={`overflow-hidden whitespace-nowrap block ${className ?? ''}`}>
-      <span
-        ref={textRef}
-        style={dx > 0 ? {
-          display: 'inline-block',
-          '--mm-dx': `-${dx}px`,
-          animation: `mm-scroll ${1.5 + dx / 80}s ease-in-out 1s infinite alternate`,
-        } as React.CSSProperties : undefined}
-      >
+    // overflow:hidden clips the scrolling text; minWidth:0 lets the element
+    // shrink inside grid/flex parents without forcing them to expand to the
+    // full text width (white-space:nowrap lives only on the inner span).
+    <span
+      ref={wrapRef}
+      style={{ overflow: 'hidden', display: 'block', minWidth: 0 }}
+      className={className}
+    >
+      <span style={{ display: 'inline-block', whiteSpace: 'nowrap', animation: animCSS || undefined }}>
         {children}
       </span>
     </span>
@@ -210,10 +234,14 @@ function ActionsModal({ entry, onClose, onOpen, onMount, onDownload, onDuplicate
   return (
     <Dialog open={entry !== null} onOpenChange={open => !open && onClose()}>
       <DialogContent className="max-w-sm">
-        <DialogHeader>
-          <DialogTitle><MarqueeText>{entry?.name || '/'}</MarqueeText></DialogTitle>
+        <DialogHeader className="overflow-hidden min-w-0">
+          {/* Keep DialogTitle for accessibility (aria-labelledby); styled text lives in the p below */}
+          <DialogTitle className="sr-only">{entry?.name || '/'}</DialogTitle>
+          <p className="text-lg font-semibold leading-none pr-6 overflow-hidden min-w-0">
+            <MarqueeText>{entry?.name || '/'}</MarqueeText>
+          </p>
           <DialogDescription>
-            {isFolder ? 'Folder' : humanFileSize(entry?.size ?? 0)}
+            <MarqueeText>{isFolder ? 'Folder' : humanFileSize(entry?.size ?? 0)}</MarqueeText>
           </DialogDescription>
         </DialogHeader>
         {entry && (