diff --git a/static/css/cookbook-research-memory-settings.css b/static/css/cookbook-research-memory-settings.css
index 3bcbb08cd..67f425dae 100644
--- a/static/css/cookbook-research-memory-settings.css
+++ b/static/css/cookbook-research-memory-settings.css
@@ -28,10 +28,6 @@
       0%, 100% { transform: scale(1); opacity: 1; }
       50% { transform: scale(1.5); opacity: 0.7; }
     }
-@keyframes research-pulse {
-      0%, 100% { background: color-mix(in srgb, var(--red) 12%, transparent); }
-      50% { background: color-mix(in srgb, var(--red) 22%, transparent); }
-    }
 #cookbook-gguf-delete-overlay {
       background:rgba(0,0,0,0.5);
       backdrop-filter:blur(4px);
diff --git a/static/style.css b/static/style.css
index 34711963c..94788c585 100644
--- a/static/style.css
+++ b/static/style.css
@@ -1480,7 +1480,6 @@ body.bg-pattern-ascii-fireflies {
       0%   { opacity: 1; transform: translateY(0)   translateX(0)   scale(1); }
       100% { opacity: 0; transform: translateY(6px) translateX(-3px) scale(0.94); }
     }
-    @keyframes spin { to { transform: rotate(360deg); } }
     .row { display:flex; gap:6px; align-items:center; }
     .list-item:hover,
     .models-row:hover {
@@ -6119,9 +6118,6 @@ body.bg-pattern-ascii-fireflies {
     #mobile-backdrop, #mobile-menu-btn { display:none !important; }
     #sidebar-backdrop { display:none !important; }
     /* ----- Loading spinner ----- */
-    @keyframes spin {
-      to { transform: rotate(360deg); }
-    }
     .spinner {
       width: 24px;
       height: 24px;
@@ -6240,14 +6236,6 @@ body.bg-pattern-ascii-fireflies {
       .session-skeleton-bubble.is-user { width: 72%; }
       .session-skeleton-line { height: 9px; margin-top: 7px; }
     }
-    @keyframes loading-bounce {
-      0%, 80%, 100% {
-        transform: scale(0);
-      }
-      40% {
-        transform: scale(1);
-      }
-    }
     /* Modal styling */
     .modal {
       position:fixed;
@@ -7555,11 +7543,6 @@ body.bg-pattern-ascii-fireflies {
       animation: pulse 1.5s infinite;
     }
     
-    @keyframes pulse {
-      0% { opacity: 1; }
-      50% { opacity: 0.7; }
-      100% { opacity: 1; }
-    }
     
     #recording-indicator {
       position: fixed;
@@ -8720,7 +8703,6 @@ pre { background: var(--code-bg, var(--hl-bg, #282c34)) !important; }
     }
     .compare-probe-start-anyway svg { color: currentColor; }
     .compare-probe-start-anyway span { font-weight: 700; }
-    @keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
     @keyframes pane-shake {
       0%, 100% { transform: translateX(0); }
       15% { transform: translateX(-3px) rotate(-0.5deg); }
diff --git a/tests/test_stylesheet_keyframe_uniqueness.py b/tests/test_stylesheet_keyframe_uniqueness.py
new file mode 100644
index 000000000..9fe26337d
--- /dev/null
+++ b/tests/test_stylesheet_keyframe_uniqueness.py
@@ -0,0 +1,52 @@
+"""No two @keyframes may share a name across the app's stylesheets.
+
+Duplicate names resolve last-wins across the whole cascade, so an earlier
+definition is dead code that still looks live at its call site. Two of them
+existed and differed from the definition that actually won, which also blocked
+moving either animation during the stylesheet decomposition: relocating one
+changes which is last and therefore changes rendered behaviour.
+"""
+
+import collections
+import re
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+STATIC = ROOT / "static"
+
+
+def _stylesheets() -> list[Path]:
+    """App-owned stylesheets, in no particular order. Vendored CSS is excluded."""
+    sheets = [STATIC / "style.css"]
+    sheets.extend(sorted((STATIC / "css").glob("*.css")))
+    return [s for s in sheets if s.exists()]
+
+
+def _keyframe_names(text: str) -> list[str]:
+    without_comments = re.sub(r"/\*.*?\*/", "", text, flags=re.S)
+    return re.findall(
+        r"@(?:-webkit-)?keyframes\s+([A-Za-z0-9_-]+)\s*\{", without_comments
+    )
+
+
+def test_app_stylesheets_exist() -> None:
+    """Guard the guard: a rename must not turn this file into a no-op."""
+    assert _stylesheets(), "no app stylesheets found to check"
+
+
+def test_no_keyframes_name_is_declared_twice() -> None:
+    counts: collections.Counter[str] = collections.Counter()
+    where: dict[str, list[str]] = collections.defaultdict(list)
+
+    for sheet in _stylesheets():
+        for name in _keyframe_names(sheet.read_text(encoding="utf-8")):
+            counts[name] += 1
+            where[name].append(sheet.relative_to(ROOT).as_posix())
+
+    duplicates = {name: where[name] for name, n in counts.items() if n > 1}
+
+    assert duplicates == {}, (
+        "duplicate @keyframes names resolve last-wins, so every definition but "
+        f"the last is dead: {duplicates}"
+    )