fix: preset thumbnails no longer conflict with main preview animation

- Inject only @keyframes (not .animated class rule) per preset thumbnail
  so the main preview's .animated rule cannot override them
- Drive thumbnail animation entirely via inline style properties
- Remove isActive/currentName — presets should never appear selected

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/animate/AnimationEditor.tsx

@@ -98,7 +98,7 @@ export function AnimationEditor() {
       </div>
 
       {/* Row 4: Preset Library */}
-      <PresetLibrary currentName={config.name} onSelect={loadPreset} />
+      <PresetLibrary onSelect={loadPreset} />
     </div>
   );
 }

components/animate/PresetLibrary.tsx

@@ -3,39 +3,29 @@
 import { useEffect, useRef } from 'react';
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
-import { cn } from '@/lib/utils/cn';
 import { PRESETS, PRESET_CATEGORIES } from '@/lib/animate/presets';
-import { buildCSS } from '@/lib/animate/cssBuilder';
+import { buildKeyframesOnly } from '@/lib/animate/cssBuilder';
 import type { AnimationConfig, AnimationPreset } from '@/types/animate';
 
 interface Props {
-  currentName: string;
   onSelect: (config: AnimationConfig) => void;
 }
 
-function PresetCard({ preset, isActive, onSelect }: {
+function PresetCard({ preset, onSelect }: {
   preset: AnimationPreset;
-  isActive: boolean;
   onSelect: () => void;
 }) {
   const styleRef = useRef<HTMLStyleElement | null>(null);
-  const key = `preset-${preset.id}`;
+  const animName = `preview-${preset.id}`;
 
-  // Each card gets its own @keyframes injected with a unique name to avoid conflicts
+  // Inject only the @keyframes block under a unique name — no .animated class rule
   useEffect(() => {
-    const renamedConfig = {
-      ...preset.config,
-      name: key,
-      keyframes: preset.config.keyframes,
-    };
+    const renamedConfig = { ...preset.config, name: animName };
     if (!styleRef.current) {
       styleRef.current = document.createElement('style');
       document.head.appendChild(styleRef.current);
     }
-    styleRef.current.textContent = buildCSS(renamedConfig).replace(
-      /animation: \S+/,
-      `animation: ${key}`
-    );
+    styleRef.current.textContent = buildKeyframesOnly(renamedConfig);
     return () => {
       styleRef.current?.remove();
       styleRef.current = null;
@@ -43,32 +33,36 @@ function PresetCard({ preset, isActive, onSelect }: {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, []);
 
+  // Cap thumbnail duration so fast presets loop nicely; slow ones cap at 1.2s
+  const thumbDuration = Math.min(preset.config.duration, 1200);
+
   return (
     <button
       onClick={onSelect}
-      className={cn(
-        'group relative flex flex-col items-center gap-2 p-3 rounded-xl border transition-all duration-200 text-left hover:border-primary/50 hover:bg-accent/30',
-        isActive ? 'border-primary bg-primary/5 shadow-sm shadow-primary/20' : 'border-border bg-card/50'
-      )}
+      className="flex flex-col items-center gap-2 p-3 rounded-xl border border-border bg-card/50 transition-all duration-200 hover:border-primary/50 hover:bg-accent/30 hover:shadow-sm"
     >
-      {/* Mini preview */}
+      {/* Mini preview — animation driven entirely by inline style, not .animated class */}
       <div className="w-full h-14 flex items-center justify-center rounded-lg bg-muted/30 overflow-hidden">
         <div
-          className="animated w-8 h-8 rounded-md bg-gradient-to-br from-violet-500 to-purple-600"
-          style={{ animationName: key, animationDuration: `${preset.config.duration}ms`, animationIterationCount: 'infinite', animationDirection: 'alternate' }}
+          className="w-8 h-8 rounded-md bg-gradient-to-br from-violet-500 to-purple-600"
+          style={{
+            animationName: animName,
+            animationDuration: `${thumbDuration}ms`,
+            animationTimingFunction: preset.config.easing,
+            animationIterationCount: 'infinite',
+            animationDirection: 'alternate',
+            animationFillMode: 'both',
+          }}
         />
       </div>
-      <span className={cn(
-        'text-[11px] font-medium text-center leading-tight',
-        isActive ? 'text-primary' : 'text-foreground/80'
-      )}>
+      <span className="text-[11px] font-medium text-center leading-tight text-foreground/80">
         {preset.name}
       </span>
     </button>
   );
 }
 
-export function PresetLibrary({ currentName, onSelect }: Props) {
+export function PresetLibrary({ onSelect }: Props) {
   return (
     <Card>
       <CardHeader>
@@ -90,7 +84,6 @@ export function PresetLibrary({ currentName, onSelect }: Props) {
                   <PresetCard
                     key={preset.id}
                     preset={preset}
-                    isActive={preset.id === currentName}
                     onSelect={() => onSelect(preset.config)}
                   />
                 ))}

lib/animate/cssBuilder.ts

@@ -61,6 +61,24 @@ export function buildAnimationShorthand(config: AnimationConfig): string {
   return `${config.name} ${config.duration}ms ${config.easing}${delay} ${iter} ${config.direction} ${config.fillMode}`;
 }
 
+export function buildKeyframesOnly(config: AnimationConfig): string {
+  const sorted = [...config.keyframes].sort((a, b) => a.offset - b.offset);
+  let out = `@keyframes ${config.name} {\n`;
+  for (const kf of sorted) {
+    const lines = buildProperties(kf.properties);
+    if (lines.length === 0) {
+      out += `  ${kf.offset}% { }\n`;
+    } else {
+      out += `  ${kf.offset}% {\n`;
+      for (const line of lines) out += `    ${line};\n`;
+      if (kf.easing) out += `    animation-timing-function: ${kf.easing};\n`;
+      out += `  }\n`;
+    }
+  }
+  out += `}\n`;
+  return out;
+}
+
 export function buildCSS(config: AnimationConfig): string {
   const sorted = [...config.keyframes].sort((a, b) => a.offset - b.offset);