feat: add stacked practice cards

src/pages/ProcessPurposePracticePage.tsx

@@ -92,6 +92,7 @@ export default function ProcessPurposePracticePage() {
   const isComposingRef = useRef(false)
   const latestInputRef = useRef<string[]>([])
   const answerTimerRef = useRef<number | null>(null)
+  const deckScrollRef = useRef<HTMLDivElement | null>(null)
   const { practiceMode } = useAppStore()
 
   const itemMap = useMemo(
@@ -102,6 +103,11 @@ export default function ProcessPurposePracticePage() {
   const totalCount = progress.order.length
   const completedCount = progress.completedIds.length
   const isFinished = completedCount >= totalCount
+  const visibleQuestionCards = progress.order
+    .slice(0, progress.currentIndex + 1)
+    .map((id, index) => ({ item: itemMap.get(id), index }))
+    .filter((card): card is { item: NonNullable<typeof currentItem>; index: number } => Boolean(card.item))
+  const nextPreviewItem = itemMap.get(progress.order[progress.currentIndex + 1])
 
   const focusFirstEmptyInput = useCallback(() => {
     setTimeout(() => {
@@ -213,6 +219,15 @@ export default function ProcessPurposePracticePage() {
     }
   }, [])
 
+  useEffect(() => {
+    const deck = deckScrollRef.current
+    if (!deck) return
+
+    requestAnimationFrame(() => {
+      deck.scrollTo({ top: deck.scrollHeight, behavior: 'smooth' })
+    })
+  }, [progress.currentIndex])
+
   const moveToNextQuestion = useCallback(() => {
     setShowAnswer(false)
     setCorrectFeedback(false)
@@ -413,8 +428,8 @@ export default function ProcessPurposePracticePage() {
   if (!currentItem) return null
 
   return (
-    <div className="flex min-h-screen flex-col bg-gray-50 dark:bg-gray-900">
-      <div className="sticky top-0 z-20 border-b border-gray-200 bg-white/90 shadow-sm backdrop-blur dark:border-gray-700 dark:bg-gray-800/90">
+    <div className="flex h-[calc(100vh-3rem)] min-h-[620px] flex-col overflow-hidden bg-gray-50 dark:bg-gray-900">
+      <div className="z-20 shrink-0 border-b border-gray-200 bg-white/90 shadow-sm backdrop-blur dark:border-gray-700 dark:bg-gray-800/90">
         <div className="mx-auto max-w-5xl px-4 py-4">
           <div className="mb-3 flex flex-col gap-3 md:flex-row md:items-center md:justify-between">
             <div>
@@ -449,40 +464,104 @@ export default function ProcessPurposePracticePage() {
         </div>
       </div>
 
-      <main className="mx-auto w-full max-w-5xl flex-1 px-4 py-8 pb-48">
-        <section
+      <main className="mx-auto flex min-h-0 w-full max-w-5xl flex-1 flex-col gap-4 overflow-hidden px-4 py-6">
+        <div
+          ref={deckScrollRef}
+          className="min-h-0 flex-1 space-y-4 overflow-y-auto overscroll-contain pr-1 scroll-smooth"
+        >
+          <AnimatePresence initial={false}>
+            {visibleQuestionCards.map(({ item, index }) => {
+              const isCurrent = index === progress.currentIndex
+              const isAnsweredHistory = index < progress.currentIndex
+
+              return (
+                <motion.section
+                  key={item.id}
+                  layout
+                  initial={{ opacity: 0, y: 24, scale: 0.98 }}
+                  animate={{
+                    opacity: isCurrent ? 1 : 0.72,
+                    y: 0,
+                    scale: isCurrent ? 1 : 0.985,
+                  }}
+                  exit={{ opacity: 0, y: -16, scale: 0.98 }}
+                  transition={{ duration: 0.28, ease: 'easeOut' }}
                   className={`rounded-2xl border bg-white p-6 shadow-sm transition-all duration-200 dark:bg-gray-800 ${
-            correctFeedback
+                    isCurrent && correctFeedback
                       ? 'border-green-300 ring-2 ring-green-100 dark:border-green-700 dark:ring-green-900/40'
-              : 'border-gray-200 dark:border-gray-700'
+                      : isCurrent
+                        ? 'border-gray-200 dark:border-gray-700'
+                        : 'border-gray-100 dark:border-gray-800'
                   }`}
                 >
                   <div className="mb-4 flex min-h-9 flex-wrap items-center justify-between gap-3">
-            <span className="rounded-full bg-blue-50 px-3 py-1 text-sm font-medium text-blue-700 dark:bg-blue-900/30 dark:text-blue-200">
-              第 {Math.min(progress.currentIndex + 1, totalCount)} / {totalCount} 题
+                    <span
+                      className={`rounded-full px-3 py-1 text-sm font-medium ${
+                        isCurrent
+                          ? 'bg-blue-50 text-blue-700 dark:bg-blue-900/30 dark:text-blue-200'
+                          : 'bg-gray-100 text-gray-500 dark:bg-gray-700/70 dark:text-gray-300'
+                      }`}
+                    >
+                      第 {index + 1} / {totalCount} 题
                     </span>
+
                     <AnimatePresence mode="wait">
-              {showAnswer ? (
+                      {isCurrent && showAnswer ? (
                         <motion.span
-                  key="answer"
+                          key="current-answer"
                           initial={{ opacity: 0, y: -4 }}
                           animate={{ opacity: 1, y: 0 }}
                           exit={{ opacity: 0, y: -4 }}
                           className="rounded-xl border border-indigo-300 bg-indigo-50 px-3 py-1 text-base font-semibold leading-6 text-indigo-800 shadow-sm shadow-indigo-100 dark:border-indigo-500/70 dark:bg-indigo-950/50 dark:text-indigo-100 dark:shadow-none"
                         >
-                  {currentItem.name}
+                          {item.name}
+                        </motion.span>
+                      ) : isAnsweredHistory ? (
+                        <motion.span
+                          key="history-answer"
+                          initial={{ opacity: 0 }}
+                          animate={{ opacity: 1 }}
+                          exit={{ opacity: 0 }}
+                          className="rounded-full bg-green-50 px-3 py-1 text-sm font-medium text-green-700 dark:bg-green-900/30 dark:text-green-200"
+                        >
+                          {item.name}
                         </motion.span>
                       ) : null}
                     </AnimatePresence>
                   </div>
-          <p className="text-xl leading-9 text-gray-900 dark:text-gray-100">
-            {currentItem.purpose}
-          </p>
-        </section>
 
+                  <p
+                    className={`leading-9 text-gray-900 dark:text-gray-100 ${
+                      isCurrent ? 'text-xl' : 'text-base'
+                    }`}
+                  >
+                    {item.purpose}
+                  </p>
+                </motion.section>
+              )
+            })}
+          </AnimatePresence>
+        </div>
+
+        {!isFinished && nextPreviewItem && (
+          <motion.section
+            key={nextPreviewItem.id}
+            initial={{ opacity: 0, y: 12 }}
+            animate={{ opacity: 0.58, y: 0 }}
+            transition={{ duration: 0.25 }}
+            className="pointer-events-none shrink-0 rounded-2xl border border-dashed border-gray-200 bg-white/70 p-5 shadow-sm blur-[0.4px] dark:border-gray-700 dark:bg-gray-800/55"
+          >
+            <div className="mb-3 inline-flex rounded-full bg-gray-100 px-3 py-1 text-sm font-medium text-gray-500 dark:bg-gray-700/70 dark:text-gray-300">
+              第 {progress.currentIndex + 2} / {totalCount} 题
+            </div>
+            <p className="line-clamp-2 select-none text-base leading-8 text-gray-500 blur-[1.5px] dark:text-gray-400">
+              {nextPreviewItem.purpose}
+            </p>
+          </motion.section>
+        )}
 
         {isFinished && (
-          <section className="mt-6 rounded-2xl border border-gray-200 bg-white p-10 text-center shadow-sm dark:border-gray-700 dark:bg-gray-800">
+          <section className="shrink-0 rounded-2xl border border-gray-200 bg-white p-10 text-center shadow-sm dark:border-gray-700 dark:bg-gray-800">
             <div className="text-2xl font-bold text-gray-900 dark:text-gray-100">
               已完成本轮练习
             </div>
@@ -501,7 +580,7 @@ export default function ProcessPurposePracticePage() {
       </main>
 
       {!isFinished && (
-        <div className="sticky bottom-0 z-10 border-t border-gray-200 bg-white/70 pb-8 backdrop-blur-md dark:border-gray-700 dark:bg-gray-800/70">
+        <div className="z-10 shrink-0 border-t border-gray-200 bg-white/70 pb-8 backdrop-blur-md dark:border-gray-700 dark:bg-gray-800/70">
           <div className="mx-auto max-w-5xl px-6">
             <div className="border-b border-gray-200/50 py-3 dark:border-gray-700/50">
               <div className="flex items-center justify-center gap-3">