Use four-step carousel per program

src/App.jsx

@@ -523,17 +523,23 @@ function FlowRow({
     return 'disabled';
   };
   const isRowClickable = Boolean(onLabelClick) && !isEditing;
-  const isWrappedStepLayout = steps.length > 5;
-  const isSingleStepLayout = steps.length === 1;
-  const stepRows = isWrappedStepLayout
-    ? steps.reduce((rows, step, index) => {
-        const rowIndex = Math.floor(index / 4);
-        rows[rowIndex] = [...(rows[rowIndex] ?? []), { step, index }];
-        return rows;
-      }, [])
-    : [];
-  const wrappedCardColumns = ['xl:col-start-1', 'xl:col-start-3', 'xl:col-start-5', 'xl:col-start-7'];
-  const wrappedArrowColumns = ['xl:col-start-2', 'xl:col-start-4', 'xl:col-start-6'];
+  const maxVisibleSteps = 4;
+  const [stepWindowStart, setStepWindowStart] = useState(0);
+  const maxWindowStart = Math.max(0, steps.length - maxVisibleSteps);
+  const visibleStepItems = steps
+    .map((step, index) => ({ step, index }))
+    .slice(stepWindowStart, stepWindowStart + maxVisibleSteps);
+  const placeholderCount = Math.max(0, maxVisibleSteps - visibleStepItems.length);
+  const canMovePrev = stepWindowStart > 0;
+  const canMoveNext = stepWindowStart < maxWindowStart;
+
+  useEffect(() => {
+    setStepWindowStart((current) => Math.min(current, maxWindowStart));
+  }, [maxWindowStart]);
+
+  const moveStepWindow = (direction) => {
+    setStepWindowStart((current) => Math.min(maxWindowStart, Math.max(0, current + direction)));
+  };
 
   const renderStepCard = (step, index, className) => (
     <div className={`relative z-10 flex flex-col gap-2 ${className}`}>
@@ -687,46 +693,59 @@ function FlowRow({
           )}
         </div>
       </div>
-      {isWrappedStepLayout ? (
-        <div className="space-y-5">
-          {stepRows.map((row, rowIndex) => (
-            <div
-              key={rowIndex}
-              className="relative flex flex-col gap-3 xl:grid xl:grid-cols-[minmax(0,1fr)_28px_minmax(0,1fr)_28px_minmax(0,1fr)_28px_minmax(0,1fr)] xl:gap-0 xl:items-stretch"
+      <div className="relative overflow-hidden rounded-[24px] bg-white/25 px-9 py-1 ring-1 ring-white/70">
+        {steps.length > maxVisibleSteps && (
+          <>
+            <button
+              type="button"
+              disabled={!canMovePrev}
+              onClick={(event) => {
+                event.stopPropagation();
+                moveStepWindow(-1);
+              }}
+              className="absolute left-2 top-1/2 z-20 flex h-8 w-8 -translate-y-1/2 items-center justify-center rounded-full bg-white/95 text-slate-500 shadow-sm ring-1 ring-slate-200 hover:bg-slate-50 disabled:opacity-25"
+              aria-label="이전 스텝 보기"
             >
-              {row.map(({ step, index }, itemIndex) => (
-                <React.Fragment key={step.id}>
-                  {renderStepCard(
-                    step,
-                    index,
-                    `min-w-0 ${wrappedCardColumns[itemIndex]}`
-                  )}
-                  {itemIndex < row.length - 1 && (
-                    <div className={`flex items-center justify-center ${wrappedArrowColumns[itemIndex]}`}>
-                      <ArrowRight className={`hidden h-5 w-5 xl:block ${accent.arrowText}`} />
-                      <ArrowDown className={`h-5 w-5 xl:hidden ${accent.arrowText}`} />
-                    </div>
-                  )}
-                </React.Fragment>
-              ))}
+              ‹
+            </button>
+            <button
+              type="button"
+              disabled={!canMoveNext}
+              onClick={(event) => {
+                event.stopPropagation();
+                moveStepWindow(1);
+              }}
+              className="absolute right-2 top-1/2 z-20 flex h-8 w-8 -translate-y-1/2 items-center justify-center rounded-full bg-white/95 text-slate-500 shadow-sm ring-1 ring-slate-200 hover:bg-slate-50 disabled:opacity-25"
+              aria-label="다음 스텝 보기"
+            >
+              ›
+            </button>
+          </>
+        )}
+        <div className="relative grid grid-cols-1 gap-3 md:grid-cols-2 xl:grid-cols-4 xl:gap-5">
+          {visibleStepItems.map(({ step, index }, itemIndex) => (
+            <div key={step.id} className="relative">
+              {renderStepCard(step, index, 'min-w-0')}
+              {itemIndex < visibleStepItems.length - 1 && (
+                <ArrowDown className={`mx-auto mt-2 h-5 w-5 xl:hidden ${accent.arrowText}`} />
+              )}
             </div>
           ))}
-        </div>
-      ) : (
-        <div className="relative flex flex-col gap-3 xl:flex-row xl:items-stretch">
-          {steps.map((step, index) => (
-            <React.Fragment key={step.id}>
-              {renderStepCard(step, index, isSingleStepLayout ? 'w-full max-w-[320px]' : 'min-w-0 flex-1')}
-              {index < steps.length - 1 && (
-                <div className="flex items-center justify-center xl:w-7">
-                  <ArrowRight className={`hidden h-5 w-5 xl:block ${accent.arrowText}`} />
-                  <ArrowDown className={`h-5 w-5 xl:hidden ${accent.arrowText}`} />
-                </div>
-              )}
-            </React.Fragment>
+          {Array.from({ length: placeholderCount }).map((_, index) => (
+            <div
+              key={`placeholder-${index}`}
+              className="hidden min-h-[220px] rounded-2xl border border-dashed border-transparent xl:block"
+            />
+          ))}
+          {visibleStepItems.slice(0, -1).map((item, index) => (
+            <ArrowRight
+              key={`arrow-${item.step.id}`}
+              className={`pointer-events-none absolute top-1/2 z-20 hidden h-5 w-5 -translate-x-1/2 -translate-y-1/2 xl:block ${accent.arrowText}`}
+              style={{ left: `${25 * (index + 1)}%` }}
+            />
           ))}
         </div>
-      )}
+      </div>
     </section>
   );
 }