data-tippy-content="`索引: ${index}<br>值: ${item.value}`">
                 <span class="font-mono text-xl font-semibold text-slate-800">{{ item.value }}</span>
            </div>
             <!-- Capacity Placeholders -->
             <div v-for="i in (capacity - size)" :key="'placeholder-' + i" class="stack-capacity-element w-4/5 bg-slate-50 border-2 border-dashed border-slate-200 p-3 my-1 rounded-lg flex items-center justify-center">
                <span class="text-slate-300 text-sm"></span>
