/* --- 1. 基礎設定 --- */
        /*body {
            font-family: "Noto Sans TC", "Microsoft JhengHei", sans-serif;
            background-color: #f4f7f6;
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            margin: 0;
            padding: 20px;
        }*/

        .calculator-card {
            background: white;
            width: 100%;
            max-width: 800px; /* 稍微加寬，讓展示區更寬敞 */
            padding: 40px;
            border-radius: 24px;
            box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
            text-align: center;
            position: relative;
			margin:80px auto;
        }

        /* --- 2. 輸入與標題區 --- */
        .header h2 {
            color: #2c3e50;
            margin: 0 0 10px 0;
        }
        .header p {
            color: #7f8c8d;
            font-size: 14px;
            margin-bottom: 30px;
        }

        .input-group {
            display: flex;
            gap: 15px;
            justify-content: center;
            margin-bottom: 25px;
        }

        input[type="number"] {
            width: 150px;
            padding: 12px;
            border: 2px solid #ddd;
            border-radius: 8px;
            font-size: 18px;
            text-align: center;
            transition: 0.3s;
        }
        input[type="number"]:focus { border-color: #e74c3c; outline: none; }

        select {
            padding: 12px;
            border: 2px solid #ddd;
            border-radius: 8px;
            font-size: 16px;
            background: white;
            cursor: pointer;
        }

        /* --- 3. 結果數字區 --- */
        .result-box {
            margin-bottom: 30px;
        }
        .result-number {
            font-size: 60px;
            font-weight: 800;
            color: #e74c3c;
            line-height: 1;
        }
        .result-unit { font-size: 20px; color: #2c3e50; font-weight: bold; }

        /* --- 4. 視覺展示區 (核心修改) --- */
        .visual-area {
            margin-top: 20px;
            position: relative;
        }

        .visual-label {
            font-size: 14px;
            color: #95a5a6;
            margin-bottom: 10px;
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 8px;
            opacity: 0;
            transition: opacity 0.3s;
        }
        .visual-label.show { opacity: 1; }

        /* 捲動容器 */
        .product-scroll-container {
            width: 100%;
            overflow-x: auto; /* 允許水平捲動 */
            padding-top: 60px; /* 預留上方空間給掉落動畫 */
            padding-bottom: 20px;
            padding-left: 20px; /* 避免第一張被切到 */
            white-space: nowrap; /* 強制不換行 */
            
            /* 讓捲動順滑 */
            scroll-behavior: smooth; 
            -webkit-overflow-scrolling: touch;
        }

        /* --- 美化捲軸 (Scrollbar) --- */
        /* 整個捲軸寬度/高度 */
        .product-scroll-container::-webkit-scrollbar {
            height: 10px; 
        }
        /* 捲軸軌道 */
        .product-scroll-container::-webkit-scrollbar-track {
            background: #f1f1f1; 
            border-radius: 10px;
            margin: 0 20px; /* 兩側留白 */
        }
        /* 捲軸本體 */
        .product-scroll-container::-webkit-scrollbar-thumb {
            background: #bdc3c7; 
            border-radius: 10px;
            border: 2px solid #f1f1f1; /* 增加層次感 */
        }
        /* 滑鼠移上去時變深 */
        .product-scroll-container::-webkit-scrollbar-thumb:hover {
            background: #95a5a6; 
        }

        /* 圖片容器 */
        .product-stack {
            display: inline-flex; /* 內容物橫向排列 */
            align-items: flex-end; /* 底部對齊 */
        }

        .product-stack img {
            height: 120px; /* 圖片高度 */
            width: auto;
            filter: drop-shadow(5px 5px 10px rgba(0,0,0,0.15)); /* 立體陰影 */
            
            /* 重疊設定 */
            position: relative;
            margin-left: -60px; /* [調整這裡] 負值越大，疊得越緊密 */
            
            /* 初始狀態：隱藏且在上方 */
            opacity: 0;
            transform: translateY(-100px); 
        }

        /* 第一張不要有負邊距 */
        .product-stack img:first-child {
            margin-left: 0;
        }

        /* --- 5. 動畫 Keyframes --- */
        @keyframes fallDown {
            0% {
                opacity: 0;
                transform: translateY(-100px); /* 從上方 100px 處開始 */
            }
            60% {
                transform: translateY(10px); /* 稍微彈一下 */
            }
            100% {
                opacity: 1;
                transform: translateY(0); /* 回到原位 */
            }
        }

        /* 用 class 觸發動畫 */
        .animate-fall {
            animation: fallDown 0.6s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
        }

        /* --- 6. 規格備註 --- */
        .specs {
            margin-top: 20px;
            padding-top: 20px;
            border-top: 1px dashed #ddd;
            font-size: 12px;
            color: #999;
        }

		.specs p {
			font-size: 12px;
		}	

        /* 手機版微調 */
        @media (max-width: 480px) {
            .product-stack img { height: 80px; margin-left: -35px; }
            .result-number { font-size: 48px; }
            .calculator-card { padding: 20px; }
        }