/* 外部サイト表示用のスタイル */
        .external-site-container {
            width: 100%;
            height: 70vh;
            display: flex;
            flex-direction: column;
        }
        
        .external-site-header {
            background-color: var(--secondary-color);
            padding: 10px 15px;
            border-bottom: 1px solid var(--border-color);
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .back-to-content {
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: 6px;
            padding: 8px 12px;
            cursor: pointer;
            font-size: 0.9rem;
            display: flex;
            align-items: center;
            gap: 5px;
            transition: all 0.3s ease;
        }
        
        .back-to-content:hover {
            background-color: var(--accent-color);
        }
        
        .external-site-url {
            font-size: 0.85rem;
            color: #666;
            word-break: break-all;
        }
        
        .external-site-iframe {
            flex: 1;
            width: 100%;
            border: none;
            background-color: white;
        }
        
        .external-site-iframe:not([src]) {
            background-color: #f5f5f5;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        
        .external-site-iframe:not([src])::before {
            content: "サイトを読み込んでいます...";
            color: #666;
        }