/* ===== 自定义播放按钮样式 ===== */
        .play-btn {
            margin-top: 30px;
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.2);
            backdrop-filter: blur(10px);
            border: 2px solid rgba(255, 255, 255, 0.4);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.3s ease;
            color: white;
            font-size: 24px;
            outline: none;
        }
        
        .play-btn:hover {
            background: rgba(255, 255, 255, 0.35);
            transform: scale(1.1);
            border-color: rgba(255, 255, 255, 0.7);
        }
        
        .play-btn:active {
            transform: scale(0.95);
        }
        
        /* 播放/暂停图标 */
        .play-btn::before {
            content: "▶";
            margin-left: 4px; /* 微调三角形位置 */
        }
        
        .play-btn.playing::before {
            content: "⏸";
            margin-left: 0;
        }
        
        /* 隐藏 audio 元素 */
        audio {
            display: none;
        }