* {
            padding: 0;
            margin: 0;
        }

        button, input, optgroup, select, textarea {
            color: black;
        }

        html, body {
            background: url("/static/bubble/images/bg-sheet0-2c64d4bc88aa0da0c20375eedba8c21b.png");
            background-size: 300%;
            color: #fff;
            overflow: hidden;
            touch-action: none;
            -ms-touch-action: none;
        }

        canvas {
            touch-action-delay: none;
            touch-action: none;
            -ms-touch-action: none;
        }

        /* 开始界面 */
        .game-start {
            position: absolute;
            width: 100%;
            height: 100%;
            background-color: rgba(125, 243, 255, 0.95);
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            z-index: 100;
            text-align: center;
            padding: 20px;
        }

        .start-screen-title {
            font-family: "Comic Sans MS", cursive, sans-serif;
            font-size: 52px;
            font-weight: bold;
            color: #1e5a8c;
            text-shadow: 0 3px 10px rgba(30, 90, 140, 0.2);
            margin-bottom: 20px;
            animation: float 3s ease-in-out infinite;
        }

        .start-screen-subtitle {
            font-size: 18px;
            margin-bottom: 40px;
            color: #2c4257;
            max-width: 600px;
            line-height: 1.6;
        }

        .mode-selection {
            background-color: rgba(255, 255, 255, 0.85);
            border-radius: 15px;
            padding: 20px 30px;
            margin-bottom: 30px;
            border: 2px dashed #3a91cb;
            box-shadow: 0 5px 15px rgba(58, 145, 203, 0.15);
        }

        .mode-selection-title {
            font-size: 22px;
            margin-bottom: 15px;
            color: #1e5a8c;
            font-weight: 600;
        }

        .mode-btn {
            background-color: rgba(58, 145, 203, 0.15);
            color: #1e5a8c;
            border: 2px solid #3a91cb;
            padding: 10px 20px;
            font-size: 18px;
            margin: 5px;
            border-radius: 25px;
            cursor: pointer;
            transition: all 0.3s;
            min-width: 100px;
            font-weight: 600;
        }

        .mode-btn:hover, .mode-btn.selected {
            background-color: #3a91cb;
            color: white;
            transform: scale(1.05);
            box-shadow: 0 0 15px rgba(58, 145, 203, 0.4);
        }

        #start-button {
            background: linear-gradient(45deg, #3a91cb, #1e5a8c);
            color: white;
            border: none;
            padding: 15px 50px;
            font-size: 24px;
            font-weight: 600;
            border-radius: 30px;
            margin-top: 20px;
            cursor: pointer;
            transition: all 0.3s;
            box-shadow: 0 5px 15px rgba(30, 90, 140, 0.3);
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }

        #start-button:hover {
            transform: translateY(-3px) scale(1.03);
            box-shadow: 0 8px 25px rgba(30, 90, 140, 0.4);
        }

        .key-hint {
            display: inline-block;
            background-color: white;
            border: 2px solid #b8d4e9;
            border-radius: 5px;
            padding: 3px 10px;
            margin: 0 5px;
            font-family: monospace;
            color: #1e5a8c;
            font-weight: 600;
        }

        @keyframes float {
            0% {
                transform: translateY(0) scale(1);
            }
            50% {
                transform: translateY(-20px) scale(1.05);
            }
            100% {
                transform: translateY(0) scale(1);
            }
        }

        /* 响应式设计 */
        @media (max-width: 768px) {
            .start-screen-title {
                font-size: 36px;
            }

            .mode-btn {
                font-size: 16px;
                padding: 8px 15px;
                min-width: 80px;
            }

            #start-button {
                font-size: 20px;
                padding: 12px 40px;
            }
        }