* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            font-family: 'Arial Black', Arial, sans-serif;
            transition: background 0.5s ease;
        }

        body.day {
            background: linear-gradient(to bottom, #4ec0ca 0%, #a7dbd8 100%);
        }

        body.night {
            background: linear-gradient(to bottom, #0f2027 0%, #203a43 50%, #2c5364 100%);
        }

        .game-container {
            position: relative;
            width: 400px;
            height: 600px;
            overflow: hidden;
            border: 4px solid #8b4513;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.3);
        }

        #gameCanvas {
            display: block;
            width: 100%;
            height: 100%;
        }

        .ui-overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
        }

        .score {
            position: absolute;
            top: 20px;
            left: 50%;
            transform: translateX(-50%);
            font-size: 48px;
            color: white;
            text-shadow: 3px 3px 0 #000, -1px -1px 0 #000, 1px -1px 0 #000, -1px 1px 0 #000;
            pointer-events: none;
            z-index: 10;
        }

        .mode-toggle {
            position: absolute;
            top: 20px;
            right: 20px;
            background: rgba(255, 255, 255, 0.9);
            border: 3px solid #333;
            border-radius: 50%;
            width: 50px;
            height: 50px;
            cursor: pointer;
            pointer-events: all;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 24px;
            transition: transform 0.2s, background 0.3s;
            z-index: 10;
        }

        .mode-toggle:hover {
            transform: scale(1.1);
        }

        .mode-toggle:active {
            transform: scale(0.95);
        }

        .start-screen, .game-over-screen {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            background: rgba(0, 0, 0, 0.7);
            pointer-events: all;
            z-index: 5;
        }

        .start-screen h1, .game-over-screen h1 {
            font-size: 48px;
            color: #ffd700;
            text-shadow: 4px 4px 0 #ff4444;
            margin-bottom: 20px;
            animation: bounce 1s infinite;
        }

        .start-screen p, .game-over-screen p {
            font-size: 20px;
            color: white;
            margin-bottom: 30px;
            text-align: center;
            padding: 0 20px;
        }

        .btn {
            padding: 15px 40px;
            font-size: 24px;
            font-weight: bold;
            color: white;
            background: linear-gradient(to bottom, #ff6b6b 0%, #ff4444 100%);
            border: 4px solid #fff;
            border-radius: 50px;
            cursor: pointer;
            pointer-events: all;
            text-transform: uppercase;
            box-shadow: 0 5px 0 #cc0000;
            transition: transform 0.1s;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 7px 0 #cc0000;
        }

        .btn:active {
            transform: translateY(2px);
            box-shadow: 0 3px 0 #cc0000;
        }

        .hidden {
            display: none !important;
        }

        .high-score {
            font-size: 18px;
            color: #ffd700;
            margin-top: 10px;
        }

        @keyframes bounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-10px); }
        }