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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    overflow: hidden;
    background: #0a0a0a;
}

#game-container {
    width: 100vw;
    height: 100vh;
    position: relative;
}

#ui-overlay {
    position: absolute;
    top: 20px;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    padding: 0 30px;
    z-index: 100;
    pointer-events: none;
}

#score, #high-score {
    color: #00ffff;
    font-size: 24px;
    font-weight: bold;
    text-shadow: 0 0 10px #00ffff, 0 0 20px #00ffff;
    letter-spacing: 2px;
}

#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, 0.85);
    z-index: 200;
    backdrop-filter: blur(5px);
}

#start-screen h1, #game-over-screen h1 {
    font-size: 64px;
    color: #00ffff;
    text-shadow: 0 0 20px #00ffff, 0 0 40px #00ffff, 0 0 60px #00ffff;
    margin-bottom: 30px;
    letter-spacing: 5px;
    animation: glow 2s ease-in-out infinite alternate;
}

@keyframes glow {
    from {
        text-shadow: 0 0 20px #00ffff, 0 0 40px #00ffff, 0 0 60px #00ffff;
    }
    to {
        text-shadow: 0 0 30px #00ffff, 0 0 60px #00ffff, 0 0 90px #00ffff, 0 0 120px #00ffff;
    }
}

#start-screen p, #game-over-screen p {
    color: #ffffff;
    font-size: 18px;
    margin: 10px 0;
    text-shadow: 0 0 5px rgba(255, 255, 255, 0.5);
}

#final-score {
    font-size: 32px !important;
    color: #ffff00 !important;
    text-shadow: 0 0 15px #ffff00, 0 0 30px #ffff00;
    margin: 20px 0 !important;
}

button {
    margin-top: 30px;
    padding: 15px 50px;
    font-size: 20px;
    font-weight: bold;
    color: #000;
    background: linear-gradient(135deg, #00ffff, #0088ff);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 3px;
    transition: all 0.3s ease;
    box-shadow: 0 0 20px rgba(0, 255, 255, 0.5);
}

button:hover {
    transform: scale(1.1);
    box-shadow: 0 0 30px rgba(0, 255, 255, 0.8), 0 0 60px rgba(0, 255, 255, 0.5);
}

button:active {
    transform: scale(0.95);
}

/* Speed indicator */
#speed-indicator {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    color: #ff00ff;
    font-size: 16px;
    font-weight: bold;
    text-shadow: 0 0 10px #ff00ff;
    z-index: 100;
    pointer-events: none;
}

/* Mobile controls */
#mobile-controls {
    display: none;
    position: absolute;
    bottom: 20px;
    left: 0;
    right: 0;
    justify-content: space-between;
    padding: 0 20px;
    z-index: 150;
}

.mobile-btn {
    width: 80px;
    height: 80px;
    background: rgba(0, 255, 255, 0.3);
    border: 2px solid #00ffff;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 30px;
    color: #00ffff;
    user-select: none;
    -webkit-user-select: none;
    touch-action: manipulation;
}

@media (max-width: 768px) {
    #start-screen h1, #game-over-screen h1 {
        font-size: 36px;
    }

    #score, #high-score {
        font-size: 18px;
    }

    #mobile-controls {
        display: flex;
    }
}