body {
    text-align: center;
    font-family: 'Press Start 2P', cursive;
    background-color: #1a1a2e;
    color: #e0e0e0;
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    /* Prevent scrollbars from button scaling */
}

@import url('https://fonts.googleapis.com/css2?family=Press+Start+2P&display=swap');

h2 {
    color: #00f0ff;
    margin-bottom: 15px;
    font-size: 2.5em;
    text-shadow: 0 0 10px rgba(0, 240, 255, 0.6);
}

h3 {
    font-size: 1.2em;
    color: #a0a0a0;
    margin-top: 0;
    margin-bottom: 25px;
    text-shadow: 0 0 5px rgba(160, 160, 160, 0.3);
}

.high-score {
    font-size: 1em;
    color: #00ff88;
    margin-bottom: 20px;
    text-shadow: 0 0 5px rgba(0, 255, 136, 0.4);
}

.btn-contain {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-gap: 25px;
    margin-top: 30px;
    padding: 20px;
    background-color: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.btn {
    height: 130px;
    width: 130px;
    border-radius: 50%;
    /* Make them perfectly round */
    border: 8px solid #333;
    cursor: pointer;
    transition: all 0.2s ease-in-out, box-shadow 0.3s ease;
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 0;
    /* Hide numbers */
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0) 70%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.btn:hover::before {
    opacity: 1;
}

.btn:active {
    transform: scale(0.95);
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.5);
}

.red {
    background-color: #e74c3c;
    border-color: #c0392b;
}

.yellow {
    background-color: #f1c40f;
    border-color: #f39c12;
}

.green {
    background-color: #2ecc71;
    border-color: #27ae60;
}

.blue {
    background-color: #3498db;
    border-color: #2980b9;
}

.flash {
    background-color: #ffffff !important;
    border-color: #ffffff !important;
    box-shadow: 0 0 25px rgba(255, 255, 255, 0.8) !important;
}

.userflash {
    background-color: #000000 !important;
    border-color: #000000 !important;
    box-shadow: 0 0 25px rgba(0, 0, 0, 0.8) !important;
}

.gameover {
    background-color: #c0392b !important;
    color: #fff !important;
    animation: gameover-flash 0.5s infinite alternate;
}

.start-button {
    padding: 15px 30px;
    font-size: 1em;
    font-family: 'Press Start 2P', cursive;
    color: #00f0ff;
    background-color: transparent;
    border: 3px solid #00f0ff;
    border-radius: 10px;
    cursor: pointer;
    margin-top: 10px;
    transition: all 0.3s ease;
    text-shadow: 0 0 5px rgba(0, 240, 255, 0.6);
    box-shadow: 0 0 15px rgba(0, 240, 255, 0.2);
}

.start-button:hover {
    background-color: #00f0ff;
    color: #1a1a2e;
    box-shadow: 0 0 25px rgba(0, 240, 255, 0.8);
}

.start-button:active {
    transform: scale(0.95);
    background-color: #00c8d4;
    box-shadow: 0 0 15px rgba(0, 200, 212, 0.6);
}

@keyframes gameover-flash {
    from {
        background-color: #c0392b;
    }

    to {
        background-color: #e74c3c;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    h2 {
        font-size: 2em;
    }

    h3 {
        font-size: 1em;
    }

    .btn {
        height: 140px;
        width: 140px;
        border-width: 6px;
    }

    .btn-contain {
        grid-gap: 15px;
        padding: 15px;
    }
}

@media (max-width: 480px) {
    h2 {
        font-size: 1.8em;
    }

    h3 {
        font-size: 0.9em;
    }

    .btn {
        height: 110px;
        width: 110px;
        border-width: 5px;
    }

    .btn-contain {
        grid-gap: 10px;
        padding: 10px;
    }
}