body {
    text-align: center;
}

.btn {
    height: 200px;
    width: 200px;
    border: 7px solid black;
    border-radius: 20%;
    margin: 2rem;
}

.btn_container {
    display: flex;
    justify-content: center;
}

.red {
    background-color: #dc2828;
}

.green {
    background-color: #0dea28;
}

.yellow {
    background-color: #f7e703;
}

.blue {
    background-color: #03b1f6;
}

.flash {
    background-color: white;
}

#startButton {
    padding: 15px 30px;
    font-size: 1.2rem;
    font-weight: bold;
    color: white;
    background-color: #5bc0de; 
    border: none;
    border-radius: 10px;
    cursor: pointer;
    box-shadow: 0 5px #3a97b2;
    margin-top: 20px;
    transition: background-color 0.2s, box-shadow 0.2s, transform 0.2s;
}

#startButton:hover {
    background-color: #46b8da;
}

#startButton:active {
    background-color: #3a97b2;
    box-shadow: 0 2px #3a97b2;
    transform: translateY(3px);
}

/* Style for when the game is already started (button hidden) */
#startButton.hide {
    display: none;
}

@media (max-width: 37.5rem) { 
    .btn {
        height: 8.5rem;  
        width: 8.5rem;   
        border-width: 0.4rem;   
        margin: 1rem;          
    }
}

@media (max-width: 23rem) { 
    .btn {
        height: 6.5rem;  
        width: 6.5rem;   
        border-width: 0.4rem;   
        margin: 1rem;          
    }
}