style.css

body {
    background-color: #3b3b3b;
    font-size: 20px;
}
.buttons {
    display: flex;
    justify-content: center;
    margin-top: 100px;
    padding-bottom: 50px;
}

.btn {
    color: #fff;
    font-size: 30px;
    background-color: #83df4e;
    border: 1px solid #79ce48;
    border-radius: 10px;
    padding: 10px 30px;
    justify-content: center;
    margin-right: 20px;
    width: 250px;
}

.btn:hover,
.btn:active {
    color: #3b3b3b;
    cursor: pointer;
}

.game-result {
    margin-top: 25px;
    display: grid;
    justify-content: center;
    font-size: 150%;
}

.score {
    display: grid;
    justify-content: center;    
    color: #ccc;
}

.score li {
    list-style: none;
}

.round-result {
    display: grid;
    justify-content: center;
}