style.css

@import url('https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.1.0/css/all.min.css');

:root {
    background-color: rgb(29, 26, 26);
}

* {
    box-sizing:border-box;
    margin: 0;
    padding: 0;
    font-size: 62.5%;
    font-family: 'Nova Square', cursive;
}

h1 {
    font-size: 5.4rem;
    color: #fff;
    margin-bottom: 5rem;
}

h2 {
    font-size: 4.2rem;
    margin-bottom: 4rem;
}

.container {
    width: 100vw;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    max-width: 80rem;
    margin: 0auto;
    padding: 2rem;
}

.flex-column {
    display: flex;
    flex-direction: column;
}

flex-center {
    justify-content: center;
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.text-center {
    text-align: center;
}

.hidden {
    display: none;
}

.btn {
    font-size: 2.4rem;
    padding: 2rem 0;
    width: 30rem;
    text-align: center;
    margin-bottom: 1rem;
    text-decoration: none;
    color: rgb(28, 26, 26);
    background: linear-gradient(90deg, rgb(76, 15, 244) 0%, rgb(38, 28, 238) 100%);
    border-radius: 4px;
}

.btn:hover {
    cursor: pointer;
    box-shadow: 0 0.4rem 1.4rem 0 rgba(8, 114, 244, 0.6);
    transition: transform 150ms;
    transform: scale(1.30);
}

.btn[disabled]:hover {
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}

#highscore-btn {
    background: linear-gradient(90deg, rgb(255, 247, 9) 0%, rgb(240,
    221, 9) 100%);
}

#highscore-btn:hover {
    box-shadow: 0 0.4rem 1.4rem 0 rgba(255, 255, 0, 0.5)
}

.fa-crown {
    font-size: 2.5rem;
    margin-left: 1rem;
}

/* End pg CSS*/
.end-form-container {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    max-width: 30rem;
}

input {
    margin-bottom: 1rem;
    width: 20rem;
    padding: 1.5rem;
    font-size: 1.8rem;
    border: none;
    box-shadow: 0 0.1rem 1.4rem 0 rgba(86, 185, 235, 0.5);
}

input::placeholder {
    color: #aaa;
}

#username {
    margin-bottom: 3rem;
    width: 100%;
    outline: none;
}