style.css

@import url('https://fonts.googleapis.com/css2?family=Source+Sans+Pro:wght@400;700&display=swap');

*, *::before, *::after {
    box-sizing: border-box;
    padding: 0;
    margin: 0;
    font-family: 'Open Sans Pro', sans-serif;
}

:root {
    --bg-default-colour: rgb(22, 22, 22);
    --bg-default-colour-hover: rgb(19, 18, 18);
    --text-colour: white;
    --overlay-colour: rgba(0, 0, 0, 0.6);
}

body {
    min-width: 100vw;
    min-height: 100vh;
    background: var(--bg-default-colour);
    background-image: url('./assets/bg2.png');
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
}

html, body {
    height: 100%;
    width: 100%;
}

.overlay {
    height: 100%;
    width: 100%;
    background: var(--overlay-colour);
}

.center-all {
    height: 100%;
    width: 100%;
    display: grid;
    place-items: center;
}

#infoBox {
    background: var(--text-colour);
    color: var(--bg-default-colour);
    border-radius: 5px;
    min-width: 30rem;
    max-width: 30rem;
    padding: 2rem 1rem 0.8rem;
    display: grid;
}

#infoBox > #avatarBox {
    margin: 0 auto;
    width: 10rem;
    height: 10rem;
    border: non;
    box-shadow: 2px 3px 10px 3px rgba(0, 0, 0, 0.486);
}

#infoBox > #usernameInput {
    margin: 1rem auto 0;
    padding: 1rem;
    text-align: center;
    font-size: 1rem;
    letter-spacing: 0.1rem;
    width: 25rem;
    border: 1px solid black;
    border-radius: 5px;
}

#usernameInput:focus {
    outline: none;
}

#infoBox > button {
    margin: 1rem auto 0;
    padding: 1rem;
    width: 10rem;
    cursor: pointer;
    border: none;
    background: var(--bg-default-colour);
    color: var(--text-colour);
    font-size: 0.9rem;
    letter-spacing: 0.1;
    text-transform: capitalize;
    transition: all 200ms;
}

#infoBox > button:hover {
    background: var(--bg-default-colour-hover);
}

#infoBox > #accountCreationDate {
    margin: 0 auto;
    font-size: 1.5rem;
    font-weight: bold;
}

#infoBox > a {
    margin: 0 auto;
    font-size: 0.75rem;
    text-decoration: none;
    color: var(--text-colour);
    background: rgb(97, 6, 36);
    padding: 12px 15px;
    border-radius: 50px;
}