random.css

body{
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: aquamarine;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}
.btn{
    padding: 1em;
    position: fixed;
    top: 5px;
    left: 5px;
    border-radius: 50%;
    cursor: pointer;
    background-color: black;
}
h2{
    padding: 0.1em;
    position: fixed;
    top: -15px;
    right: 7px;
    cursor: pointer;
}
h2 a{
    text-decoration: none;
}
.btnchange{
    background-color: white;
}
.change{
    background-color: black;
    color: white;
}
#name{
    font-size: 3rem;
    font-family: Arial, Helvetica, sans-serif;
    font-weight: bold;
    position: absolute;
    top: 50%;
    left: 5%;
}
.container{
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    margin-right: 2%;   
    flex-direction: column;
}
input{
    display: flex;
    flex-direction: column;
    margin-bottom: 10px;
    margin-top: 10px;
}
input[type="submit"],.info,#check{
    position: relative;
    margin-left: 30px;
    font-size: 18px;
    font-weight: 500;
}
label{
    font-size: 18px;
}