IPv4 Address Validator

style.css

@import url('https://fonts.googleapis.com/css?family=Roboto&display=swap');

body, p, h1, h2, li, input {
    font-family: 'Roboto', sans-serif;
}

h2 {
    color: #FFF;
}

button:hover {
    background-color: #000;
    color: white;
}

button {
    background-color: #FFF;
    color: black;
    font-size: 1em;
    border: 2px solid;
}

.container {
    margin: auto;
    padding: 12px;
    width: 40em;
    background: #5882FA;
    border-radius: 23px;
}

ul {
    list-style-type: none;
}

input {
    font-size: 20pt;
}

input:focus, textarea:focus {
    background-color: #E0F8F1;
}

input submit {
    font-size: 12pt;
}

.rq {
    color: #FF0000;
    font-size: 10pt;
}