Login Form HTML & CSS Desain Kedua: https://www.duniacara.com/cara-membuat-login-form-dengan-html-dan-css-desain-2/

style.css

* {
    padding: 0;
    margin: 0;
    font-family: sans-serif;
    box-sizing: border-box;
}

a {
    text-decoration: none;
}

body {
    background: #86c8c6;
}

div.konten {
    background: #fff;
    width: 380px;
    margin: 150px auto 50px;
    min-height: 400px;
    border-radius: 5px;
}

div.atas {
    height: 200px;
    padding: 10px 50px 0;
}

div.grup {
    margin: 10px 0;
    position: relative;
}

div.grup.input i.fa {
    position: absolute;
    left: 10px;
    top: 7px;
    color: #bfbfbf;
    font-size: 14px
}

div.grup.social {
    margin: 20px 0 30px;
}

div.grup.tengah {
    text-align: center;
}

div.input-grup {
    display: inline-block;
    font-size: 13px;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    height: 30px;
    border: 2px solid #9ee1d8;
    border-radius: 5px;
    padding: 0 10px 0 28px;
    font-size: 12px;
}

div.bawah {
    background: #f9f9f9;
    height: 225px;
    padding: 20px 20px 0;
}

div.bawah.tengah {
    text-align: center;
}

div.bawah p {
    font-size: 12px;
    color: #454545;
}

h2.judul {
    text-align: center;
}

h2.judul.sedang {
    font-size: 18px;
    margin-bottom: 16px;
}

h2.judul.kecil {
    font-size: 14px;
    margin-bottom: 5px;
}

a.a {
    font-size: 13px;
    color: #d44837;
}

a.a:hover {
    text-decoration: underline;
}

a.a.kanan {
    float: right;
}

input[type="submit"] {
    background: #2dc2bc;
    color: #fff;
    padding: 3px 16px;
    border: none;
    font-weight: bold;
    border-radius: 2px;
}

div.kaki {
    border-top: 2px solid #dcdcdc;
    padding-top: 16px;
}

a.tombol {
    width: 32.4%;
    background: #000;
    display: inline-block;
    color: #fff;
    font-size: 13px;
}

a.tombol.social {
    line-height: 30px;
    border-radius: 2px;
}

a.tombol.social i.fa {
    float: left;
    display: inline-block;
    padding: 8px 0;
    width: 30px;
}

a.tombol.social i.fa-twitter {
    background: #23a1dc;
}

a.tombol.social i.fa-facebook {
    background: #34518d;
}

a.tombol.social i.fa-google-plus {
    background: #c84533;
}

a.tombol.daftar {
    background: #2dc2bc;
    color: #fff;
    padding: 4px 10px;
    border: none;
    font-weight: bold;
    border-radius: 2px;
    width: 88px;
    margin: 14px 0;
}

a.tombol.daftar:hover,
input[type="submit"]:hover {
    background: #2cbab5;
    cursor: pointer;
}

a.tombol.social.twitter {
    background: #1aade1;
}

a.tombol.social.facebook {
    background: #3957a0;
}

a.tombol.social.googleplus {
    background: #d44837;
}

a.tombol.social.twitter:hover {
    background: #23a1dc;
}

a.tombol.social.facebook:hover {
    background: #34518d;
}

a.tombol.social.googleplus:hover {
    background: #c84533;
}