style1.css

*{
    margin: 0;
    padding: 0;
    text-decoration: none;
    font-family: 'ZCOOL KuaiLe', cursive;
    font-family: 'Montserrat', sans-serif;
    box-sizing: border-box;
}

body{
    min-height: 100vh;
    background-image: linear-gradient(120deg,#3498db,#8e44ad);
}

.login-form{
    width: 360px;
    background: #f1f1f1;
    height: 580px;
    padding: 80px 40px;
    border-radius: 10px;
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%,-50%);
}

.login-form h1{
    text-align: center;
    margin-bottom: 60px;
}

.txtb{
    border-bottom: 2px solid #adadad;
    position: relative;
    margin: 30px 0;
}

.txtb input{
    font-size: 15px;
    color: #333;
    border: none;
    width: 100%;
    outline: none;
    background: none;
    padding: 0 5px;
    height: 40px;
}

.txtb span::before{
    content: attr(data-placeholder);
    position: absolute;
    top: 50%;
    left: 5px;
    color: #adadad;
    transform: translateY(-50%);
    z-index: -1;
    transition: .5s;
}

.txtb span::after{
    content: '';
    position: absolute;
    width: 0%;
    height: 2px;
    background: linear-gradient(120deg,#3498db,#8e44ad);
    transition: .5s;
    right: 70%;
    top: 100%;
    left: 0%;
}

.focus + span::before{
    top: -5px;
}

.focus + span::after{
    width: 100%;
}

.logbtn{
    display: block;
    width: 100%;
    height: 50px;
    border: none;
    background: linear-gradient(120deg,#3498db,#8e44ad);
    background-size: 200%;
    color: #fff;
    outline: none;
    cursor: pointer;
    transition: .5s;
}

.logbtn:hover{
    background-position: right;
}

.bottom-text{
    margin-top: 60px;
    text-align: center;
    font-size: 13px;
}