style.css

*{
        margin: 0;
        padding: 0;
        font-family: 'Franklin Gothic Medium', 'Arial Narrow', Arial, sans-serif;    
}

body{
    background: rgba(0, 0, 0, 0);
    background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url(linux.JPG);
    height: 100vh;
    background-repeat: no-repeat;
    width: 100%;
    background-size: cover;
    font-family: sans-serif;
    color: white;
    min-height: 100vh;
    padding: 150px 0;
    box-sizing: border-box;
}

.newsletter{
    background: #444f62;
    margin: 0 auto;
    text-align: center;
    max-width: 330px;
    padding: 70px 40px;
    border-radius: 10%;
    color: #fff;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

.newsletter hr{
    width: 70px;
    height: 3px;
   margin: 30px auto;
    border: 0;
    background: rgba(255,255,255,0.5);
}
.newsletter p{
    font-size: 18px;
    line-height: 24px;
    color: rgba(255,255,255,0.8);
    margin-bottom: 30px;
}

.email-box{
    height: 40px;
    display: flex;
    justify-content: center;
}

.email-box i{
    background: #2f3542;
    width: 40px;
    line-height: 40px;
}

.tbox, .btn{
    border: none;
    outline: none;
}

.tbox{
    width: 0px;
    transition: 0.6s;
}

.email-box.email-box:hover > .tbox, .tbox:focus{
    width: 260px;
    padding: 0 10px;
}

.btn{
    background:#2f3542;
    color: rgb(255, 255, 255);
    padding: 0 10px;
    text-transform: uppercase;
    cursor: pointer;
}