style.css

*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body,html{
    height: 100%;
    width: 100%;
}

.main{
    height: 100%;
    width: 100%;
    position: relative;
    background-color: #3498db;
}
.center{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    text-align: center;
}
h1{
    text-transform: capitalize;
    margin-bottom: 30px;
    text-shadow: 1px 2px 3px #2980b9;
    font-size: 2.1rem;
    color: #ecf0f1;
}
h2{
    text-align: center;
}
textarea{
    background-color: #444;
    box-shadow: 0 0 1px rgba(0,0,0,0,2);
    border-radius: 10px 10px 0 0;
    border: 10px solid rgb(69, 63, 63);
    color: white;
}
#btn{
    padding: 10px 20px;
    border-radius: 20px;
    border: 5px solid #2980b9;
    background: #ecf0f1;
    font-size: 1rem;
}