style.css

body{
    background-color: #f4f4ed;

}
h1{
    text-align: center;
    margin-top: 40px;
    color: #1a53ff;
}
.container{
    background:#f2f2f2;
    border-radius: 1px;
    width: 426px;
    margin: auto;
    padding: 0px 10px 18px 20px;
    margin-top: 4%;
    box-shadow: 0 0 10px rgba(171,186,190);
}

#entry{
    padding: 40px 0px 40px 7px;
    background:#f2f2f2;
    text-align: right;
    direction: ltr;
    outline: none;
    border: none;
    font-size: 33px;
}
.btn{
    background-color:white;
    border-radius: 1px;
    width: 100px;
    height: 50px;
    border:none;
    outline: none;
    margin-top: 3px;
}

.btnEqual{
    background-color:white;
    width: 308px;
    height: 50px;
    border:none;
    outline: none;
    margin-top: 3px;
}

.btn:hover, .btnEqual:hover{
 background-color: rgba(128, 128, 128, 0.1);
}