style.css

body{
    display: flex;
    align-items: center;
    justify-content: center;  
}

.outer_part{
    border-radius: 10px;
    padding-top: 20px;
    padding-bottom: 20px;
    padding-left: 20px;
    padding-right: 20px;
    background-color: rgb(227, 227, 227);
    height: 350;
    width: 200px;
    text-align: center;
    
    
}

#input{
    border-radius: 10px;
    border: none;
    float: right;
    
    font-size: 20px;
    height: 40px;
    width: 200px;
}

#input:focus{
    outline: none;
}

#input[placeholder]{
    padding-left: 10px;
}

#logo{
    padding-left: -30px;
    font-size: 20px;
    color: rgb(66, 66, 66);
    font-family: sans-serif;
}

.number{
    border: none;
    height: 40px;
    width: 40px;
    font-size: 17px;
    background-color: white;
}

.operater{
    border: none;
    height: 40px;
    width: 40px;
    font-size: 17px;
    background-color: white;
}

.equal{
    border: none;
    height: 40px;
    width: 40px;
    font-size: 17px;
    color: white;
    background-color: rgb(7, 223, 104);
}


.clear{
    border: none;
    height: 40px;
    width: 40px;
    font-size: 17px;
    color: white;
    background-color: rgb(223, 7, 7);
}

.number:hover, .operater:hover{
    border-radius: 10px;
    border: 1px solid black;
}