style.css

body{
    background-image: linear-gradient( 132.6deg,  rgba(71,139,214,1) 23.3%, rgba(37,216,211,1) 84.7% );
    display: flex;
    justify-content: center;
}

#display{
    width: 100%;
    height: 30vh;
    background-color:rgb(0, 0, 0);
    border-radius: 40px;
    border: none;
    font-size: 60px;
    color: beige;  
                        
}
input{
    text-align: end;
}
#calculator{
    width:28%;
    height:97vh;
    background-color: rgb(0, 0, 0);
    border-radius: 40px;
    border: 3px solid black;
    box-shadow: 10px 10px 10px rgb(63, 63, 63);
}
#content{
    padding: 10px;
    display:block;
}
#keys{
    padding-left: 20px;
    padding-top: 5px; 
    padding-bottom: 10px; 
    display: grid;
    grid-template-columns: repeat(4,1fr); 
    row-gap: 10px; 
    
}
.button0{
    grid-column: 1 / span 2;
    border-radius: 40px;
    text-align: start;
    padding-left: 30px;
    width: 156px;
}
button{
    width:64px;
    height:64px;
    border-radius: 32px;
    border:none;
    font-size:x-large;
    font-weight: bold;
    color: white;
    background-color: rgb(75, 75, 75);
    
}
button:hover{
    cursor: pointer;
    border: 2px solid rgb(0, 0, 0);
}
.fade{
    color: black;
    background-color: rgb(189, 189, 189);
}
.orange{
    background-color: orange;
}
@media screen and (max-width: 600px) {
    #calculator {
        width: 90%;
        max-width: none;
    }
    #keys {
        padding-left: 5px;
    }
    button {
        font-size: large;
    }
}