* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
/* Fix display
add java script
*/
body{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-image: url(lfi.jpg);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    background-attachment: fixed;
}
button{
    width: 100px;
    height: 100px;
    border-radius: 50px;
    background-color: hsl(271, 76%, 33%);
    color: white;
    font-size: 2.2rem;
    font-weight: bold;
    cursor: pointer;
}
#keys{
    display: grid;
    grid-template-columns:repeat(4, 1fr);
    gap: 7px;
    padding: 25px;
    
}
#calculator{
/* From https://css.glass */
background: rgba(83, 25, 25, 0.2);
border-radius: 18px;
box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
backdrop-filter: blur(2.8px);
-webkit-backdrop-filter: blur(2.8px);
border: 6px solid hsla(0, 0%, 0%, 0.3);
overflow: hidden;
max-width: 500px;
}
#display{
    width: 100%;
    box-sizing: border-box;
    padding: 25px;
    text-align: right;
    background-color: hsl(0, 0%, 80%);
    color: hsl(0, 0%, 0%);
    border-color: black;
    font-size: 5rem;
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
}
button:hover{
    background-color: hsl(271, 76%, 53%);
}
button:active{
    background-color: hsl(271, 76%, 93%);
}
.operator-btn{
    background-color: hsl(240, 100%, 50%);
}
.operator-btn:hover{
    background-color: hsl(240, 100%, 70%);
}
.operator-btn:active{
    background-color: hsl(240, 100%, 90%);
}
#equal-btn{
   background-color: hsl(39, 100%, 50%);
    grid-column: span 4;   
    width: auto;
    border-radius: 20px;
}
#equal-btn:hover{
    background-color: hsl(39, 100%, 70%);
}
#equal-btn:active{
    background-color: hsl(39, 100%, 90%);
}