body {
    margin: 0px;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background-color: hsl(0, 0%, 95%);
    border: 1px solid black;
    border-collapse: collapse;
    border-radius: 10px;
    font-size: 5px;
    
}

#calculator {
    font-family: monospace;
    background-color: hsl(0, 0%, 15%);
    border-radius: 10px;
    max-width: 400px;
    overflow: hidden;
    width: 600px;
    height: 600px;
}

#calculator #display {
    width: 90%;
    padding: 20px;
    font-size: 3rem;
    text-align: left;
    border: none;
    background-color: hsl(0, 0%, 20%);
    color: white;
}

#keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    padding: 25px;
}

button {
    width: 70px;
    height: 70px;
    border-radius: 50px;
    border: none;
    background-color: hsl(0, 0%, 30%);
    color: white;
    font-size: 3rem;
    font-weight: bold;
}

button:hover {
    background-color: hsl(0, 0%, 40%);
}

button:active {
    background-color: hsl(0, 0%, 50%);
    transition: .5s ease;
    transform: scale(.8);
}

.operator-button {
    background-color: hsl(0, 0%, 30%);
    color: hsl(35, 100%, 50%);
}


.equalizer {
    background-color: hsl(35, 100%, 50%);
}

.equalizer:hover {
    background-color: hsl(35, 100%, 75%);
}

.dei {
    color: #EF0000;
    }}
button {
    width: 70px;
    height: 70px;
    border-radius: 50px;
    border: none;
    background-color: hsl(0, 0%, 30%);
    color: white;
    font-size: 3rem;
    font-weight: bold;
}
button:hover{
    background-color: hsl(0, 0%, 40%);
}
button:active{
    background-color: hsl(0, 0%, 50%);
    transition: .5s ease;
    transform: scale(.8);
}
.operator-button{
    background-color: hsl(0, 0%, 30%);
    color: hsl(35, 100%, 50%);
}


.equalizer{
    background-color: hsl(35, 100%, 50%);
}
.equalizer:hover{
    background-color: hsl(35, 100%, 75%);
}

.dei{
    color: #EF0000;
                          }