body {
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    height: 95vh;
}

#calculator{
    padding: 10px;
    background: #787878;
    border-radius: 8px;
    box-shadow: rgba(0, 0, 0, 0.1) 15px 16px 7px;
}

#calculator .button:hover{
    opacity: 0.8;
}

#calculator button.button.null {
    visibility: hidden;
}

#calculator .button.number {
    border: 1px solid blue;
    background-color: rgb(238, 238, 255);
}

#calculator .button.operator {
    border: 1px solid green;
    background-color: rgb(238, 255, 238);
}

#calculator .button.clear,
#calculator .button.equal {
    border: 1px solid yellow;
    background-color:rgb(255, 255, 235);
}

/* TOP */
#calculator .top{
    text-align: center;
    position: relative;
}

#calculator .top input{
    border-radius: 10px;
    text-align: right;
    font-size: 20px;
    font-weight: bold;
    pointer-events: none;
    height: 30px;
    width: 95%;
}#calculator .top input#operator{
    color: rgb(231 215 27 / 63%);
    background-color: #303030;
    border: 1px solid;
    position: absolute;
    left: 0px;
    margin-top: 1px;
    width: 20px;
    text-align: center;
}

/* MIDDLE */
#calculator .middle,
#calculator .bottom
{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

#calculator button {
    padding: 15px;
    font-size: 18px;
    cursor: pointer;

    border: none;
    border-radius: 5px;
    background: #eee;
}


/* BOTTOM */