html {
    font-size: 70%;
    box-sizing: border-box;
}

body{
    background-image: url(../images/aiCalc_img.png);
}

*::before,
*::after {
    margin:0;
    padding: 0;
    box-sizing: inherit;
}

.calculator{
    background-color: rgb(227, 226, 247);
    border: 1.2px solid darkslategrey;
    border-radius: 7px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 500px;
}

.calculator-screen {
width: 92%;
font-size: 5rem;
height: 80px;
border: none;
background-color: black;
color: white;
text-align: right;
padding-right: 20px;
padding-left: 20px;
border-radius: 7px 7px 0px 0px;
}

button{
    height: 70px;
    border-radius: 3px;
    border: 1px solid darkslategray;
    background-color: transparent;
    font-size: 3.2rem;
    color: black;
    background-image: linear-gradient(to button, transparent, transparent 50%, rgb(0, 0, 0, 0.6));
    text-shadow: 0 1px rgba(255, 255, 255, .4);
    /*Each value below is separated by coma ',' after the rgba values*/
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .5),
    inset 0 1px 0 0 rgba(255, 255, 255, .5),
    inset 0 -1px 0 0 rgba(255, 255, 255, .5),
    0 1px 0 0 rgba(255, 255, 255, .05);
}

button:rover{
    background-color: #e1e1e1;
}

.operator{
    color: black;
    background-image: linear-gradient(to bottom, transparent, transparent -50% rgba(0, 0, 0, 0.5));
    background-color: lightgray;
}

.all-clear{
    background-color: red;
    border-color: darkslategray;
    color: #ffffff;
}

.equal-sign{
    background-color: blue;
    border-color: darkslategray;
    color: #fff;
    height: 100%;
    grid-area: 2/4/6/5;
}

.equal-sign:hover{
    background-color: darkblue;
}

.calculator-keys{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 20px;
    padding: 20px;
}