*,*::before,*::after {
    box-sizing: border-box;
    font-family: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
    font-weight: 400;
}
body {
    padding: 0%;
    margin: 0%;
    background: url(./assets/bg.png) ;
    background-image: cover;
}
.calculator-grid {
    display: grid;
    justify-content: center;
    align-content: center;
    min-height: 100vh;
    grid-template-columns: repeat(4,100px);
    grid-template-rows: minmax(120px,auto)repeat(5,100px);
}

.calculator-grid > button {
    cursor: pointer;
    font-size: 2rem;
    border: 1px solid whitesmoke;
    outline: none;
    background-color: rgba(255,255,255, .80);
}

.calculator-grid > button:hover {
    background-color: rgba(255,255,255, .99);
}

.span-two {
    grid-column: span 2;
}
.output {
    grid-column: 1 / -1;
    background-color: rgba(43, 38, 38, 0.75);
    display: flex;
    align-items: flex-end ;
    justify-content: space-around;
    flex-direction: column;
    padding: 10px;
    word-wrap: break-word;
    word-break: break-all;
}

.output .previous-operand {
    color: whitesmoke;
    font-size: 1.5rem;
}
.output .current-operand {
    color: white;
    font-size: 2.5rem;
}