* {
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
    margin: 0;
    font-weight: normal;
}

body{
    background: linear-gradient(to right, #00AAFF, #00FF6C);

}

.calculator-grid {
    display: grid;
    justify-content: center;
    align-content: center;
    min-height: 100vh;
    grid-template-columns: repeat(4 , 100px );
    grid-template-rows: minmax(100px, auto) repeat(5,100px);

}

.calculator-grid > button {
    cursor: pointer;
    font-size: 2rem;
    border: 1px solid white;
    outline: none;
    background-color: rgba(255,255,255, 0.75);
}
.calculator-grid > button:hover{
    background-color: rgba(255,255,255, 0.9);
}
.span-two {
    grid-column: span 2;
}
.output {
    grid-column: 1 / -1;
    background-color: rgba(0,0,0, 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 {
    color: rgba(255,255,255, 0.75);
    font-size: 1.5rem;
}
.output .current {
    color: rgba(255,255,255, 1);
    font-size: 2rem;
}