@import url('https://fonts.googleapis.com/css?family=Poppins:300,400,500,600,700,800,900&display=swap');
*
{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}
body
{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #fff;
}
.calculator
{
    position: relative;
    display: grid;
}
.calculator .value
{
    grid-column: span 4;
    height: 100px;
    text-align: right;
    border: 1px solid #7a7a7a;
    outline: none;
    padding: 10px;
    font-size: 18px;
    position: relative;
    border: none;
    margin: 15px 0 20px;
    background: transparent;
    outline: none;
    box-sizing: border-box;
    border-radius: 8px;
    color: #333;
    box-shadow: -4px -4px 10px rgba(255,255,255,1),
                inset 4px 4px 10px rgba(0,0,0,0.07),
                inset -4px -4px 10px rgba(255,255,255,1),
                4px 4px 10px rgba(0,0,0,0.07);
    
}
.calculator span
{
    display: grid;
    width: 60px;
    height: 60px;
    color: #fff;
    background: #21282b73;
    place-items: center;
    border: 1px solid #fff;
    border-radius: 8px;
    box-shadow: inset 4px 4px 10px rgba(0, 0, 0, 0.062),
    4px 4px 10px rgba(0, 0, 0, 0.199);

}
.calculator span:active
{
    background: #7a7a7a;
    color: #111;
}
.calculator span.clear
{
    grid-column: span 2;
    width: 120px;
    background: #7a7a7a;
}
.calculator span.plus
{
    grid-row: span 2;
    height: 120px;
}
.calculator span.equal
{
    background: #7a7a7a;
}