style.css

@import url('https://fonts.googleapis.com/css2?family=Quicksand:wght@300;400;500&display=swap');
*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Quicksand', sans-serif;
}
body{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #091921;
    
}
body::before{
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(#e91e63,#ffc107);
    clip-path: circle(22% at 30% 20%);
}
body::after{
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(#ffffff,#da00ff);
    clip-path: circle(20% at 70% 90%); 
}
.container{
    position: relative;
    background: rgba(255,255,255,0.05);
    border-radius: 6px;
    overflow: hidden;
    z-index: 10;
    backdrop-filter: blur(15px);
    border-top: 1px solid rgba(255,255,255,0.2);
    border-left: 1px solid rgba(255,255,255,0.2);
    box-shadow: 5px 5px 30px rgba(0,0,0,0.2);
    /* flex: 1 1 50rem; */
}
.container .calculator{
    position: relative;
    display: grid;
    /* flex: 1 1 50rem; */
}
.container .calculator .value{
    grid-column: span 4;
    height: 140px;
    width: 300px;
    text-align: right;
    border: none;
    outline: none;
    padding: 10px;
    font-size: 30px;
    background: transparent;
    color: #fff;
    
    border-top: 1px solid rgba(255,255,255,0.05);
    border-left: 1px solid rgba(255,255,255,0.05);

}
.container .calculator span {
    display: grid;
    place-items: center;
    height: 75px;
    width: 75px;
    color: #fff;
    font-weight: 400;
    cursor: pointer;
    font-size: 20px;
    user-select: none;
    border-top: 1px solid rgba(255,255,255,0.05);
    border-left: 1px solid rgba(255,255,255,0.05);
    transition: .5s;
}

.container .calculator span:hover {
    transition: 0s;
    background:rgba(255,255,255,0.05) ;
}
.container .calculator span:active{
    background: #14ff47;
    color:#192f00;
    font-size: 24px;
    font-weight: 500;
}
.container .calculator .clear{
    grid-column: span 2;
    width: 150px;
    background: rgba(255,255,255,0.05);
}
.container .calculator .plus{
    grid-row: span 2;
    height: 150px;
}
.container .calculator .equal{
    background: rgba(255,255,255,0.05);
}