*{ margin:0; padding:0; } 
body{ background: #1c1c25; font-family: 'Poppins', sans-serif; }
button{ outline:none; }
.main{
    width: 300px;
    height: 560px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    border-radius: 10px;
    background: #1c1c25;
    box-shadow: 0 15px 35px rgba(0,0,0,0.5);   
    border-width: 0.1px;
    border-style: solid;
    border-color: rgba(255, 255, 255, 0.425);
    z-index: 40;
    color: #fff;
}
.main:after {
    content: "";
    position: absolute;
    top: 0%;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        120deg, rgba(#fff, 22%), 
        rgba(#fff, 2%));
    border-radius: 15px;
    backdrop-filter: blur(50px);
}
.circle1, .circle2, .circle3,
.circle4, .circle5{
    position: absolute;
    width: 170px;
    height: 170px;
    border-radius: 50%;
}
.circle1{
    top: -8%;
    right: -20%;
    background: linear-gradient(#f00, #f0f);
}
.circle2{
    top: 0%;
    left: 0%;
    background: linear-gradient(#6dceb6, #04996c);
}
.circle3{
    bottom: 0%;
    right: 0%;
    background: linear-gradient(rgb(221, 219, 83), rgb(24, 231, 76));
}
.circle4{
    bottom: -6%;
    left: -20%;
    background: linear-gradient(#0098f0, #0457d3);
}
.circle5{
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: linear-gradient(rgb(255, 84, 184), rgb(37, 255, 255));
}
.heading{
    height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    padding: 0 28px;
    z-index: 1;
}
.heading span{
    font-size: 16px;
}
.heading span:nth-child(1),
.heading span:nth-child(3){
    cursor: pointer;
    font-size: 12px;
}
.heading span:nth-child(2){
    margin-top: 5px;
}
.heading span:nth-child(2)::after{
    width: 115px;
    content: '';
    position: absolute;
    bottom: -5%;
    border-bottom: 3px solid rgba(255, 255, 255, 0.014);
    z-index: 100;
    left: 30%;
    border-radius: 10px;
}
.result{
    height: 30%;
    position: relative;
    border-top: 1px solid rgba(255,255,255,.3);
    border-bottom: 1px solid rgba(255,255,255,.1);
    z-index: 1;
}
.upper-value{
    position: absolute;
    text-align: right;
    bottom: 30%;
    right: 5%;
    font-size: 32px;
}
.lower-value{
    position: absolute;
    text-align: right;
    bottom: 2%;
    right: 5%;
    font-size: 32px;
}
#keyboard{
    padding: 30px 20px;
    
}
.operator,
.number{
    width: 45px;
    height: 45px;
    border-radius: 50%;
    background: rgba(255,255,255,.3);
    border: none;
    font-size: 18px;
    cursor: pointer;
    z-index: 1;
}
.group{
    width: 185px;
    float: left;
}
.top-section{
    height: auto;
    position: relative;
    display: flex;
    justify-content: space-around;
    margin-top: 3px;
    margin-bottom: 6px;
    border-radius: 30px;
    margin-left: 10.4px;
}
.top-section button{
    margin-top: 2px;
}
.middle-section{
    height: auto;
    position: relative;
    display: flex;
    justify-content: space-between;
    flex-direction: column;
    align-items: center;
    border-radius: 30px;
    margin-top: 2px;
    margin-left: 10.4px;
    z-index: 1;
}
.middle-section button{
    margin: 3px 5px;
    color: #fff;
    font-weight: 600;
}
.side-section{
    float: left;
    height: 254px;
    position: relative;
    display: flex;
    flex-direction: column;
    padding: 5px 4px;
    border-radius: 30px;
    justify-content: space-between;
    margin-left: 10px;
}
.side-section button{
    margin-left: 2px;
}
.equal{
    background: rgba(255,255,255,.3);
    border: none;
}
.operator{
    color: #fff;
}

.fas{
    cursor: pointer;
}