style.css

@import url('https://fonts.googleapis.com/css2?family=Quicksand:wght@300;500;700&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: #0B1126;
}
body::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(#4DC98D, #a8f7d1, #9df7cb);
    clip-path: circle(22% at 30% 20%);
}
body::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(#ffa400, #ffad15, #fab534);
    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, 0.02);
    border-left: 1px solid rgba(255, 255, 255, 0.02);
    box-shadow: 5px 5px 30px rgba(0,0,0,0.2);
}
.container .calculadora
{
    position: relative;
    display: grid;
}
.container .calculadora .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-bottom: 1px solid rgba(255, 255, 255, 0.05);
    border-right: 1px solid rgba(255, 255, 255, 0.05);
}
.container .calculadora span 
{
    display: grid;
    place-items: center;
    width: 75px;
    height: 75px;
    color: #fff;
    font-weight: 400;
    cursor: pointer;
    font-size: 20px;
    user-select: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    border-right: 1px solid rgba(255, 255, 255, 0.05);
    transition: 0.5s;
}
.container .calculadora span:hover
{
    transition: 0%;
    background: rgba(255, 255, 255, 0.05);
}
.container .calculadora span:active
{
    background: #14ff47;
    color: #192f00;
    font-size: 24px;
    font-weight: 500;
}
.container .calculadora .clear
{
    grid-column: span 2;
    width: 150px;
    background: rgba(255, 255, 255, 0.05);
}
.container .calculadora .plus
{
    grid-row: span 2;
    height: 150px;
}
.equal
{
    background: rgba(255, 255, 255, 0.05);
}