indexCSS.css

*{
    margin: 0;
    padding: 0;
    font-family: sans-serif;
    box-sizing: border-box;
}
.container{
    width: 100%;
    min-height: 100vh;
    background: linear-gradient(135deg, #4203a9,#90bafc);
    color: #fff;
    padding: 10px;
}
.calculator{
    width: 100%;
    max-width: 550px;
    margin-left: 150px;
    margin-top: 150px;
}
.calculator h1 span{
    color: #ffff76;
}
.calculator h1{
    font-size: 40px;
}
.input-box{
    margin: 40px 0;
    padding: 35px;
    border-radius: 10px;
    background: rgba(255,255,255,0.3);
    display: flex;
    align-items: center;
}
.input-box input{
    flex: 1;
    margin-right: 20px;
    padding: 14px 20px;
    outline: 0;
    border: 0;
    font-size: 18px;
    border-radius: 5px;
    position: relative;
}
.input-box button{
    background: #ffff76;
    outline: 0;
    border: 0;
    padding: 15px 30px;
    border-radius: 5px;
    font-weight: 400;
    color: #333;
    cursor: pointer;
}
/* this will make complete input clickable */
.input-box input::-webkit-calendar-picker-indicator{
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    height: auto;
    width: auto;
    position: absolute;
    background-position: calc(100% - 10px);
    background-size: 30px;
    cursor: pointer;
}

#result{
    font-size: 20px;
}
#result span{
    color: #ffff76;
}