style.css

html body {
    margin: 0;
    padding: 0;
    background-color: rgb(225, 149, 149);
}
.display-items{
    width: 100%;
    height:60px;
    padding: 40px 0;
    background: red;
    border-top-left-radius: 14px;
    border-top-right-radius: 14px;
}
.button-items{
padding: 20px 20px 0px 20px;
}
/* .row-cal{
    width: 280px;
    float: left;
} */
.btn:hover{
    background: coral;
    color: aliceblue;
}
input[type=button]{
    width:60px;
    height:60px;
    float: left;
    padding: 0;
    margin: 5px;
    box-sizing: border-box;
    line-height: 30px;
    background-color: rgb(92, 182 , 205);
    border-radius: 75px;
    border: none;
    font-size: 30px;
    font-weight: 700;
    color: aliceblue;
    cursor: pointer;
}
input [type=text]{
    width:275px;
    height:60px;
    float: left;
    padding: 0;
    margin: 0 25px;
    box-sizing: border-box;
    line-height: 60px;
    background-color: none;
    border:none;
    font-size: 30px;
    font-weight: 700;
    cursor: pointer;
}
.container-cal{
    position: fixed;
    top:50%;
    left:50%;
    border: 20px;
    background-color: blueviolet;
    border-radius: 15px;
    padding-bottom: 18px;
    width: 325px;
    transform: translate(-50%,-50%);
    box-shadow: 0px 0px 10px 0px rgba(123,235,168,175);
}
.cal-bg{

    background:-moz-linear-gradient(90deg, rgba(255, 255, 0, 1) 0%, rgba(0, 188, 212, 1) 50%, rgba(238, 130, 238, 1) 100%); 

    background:-webkit-linear-gradient(90deg, rgba(255, 255, 0, 1) 0%, rgba(0, 188, 212, 1) 50%, rgba(238, 130, 238, 1) 100%);

    background:-o-linear-gradient(90deg, rgba(255, 255, 0, 1) 0%, rgba(0, 188, 212, 1) 50%, rgba(238, 130, 238, 1) 100%);

    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ee82ee', endColorstr='#FFFF00', GradientType=0 );

    background:-ms-linear-gradient(90deg, rgba(255, 255, 0, 1) 0%, rgba(0, 188, 212, 1) 50%, rgba(238, 130, 238, 1) 100%);

    background:linear-gradient(90deg, rgba(255, 255, 0, 1) 0%, rgba(0, 188, 212, 1) 50%, rgba(238, 130, 238, 1) 100%);

}