Calendar_Template_in_PHP/calendar.css

:root { 
    --bordercolor: rgba(195, 203, 248, 1);
    --backgroundcolor: rgba(195, 203, 248, 0.8);
    --currentcolor:  rgba(0, 255, 0, 0.6); // rgba(255, 255, 0, 0.6); //#FFFF00; //#20FF20;
    --holidaycolor: rgba(255, 0, 0, 0.6);
    --hovercolor: rgba(195, 203, 248, 1);
}
.calendar {
    width: 680px;
    height: 300px;
    margin:0px auto;
    padding:0px;
    font-family: "Segoe UI",Arial,sans-serif;
}

table.heading {
    table-layout: fixed;
    width: 100%;
    height: 60px;
    text-align: center;
    background-color: white;
    border-spacing: 0px;
    border-collapse: collapse;
    border: 0;
}

table.heading td {
    border: 0;
    background-color: var(--backgroundcolor);
}

table.heading a {
    text-decoration: none;
    display: inline-block;
    color: white;
    font-size: 14px;
    padding: 8px 16px;
}

table.calendar {
    width: 100%;
    height: 100%;
    text-align: center;
    background-color: transparent;
    border-spacing: 0px;
    border-collapse: collapse;
}

table.calendar td {
    border: 1px solid var(--bordercolor);
    background-color: var(--backgroundcolor);
}

table.calendar td.current {
    background-color: var(--currentcolor);
}

table.calendar td.holiday {
    background-color: var(--holidaycolor);
}

table.calendar button {
    width: 100%;
    height: 100%;
    text-align: center;
    cursor: pointer;
    border: none;
    background-color: transparent;
}

table.calendar button:hover {
    background-color: var(--hovercolor);
}

table.heading a:hover {
    background-color: var(--hovercolor);
}