Here is the complete CSS:
<style type="text/css">
.ext-color-4,
.ext-ie .ext-color-4-ad,
.ext-opera .ext-color-4-ad {
color: #306da6;
}
.ext-cal-day-col .ext-color-4,
.ext-dd-drag-proxy .ext-color-4,
.ext-color-4-ad,
.ext-color-4-ad .ext-cal-evm,
.ext-color-4 .ext-cal-picker-icon,
.ext-color-4-x dl,
.ext-color-4-x .ext-cal-evb {
background: #306da6;
}
.ext-color-4-x .ext-cal-evb,
.ext-color-4-x dl {
border-color: #29527A;
}
</style>
You can add as many as you like by replacing 4s with 5s, 6s, ...
Aboce CSS replicates colors of Calendar1. Change them with your favorite colors.