semi-design/packages/semi-ui/datePicker/_story/RenderFullDate/index.scss

.components-datepicker-demo-day-today {
    color: #0077fa;
    background: rgba(46, 50, 56, 0.09);
}

.components-datepicker-demo-day-inrange {
    background: #eaf5ff;
}

.components-datepicker-demo-day-hover {
    background: rgba(46, 50, 56, 0.09);
}

.components-datepicker-demo-day-selected,
.components-datepicker-demo-day-selected-start,
.components-datepicker-demo-day-selected-end {
    color: #fff;
    background: #0077fa;
}

.components-datepicker-demo-day-disabled {
    background: rgba(46, 50, 56, 0.04);
}