Your comments

Hi Michael,

That's a good question - I'm not really sure since the only digital calendar I use is hebcal!  My input will go only as far as to point out that there should be one corresponding color/theme for a complete chol hamoed day, and another color/theme for a day where a yom tov begins whether that's within chol hamoed or at the start of the chag.

My reasoning here being that the whole point of a digital calendar is to block off time as either work or personal time(or vacation days) and since erev chag is treated differently from a complete day off like chol hamoed (especially in Israel as one is legitimate gov't day off vs chol hamoed which is not).