Change a columns fill or border color based on current date

I have a simple spreadsheet. A column for a persons name and 31 columns, one for each day of the month. I want to apply conditional formatting, either fill color or border color, to the date column of the current date when the spreadsheet is opened. Thanx

Apply a conditional formatting rule like:

=day(today())=B$1

Where B$1 is your header containing the day number.

See attachment for example

that's what I'm looking for. was missing the =B$1 part. Thank you.