First of all, I wish you a very happy new year, a year that brings a lot of happy moments to your life and makes you prosperous in all respects.
After seeing the demo above, you might have already guessed the trick. Anyways, the trick is that you should apply a width of 1em and text-transform set to uppercase to the element you want to make the text of vertical something like this:
There is one more step. The text that you want to appear vertically should be separated by an space or more specifically each letter should be separated by an space character, that is exactly where a width of 1em plays. Here is an example:
H E L L O
Now you might have seen the vertical text often on blogs posts (or other places) where the date information is shown vertically. I have also created a demo page you can check out:
So that is all there is to creating vertical text with CSS. I hope you came to know about something useful.