This CSS only affects the header, not the whole column, which is where the problem is. I think you can fix the table layout with a combination of the following changes:

* make the first column a combined _Title & location_ with the flag and city on a second line and the title on the first line
* make the dates two separate _Start_ end _End_ columns
* change the last heading to just _Materials_ to save horizontal space, since it's obvious from the values that this these are languages.