custom field? how to make the field name appear in bold?

my page is https://www.postgraduatesinsport.com/?page_id=36

i would like to make the custom field name/heading appear in bold on the page.

eg on the url above the ‘Country : UK’ listing of unis is not in bold.

how do i make the word ‘Country :’ appear in bold
am happy for the country to be normal eg ‘UK’ not in bold

wher eon the css or in what other file would this need Country : adding?

thanks!