List indenting not working on first item

Dear Mr., Mrs.,

Today I updated a website using the ‘Twenty Seventeen’ theme. Unfortunately I’m having a bit difficulties with creating ‘nicely’ looking list. In the provided example you can see that the first list item is not indented at all, while for all following items I’m able to adjust the indent.
Can you take a look at that and suggest a workaround to overcome my encountered issue?

Thanks in advance!

The page I need help with: [log in to see the link]