I'm using the debut theme. When i try to set text as italics, it appears in both italic and bold. I used F12 to inspect what could be making it bold but cant seem to find anything. I also tried setting the font-weight to light but that didn't work either. Ill attach screen shots of example text. Note, when i did set the font weight as light, it appeared in the back end as light but on the live site as bold.
Please share your store URL and reference site URL.
So that I can check and let you know the exact solution for this.