Stylesheet not active

Hi Sakin, so far, I avoided putting code into the "Custom CSS" section of the "Theme Options". I prefered the stylesheet I had created myself in a child of your theme. But now there is something weird going on. I had used a special font for my websites headings, header and menu bar (Noto Sans), which I now decided to not use anymore. So I deleted the code for this from my stylesheet.css in the Childtheme, and also deleted the code I had to put into Appearance-> Theme Options->Tools->Headern and Footer Codes from the header section. But my website is still using this font! I'm using W3 Total Cache, but even though I emptied the cache, the old font is still there. Any ideas what's wrong here?