Social icons not displaying correctly

Hi, The social icons (for sharing blog articles on social media) do not display correctly. On my blog page, icons are only shown as a coloured circle, without the social media logo in it. When going to a specific blog article, the icons are shown correctly there. I suspect this has something to do with CSS code, but don't know how to fix. PS: I'm using the Jetpack plugin. Brgds, Tomas