Text in embedded Google Sheets Pie Chart gets crusty on however

On my website: www.jesperb.com (desktop) I have an embedded Pie chart from Google Sheets to show my portfolio.
But when I hover over it (it's interactive) the text changes and gets all crusty. I have no idea why - does someone have an idea?

Also, the reason it's currently only showing on desktop is because I don't know how to scale a code block... It seems to ignore setting a max width for example. I would love to have it visible on mobile as well, but right now it simply becomes too wide, so I put in some custom CSS to hide it on smaller screens.