Email newsletters render weirdly in Thunderbird because our media-queries are being ignored

[finnbar]

All newsletters sent to Thunderbird don't render correctly on large screens due to Thunderbird now ignoring media queries: https://litmus.com/community/discussions/8621-thunderbird-and-responsive-emails-media-queries

There's a workaround in the article that would have to be applied. But there's no rush - I expect Thunderbird isn't really used much to read our newsletters, and it only means that the images are a bit larger than expected.