Gap between borders with Grid

I help on another server where a newbie is learning position too early IMO (I agree with a learning order like https://web.dev/learn/css), so I wanted to push them towards Flexbox & CSS Grid early instead. They were making the pictured, but when I try to reproduce it using CSS Grid, I get a small gap between the borders and I can't figure out why: https://jsfiddle.net/Matthais/3m9r4c1f/
3 Replies
Matthais
Matthais17mo ago
This gap on the right and bottom:
MarkBoots
MarkBoots17mo ago
it's a render thing (you are zoomed in a lot and borders will not overlap). use outline instead of border (or just a background-color) and you'll see it's okay.
Matthais
Matthais17mo ago
You were kind of right - I was zoomed out by 10% (90%) without realising. My bad