Grid builds a CSS grid the visual way — set the number of columns and rows, the gaps, and how items line up, watch it update live, then copy the CSS straight into your stylesheet. Use the custom track boxes for things like 200px 1fr 1fr. Nothing is uploaded.
Paste onto your container element.
The preview fills the grid with numbered items so you can see the tracks; your real content replaces them. fr units share the leftover space, px fixes a track, and auto sizes to content. Custom track strings take priority over the column/row counts. Everything runs on your device.