How do I create a crossword style grid / large number of divs or others?

so I need to have a grid on the screen in web browser / mobile so that each grid item saves 1 letter.

A bit like a crossword puzzle, but using most of the screen. Doing this with a div seems to be difficult as the performance is not very great to support creating a screen with 1000 sections as you can fit a lot of text on the screen with so many divs.

Any suggestions as a way to achieve this text / grid layout?