XXX

I was keen to find a two player game for this tutorial, one where the player plays against the computer.

I thought of Noughts and Crosses (Tic-Tac-Toe) but, as you know, this is a boring game which usually ends in a draw.

Then I came across this neat idea: check it out here.

the grid

You should be able to easily make a 3 x 3 grid by now but how to get rid of the outer border?

My styles.css will show you one way:

styles.css
body {
  background-color: linen;
}
#grid {
  width:54vmin;
  height:54vmin;
  outline:1vmin solid linen;
  outline-offset:-1vmin;
}  
.row {
  display:flex;
}
.square {
  width:18vmin;
  height:18vmin;
  outline:1vmin solid grey;
  outline-offset:-1vmin;
  display:flex;
  justify-content: center;
  align-items: center;
  font-size:15vmin;
  font-family:arial;
  font-weight:bold;
  color:blue;
  background-color: linen;
}