Styling a sudoku grid

Question

I’ve created a sudoku puzzle creator / solver and need a bit of help with some CSS to style it.

Typically they are styled like this:

.

Some naming I’m us

Answer 1

The following is a slight modification of an example in the table element section in HTML5 CR, illustrating the use of colgroup for grouping columns and tbody for grouping rows. This grouping lets you set different borders around the groups than otherwise around cells.

  
Sudoku of the day
  
  
  
  

   
 
1 
  
3 
6 
  
4 
7 
  
9
   
 
  
2 
  
  
9 
  
  
1 

   
 
7 
  
  
  
  
  
  
  
6
  

   
 
2 
  
4 
  
3 
  
9 
  
8
   
 
  
  
  
  
  
  
  
  

   
 
5 
  
  
9 
  
7 
  
  
1
  

   
 
6 
  
  
  
5 
  
  
  
2
   
 
  
  
  
  
7 
  
  
  

   
 
9 
  
  
8 
  
2 
  
  
5