CSS grid framework to construct content by providing commonly used dimensions

| lundi |   9.15 à 11.30   | 
--- | 
| mardi | 9.15 à 11.30 | 14.30 à 17.00 | 
| mercredi | --- | --- | 
| jeudi | 9.15 à 11.30 | 14.30 à 19.00 | 
| vendredi | 9.15 à 11.30 |           --- | 
| samedi | 9.15 à 11.30 | --- | 
| dimanche | --- | --- | 
