Minor bugs to fix on the website

[BenjMy]

Index.html

• [x] Non uniform font-familly
• [x] Missing tick case on the map legend
• [x] Table width too short (need to see details collumn)
• [ ] Download button not working
• [ ] Non uniform date format

Contribution details.html

• [ ] Metadata empty field attributes not removed with Notebooks/Datasets contribution
• [ ] Licence type cover pics not set (below pic) (see #14 )

[BenjMy]

Great job thanks a lot @sagitta1618 !