Add letter spacing to headings

Signed-off-by: Aniket Pant <me@aniketpant.com>
Update stylesheet

Signed-off-by: Aniket Pant <me@aniketpant.com>
Update layouts

Signed-off-by: Aniket Pant <me@aniketpant.com>
Update pages

Signed-off-by: Aniket Pant <me@aniketpant.com>