Update configuration and usage of font weights

[victorlin]

These are the weights that have been configured to be available for Lato: 300, 400, 700

These are the weights used in styles: 200, 300, 400, 500, 700 (used for bold)

For the weights that are used but not available (200, 500), the browser will use an available weight. What's chosen seems to vary per browser.

Possible solutions

1. ⛔️ Install weights of 200 and 500.
   • These are not available for Lato.
2. Replace usage of 200 with 300, and 500 with 400.

[jameshadfield]

Related commit message

[victorlin]

Updated the issue description to reflect that 700 is used for bold text.