Minor amends to the first paragraph of css-recommendations.md (SharePoint#832)

Changes for readability.

Author: mcjim

docs/spfx/css-recommendations.md

@@ -1,6 +1,6 @@
 # Recommendations for working with CSS in SharePoint Framework solutions
 
-When building SharePoint Framework solutions, you can use CSS to define how your customization should look like and behave. This article describes how you can make the best use of the capabilities provided with the SharePoint Framework and build your CSS styles in a robust way.
+When building SharePoint Framework solutions, you can use CSS to define how your customizations should look and behave. This article describes how you can make the best use of the capabilities provided by the SharePoint Framework and build your CSS styles in a robust way.
 
 ## SharePoint Framework customizations are part of the page
 
@@ -220,4 +220,4 @@ By making your customizations look and behave like the standard functionality of
 
 ## Use theme colors
 
-SharePoint allows users to choose the theme color for their sites. In your SharePoint Framework customizations you should follow the theme selected by the users to make your customization look like an integral part of the site rather than unnecessarily stand out. Because the theme is set by users in their site, you cannot tell upfront which colors your customization should use, but SharePoint Framework can dynamically load the currently active color scheme automatically for you. For more information about this capability read the [guide on using theme colors](./use-theme-colors-in-your-customizations).
+SharePoint allows users to choose the theme color for their sites. In your SharePoint Framework customizations you should follow the theme selected by the users to make your customization look like an integral part of the site rather than unnecessarily stand out. Because the theme is set by users in their site, you cannot tell upfront which colors your customization should use, but SharePoint Framework can dynamically load the currently active color scheme automatically for you. For more information about this capability read the [guide on using theme colors](./use-theme-colors-in-your-customizations).