Do not set colors in a WYSIWYG content editor. Text color is configured by site styling and other tags (layouts, modules, etc). Please contact For Purpose if you want us to modify colors of specific module/layouts across the board.
Do not use header tags in a WYSIWYG content editor to increase text size - only use it to properly split up content sections with headers.
Page headers must occur in hierarchical order. Most pages, basic content layouts, or modules will have an h1 tag and potentially h2 tags already - so best to check the individual page.
Page headers must be followed by content - do not follow headers with other headers.