* Translate challenge subtitles and example challenge text to Spanish
* Corrected errors in syntax and punctuation
* Multiple corrections of it/s to its plus other grammar corrections
* Correction and added paragraph to CSS Flex article
* Corrected my own typo
* Corrected capitalization, American spellings and typos
Changed 'It' to 'AWS' and added commas at the end of the first paragraph - for better readability.
Capitalised the 'c' in the Certifications hyperlink at the very end.