changed body font-family to helvetica

Also added the style tag to each element for future use.
changed font colors for headers and lists
finished index_inline.html; changed font colors again, changed font size
added index_embedded.html
edited header font color, and changed paragraph font size
added link properties
added pseudo-element for paragraph's first letter, and changed the ordered list's color and font size
finished; added a class for orange paragraphs and an id for a grey paragraph
added index_linked.html
removed style tag css and added link tag to head
finished; added main.css and pasted style elements from index_embedded doc