Front End UI

[liumcse]

TODOS:

• [x] Enhance the requirements section.

• [ ] Write an about page (postponed to next feature)

• [x] Function the side bar (changed to horizontal menu).

• [x] Disable selection for headers.

• [x] Write the rate/comment interface.

• [ ] Add a help page (postponed to next feature)

[liumcse]

Two pages are almost done: homepage and course detail page. Will add more pages later.