Responsiveness for navigation header

[fmondragon]

The nav could use more styles for breakpoints.

Issues:

1. The "Try This? Real Skills, Real Growth" text wraps awkwardly.
2. The Submit Challenge nav item does too.

Solutions:

1. add a fixed width on the logo and tagline's container leaving the navigation items' container flexible until a certain point.
2. add white-space:nowrap or similar to the nav items. or change the margin on the buttons in the navigation. could be flexbox so that the browser figures out the spacing.

[UTKRISHT-ICS52]

this issue has been already resolved .