How do I change the font color of the mode-line to make it more visible?
What you call the bottom bar is the "mode line". I recommend reading the first fews sections of the manual, especially this one to know the names of the various screen elements (this is not difficult at all, but not straightforward for newcomers.) The graphical attributes of text in emacs are grouped in "faces". As mentionned in the manual:
By default, the mode line of nonselected windows is displayed in a different face, called mode-line-inactive. Only the selected window is displayed in the mode-line face. This helps show which window is selected.
So the answer is to customize the face
mode-line. To do so, you can look at the face definition by typing
M-x describe-face RET mode-line RET and from that select the "customize this font" link (or you can directly use
M-x customize-face). Customization is rather straightforward, but if you want to know more, see the manual section on customizing faces.