batharoy

You definitely should be using a child theme for editing PHP files otherwise all the changes you have made will be overwritten if you update the theme. CSS only edits can get away with a plugin but IMO you should use a child for any customization.
EDIT: At least your learning this before you update the theme 😉

See this thread
http://wordpress.org/support/topic/site-disappeared-please-help?replies=11

You can activate Jetpacks custom css module and add the following code to hide it.

#author-info {
display: none;
}

EDIT: And just for info WordPress.com only handles sites they host, WordPress.org is for self hosted sites.

Try this in your childs css file.

.home #footer-area {
    display: none;
}

You need to use more specific declarations.

#content p {
    font-size: 20px
}

.entry-content p {
    font-size: 20px
}

Link text:

.entry-content a {
color: red;
}

Change color when hover:

.entry-content a:hover {
color: orange;
}

Try this

.logo-container {
height: 150px;
}

That all looks good.
Have you tried activating it when its empty just too see if it shows while viewing page source?