3) the color links (hyperlink) to red
To change the link color in the Quintus theme to red, add this:
.content a {
color: red;
}
That will change anything that doesn't have a more specific rule for color set, including post titles. If you wanted to change post titles back to black, you could add this:
.entry-title a {
color: black;
}
There are additional, specific color rules set for some links in the Quintus theme which you can identify and update separately if you'd like. You can look for any "color" settings in the original Quintus stylesheet to see which links have specific color settings.