Trying to change font style for list but no luck

Utter newbie, still learning-by-doing (and reading), but a bit stuck.
This is so basic you are likely rolling your eyes.

I’ve been going along quite well, but now rather stuck.
I am trying to change the font style (if that is the right term!) of a sidebar for the Whitespace theme.

I added:

<?php wp_list_pages(‘exclude=2,13&sort_column=menu_order&title_li=’); ?>

to the l_sidebar.php file so i have a nice non-bulleted list in the sidebar, which is great!
Now I try to change the color and simply have no luck.
I have figured out how to change the Stylesheet so the Pages won’t appear underlined when I hover, so I know I’m in the right spot.
But I try changing the color to a nice grey #999999 (I’m trying to match the color/style in the header), but nothing changes…still the blue/green color (and same font and size)
Here is the area I figure I need to change:

#l_sidebar ul {
list-style: none;
margin: 0px;
padding: 0px 0px 10px 0px;
}

#l_sidebar ul li {
padding: 0px 0px 3px 0px;
margin: 0px;
}

#l_sidebar ul li a, #l_sidebar ul li a:visited {
color: #017F8D;
text-decoration: none;
margin: 0px;
padding: 0px;
}

#l_sidebar ul li a:hover {
color: #017F8D;
text-decoration: underline;
}

But when I change these colors, no change…

I’m trying to mimic the Page links in the header, which I think are styled using this section of the Stylesheet:
#headerright ul li a, #headerright ul li a:visited {
color: #999999;
font-family: Arial, Tahoma, Verdana;
font-size: 14px;
font-weight: normal;
margin: 0px 5px 0px 5px;
padding: 5px 5px 5px 5px;
text-decoration: none;
text-transform: lowercase;
}

Any advice to push me over this mini-hill to understand what is happening would be great. Thank you! -J

As another note…if anyone has advice on a good “starter” book for someone who doesn’t need to know all the code in the word, but just how to make minor edits to Themes, that would be awesome.

Thanks!