Customizing CSS classes in ASP.NET

There isn't any problem in having color inside your CSS file and also inline on any HTML element, since inline styles will override the color defined on the file.

Imagine your CSS have this:

a#lnkTest { color: #ff0000; }

But you do it on your aspx.vb:

lnkTest.ForeColor = Color.Blue;

Your generated HTML will be:

 <a id="lnkTest" style="color: #0000ff">Bla bla bla</a>

So, the overrided color works without problems. Also, if you want to do it with JavaScript, it works in the same way:

document.getElementById("lnkTest").style.color = "#0000ff";

Use a label control between the <h1> tags and use System.Drawing.Color to apply the color.

You could use a dynamically created css file, i.e. an aspx page that only output css.

<%@ Page Language="C#" %>

h1 {
font-size: 15px;
color: <%= myUsersColor () %>;
}

Use javascript to dynamic change the style of the element.

If you are letting user's pick just their own font color, it's probably easiest to set the Font-Color attribute or set an inline style attribute on the client side. If you did it on the client side, the interface would be snappier (not requiring a postback for a color change), but you would need to save the user's choice somewhere and set it again on postback.

Here's an example of setting the header colors on the client-side:

With jQuery

function setHeaderColor(color) {
    // The color parameters should be of the form '#000000'
    $('h1, h2, h3').css({ color: color });
}

Without jQuery

function setHeaderColor(color) {
    var hdrs = [].concat(document.getElementsByTagName('h1'))
                 .concat(document.getElementsByTagName('h2'))
                 .concat(document.getElementsByTagName('h3')),
        ii, jj;

    for (ii = 0; ii < hdrs.length; ii += 1) {
        for (jj = 0; jj < hdrs[ii].length; jj += 1) {
            hdrs[ii].item(jj).style.color = color;
        }
    }
}