title: Dynamically change color to lighter or darker by percentage CSS
body: <p>We have a big application on the site and we have a few links which are, let's say blue color like the blue links on this site. Now I want to make some other links, but with lighter color. Obviously I can just do simply by the hex code adding in the CSS file, but our site lets user decide what colors they want for their customized profile/site (like Twitter). </p>
  
  <p>So, my question is: can we reduce the color by percentage?</p>
  
  <p>Let's say the following code is CSS:</p>
  
  <pre><code>a {
    color: blue;
  }
  
  a.lighter {
    color: -50%; // obviously not correct way, but just an idea
  }
  </code></pre>
  
  <p>OR</p>
  
  <pre><code>a.lighter {
    color: blue -50%;  // again not correct, but another example of setting color and then reducing it
  }
  </code></pre>
  
  <p>Is there a way to reduce a color by a percentage?</p>