title: CSS + adding to height and width of inherited divs
body: <p>For work I have to go through and create a ton of html pages and I find that many of the custom classes I have created can be used repeatedly if I can figure out a way to add to attributes such as height and width.</p>
  
  <p>example:</p>
  
  <pre><code>.custom_class{font-size:1em;height:100px;width:80px;}
  </code></pre>
  
  <p>Lets say I have that class that I use on many of the divs in my pages but I stumble upon a template I am creating where the width needs to be a little bit wider. We will say I need the width to be 95px. Is there a way to add +15px to the current width and not have to go in and find out the current width of 80px and then either make a new class or right inline css to compensate for it?</p>
  
  <pre><code>.custom_class_differnt{font-size:1em;height:100px;width:95px;}
  </code></pre>
  
  <p>I dont want to have to recreate this entirely. I was hoping there was a way to just do maybe style="width:+15px;" or something. (a little in line css is fine, no more than that though)</p>
  
  <p>thanks</p>