title: Custom LESS styles like Bootstrap's "spanX"
body: <p>I want to make a LESS style like so:</p>
  
  
  
  <pre class="lang-css prettyprint-override"><code>.td-middle50
  {
     line-height:50px;
     vertical-align:middle;
  }
  </code></pre>
  
  <p>that I can apply to  to make all the  elements have a line-height of 50px and be vertically aligned.</p>
  
  <p><strong>Where 50 is a variable.</strong></p>
  
  <p>This is as far as I have got:</p>
  
  <pre class="lang-css prettyprint-override"><code>.td-middle(@vheight){
      line-height:(@vheight);
      vertical-align:middle;
  }
  </code></pre>
  
  <p>But this:
  A) Doesn't even work
  B) I would have to apply to each td instead of the tr</p>