title: How to make a pure css triangle which has a white center
body: <p>I want to create an upward and downward facing arrow with css like the following: <a href="http://apps.eky.hk/css-triangle-generator/" rel="noreferrer">http://apps.eky.hk/css-triangle-generator/</a></p>
  
  <p>However, instead of a solid color, I want to set it up so the inside is white and there is just a border around the triangle. (So the triangle would be multi-colored, one color on the inside and a different colored border).</p>
  
  <p>Is this possible, and if so, how can it be done?</p>