title: Conditional formatting based on another cell's value
body: <p>I'm using Google Sheets for a daily dashboard.  What I need is to change the background color of cell B5 based on the value of another cell - C5.  If C5 is greater than 80% then the background color is green but if it's below, it will be amber/red.  </p>
  
  <p>Is this available with a Google Sheets function or do I need to insert a script?</p>