title: How to calculate the `font-size` from base size to viewports?
body: <p>In my app, I am trying to set the <code>font-size</code> from the <code>mock-up</code>. but i am not getting correct result.</p>
  
  <p>my mock-up width size is : <code>1280px</code> so, I resets the css for <code>10px</code> using the browser default <code>font-size</code>(16).  now my <code>1280px</code> view port has <code>62.5%</code> and i got <code>10px</code> exactly.</p>
  
  <p>but how to calculate the font-size from this base size to other view ports?</p>
  
  <p>i tried for view port size of <code>1600px</code> like this:</p>
  
  <p><code>1600/1280 = 1.25.. so 65.5/100 = 6.5 + 1.25 = 63.5%</code> - but i am not getting correct result here in <code>1600px</code> view port.</p>
  
  <p>What is the correct way to calculate from the base site?</p>
  
  <p>I am using <code>em</code> measurement here.</p>
  
  <p>Thanks in Advance.</p>