Adjusting iFrame scale and position?

Hey all!  love how helpful this forum is - thank you for any and all help on my little issue;
I've inserted an iFrame code snippet for a 3d model viewer feature, but I want the feature to be borderless, centered on-page and adjusted to the width of the screen or at least much larger than its appearing on my test page:

https://www.lovemachinesurfboards.com/backdoor

I've adjusted the code below with larger width and height, and tried changing the border style color, but it doesn't appear to affect the page at all.  
the source code I am using is:

 

<iframe src= https://www.shape3d.com/Viewers/Viewer3D.aspx?Board=9399&BackgroundOnlyInFullScreen=true”style=“border-style:none; overflow:hidden; width:1000px;height:1000px;” webkitallowfullscreen mozallowfullscreen allowfullscreen ></iframe>

 

Add to Design > Custom CSS

iframe[src*="shape3d"] {
    width: 100% !important;
    height: 500px;
}

thank you!! worked like a charm!

You'll want to replace the smart quotes in your code with dumb quotes ( " ).