Can't Fix Slider Movement Distance When Browser Zoomed

My client is upset that the image slider on his homepage does not slide the correct distance when the browser zoom level is not at 100%. You are able to see half of one slide and half of another slide at the stop points. I have looked for CSS styles that might prevent zooming on these elements and tried to fix it with JS, but no luck -- and I'm not certain it's even possible to fix.

The slider can be found here: http://petropower.com/

The issue i开发者_Python百科s reproducible in Chrome and IE, so I assume FF as well. Anyone know a trick that might work? Many thanks.

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In situations like this, it's worth explaining to the client that many/most big websites have layout issues when the zoom level is adjusted. We do what we can with the technology we have.