Flash plugin plugin wordpress fix

I am using the "flashcard slider" plugin for my wordpress blog and I find it shows an extra 1 pixel width after each name of the flash card. I found a fix, but I don't know why when I load after editing the corresponding file that defines the style, it doesn't make the change.

The slider I'm trying to change is at: http://www.digitaalcursussen.nl/gratis/grieks-belangrijkste-woorden/

The problem is explained below:

Now, to fix this, all I have to do is change the value of the style tags from the current style:

style="position: absolute; top: 0px; left: 0px; display: block; z-index: 3; opacity: 1; padding-right: 25px;"

      

        
        
        
      

    

to

style="position: absolute; top: 0px; left: 0.5px; display: block; z-index: 3; opacity: 1; padding-right: 25px;"

      

        
        
        
      

    

You can check it on the website. In the plugin php file, the style defining code has been edited as follows:

$html .='<div class="flashcard_front flashcard_side" style="position: absolute; top: 0px; left: 0.5px;  display: block; z-index: 3; opacity: 1; padding-right:25px">
                    '.$title_up_html
                    .$slider_content_front
                    .$toback_control.
                '</div>

      

        
        
        
      

    

but i dont know why after loading the php file the left: 0.5px attribute returns to the left: 0px

What is the reason? I've spent several hours on this, so please help me.

As far as write permissions and all confirmations are concerned, yes, I can edit some other attributes like padding-right: 35 px, I tried this and it changed on the website and after upload, but I don't know why the left one: 0px doesn't change at all?