After looking over the code and running it locally, I see that there is some padding on the left that is causing the issue. It looks like it is a padding on the parallax scene shortcode. I would suggest using the code below. The Content Section and Parallax Scene shortcodes are almost duplicates of each other, the main difference is that the Parallax Scene allows for layers of scenes to be stacked upon one another to make layers. The Content Section gives more options and still has the parallax background options. I just changed [intense_parallax_scene] to [intense_content_section] and made a few changes to the centering. Some of the p tags were unnecessary.
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