I'm puzzled by the issue with the footer on my webpage, especially the strange line of black opacity that shouldn't be there. I'm unsure why this is occurring. You can view the problematic page here. I've also created a codepen with the HTML and CSS here. As a newbie, I'm struggling to figure this out, so any assistance would be greatly appreciated.
<footer>
<img id="imgfoot" src="img/aperture_labs_bot.png" alt="aperture laboratories footer line" ><!-- width= "2400" height= "68" -->
<div class="center1"><h3>Aperture science, we do what we must because we can.</h3>
</div>
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<div class="center1"><h4> Questions or Comments? Contact us!</h4>
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<a href="tel:425-889-9642">
<div id="left">
<div class="overlay1">
<span class="text">Phone: 425-889-9642</span> </div></div></a>
<a href="https://goo.gl/maps/Ln7Pshy1htM2">
<div id="center">
<div class="overlay2">
<span class="text">P.O. Box 1688 Bellevue, WA 98009</span> </div></div></a>
<a href="mailto:Aperture.Science.gmail.com?subject=The-Cake-is-not-a-lie!">
<div id="right">
<div class="overlay1">
<span class="text">Aperture.Science.gmail.com</span> </div></div></a>
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<div class="center1"><h4> Do you want to apply to be a test subject? Do you also like free cake and $60? Apply now! <a div id="redacted" href="WebForm.html"><span style="background-color: #000000">REDACTED.</span></div></h4></div>
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