Changing/removing the black lines built in with my theme

Hi,
I am using the premium SimpleMag theme on my site anothergaze.com and have two line-related problems.

1) As you can see, the line on either side of the ‘Latest’ has a white thing around it, which would be find if my background was pure white, but it isn’t. I’m trying to find it in the code. I don’t think it’s an image, but have searched ‘line’ in the style sheet and can’t seem to find it.

2) When I click on the different categories, there are ugly thick black lines under every post, as you can see here : https://www.anothergaze.com/category/in-conversation-with/
Again, how can I completely get rid of these?

I have looked in Theme Options as you can modify the style of the lines here, but neither of these lines are available in the Theme options.

Many thanks