@dfjama:
1. You can add the following css in “Appearance => Theme Options => Custom CSS” box.
#site-generator { background-color: #000; }
2. You can add the following css in “Appearance => Theme Options => Custom CSS” box to hide the slider text.
#main-slider .entry-container { display: none; }
Note: I see that you have replaces the images inside ‘catch-kathmandu’ core theme directory. You should not edit any core theme files as these changes will be reverted back to original when you update or upgrade your theme. To change the images in the Slider in Catch Kathmandu Free theme, you need to create post from “Add New => Posts” and add featured image in your post. Then you need to go to “Appearance => Theme Options => Featured Slider => Featured Post Slider Options” and add in the post ID. You will be able to see the post ID in your all “Posts” section.
Fore more check our theme instructions page at http://catchthemes.com/theme-instructions/catch-kathmandu/ and check in “How to add Featured Image in Post/Page?” and “Featured Slider” section.
3. Which text you want to justify. In web justify text is not so common and we let it align left.
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