Hi, your design is interesting. Though, there are multiple aspects you should work on.

Know the project

[...] I directly search for valuable project that I think needs logo in Github.

If you searched enough, you would know that the project is a result of a Udacity course for React developers. Thus, it makes me question your statement about the valuable project.

The starting point for the project can be found at https://github.com/udacity/reactnd-project-myreads-starter and a quick search on GitHub will give you an idea that the core of the project is not that unique https://github.com/search?q=myreads

Did you try the app?

Know what you present

You say that you created 3 different designs yet you do not present all of them. Is there a reason why you don't want to share them with the readers? Although they can be found in the GitHub issue, you should focus on your readers and your presentation.

Also, even though Utopian has a given template for the submission, you don't have to write the post as if you do it for Utopian. I miss any enjoyable parts in your post.

Make sure that your images in presentation do not depend on the background

You use a transparent background in majority of your images in the post. In my opinion it is not suitable at all. You rely on the background of the web app the reader uses. However, if they use an app with nightmode or a dark background in general, your images are not readable.

Also, for some reason, you have an image of a book behind the text.

Make sure that your design works in all colours and variations you present

A half of your presentation contains the one-coloured version of your design. Honestly to say, you lost all details you got by using different shades of the colours.

Don't create one coloured version just because it is recommended to do so. Spend more time with it, think about preserving the details using only one colour.

Learn using markdown

It may not be obvious how to highlight text in Steem apps by using markdown. You use headings for highlighting links to other websites and your files. That is a wrong use of headings, which are supposed to structure your text, not highlight simple words.

It would be more appropriate if you wrote some words to each section. Otherwise, making the text bold with **text** should do the work just fine.

The post should be informative but also enjoyable to read.