Git Blog - the pelican template disappears in the new deployed blog but exists in localhost
From your Question, what I understood is you are having problem publishing          pelican site on git hub. As per my knowledege below is the way to publish it.I don't know why you got 404 Error though.
Step1: 
    First you need to create repository in github.To create it follow the below steps:
goto github.com--sign In--select git hub pages(Project Pages)--click on '+' to create new repository--give repository name (eg.Blog,Order System)--Check 'public' radio Button--check 'Initialize with READ Me' check box --Click Create Repository
Note:Make sure you use a .gitIgnore file before comminting file
Step2:
Once repository is created you will be on master pages  Branch.
Click on Master--create gh-pages--in branch section update default page as gh-pages branch--click on 'code' in menu bar and delete master branch.
Now you need to download READ Me file on local machine.
Copy READ Me file from gh-Pages branch--go to directory where all the files of you project are stored on you machine--goto command prompt--cd directory name(eg. here we have order systems)--
    order systems>git add  click enter
    order systems>git commit -a initialize  click enter
    order systems>git push origin gh-pages  click enter
It will ask you to enter git credentials. Enter those and sign In.
Go to settings. You can see pages are published.
I hope this is helpful for you.
Sorry if I didn't express the question correctly - I am trying to set up a blog on Git using pelican, but I am new to both of it. 
So I followed some websites and tried to release one page, however when I did make serve on my local drive the blog looks ok on localhost:/8000
But after pushing to Git, the template of the blog disappears and the webpage looks pretty ugly. Also, if I click on "Read more" hyperlink, the page navigates to a 404 error.
Did I miss anything here? Many thanks if anyone could shed some light on!