I am more convient to go to blogger community from my dashboard.
So this article tells you how to get rid from navbar completely.
I found a total solution from an article. Unlike the old approach that call navbar-iframe, like a magic, the code tells blogger engine not to display the navbar. This step doesn't follow html protocol at all.
The article says that this code cause some features not working, such as you will not see edit icon in articles, but I don't see any of these problems.
So let's do it, just follow the below simple steps.
1. Login to your blogger account.
2. Open Template menu from the left bar in Blogger dashboard.
3. You have to download the design template, click Backup/Restore button and save to your local drive. The file is saved in xml format.
4. Open the xml file using your favorite editor.
5. Find <body> tag in the template code. Put below code just above it.
6. Save the file. Then back to the Blogger dashboard, upload the file, click Backup/Restore button to upload the file. Now your blog is clean without navbar like what you see in this blog.
Note: Step 3 may or may not be required. I tried directly using the option to edit html from browser but I got an error when saving the template. So this step is my trick to edit the template locally. This also helps me edit the xml file a lot easier.