After restart browser, the loaded css with HTML become text

[CnBDM-Su]

Problem

I am using IPython HTML to load css to jupyter lab.
It works well if I keep the browser alive. However, after the kernel is end and the browser get refreshed. There will show the original css text like: "<style> .left-label { width: 30%; } </style>"

Proposed Solution

I can totally understand the css will be lost after end the kernel. But is there any way to remove all this text if the kernel died. It is very ugly, especially when i use ipython.event.register. In each frame, there will be the original css text.