1. Navbar: added the active class. Now, when browsing a section, the corresponding navbar item gets a darker background color.
2. Learning: added the C Language notes. Imported the Prism syntax highlighting library (.js and .css files) to enable code highlighting.
3. Learning: added a table of contents to the existing C Language HTML structure, using anchor links to index each item to its corresponding content.
4. Essays: added the article "We Are Born with the Right to Be Ordinary."
5. Learning: added the Japanese notes. Used Typora's export from .md to .html to preserve layout.