`<a>` tags in headings are set to apply the style of `%anchor` in `module.scss` and `common.scss`.
Therefore, if I put a link in a heading, the link will have the same style as the anchor,
which means that the font size becomes smaller and the link will not be displayed unless I hover the mouse over it.
My suggestion is to set an `anchor` class for the `<a>` tag of the anchor and apply style settings to the `anchor` class, not to the `a` tag.