[html2] generated api documentation section headers are white on white on mouseover

Description

The html2 documentation generated by codegen creates navigation section headers ("API SUMMARY", "API METHODS - DEFAULT", etc) which, on mouseover, become white text on a white background.

Swagger-codegen version

3.0.8

Swagger declaration file content or url

N/A - using api.swaggerhub.com

Command line used for generation

N/A - using api.swaggerhub.com

Steps to reproduce

1. Create a valid OAS API in SwaggerHub online
2. Download autogenerated documentation by clicking Export > Documentation > html2
3. Open the resulting index.html file in a browser
4. Note the navigation section headers in the upper left (white text on blue background)
5. Hover over them with the mouse
6. Note the css :hover effect: background turns white, but text remains white and so disappears

Related issues/PRs

None found

Suggest a fix/enhancement

In styles.mustache, after

  .sidenav > li > a:hover {
    background-color: #ffffff;
  }

(around line 304), a class could be added as follows:

  .sidenav > li.nav-header > a:hover {
    color: #4c8eca;
  }

Start in modules/swagger-codegen/src/main/resources/htmlDocs2/styles.mustache around the .sidenav hover rules near line 301. Reproduce the generated html2 documentation in a browser and verify that navigation section headers retain readable text when hovered; confirm the result in the generated index.html.