* fix(v1): Fix page title render issue when referred by search result
When Algolia DocSearch query finds a match for a page's title, it attempts to generate
a permalink. Because the page title element (`h1`) does not have an `id`, Algolia
generates uses the `id` from closes parent element. Because of this, the page title
scrolls to a position that is slightly overlayed by the fixed top navigation bar.
This fix sets an `id` for the page title so that the search result is able to generate
a more accurate permalink.
* Adjust css for handling post title to be on the top when referred by an anchor
The post title can sometimes be referred by an anchor using the "id" of that element.
In that case the title will be automatically be the first element within the viewport.
Since we have a header fixed at the top of the view port, the title becomes hidden or
not visible. That's why some css adjustments are needed so that if any user ends up
with a link to a page that is referring to the post title (i.e. auto generated anchor
link by algolia DocSearch).
The css code uses pseudo element `:before` to make the adjustments. Details on this
can be found in the following article:
https://css-tricks.com/hash-tag-links-padding/
* Adjust CSS so that different selectors are on separate lines
The approach here is to first strip the HTML from the heading's content, then rendered it with markdown to get the HTML content for the TOC entry, then to strip the HTML from the rendered content again, as to get the text for the TOC entry's link.
Adds an additional dependency of striptags (MIT licensed)
Example TOC Entry, given the heading of:
```markdown
```
```javascript
{
hashLink: 'foo',
rawContent: '<a name="foo"></a> _Foo_',
content: '<em>Foo</em>',
children: []
}
```
Previously this TOC entry would be:
```javascript
{
hashLink: 'a-name-foo-a-_foo_',
rawContent: '<a name="foo"></a> _Foo_',
content: '<a name="foo"></a> <em>Foo</em>',
children: []
}
```
closes issue #1703
The warning is produced on `cssnano` call. See below:
> Without `from` option PostCSS could generate wrong source map and will not find Browserslist config. Set it to CSS file path or to `undefined` to prevent this warning.
Reproduction:
```shell
mkdir work
cd work
npx docusaurus-init
cd website
yarn install
yarn run build
```
Environments:
- Node: 12.6.0
- Yarn: 1.17.3
Currently the items in table of contents are highlighted as bold based on items being
viewed on the screen or as the user scrolls up/down on a page. Added the `primaryColor`
of the site's configuration to make the current section being viewed standout more
in the table of content.
closes#1608
