***$theme-default:** using '.theme-default-content' to replace '.content' in 404 layout ([#1646](https://github.com/vuejs/vuepress/issues/1646)) ([f0d1344](https://github.com/vuejs/vuepress/commit/f0d1344))
### Features
***$theme-default:** enhance the styles of `blockquote` ([9d20d5f](https://github.com/vuejs/vuepress/commit/9d20d5f))