make and merge a pull request from fiona

## `@todo`
* [ ] merge https://github.com/fionataeyang/smartcontract.codes

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**New feature update:**
themeSwitch.js
searchGuide.js
footer.js
footerSticker.js
unfocusElement.js
add new icons (plugin, hamburger menu, twitter, gitter, github)
adjust header
add viewport into html head for device browsing