docs(toolbar): made it responsive

[yashints]

Addressing issue #276

[codecov-io]

Codecov Report

Merging #306 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #306   +/-   ##
=======================================
  Coverage   90.78%   90.78%           
=======================================
  Files         116      116           
  Lines         445      445           
  Branches        9        9           
=======================================
  Hits          404      404           
  Misses         40       40           
  Partials        1        1

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[yashints]

@JakeWharton this is a small one for the header, FYI