Removed 'overlay' styles.

Overlay is not used anymore.
Removed distracting transitions.

style.less:
  Replaced 'all' transitions with 'top' and 'left'.
  Animating every change does not look good.
Added progress-bars as backgrounds to stats.

Added divs with dynamic widths behind the stats
  'seconds-left', 'clicks', and 'score'
  to behave as progress-bars.