update css articles

Change-Id: I91d62496e0cb523ccd7cccb5464489cee1c0c18d
add SASS IE functions

Change-Id: I1f2616cbf4dfbc97aa661856468c1b3ea4627b0a
add article about sass architecture

Change-Id: I49cd441c2c30e31e3717935cca63cfd2e1aa6487
add article about Sass code quality

Change-Id: Ibd2d15312b5d4400d0d83433b54918bdc366e6fa
clean up js files

Change-Id: I5056e82760c05fd8c2c3271e46997afce2a1a286