Coding Style Guideline

All

indent using two spaces
add Newline to file

Template

one Line between every tag except multiple inline tags

CSS

write everything in Less, not CSS. Otherwise your changes will be overwritten
sort properties alphabetically
do not use browser prefixes, we run the code through autoprefixer
use lowercase for color-codes
only classes, no IDs
max three level deep selectors
do not use !important
remove leading zeros from numbers