Global style variables

Just create admin/src/styles/shared.styl file and define your stuff here. Note that this file does not suppress the original vue-admin-front/src/styles/shared.styl so you do not need to import it manually. Both files will be included in every component style or a standalone stylus file.

Do not add any styles or other code producing side effects here! shared.styl is only for shared variables and mixins.