[Vuejs]-How to change body style from vue.obserable store value

Some thing might be missing in your second block but i assume that you successfully can use true or false value as isSideBarOpen. All you need to do is to use style binding(you can also use class binding but you need to define specific class for padding right) Here is what you need:

<div id="app" :style="(isSideBarOpen) ? 'padding-right: 10px;' : ''">
/* code */
</div>