[Vuejs]-Vue not applying styles when inserting with v-for directive

Customized checkboxes are not merely styled with CSS, they are proxied: the real checkbox widget is hidden and other elements are inserted and styled in their place.

As such, there must be some call that examines the HTML and does the widget replacement. You need that to happen to each element that gets inserted. You do that by writing a wrapper component. Typically, in its mounted hook, you would apply the initialization of the widget to this.$el (or something inside it).