How to add a class with new styles css to v-dialog, vuetify?

Use "content-class" is the correct answer as mentioned by @mxmass, but if you're trying to add the class in scoped level, it won't work.

Add the style in the beginning, so let's say if you're using nuxt, create a main styling file such as main.scss, then in nuxt.config.js, add that file in css section. That way, your styling class is available when you're using "content-class". Hope this helps.

Passing "class" to the v-dialog won't work.

Use "content-class" instead. In your case

<v-dialog content-class="vdialognew" v-model="mostrarIndicator" persistent>

should work.

Have a look at the v-dialog docs