title: Vuetifyjs how to set custom RGBA color?
body: <p>As <a href="https://v15.vuetifyjs.com/en/framework/theme#customizing" rel="nofollow noreferrer">explained here</a> vuetify colors can be customized as </p>
  
  <pre><code>Vue.use(Vuetify, {
    theme: {
      primary: '#3f51b5',
      secondary: '#b0bec5',
      accent: '#8c9eff',
      error: '#b71c1c'
    }
  })
  </code></pre>
  
  <p><strong>but how can I use a custom RGBA color?</strong></p>