ionic-framework/e2e/button/outline/main.html

<ion-toolbar>
  <ion-title>Outline Buttons</ion-title>
</ion-toolbar>

<ion-content padding style="text-align:center" class="outer-content">

  <p>
    <button outline>Default</button>
    <button outline class="activated">Default.activated</button>
  </p>

  <p>
    <button outline primary>Primary</button>
    <button outline primary class="activated">Primary.activated</button>
  </p>

  <p>
    <button outline secondary>Secondary</button>
    <button outline secondary class="activated">Secondary.activated</button>
  </p>

  <p>
    <button outline danger>Danger</button>
    <button outline danger class="activated">Danger.activated</button>
  </p>

  <p>
    <button outline light>Light</button>
    <button outline light class="activated">Light.activated</button>
  </p>

  <p>
    <button outline dark>Dark</button>
    <button outline dark class="activated">Dark.activated</button>
  </p>

  <p>
    <button outline block>button[outline][block]</button>
  </p>

  <p>
    <button outline block class="activated">[outline][block].activated</button>
  </p>

  <p>
    <button outline block secondary>button[outline][block][secondary]</button>
  </p>

  <p>
    <button outline block secondary class="activated">[outline][block][secondary].activated</button>
  </p>

</ion-content>