Use buttons as triggers for actions. Try to avoid the usage of buttons for navigation and use links for that purpose instead.
<button class="a-btn -solid">solid</button>
<button class="a-btn -icon -solid">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -outline">outline</button>
<button class="a-btn -icon -outline">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -flat">flat</button>
<button class="a-btn -icon -flat">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -float">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -primary -solid">solid</button>
<button class="a-btn -primary -icon -solid">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -primary -outline">outline</button>
<button class="a-btn -primary -icon -outline">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -primary -flat">flat</button>
<button class="a-btn -primary -icon -flat">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -primary -float">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -danger -solid">solid</button>
<button class="a-btn -danger -icon -solid">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -danger -outline">outline</button>
<button class="a-btn -danger -icon -outline">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -danger -flat">flat</button>
<button class="a-btn -danger -icon -flat">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -danger -float">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -info -solid">solid</button>
<button class="a-btn -info -icon -solid">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -info -outline">outline</button>
<button class="a-btn -info -icon -outline">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -info -flat">flat</button>
<button class="a-btn -info -icon -flat">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -info -float">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -dark -solid">solid</button>
<button class="a-btn -dark -icon -solid">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -dark -outline">outline</button>
<button class="a-btn -dark -icon -outline">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -dark -flat">flat</button>
<button class="a-btn -dark -icon -flat">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -dark -float">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -small">small</button>
<button class="a-btn -small -icon">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -medium">medium</button>
<button class="a-btn -medium -icon">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn -large">large</button>
<button class="a-btn -large -icon">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
<span>Button</span>
</div>
</button>
<button class="a-btn">
<div class="a-btn__content">
<span>Button</span>
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>
<button class="a-btn">
<div class="a-btn__content">
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
<span>Button</span>
<div class="a-icon">
<svg>
<use xlink:href="#workspace"></use>
</svg>
</div>
</div>
</button>