Knappen med et ikon skal have helt runde hjørner og have reduceret padding på højre side til 0.675rem.
<div class="exercise">
<button>Normal</button>
<button>
<span>w/ icon</span>
<svg width="32" height="32" viewBox="0 0 24 24"><path fill="currentColor" d="m14.475 12l-7.35-7.35q-.375-.375-.363-.888t.388-.887t.888-.375t.887.375l7.675 7.7q.3.3.45.675t.15.75t-.15.75t-.45.675l-7.7 7.7q-.375.375-.875.363T7.15 21.1t-.375-.888t.375-.887z"/></svg>
</button>
</div>