Changing font

Any idea on how to update the font used in my custom buttons? Trying to get them to match the custom content widget font

My CSS:

/* Custom Buttons PU Page */

.button_PU_page {
  border-radius: 4px;
  background-color: #105074;
  border: none;
  color: #FFFFFF;
  font-style: bold;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 28px;
  text-align: center;
  padding: 28px;
  height: auto;
  width: 100%;
  transition: all 0.5s;
  cursor: pointer;
}

.button_PU_page span {
  cursor: pointer;
  display: inline-block;
  position: relative;
  transition: 0.5s;
}

.button_PU_page span:after {
  content: '\00bb';
  position: absolute;
  opacity: 0;
  top: 0;
  right: -20px;
  transition: 0.5s;
}

.button_PU_Page:hover span {
  padding-right: 25px;
}

.button_PU_page:hover span:after {
  opacity: 1;
  right: 0;
}

My Html on the widget:

<a href="/pages/384/trace-power-user-guides">
<button class="button_PU_page"><span>Power User Guides</span></button>

</a>

Any help would be super appreciated - I’ve tried so many different lines of code but nothing is working