<div class="block">
  <p class="text">Задана властивість: <code>font-feature-settings: "liga" off;</code></p>
  <span class="off">fi</span>
</div>
<div class="block">
   <p class="text">Задана властивість: <code>font-feature-settings: "liga" on;</code></p>
  <span class="on">fi</span>
</div>

@import url('https://fonts.googleapis.com/css?family=Life+Savers');

body {
  font-family: 'Life Savers', serif;
  font-size: 35vw;
  display: flex;
  text-align: center;
}
code{
  font-weight: bold;
}
.text{
  font-size: 20px;
}
.off {
  font-feature-settings: "liga" off;
  color: gray;
}

.on {
  font-feature-settings: "liga" on;
  color: blue;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.