CSS not working on home page for section class

Question

Trying to add css to my site however when I created a new section class and tried to add css to it, it will not align to the centre or edit the text that im trying to. It works for other section classes within home.aspx however not this one.

.machinesetup {
  width: 80%;
  margin: auto;
  text-align: center;
  padding-top: 100px;
}

h1 {
  font-size: 36px;
  font-weight: 600;
}

p {
  color: #777;
  font-size: 14px;
  font-weight: 300;
  line-height: 22px;
  padding: 10px;
}

<section class="machinesetup">
  <h1>Employees </h1>
  <p>Hear What Our Recent Graduates Have To Say</p>
  <div class="row">
    <div class="course-col">
      <h3>James - Application Developer Analyst</h3>
      <p>"I'm a big fan of efficiency and engaging work, so it's been really satisfying to contribute to making processes better."</p>
    </div>
    <div class="course-col">
      <h3>Alisha - UX Designer</h3>
      <p>"It feels good to know our work directly promotes our business goals of consumer centricity and it enables leadership to take action to promote our shared purpose - helping our customers through life's uncertainties."</p>
    </div>
    <div class="course-col">
      <h3>PJ - Developer</h3>
      <p>"My favourite thing about my job is my team. Since the beginning, everyone has been very supportive of me and are always welcoming if I had any issues or questions."</p>
    </div>
  </div>
</section>