Styling for example.html

example.css

h3 {
  font-family: "Helvetica-Neue", sans-serif;
  font-size: 1.5em;
}

.section-container {
  max-width: 1100px;
  background-color: black;
  margin: auto;
  overflow: hidden;
  padding: 5px;
}

.section {
  min-width: calc(50% - 50px);
  background-color: #fafafa;
  float: left;
  margin: 5px;
  padding: 20px;
}

@media screen and (max-width: 780px) {
  .section-container: {
    width: 100%;
    margin: 10px;
    overflow: auto;
  }

  .section {
    width: initial;
    float: none;
    margin: 5px;
    margin-top: 10px;
    margin-bottom: 10px;
  }

  .section:first-child {
    margin-top: 5px;
  }

  .section:last-child {
    margin-bottom: 5px;
  }
}