Always visible sidebar example

HTML

<link rel="stylesheet" href="https://semantic-ui.com/dist/semantic.css">
<script src="https://semantic-ui.com/dist/semantic.js"></script>
<div class="flexbox">
  <div class="sidebar">
    <div class="ui left vertical inverted visible sidebar menu">
      <a class="item">
        Overview
      </a>
      <a class="item">
        Upcoming
      </a>
    </div>
  </div>
  <div class="main">
    <div class="ui container">
      <div class="ui cards">
        <div class="card">
          <div class="content">
            <div class="header">
              Test
            </div>
            <div class="meta">
              Test
            </div>
          </div>
          <div class="extra content">
            <div class="ui two buttons">
              <div class="ui basic green button">Edit</div>
              <div class="ui basic red button">Delete</div>
            </div>
          </div>
        </div>
        <div class="card">
          <div class="content">
            <div class="header">
              Test
            </div>
            <div class="meta">
              Test
            </div>
          </div>
          <div class="extra content">
            <div class="ui two buttons">
              <div class="ui basic green button">Edit</div>
              <div class="ui basic red button">Delete</div>
            </div>
          </div>
        </div>
        <div class="card">
          <div class="content">
            <div class="header">
              Test
            </div>
            <div class="meta">
              Test
            </div>
          </div>
          <div class="extra content">
            <div class="ui two buttons">
              <div class="ui basic green button">Edit</div>
              <div class="ui basic red button">Delete</div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

CSS

.flexbox {
    display: flex;
}

.sidebar {
  flex: 0 0 auto;
  width: 260px;
}

.main {
  flex: 1 1 auto;
}

  .ui.container {
    margin-left: 3em !important;
    margin-right: 3em !important;
    width: auto !important;
    max-width: 960px !important;
  }

JavaScript

// Add javascript here