HTML редактор

<!DOCTYPE html>
<html lang="ru">

<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <title>JavaScript - Как сделать слайдер для сайта</title>
  <link rel="stylesheet" href="/examples/libs/chiefslider/chiefslider.css">
  <style>
    *,
    *::before,
    *::after {
      box-sizing: border-box;
    }

body {
      margin: 0;
      font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
        'Helvetica Neue', Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji',
        'Segoe UI Symbol';
    }

.container {
      max-width: 900px;
      margin: 0 auto;
    }

.slider__container {
      padding-left: 0;
      padding-right: 0;
    }

.slider__item {
      flex: 0 0 33.3333333333%;
      max-width: 33.3333333333%;
    }

.slider__item-container {
      line-height: 250px;
      font-size: 100px;
      text-align: center;
      height: 250px;
      color: #fff;
    }

.slider__item:nth-child(1) .slider__item-content {
      background-color: #f44336;
    }

.slider__item:nth-child(2) .slider__item-content {
      background-color: #9c27b0;
    }

.slider__item:nth-child(3) .slider__item-content {
      background-color: #3f51b5;
    }

.slider__item:nth-child(4) .slider__item-content {
      background-color: #03a9f4;
    }

.slider__item:nth-child(5) .slider__item-content {
      background-color: #4caf50;
    }
  </style>
</head>

<body>

</div>

</html>