Код IT Загрузка примера кода…

HTML main.html 
<!DOCTYPE html>
<html lang="ru">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Shimmer</title>
  <style>
    body {
      margin: 0;
      padding: 2rem;
      font-family: system-ui, sans-serif;
      background: #fff;
    }
    .skeleton {
      max-width: 320px;
    }
    .skeleton__line {
      height: 14px;
      margin-bottom: 12px;
      border-radius: 6px;
      background: linear-gradient(
        90deg,
        #e2e8f0 0%,
        #f1f5f9 50%,
        #e2e8f0 100%
      );
      background-size: 200% 100%;
      animation: shimmer 1.4s ease-in-out infinite;
    }
    .skeleton__line--short { width: 60%; }
    .skeleton__line--title { height: 20px; width: 80%; margin-bottom: 16px; }
    @keyframes shimmer {
      0%   { background-position: 200% 0; }
      100% { background-position: -200% 0; }
    }
  </style>
</head>
<body>
  <div class="skeleton" aria-busy="true" aria-label="Загрузка контента">
    <div class="skeleton__line skeleton__line--title"></div>
    <div class="skeleton__line"></div>
    <div class="skeleton__line"></div>
    <div class="skeleton__line skeleton__line--short"></div>
  </div>
</body>
</html>
<!DOCTYPE html>
<html lang="ru">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Shimmer</title>
  <style>
    body {
      margin: 0;
      padding: 2rem;
      font-family: system-ui, sans-serif;
      background: #fff;
    }
    .skeleton {
      max-width: 320px;
    }
    .skeleton__line {
      height: 14px;
      margin-bottom: 12px;
      border-radius: 6px;
      background: linear-gradient(
        90deg,
        #e2e8f0 0%,
        #f1f5f9 50%,
        #e2e8f0 100%
      );
      background-size: 200% 100%;
      animation: shimmer 1.4s ease-in-out infinite;
    }
    .skeleton__line--short { width: 60%; }
    .skeleton__line--title { height: 20px; width: 80%; margin-bottom: 16px; }
    @keyframes shimmer {
      0%   { background-position: 200% 0; }
      100% { background-position: -200% 0; }
    }
  </style>
</head>
<body>
  <div class="skeleton" aria-busy="true" aria-label="Загрузка контента">
    <div class="skeleton__line skeleton__line--title"></div>
    <div class="skeleton__line"></div>
    <div class="skeleton__line"></div>
    <div class="skeleton__line skeleton__line--short"></div>
  </div>
</body>
</html>