<section class="sezione">
  <div class="container">
    <h1>Titolo sezione</h1>
    <p>Lorem ipsum dolor sit, amet consectetur adipisicing elit. Tempore, atque vero. Quod, quia maiores unde beatae doloremque quisquam laboriosam impedit. Numquam modi libero perspiciatis, sunt minima aliquid. Explicabo, debitis totam?</p>
  </div>
  
  <svg class="section-divider" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 1920 90"><defs><clipPath id="b"><rect width="1920" height="90"/></clipPath></defs><g id="a" clip-path="url(#b)"><rect width="1920" height="90" fill="#fff"/><path d="M-75.5-17.353S71.727,58.694,485.519,61.4s574-39.163,791.843-39.163,654.853,67.942,654.853,67.942V-17.353Z" fill="#333"/></g></svg>
</section>
.sezione {
  padding: 60px 0;
  background-color: #333;
  color: #fff;
  position:relative;
  margin-bottom:90px
}

.section-divider {
  display:block;
  position:absolute;
  top:100%;
  left:0;
  width:100%;
  height: auto;
}

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.1.3/css/bootstrap.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.