JSFiddle - React, Tailwind, and code Playground

HTML

<section id="inicio">
  <div class="imagem"></div>
</section>

<section id="quemsomos">
  Quem Somos
</section>

<section id="projetos">
  Projetos
</section>

CSS

body {
  padding: 0;
  margin: 0;
}

section, .imagem {
  width: 100vw;
  height: 100vh;
}

.imagem {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -10;
  background: url('http://placehold.it/600x600') no-repeat center center;
  background-size: cover;
}

#quemsomos {
  background: black;
  color: white;
}
#projetos {
  background: blue;
  color: white;
}