se eu tento fazer igual do professor erro

.cabecalhoPrincipal .container { display: flex; align-items: center; justify-content: space-between; }

.cabecalhoPrincipal-nav { display: flex; }

.rodapePrincipal-patrocinadores .container { display: flex; justify-content: space-between; }

.rodapePrincipal-patrocinadores-list { display: flex; align-items: center; justify-content: space-around; width: 70%; margin-right: 5%; }

.rodapePrincipal-contatoForm { width: 25%; }

.rodapePrincipal-contatoForm-fieldset { display: flex; }

.rodapePrincipal-navMap-list { display: flex; flex-direction: column; flex-wrap: wrap; height: 250px; }

.conteudoPrincipal-cursos { display: flex; flex-wrap: wrap; }

.conteudoPrincipal-cursos-link { width: 23%; margin: 1%;

}

.conteudoPrincipal-cursos-link:nth-child(4n) { margin-right: 0; }

.conteudoPrincipal-cursos-link:nth-child(4n+1) { margin-left: 0; }