body.exercicio {
    grid-template-rows: 120px 60px 1fr 60px;
    grid-template-areas: 
        "cabecalho"
        "navegacao"
        "principal"
        "rodape";
}

.principal {
    height: calc(100vh - 240px);
}

.navegacao {
    grid-area: navegacao;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    background-color: #555;
}

.navegacao a {
    text-decoration: none;
    color: #FFF;
    font-weight: 300;
    font-size: 1.3rem;
    background-color: rgb(33, 150, 243);
    padding: 5px 10px;
    margin-right: 10px;
}

.navegacao a.verde { background-color:  #4CAF50; }
.navegacao a.vermelho{background-color :#F44336; }

.conteudo {
    font-size: 2rem;
}

.conteudo .titulo {
    font-size: 2.5rem;
    font-weight: 300;
    padding-bottom: 10px;
    border-bottom: 1px solid #999;
    margin-bottom: 20px;
}