body *{ margin: 0;}
header { width: 1200px; height: 100px; border-bottom: black 3px groove; margin-inline: auto; display: flex; justify-content:space-between;}
section { width: 50px; height: 50px; background-color: black; margin-block: auto;}
nav { display: flex; justify-content: center; gap: 20px; align-items: center;}
h3 { margin-block: auto;}