header {
  padding: 1rem 4rem;
  position: relative;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  background-color: #fff;
  border-radius: 92px;

  border: none;

  width: calc(100% - 8rem + 2rem);
  margin-left: -1rem;
  z-index: 1;
}
header::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 92px;
  border: 5px solid #CFEDF2;
  border-top: none;
  pointer-events: none;

  -webkit-mask-image: linear-gradient(to bottom, transparent 50%, black 50%);
          mask-image: linear-gradient(to bottom, transparent 50%, black 50%);
}

header nav ul{
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  list-style: none;
  padding: 0;
  margin: 0;
}

header a {
  text-decoration: none;
  color: #000;
}

header a.active {
    color: #1e1e1e;
    border-bottom: 2px solid #1e1e1e;
}

header h1 a.active {
    border-bottom: 4px solid #1e1e1e;
}

@media (max-width: 600px) {
  header {
    flex-direction: column;
    text-align: center;
  }
  header nav ul{
    justify-content: center;
  }
}