header {
  width: 100%;
  height: 6vh;
  display: flex;
  flex-direction: row;
  align-items: center;
  justify-content: space-between;
  position: fixed;
  left: 0;
  right: 0;
  top: 0;
  background-color: #fff;
  z-index: 999;
}

header a img {
  width: 30px;
  margin-right: 50px;
  transition: transform 0.7s;
}

header a img:hover {
  transform: scale(1.2);
}