Untitled

.header {
    top: 0px;
    left: 0px;
    right: 0px;
    position: fixed;
}

.header {
  height: 50px;
  background-color: rgba(0,0,0,.9);
  border: 1px solid lightgray;
}
.container {
  height: inherit;
  display: flex;
  justify-content: space-between;
  padding: 0 40px;
}
h1 {
  font-size: 1em;
  align-self: center;
  color: aliceblue;
}
.menu {
  height: 30px;
  align-self: center;
  position: relative;
}
main {
  margin-top: 40px;
}