/* Header */
header {
  background: var(--color-header-background);
  color: var(--color-header-font);
  text-align: center;
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--size-header-height);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
}