header {
    background-color:#133269;
    width:100%;
    height:100px;
    box-sizing:border-box;
      display: flex;
  justify-content: center;  /* horizontally center the <ul> */
  align-items: center;      /* vertically center the <ul> */
    }
  body {
    background-color: #57ab87;
    color:white;
    } 
  header ul {
      list-style: none;         /* removes bullets */
       padding: 0;               /* removes padding */
       margin: 0;                /* removes margin */
       display: flex;            /* makes list items horizontal */
      align-items: center; /* optional: vertical centering */
      height:100%;
  }
  header li {
  font-weight: bold;
  margin-right: 200px; /* creates space between list items */
  font-size: 30px;
}

header li:last-child {
  margin-right: 0; /* remove margin on last item */
}
nav li a:hover {
  text-decoration: underline;
}
nav li a {
  text-decoration: none;
  color: white;
  font-weight: bold;
}