header {
  display: flex;
  width: 100%;
  height: 100px;
  background-color: darkgrey;
  align-items: center;
}
 
.title {
  margin-right: auto;
}
 
.menu-item {
  list-style: none;
  display: inline-block;
  padding: 10px;
}

h2 {
  padding: 0.4em 0.5em;/*文字の上下 左右の余白*/
  color: #494949;/*文字色*/
  background: #f4f4f4;/*背景色*/
  border-left: solid 5px #7db4e6;/*左線*/
  border-bottom: solid 3px #d7d7d7;/*下線*/
}