html,
body {
  margin: 0;
  padding: 0;
}
.header_html_root {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin: 0 auto;
  width: 1000px;
  font-size: 16px;
  line-height: 50px;
  font-weight: bold;
  box-sizing: border-box;
}
.header_html_root .header_html_item {
  margin: 0 24px;
  padding: 0 10px;
  color: #333;
  border-bottom: 4px solid transparent;
  cursor: pointer;
}
.header_html_root .header_html_item:hover,
.header_html_root .header_html_item.selected {
  border-bottom: 4px solid #2d8cf0;
}