html {
  box-sizing: border-box;
}

*, *::after, *::before {
  box-sizing: inherit;
}

ul.tabs {
  width: 100%;
  margin: 0 0 5px;
  border-bottom: 1px solid #ddd;
}

ul.tabs li {
  display: inline-block;
}

ul.tabs a {
  display: block;
  border: 1px solid #ddd;
  border-bottom: 0;
  border-radius: 3px 3px 0 0;
}