* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

ul {
  list-style: none;
}

a {
  text-decoration: none;
}

#menu-ngang {
  display: flex;
  background-color: #29abe2;
}

#menu-ngang li a {
  display: block;
  padding: 10px 20px;
  color: #fff;
  font-size: 14px;
}

#menu-ngang li a:hover {
  background-color: yellow;
  color: #333;
  font-weight: bold;
  border-radius: 5px;
}

#menu-doc {
  width: 160px;
  background-color: #29abe2;
}

#menu-doc li a {
  display: block;
  padding: 10px 15px;
  color: #fff;
  font-size: 14px;
  border-bottom: 1px solid #fff;
}

#menu-doc li a:hover {
  background-color: #55c8f0; 
  font-style: italic;
}