body {
    background: #eef0f3;
    font-family: Arial, sans-serif;
    text-align: center;
    overflow-x: hidden;
  }
  .tree {
    display: flex;
    justify-content: center;
    padding: 40px 0;
    overflow-x: auto;
  }
  .tree ul {
    position: relative;
    margin: 0;
    list-style: none;
    width: 35%;
    display: block;
    padding-left: 0;
  }
  .tree ul ul {
    display: none;
    padding-left: 15px;
    border-left: 2px solid #007bff;
    margin: 5px 0;
    padding-top: 0;
  }
  .tree ul:has(> li:only-child)::before {
    height: 40px;
  }
  .tree li {
    text-align: center;
    position: relative;
    margin-bottom: 10px;
    width: 100%;
    padding: 0;
  }
  .tree li:last-child {
    margin: 0;
  }
  .tree li::before,
  .tree li::after,
  .tree ul::before {
    display: none;
  }
  .tree a {
    display: block;
    background-color: #f5faff;
    color: #007bff;
    padding: 10px 15px;
    border: 1px solid #007bff;
    border-radius: 5px;
    font-weight: bold;
    text-decoration: none;
    position: relative;
    cursor: pointer;
    user-select: none;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    line-height: 1.4;
    overflow: hidden;
  }
  .tree a:hover {
    background: #007bff;
    color: white;
  }
  .tree li.has-children > a {
    padding-right: 45px;
    position: relative;
  }
  .tree li.has-children > a .toggle-icon{
    position: absolute;
    right: 0;
    top: 0;
    font-size: 24px;
    cursor: pointer;
    user-select: none;
    height: 100%;
    background: #f5faff;
    color: #007bff;
    border-left: 1px solid #007bff;
    width: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1;
  }
  .tree li.has-children > a .toggle-icon .icon{
    position: absolute;
    transition: transform 0.3s ease;
  }
  .tree li.has-children.active > a .toggle-icon .icon{
    transform: translateY(-0%) rotate(180deg);
  }
  .tree li.active > ul {
    display: block;
    padding-top: 15px;
    margin-bottom: 25px;
    width: 85%;
  }
  .tree > ul > li.active > ul {
    display: block;
  }
  .tree li.active a {
    background-color: #cce9ff;
    color: #007bff;
    border-color: #007bff;
  }
  .tree li.active > a {
    background: #007bff;
    color: white;
    border-color: #007bff;
  }
  @media (max-width:1399px){.tree ul {width: 50%}}
  @media (max-width:991px){.tree ul {width: 75%}}
  @media (max-width:767px){.tree ul {width: 90%}}