.menu-toggle {
  display: none;
  font-size: 1.8em;
  cursor: pointer;
  color: var(--text-dark);
  background: none;
  border: none;
  padding: 5px;
  z-index: 1002;
}

@media (max-width: 768px) {
  .main-nav {
    position: fixed;
    top: 0;
    right: -300px; /* Ẩn bên phải */
    width: 300px;
    height: 100vh;
    background: white;
    box-shadow: -4px 0 12px rgba(0,0,0,0.1);
    z-index: 1001;
    transition: right 0.3s ease;
    overflow-y: auto;
    padding-top: 80px; /* Để tránh đè lên header */
  }

  .main-nav.active {
      right: 0; /* Trượt vào */
  }

  .main-nav ul {
      flex-direction: column;
      padding: 20px 0;
      margin: 0;
      list-style: none;
  }

  .main-nav li {
      margin: 0;
      border-bottom: 1px solid #eee;
  }

  .main-nav a {
      display: block;
      padding: 15px 20px;
      text-decoration: none;
      color: var(--text-dark);
      font-size: 1.1em;
      transition: all 0.3s ease;
  }

  .main-nav a:hover,
  .main-nav a.active {
      background: var(--bg-alt, #f5f5f5);
      padding-left: 30px;
  }

  .menu-toggle {
      display: block;
      color: var(--text-dark);
      position: relative;
  }

  .main-header .container {
      position: relative;
      display: flex;
      justify-content: space-between;
      align-items: center;
  }

  /* Overlay khi menu mở */
  .menu-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0,0,0,0.5);
      z-index: 1000;
      opacity: 0;
      visibility: hidden;
      transition: all 0.3s ease;
  }

  .menu-overlay.active {
      opacity: 1;
      visibility: visible;
  }
}