/* ===================== RESPONSIVE ===================== */
@media (max-width: 980px){
  #desktop-nav{ display:none; }
  #hamburger-nav{ display:flex; justify-content: space-between; align-items:center; }

  .hero-grid{
    grid-template-columns: 1fr;
    gap: 1.4rem;
  }

  .hero-left{ display:flex; justify-content:center; }
  .hero-photo{ max-width: 520px; }

  .about-layout{ flex-direction: column; }
  .about-image{ justify-content:center; }

  .solar-system{ margin: 1.6rem auto 0.5rem; }

  .edu-box{
    flex-direction: column;
    gap: 0.8rem;
  }
  .edu-left{ width: 100%; justify-content:flex-start; }

  .research-box{ grid-template-columns: 1fr; }
}

@media (max-width: 760px){
  .title{ font-size: 1.7rem; }
  .section__text__p2{ font-size: 1rem; }

  /* ✅ Mobile-safe HERO TREE: rows wrap into a simple grid, connectors hidden */
  .tree-row{
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.8rem;
  }

  .tree-top::before,
  .tree-branch{ display:none; } /* hide connector lines on mobile */

  .tree-node{
    width: 42%;
    aspect-ratio: auto;
    min-height: 78px;
  }
}

@media (max-width: 420px){
  .tree-node{
    width: 100%; /* single column for very small phones */
  }
}