/* =====================================================
   RESPONSIVE — TABLET (≤ 900px)
   ===================================================== */
@media (max-width: 900px) {
  .hero {
    gap: 40px;
  }

  .hero-img-container {
    width: 220px;
    height: 220px;
  }

  .about-content {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .stats-row {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* =====================================================
   RESPONSIVE — MOBILE (≤ 768px)
   ===================================================== */
@media (max-width: 768px) {

  /* Hamburger visible */
  .hamburger {
    display: flex;
  }

  /* Nav desktop links hidden by default on mobile */
  .nav-links {
    position: fixed;
    top: 0;
    right: -280px; /* slide from right */
    left: auto;
    width: 280px;
    height: 100vh;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    text-align: left;
    padding: 80px 28px 40px;
    gap: 4px;
    background: var(--glass-bg);
    backdrop-filter: blur(28px);
    -webkit-backdrop-filter: blur(28px);
    border-left: 1px solid var(--border);
    transition: right 0.35s var(--ease);
    z-index: 1001;
    box-shadow: -4px 0 40px rgba(0, 0, 0, 0.3);
    pointer-events: none; /* prevent clicks when off-screen */
  }

  /* Slide in from right */
  .nav-links.active {
    right: 0;
    pointer-events: auto; /* re-enable clicks when open */
  }

  .nav-links a {
    font-size: 1.1rem;
    font-weight: 600;
    display: block;
    padding: 12px 16px;
    width: 100%;
    border-radius: 12px;
  }

  /* Nav close button */
  .nav-close-btn {
    display: flex;
    position: absolute;
    top: 22px;
    right: 20px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--text-main);
    width: 36px;
    height: 36px;
    border-radius: 9px;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background 0.2s, border-color 0.2s, transform 0.2s;
    z-index: 1002;
  }

  .nav-close-btn:hover {
    background: rgba(37, 99, 235, 0.1);
    border-color: var(--border-hover);
    transform: rotate(90deg);
  }

  /* Nav overlay backdrop */
  .nav-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s var(--ease);
  }

  .nav-overlay.active {
    opacity: 1;
    pointer-events: auto;
  }

  /* Theme toggle — inside the slide panel on mobile */
  .mode-btn-panel {
    display: flex;
    margin-top: 24px;
    margin-left: 0;
    align-self: flex-start;
  }

  /* Hide the nav-bar toggle on mobile (it's now inside the panel) */
  .mode-btn-nav {
    display: none;
  }

  /* Hero */
  .hero {
    flex-direction: column-reverse;
    text-align: center;
    gap: 30px;
  }

  .hero-btns {
    justify-content: center;
    flex-wrap: wrap;
  }

  .subtitle {
    margin: 0 auto 24px;
  }

  .hero-badge {
    margin: 0 auto 16px;
  }

  .hero-img-container {
    width: 180px;
    height: 180px;
  }

  /* Stats */
  .stats-row {
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
  }

  .stat-number {
    font-size: 1.6rem;
  }

  .stat-label {
    font-size: 0.7rem;
  }

  /* Certs */
  .cert-card {
    flex-direction: column;
    text-align: center;
  }

  /* Project grid single column on very narrow */
  .project-grid,
  .blog-grid {
    grid-template-columns: 1fr;
  }

  /* Back to top smaller — centered */
  #back-to-top {
    bottom: 16px;
    left: 50%;
    right: auto;
    width: 42px;
    height: 42px;
  }

  /* Section divider */
  .section-divider {
    margin: 0 4%;
  }
}

/* =====================================================
   RESPONSIVE — SMALL MOBILE (≤ 480px)
   ===================================================== */
@media (max-width: 480px) {
  h1 {
    letter-spacing: -1px;
  }

  .stats-row {
    grid-template-columns: repeat(3, 1fr);
  }

  .cert-grid {
    grid-template-columns: 1fr;
  }

  .btn {
    padding: 11px 18px;
    font-size: 0.9rem;
  }

  .hero-img-container {
    width: 150px;
    height: 150px;
  }

  .social-links {
    gap: 10px;
  }

  .social-btn {
    width: 44px;
    height: 44px;
  }
  
  /* Chatbot */
  #portfolio-chatbot-widget {
    bottom: 16px;
    right: 16px;
  }

  #chatbot-window {
    width: calc(100vw - 32px);
    right: 16px;
    bottom: 80px;
    height: 60vh;
  }
}