:root {
    --bg: #f5f7fa;
    --accent: #1565c0;
    --accent2: #7c3aed;
    --gold: #d97706;
    --text: #1a2636;
    --text-muted: #5a718a;
    --card: #ffffff;
    --border: rgba(21,101,192,0.13);
    --shadow: rgba(21,101,192,0.08);
  }

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

  body {
    font-family: 'DM Sans', sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
  }

  body::after {
    content: '';
    position: fixed;
    inset: 0;
    background-image: radial-gradient(circle, rgba(21,101,192,0.06) 1px, transparent 1px);
    background-size: 28px 28px;
    pointer-events: none;
    z-index: 0;
  }

  body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
      radial-gradient(ellipse 70% 50% at 10% 0%, rgba(21,101,192,0.07) 0%, transparent 55%),
      radial-gradient(ellipse 50% 40% at 90% 100%, rgba(124,58,237,0.05) 0%, transparent 55%);
    pointer-events: none;
    z-index: 0;
  }

  header {
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 16px 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(245,247,250,0.96);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(12px);
    box-shadow: 0 2px 16px var(--shadow);
  }

  .logo { font-family: 'DM Serif Display', serif; font-size: 1.5em; color: var(--accent); letter-spacing: -0.5px; }
  .logo span { color: var(--gold); }

  nav {
    display: flex;
    gap: 4px;
    background: #fff;
    padding: 4px;
    border-radius: 12px;
    border: 1px solid var(--border);
    box-shadow: 0 1px 6px var(--shadow);
  }

  nav button {
    background: none;
    border: none;
    color: var(--text-muted);
    padding: 10px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-family: 'DM Sans', sans-serif;
    font-size: 0.9em;
    font-weight: 500;
    transition: all 0.2s;
    white-space: nowrap;
  }
  nav button:hover { color: var(--accent); background: rgba(21,101,192,0.06); }
  nav button.active:not(.nav-ai) {
    background: linear-gradient(135deg, rgba(21,101,192,0.12), rgba(124,58,237,0.08));
    color: var(--accent);
    border: 1px solid rgba(21,101,192,0.25);
  }

nav button.nav-ai {
    color: var(--accent2);
    border: 1px solid transparent;
    background: none;
    position: relative;
  }

  nav button.nav-ai::after {
    content: '';
    position: absolute;
    top: 6px; right: 6px;
    width: 6px; height: 6px;
    border-radius: 50%;
    background: #22c55e;
    animation: pulse-ai 2s ease-in-out infinite;
  }
  @keyframes pulse-ai {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(0.7); }
  }
  nav button.nav-ai:hover {
    background: rgba(124,58,237,0.12);
    color: var(--accent2);
  }
  nav button.nav-ai.active {
    background: linear-gradient(135deg, rgba(124,58,237,0.15), rgba(21,101,192,0.08));
    color: var(--accent2);
    border: 1px solid rgba(124,58,237,0.35);
  }

  main {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 40px;
  }

  .tab-panel { display: none; animation: fadeIn 0.35s ease; }
  .tab-panel.active { display: block; }

  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(14px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  /* ABOUT */
  .about-hero {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 48px;
    align-items: center;
    margin-bottom: 32px;
  }

.avatar {
    width: 160px; height: 160px;
    border-radius: 50%;
    background: linear-gradient(135deg, #1565c0, #7c3aed);
    display: flex; align-items: center; justify-content: center;
    font-size: 4em; flex-shrink: 0;
    box-shadow: 0 8px 32px rgba(21,101,192,0.22);
    border: 3px solid #fff;
    overflow: hidden;
  }

  .hero-text h1 {
    font-family: 'DM Serif Display', serif;
    font-size: clamp(2em, 5vw, 3em);
    color: var(--text);
    line-height: 1.15;
    margin-bottom: 8px;
  }
  .hero-text h1 em { font-style: italic; color: var(--accent); }
  .hero-subtitle { color: var(--text-muted); font-size: 1.05em; margin-bottom: 28px; line-height: 1.5; }

  .social-links { display: flex; gap: 12px; flex-wrap: wrap; }
  .social-btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 12px 22px; border-radius: 8px; text-decoration: none;
    font-size: 0.9em; font-weight: 500; transition: all 0.2s; border: 1px solid;
  }
  .btn-linkedin { background: #0077b5; border-color: #0077b5; color: #fff; }
  .btn-github   { background: #24292e; border-color: #24292e; color: #fff; }
  .social-btn:hover { transform: translateY(-2px); box-shadow: 0 4px 12px var(--shadow); }

  .about-bio {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 4px 24px var(--shadow);
  }
  .about-bio h3 {
    font-family: 'DM Serif Display', serif;
    font-size: 1.4em; color: var(--accent);
    margin-bottom: 18px; padding-bottom: 12px;
    border-bottom: 1px solid var(--border);
  }
  .about-bio p  { color: var(--text-muted); line-height: 1.8; margin-bottom: 14px; font-size: 0.97em; }
  .about-bio strong { color: var(--text); }
  .about-bio ul { padding-left: 20px; margin-bottom: 14px; }
  .about-bio li { color: var(--text-muted); line-height: 1.8; margin-bottom: 4px; font-size: 0.97em; }

  .cert-badge {
    display: inline-flex; align-items: center; gap: 6px;
    background: rgba(217,119,6,0.08); border: 1px solid rgba(217,119,6,0.25);
    color: var(--gold); padding: 5px 12px; border-radius: 20px; font-size: 0.82em; margin: 3px;
  }

  /* SECTION HEADER */
  .section-header { text-align: center; margin-bottom: 48px; }
  .section-header h2 {
    font-family: 'DM Serif Display', serif;
    font-size: clamp(2em, 5vw, 2.8em); margin-bottom: 10px; color: var(--text);
  }
  .section-header h2 span { color: var(--accent); }
  .section-header p { color: var(--text-muted); font-size: 1.05em; }

  /* CARDS */
  .projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 24px;
  }

  .project-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 28px;
    display: flex; flex-direction: column; gap: 14px;
    box-shadow: 0 2px 12px var(--shadow);
    transition: all 0.3s;
    position: relative; overflow: hidden;
  }
  .project-card::before {
    content: '';
    position: absolute; top: 0; left: 0; right: 0; height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent2));
    opacity: 0; transition: opacity 0.3s;
  }
  .project-card:hover {
    border-color: rgba(21,101,192,0.3);
    transform: translateY(-4px);
    box-shadow: 0 16px 40px rgba(21,101,192,0.12);
  }
  .project-card:hover::before { opacity: 1; }

  .project-card h3 { font-family: 'DM Serif Display', serif; font-size: 1.15em; color: var(--text); line-height: 1.3; }
  .project-meta { font-size: 0.8em; color: var(--text-muted); }
  .project-desc { color: var(--text-muted); font-size: 0.9em; line-height: 1.7; flex-grow: 1; }

  .tags { display: flex; flex-wrap: wrap; gap: 6px; }
  .tag {
    background: rgba(21,101,192,0.07); border: 1px solid rgba(21,101,192,0.17);
    color: var(--accent); padding: 4px 10px; border-radius: 20px; font-size: 0.75em; font-weight: 500;
  }

  .card-actions { display: flex; gap: 10px; margin-top: auto; }
  .card-btn {
    flex: 1; padding: 11px 16px; border-radius: 8px; text-decoration: none;
    font-size: 0.85em; font-weight: 500; text-align: center;
    transition: all 0.2s; border: 1px solid;
    display: flex; align-items: center; justify-content: center; gap: 6px;
  }
  .btn-demo { background: rgba(21,101,192,0.08); border-color: rgba(21,101,192,0.28); color: var(--accent); }
  .btn-gh   { background: rgba(0,0,0,0.03); border-color: rgba(0,0,0,0.11); color: #555; }
  .card-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 12px var(--shadow); }

  /* EXPLORE */
  .explore-controls {
    background: var(--card); border: 1px solid var(--border);
    border-radius: 16px; padding: 28px; margin-bottom: 32px;
    box-shadow: 0 2px 12px var(--shadow);
  }
  .search-wrap { position: relative; margin-bottom: 20px; }
  .search-wrap input {
    width: 100%; background: var(--bg); border: 1px solid var(--border);
    border-radius: 10px; padding: 14px 20px 14px 48px;
    color: var(--text); font-family: 'DM Sans', sans-serif; font-size: 0.97em;
    outline: none; transition: border-color 0.2s, box-shadow 0.2s;
  }
  .search-wrap input:focus { border-color: rgba(21,101,192,0.4); box-shadow: 0 0 0 3px rgba(21,101,192,0.07); }
  .search-wrap input::placeholder { color: var(--text-muted); }
  .search-icon { position: absolute; left: 16px; top: 50%; transform: translateY(-50%); color: var(--text-muted); }

  .filter-label { font-size: 0.82em; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 12px; }
  .tag-filters { display: flex; flex-wrap: wrap; gap: 8px; }
  .tag-filter-btn {
    background: var(--bg); border: 1px solid var(--border); color: var(--text-muted);
    padding: 7px 14px; border-radius: 20px; font-size: 0.82em; cursor: pointer;
    transition: all 0.2s; font-family: 'DM Sans', sans-serif;
  }
  .tag-filter-btn:hover { border-color: rgba(21,101,192,0.35); color: var(--accent); }
  .tag-filter-btn.active { background: rgba(21,101,192,0.09); border-color: rgba(21,101,192,0.38); color: var(--accent); font-weight: 500; }

  .results-count { font-size: 0.85em; color: var(--text-muted); margin-bottom: 20px; }
  .results-count span { color: var(--accent); font-weight: 600; }

  /* CONTACT */
  .contact-wrap { max-width: 700px; margin: 0 auto; text-align: center; }
  .contact-wrap h2 { font-family: 'DM Serif Display', serif; font-size: clamp(2em, 5vw, 2.8em); margin-bottom: 20px; }
  .contact-wrap p { color: var(--text-muted); line-height: 1.8; margin-bottom: 12px; }

  .contact-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 16px; margin: 40px 0; }
  .contact-card {
    background: var(--card); border: 1px solid var(--border); border-radius: 16px;
    padding: 28px 20px; text-decoration: none; transition: all 0.3s; display: block;
    box-shadow: 0 2px 12px var(--shadow);
  }
  .contact-card:hover { border-color: rgba(21,101,192,0.35); transform: translateY(-4px); box-shadow: 0 12px 32px rgba(21,101,192,0.12); }
  .contact-card .icon  { font-size: 2.2em; margin-bottom: 12px; }
  .contact-card .label { color: var(--text); font-weight: 500; font-size: 0.97em; }
  .contact-card .sublabel { color: var(--text-muted); font-size: 0.82em; margin-top: 4px; }

  .quote-block {
    background: linear-gradient(135deg, rgba(21,101,192,0.05), rgba(124,58,237,0.04));
    border: 1px solid rgba(21,101,192,0.14); border-radius: 16px; padding: 36px;
    margin-top: 40px; position: relative;
  }
  .quote-block::before {
    content: '"'; font-family: 'DM Serif Display', serif; font-size: 6em;
    color: rgba(21,101,192,0.1); position: absolute; top: -10px; left: 20px; line-height: 1;
  }
  .quote-block p { font-family: 'DM Serif Display', serif; font-style: italic; font-size: 1.15em; color: var(--text); line-height: 1.6; margin: 0; }
  .quote-block cite { display: block; margin-top: 12px; color: var(--accent); font-size: 0.85em; font-style: normal; }

  footer {
    position: relative; z-index: 1; text-align: center;
    padding: 28px 40px; border-top: 1px solid var(--border);
    color: var(--text-muted); font-size: 0.85em; background: var(--card);
  }

  .no-results { text-align: center; padding: 60px 20px; color: var(--text-muted); font-size: 1.1em; }

  /* ===================== CHAT TAB ===================== */
  .chat-layout {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 28px;
    align-items: start;
  }

  .chat-container {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 20px;
    box-shadow: 0 4px 24px var(--shadow);
    display: flex;
    flex-direction: column;
    height: calc(100vh - 280px);
    overflow: hidden;
  }

  .chat-header {
    padding: 20px 28px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 14px;
    background: linear-gradient(135deg, rgba(21,101,192,0.04), rgba(124,58,237,0.03));
    flex-shrink: 0;
  }

  .chat-avatar {
    width: 44px; height: 44px;
    border-radius: 50%;
    background: linear-gradient(135deg, #1565c0, #7c3aed);
    display: flex; align-items: center; justify-content: center;
    font-size: 1.3em;
    flex-shrink: 0;
    box-shadow: 0 2px 10px rgba(21,101,192,0.3);
  }

  .chat-header-info { flex: 1; }
  .chat-header-name {
    font-family: 'DM Serif Display', serif;
    font-size: 1.05em;
    color: var(--text);
    line-height: 1.2;
  }
  .chat-header-status {
    font-size: 0.78em;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 5px;
    margin-top: 2px;
  }
  .status-dot {
    width: 7px; height: 7px;
    border-radius: 50%;
    background: #22c55e;
    display: inline-block;
    animation: pulse-dot 2s ease-in-out infinite;
  }
  @keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
  }

  .chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    scroll-behavior: smooth;
  }

  .chat-messages::-webkit-scrollbar { width: 4px; }
  .chat-messages::-webkit-scrollbar-track { background: transparent; }
  .chat-messages::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

  .message {
    display: flex;
    gap: 10px;
    align-items: flex-end;
    animation: msgIn 0.28s ease;
  }
  @keyframes msgIn {
    from { opacity: 0; transform: translateY(10px); }
    to   { opacity: 1; transform: translateY(0); }
  }

  .message.user { flex-direction: row-reverse; }

  .msg-avatar {
    width: 30px; height: 30px;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 0.85em; flex-shrink: 0;
    margin-bottom: 2px;
  }
  .message.bot .msg-avatar {
    background: linear-gradient(135deg, #1565c0, #7c3aed);
  }
  .message.user .msg-avatar {
    background: rgba(21,101,192,0.12);
    border: 1px solid var(--border);
  }

  .msg-bubble {
    max-width: 75%;
    padding: 12px 16px;
    border-radius: 18px;
    font-size: 0.9em;
    line-height: 1.65;
  }

  .message.bot .msg-bubble {
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    border-bottom-left-radius: 4px;
  }

  .message.user .msg-bubble {
    background: linear-gradient(135deg, var(--accent), #1976d2);
    color: #fff;
    border-bottom-right-radius: 4px;
    box-shadow: 0 2px 12px rgba(21,101,192,0.28);
  }

  .msg-time {
    font-size: 0.7em;
    color: var(--text-muted);
    margin-top: 4px;
    padding: 0 4px;
  }
  .message.user .msg-time { text-align: right; }

  /* Typing indicator */
  .typing-indicator {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    animation: msgIn 0.28s ease;
  }
  .typing-dots {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 18px;
    border-bottom-left-radius: 4px;
    padding: 14px 18px;
    display: flex;
    gap: 5px;
    align-items: center;
  }
  .typing-dots span {
    width: 6px; height: 6px;
    background: var(--text-muted);
    border-radius: 50%;
    animation: bounce 1.2s ease-in-out infinite;
  }
  .typing-dots span:nth-child(2) { animation-delay: 0.2s; }
  .typing-dots span:nth-child(3) { animation-delay: 0.4s; }
  @keyframes bounce {
    0%, 60%, 100% { transform: translateY(0); }
    30% { transform: translateY(-6px); }
  }

  /* Input area */
  .chat-input-area {
    padding: 16px 20px;
    border-top: 1px solid var(--border);
    display: flex;
    gap: 10px;
    align-items: flex-end;
    background: rgba(245,247,250,0.6);
    flex-shrink: 0;
  }

  .chat-input {
    flex: 1;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px 16px;
    color: var(--text);
    font-family: 'DM Sans', sans-serif;
    font-size: 0.92em;
    outline: none;
    resize: none;
    line-height: 1.5;
    max-height: 120px;
    transition: border-color 0.2s, box-shadow 0.2s;
  }
  .chat-input:focus {
    border-color: rgba(21,101,192,0.45);
    box-shadow: 0 0 0 3px rgba(21,101,192,0.08);
  }
  .chat-input::placeholder { color: var(--text-muted); }

  .send-btn {
    width: 44px; height: 44px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--accent), #1976d2);
    border: none;
    color: #fff;
    cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.1em;
    transition: all 0.2s;
    flex-shrink: 0;
    box-shadow: 0 2px 10px rgba(21,101,192,0.3);
  }
  .send-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 16px rgba(21,101,192,0.4); }
  .send-btn:active { transform: translateY(0); }
  .send-btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

  /* Sidebar */
   .chat-sidebar { display: flex; flex-direction: column; gap: 12px; }

.chat-info-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 16px;
    box-shadow: 0 2px 12px var(--shadow);
  }

.chat-info-card h4 {
    font-family: 'DM Serif Display', serif;
    font-size: 1.05em;
    color: var(--accent);
    margin-bottom: 10px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
  }

  .suggested-questions { display: flex; flex-direction: column; gap: 8px; }
  .suggested-q {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 7px 12px;
    font-size: 0.83em;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
    font-family: 'DM Sans', sans-serif;
    line-height: 1.4;
  }
  .suggested-q:hover {
    border-color: rgba(21,101,192,0.35);
    color: var(--accent);
    background: rgba(21,101,192,0.04);
    transform: translateX(3px);
  }

  .topic-chips { display: flex; flex-wrap: wrap; gap: 7px; }
  .topic-chip {
    background: rgba(21,101,192,0.07);
    border: 1px solid rgba(21,101,192,0.17);
    color: var(--accent);
    padding: 5px 11px;
    border-radius: 20px;
    font-size: 0.78em;
    font-weight: 500;
  }

  .chat-disclaimer {
    font-size: 0.75em;
    color: var(--text-muted);
    text-align: center;
    padding: 8px 0 0;
    line-height: 1.5;
  }

  /* Mock badge */
  .mock-badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    background: rgba(217,119,6,0.09);
    border: 1px solid rgba(217,119,6,0.28);
    color: var(--gold);
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75em;
    font-weight: 500;
  }

  @media (max-width: 900px) {
    .chat-layout { grid-template-columns: 1fr; }
    .chat-sidebar { display: grid; grid-template-columns: 1fr 1fr; }
  }

  @media (max-width: 768px) {
    header { padding: 14px 20px; flex-direction: column; gap: 12px; }
    nav button { padding: 9px 13px; font-size: 0.82em; }
    main { padding: 36px 20px; }
    .about-hero { grid-template-columns: 1fr; text-align: center; gap: 24px; }
    .avatar { margin: 0 auto; width: 120px; height: 120px; font-size: 3em; }
    .social-links { justify-content: center; }
    .projects-grid { grid-template-columns: 1fr; }
    .chat-sidebar { grid-template-columns: 1fr; }
    .chat-container { height: 520px; }
  }