/* Light theme (default) */
  :root {
    --bg: #f8f9fa;
    --surface: #ffffff;
    --surface2: #f1f3f5;
    --border: #e9ecef;
    --accent: #4f7cff;
    --accent2: #7c3aed;
    --accent-glow: rgba(79, 124, 255, 0.1);
    --text: #212529;
    --text-muted: #6c757d;
    --text-dim: #9fa6b2;
    --heading-color: #141720;
    --tag-bg: rgba(79, 124, 255, 0.1);
    --tag-border: rgba(79, 124, 255, 0.2);
  }

  body[data-theme='dark'] {
    --bg: #0d0f14;
    --surface: #141720;
    --surface2: #1c2030;
    --border: #272c3f;
    --accent-glow: rgba(79,124,255,0.18);
    --text: #e8ecf4;
    --text-muted: #7a82a0;
    --text-dim: #4a5070;
    --heading-color: #ffffff;
    --tag-bg: rgba(79,124,255,0.12);
    --tag-border: rgba(79,124,255,0.3);
  }

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

  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    line-height: 1.7;
    min-height: 100vh;
  }

  /* Ambient background */
  body::before {
    content: '';
    position: fixed;
    top: -200px; left: -200px;
    width: 700px; height: 700px;
    background: radial-gradient(circle, rgba(79,124,255,0.05) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
  }
  body[data-theme='dark']::before {
    background: radial-gradient(circle, rgba(79,124,255,0.07) 0%, transparent 70%);
  }

  body::after {
    content: '';
    position: fixed;
    bottom: -200px; right: -200px;
    width: 600px; height: 600px;
    background: radial-gradient(circle, rgba(124,58,237,0.04) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
  }

  body[data-theme='dark']::after {
    background: radial-gradient(circle, rgba(124,58,237,0.06) 0%, transparent 70%);
  }

  .wrapper {
    position: relative;
    z-index: 1;
    max-width: 860px;
    margin: 0 auto;
    padding: 48px 24px 80px;
  }

  /* Header */
  .header {
    text-align: center;
    margin-bottom: 48px;
    animation: fadeUp 0.7s ease both;
  }

  .logo-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 50px;
    padding: 8px 20px;
    margin-bottom: 24px;
    font-size: 13px;
    color: var(--text-muted);
    letter-spacing: 0.05em;
  }

  .logo-dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 10px var(--accent);
    animation: pulse 2s ease-in-out infinite;
  }

  h1 {
    font-family: 'Syne', sans-serif;
    font-size: clamp(2.6rem, 6vw, 4rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.1;
    margin-bottom: 16px;
    background: linear-gradient(135deg, #141720 0%, #4f7cff 50%, #7c3aed 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
  }

  body[data-theme='dark'] h1 {
    background: linear-gradient(135deg, #ffffff 0%, #a8b8ff 50%, #c084fc 100%);
  }

  .subtitle {
    font-size: 1.05rem;
    color: var(--text-muted);
    max-width: 520px;
    margin: 0 auto;
    font-weight: 300;
  }

  /* Language Tabs */
  .lang-tabs {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-bottom: 40px;
    animation: fadeUp 0.7s 0.1s ease both;
  }

  .lang-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text-muted);
    padding: 9px 24px;
    border-radius: 50px;
    font-family: 'Syne', sans-serif;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.06em;
    cursor: pointer;
    transition: all 0.2s ease;
  }

  .lang-btn:hover {
    border-color: var(--accent);
    color: var(--text);
  }

  .lang-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
    box-shadow: 0 4px 20px rgba(79,124,255,0.35);
  }

  /* Content panels */
  .lang-panel { display: none; }
  .lang-panel.active { display: block; animation: fadeIn 0.4s ease both; }

  /* Section nav */
  .section-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 36px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
  }

  .nav-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-dim);
    padding: 6px 14px;
    border-radius: 6px;
    font-family: 'DM Sans', sans-serif;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    letter-spacing: 0.03em;
  }

  .nav-btn:hover { border-color: var(--accent); color: var(--text-muted); }
  .nav-btn.active { background: var(--tag-bg); border-color: var(--tag-border); color: var(--accent); }

  /* Sections */
  .section { display: none; animation: fadeIn 0.35s ease both; }
  .section.active { display: block; }

  /* Cards */
  .card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 28px 32px;
    margin-bottom: 16px;
    position: relative;
    overflow: hidden;
    transition: border-color 0.2s ease;
  }

  .card:hover { border-color: rgba(79,124,255,0.3); }

  .card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(79,124,255,0.4), transparent);
    opacity: 0;
    transition: opacity 0.3s;
  }
  .card:hover::before { opacity: 1; }

  .card-accent {
    border-left: 3px solid var(--accent);
    border-radius: 0 16px 16px 0;
  }

  .section-title {
    font-family: 'Syne', sans-serif;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--heading-color);
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .section-title .icon {
    width: 36px; height: 36px;
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    font-size: 16px;
    flex-shrink: 0;
  }

  .icon-blue { background: rgba(79,124,255,0.15); }
  .icon-purple { background: rgba(124,58,237,0.15); }
  .icon-green { background: rgba(34,197,94,0.12); }
  .icon-orange { background: rgba(251,146,60,0.12); }
  .icon-pink { background: rgba(236,72,153,0.12); }
  .icon-teal { background: rgba(20,184,166,0.12); }

  p { color: var(--text-muted); margin-bottom: 12px; font-weight: 300; }
  p:last-child { margin-bottom: 0; }
  p strong { color: var(--text); font-weight: 500; }

  /* Tag list */
  .tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
  }

  .tag {
    background: var(--tag-bg);
    border: 1px solid var(--tag-border);
    color: var(--accent);
    font-size: 12px;
    padding: 4px 12px;
    border-radius: 50px;
    font-weight: 500;
  }
  body[data-theme='dark'] .tag {
    color: #a8b8ff;
  }

  .tag.green { background: rgba(34,197,94,0.1); border-color: rgba(34,197,94,0.25); color: #166534; }
  .tag.purple { background: rgba(167,139,250,0.1); border-color: rgba(167,139,250,0.25); color: #5b21b6; }
  .tag.orange { background: rgba(251,146,60,0.1); border-color: rgba(251,146,60,0.25); color: #b45309; }

  body[data-theme='dark'] .tag.green {
    color: #86efac;
  }
  body[data-theme='dark'] .tag.purple {
    color: #c4b5fd;
  }
  body[data-theme='dark'] .tag.orange {
    color: #fdba74;
  }

  /* Feature grid */
  .feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 12px;
    margin-top: 12px;
  }

  .feature-item {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 14px 16px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 13.5px;
    color: var(--text-muted);
    transition: all 0.2s ease;
  }

  .feature-item:hover { border-color: rgba(79,124,255,0.3); color: var(--text); }

  .feature-check {
    color: var(--accent);
    font-size: 14px;
    flex-shrink: 0;
    margin-top: 1px;
  }

  /* Two column */
  .two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }

  @media (max-width: 600px) {
    .two-col { grid-template-columns: 1fr; }
    .feature-grid { grid-template-columns: 1fr; }
    h1 { font-size: 2.2rem; }
    .wrapper { padding: 32px 16px 60px; }
  }

  /* Tech stack */
  .tech-row {
    margin-bottom: 16px;
  }

  .tech-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-dim);
    margin-bottom: 8px;
    font-weight: 600;
  }

  /* Highlight box */
  .highlight-box {
    background: linear-gradient(135deg, rgba(79,124,255,0.08), rgba(124,58,237,0.08));
    border: 1px solid rgba(79,124,255,0.2);
    border-radius: 14px;
    padding: 22px 26px;
    margin-bottom: 16px;
  }

  .highlight-box p { color: var(--text); font-weight: 300; }

  /* Keylines */
  .kl {
    color: var(--accent);
    font-weight: 600;
    font-size: 0.95rem;
  }

  /* Footer */
  .footer {
    text-align: center;
    margin-top: 60px;
    padding-top: 32px;
    border-top: 1px solid var(--border);
    color: var(--text-dim);
    font-size: 13px;
  }

  .footer a { color: var(--accent); text-decoration: none; }

  /* Animations */
  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(18px); }
    to   { opacity: 1; transform: translateY(0); }
  }
  @keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
  }
  @keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.4; }
  }

  /* Divider */
  .divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border), transparent);
    margin: 20px 0;
  }

  ul.clean {
    list-style: none;
    padding: 0;
  }
  ul.clean li {
    color: var(--text-muted);
    font-weight: 300;
    padding: 4px 0;
    padding-left: 16px;
    position: relative;
    font-size: 14px;
  }
  ul.clean li::before {
    content: '–';
    position: absolute;
    left: 0;
    color: var(--accent);
  }

  .status-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(34,197,94,0.1);
    border: 1px solid rgba(34,197,94,0.25);
    color: #166534;
    font-size: 11px;
    padding: 3px 10px;
    border-radius: 50px;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-left: 12px;
    vertical-align: middle;
  }

  body[data-theme='dark'] .status-badge {
    color: #86efac;
  }

  .status-dot {
    width: 6px; height: 6px;
    border-radius: 50%;
    background: #4ade80;
    animation: pulse 1.8s ease-in-out infinite;
  }
  
  /* Theme Toggle Button */
  .theme-toggle-container {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 100;
  }
  
  #theme-toggle {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text-muted);
    width: 42px;
    height: 42px;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
  }
  
  #theme-toggle:hover {
    border-color: var(--accent);
    color: var(--accent);
  }