:root {
    --bg: #091413;
    --surface: #285A48;
    --surface2: #408A71;
    --border: rgba(255,255,255,0.08);
    --border-hover: rgba(255,255,255,0.18);
    --text: #F5F4F2;
    --muted: #B0E4CC;
    --accent: #c8f565;
    --accent-dim: rgba(200,245,101,0.12);
    --accent-text: #1a2600;
    --red: #ff6b6b;
    --blue: #64b5f6;
    --radius: 12px;
    --radius-sm: 8px;
  }

  body.light {
    --bg: #F2F2F2;
    --surface: #e4e5f1;
    --surface2: #f0ede8;
    --border: rgba(0,0,0,0.09);
    --border-hover: rgba(0,0,0,0.2);
    --text: #1a1a18;
    --muted: #403E3D;
    --accent: #2588E6;
    --accent-dim: rgba(74,124,0,0.10);
    --accent-text: #f4f2ee;
  }

  body.light select option { background: #ffffff; color: #1a1a18; }

  body {
    font-family: 'Syne', sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 0 0 4rem;
    transition: background 0.25s, color 0.25s;
  }

  /* ---- TOP NAVBAR ---- */
  .navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 5px;
    border-bottom: 1px solid var(--border);
    background: var(--surface);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    transition: background 0.25s, border-color 0.25s;
  }

  .navbar-logo {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    text-decoration: none;
  }

  .navbar-logo .logo-icon {
    border-radius: 8px;
    padding: 3px;
    background: #fafafa;
    display: flex; align-items: center; justify-content: center;
    font-size: 1rem;
    flex-shrink: 0;
    color: var(--accent);
  }

  .navbar-logo .logo-text {
    font-family: 'Syne', sans-serif;
    font-weight: 800;
    font-size: 1.05rem;
    letter-spacing: -0.02em;
    color: var(--text);
    line-height: 1;
  }

  .navbar-logo .logo-text span { color: var(--accent); }

  .theme-toggle {
    display: flex;
    align-items: center;
    gap: 8px;
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 40px;
    padding: 4px 6px;
    cursor: pointer;
    transition: all 0.2s;
  }

  .theme-toggle:hover { border-color: var(--border-hover); }

  .theme-toggle .t-icon {
    width: 28px; height: 28px;
    border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    font-size: 0.85rem;
    transition: all 0.2s;
    color: var(--muted);
  }

  .theme-toggle .t-icon.active {
    background: var(--accent);
    color: var(--accent-text);
  }

  .page-body {
    padding: 1rem 1rem 0;
  }

  .header {
    text-align: center;
    margin: 2px;
  }

  .header h4 {
    font-size: 20px;
    font-weight: 200;
    color: var(--text);
  }

  .header h4 span { color: var(--accent); }

  .header p {
    color: var(--muted);
    font-size: 0.85rem;
    margin-top: 0.4rem;
    font-family: 'DM Mono', monospace;
    font-weight: 300;
  }

  .tabs-wrap {
    max-width: 800px;
    margin: 0 auto;
  }

  .tab-bar {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 4px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 4px;
    margin-bottom: 1.5rem;
  }

  .tab-btn {
    background: transparent;
    border: none;
    color: var(--muted);
    font-family: 'Syne', sans-serif;
    font-weight: 500;
    font-size: 0.72rem;
    padding: 0.65rem 0.4rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    letter-spacing: 0.01em;
    line-height: 1.3;
    text-align: center;
  }

  .tab-btn .icon {
    font-size: 1.1rem;
    line-height: 1;
  }

  .tab-btn:hover { color: var(--text); background: var(--surface2); }

  .tab-btn.active {
    background: var(--accent);
    color: var(--accent-text);
    font-weight: 700;
  }

  .tab-panel { display: none; }
  .tab-panel.active { display: block; }

  .panel-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.8rem;
  }

  .panel-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.6rem;
  }

  .panel-title span.dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    background: var(--accent);
    display: inline-block;
    flex-shrink: 0;
  }

  label {
    display: block;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--muted);
    margin-bottom: 0.4rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
  }

  input[type=text], input[type=number], select, textarea {
    width: 100%;
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-family: 'DM Mono', monospace;
    font-size: 0.9rem;
    padding: 0.7rem 0.9rem;
    outline: none;
    transition: border-color 0.2s;
    appearance: none;
  }

  input[type=text]:focus, input[type=number]:focus, select:focus, textarea:focus {
    border-color: var(--accent);
  }

  select option { background: #1a1a1a; }

  .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    background: var(--accent);
    color: var(--accent-text);
    border: none;
    border-radius: var(--radius-sm);
    font-family: 'Syne', sans-serif;
    font-weight: 700;
    font-size: 0.85rem;
    padding: 0.65rem 1.4rem;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.1s;
    letter-spacing: 0.02em;
  }

  .btn:hover { opacity: 0.88; }
  .btn:active { transform: scale(0.97); }

  .btn-ghost {
    background: var(--surface2);
    color: var(--text);
    border: 1px solid var(--border);
  }

  .btn-ghost:hover { border-color: var(--border-hover); }

  .result-box {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 1.1rem 1.2rem;
    font-family: 'DM Mono', monospace;
    font-size: 0.9rem;
  }

  .result-box .result-label {
    font-size: 0.7rem;
    color: var(--muted);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    margin-bottom: 0.4rem;
  }

  .result-value {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--accent);
    font-family: 'Syne', monospace;
  }

  .grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
  .grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1rem; }

  .mt { margin-top: 1rem; }
  .mt2 { margin-top: 1.5rem; }

  .sep {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin: 1.2rem 0;
    color: var(--muted);
    font-size: 0.75rem;
    font-family: 'DM Mono', monospace;
  }

  .sep::before, .sep::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
  }

  .swap-btn {
    background: var(--surface2);
    border: 1px solid var(--border);
    color: var(--accent);
    border-radius: 50%;
    width: 36px; height: 36px;
    font-size: 1.1rem;
    cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    align-self: flex-end;
    margin-bottom: 0;
    transition: background 0.2s;
    flex-shrink: 0;
  }

  .swap-btn:hover { background: var(--accent-dim); }

  #qr-output {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    background: white;
    border-radius: var(--radius-sm);
    padding: 1.2rem;
    margin-top: 1.2rem;
  }

  #qr-output canvas, #qr-output img { display: block; }

  .badge {
    display: inline-block;
    font-size: 0.68rem;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 4px;
    background: var(--accent-dim);
    color: var(--accent);
    letter-spacing: 0.05em;
  }

  .upload-zone {
    border: 1.5px dashed var(--border-hover);
    border-radius: var(--radius);
    padding: 2rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    background: transparent;
  }

  .upload-zone:hover, .upload-zone.drag-over {
    border-color: var(--accent);
    background: var(--accent-dim);
  }

  .upload-zone input { display: none; }

  .upload-icon {
    font-size: 2rem;
    margin-bottom: 0.6rem;
    opacity: 0.5;
  }

  .upload-zone p {
    font-size: 0.85rem;
    color: var(--muted);
    margin-bottom: 0.3rem;
  }

  .img-thumb-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: 8px;
    margin-top: 1rem;
  }

  .img-thumb {
    position: relative;
    aspect-ratio: 1;
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid var(--border);
  }

  .img-thumb img {
    width: 100%; height: 100%;
    object-fit: cover;
  }

  .img-thumb .rm {
    position: absolute;
    top: 2px; right: 2px;
    width: 18px; height: 18px;
    background: rgba(0,0,0,0.75);
    color: #fff;
    border-radius: 50%;
    font-size: 10px;
    display: flex; align-items: center; justify-content: center;
    cursor: pointer;
    border: none;
  }

  .size-bar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8rem;
    color: var(--muted);
    margin-top: 0.3rem;
    font-family: 'DM Mono', monospace;
  }

  .size-bar .bar {
    flex: 1;
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
  }

  .size-bar .bar-fill {
    height: 100%;
    background: var(--accent);
    border-radius: 2px;
    transition: width 0.4s;
  }

  .info-chip {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: 0.75rem;
    font-family: 'DM Mono', monospace;
    color: var(--muted);
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 3px 10px;
  }

  .row-flex {
    display: flex;
    align-items: flex-end;
    gap: 0.8rem;
  }

  .row-flex > * { flex: 1; }
  .row-flex > .flex-none { flex: none; }

  @media (max-width: 500px) {
    .grid-2, .grid-3 { grid-template-columns: 1fr; }
    .tab-btn { font-size: 0.65rem; padding: 0.55rem 0.2rem; }
    .panel-card { padding: 1.2rem; }
  }