/* Enhanced styles for subnetting tool */
    .mode-toggle {
      display: inline-flex;
      border-radius: 999px;
      background: rgba(26, 31, 58, 0.9);
      border: 1px solid var(--border-color);
      padding: 4px;
      margin-bottom: 20px;
    }

    .mode-btn {
      border: none;
      background: transparent;
      color: var(--text-secondary);
      font-size: 0.9rem;
      padding: 8px 18px;
      border-radius: 999px;
      cursor: pointer;
      transition: all 0.2s ease;
      display: flex;
      align-items: center;
      gap: 8px;
      white-space: nowrap;
      font-weight: 500;
    }

    .mode-btn.active {
      background: linear-gradient(135deg, var(--primary-cyan), var(--secondary-blue));
      color: var(--dark-bg);
      font-weight: 700;
      box-shadow: 0 4px 12px rgba(0, 212, 255, 0.3);
    }

    .mode-btn .badge {
      font-size: 0.7rem;
      padding: 2px 8px;
      border-radius: 999px;
      background: rgba(10, 14, 39, 0.6);
      color: var(--primary-cyan);
    }

    .mode-btn.active .badge {
      background: rgba(10, 14, 39, 0.8);
      color: var(--primary-cyan);
    }

    .grid {
      display: grid;
      grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
      gap: 20px;
      margin-top: 24px;
    }

    @media (max-width: 960px) {
      .grid {
        grid-template-columns: minmax(0, 1fr);
      }
    }

    .card-header {
      display: flex;
      justify-content: space-between;
      gap: 12px;
      margin-bottom: 16px;
      align-items: flex-start;
    }

    .card-header h2 {
      margin: 0 0 4px 0;
      font-size: 1.2rem;
    }

    .card-header p {
      margin: 0;
      font-size: 0.9rem;
      color: var(--text-secondary);
    }

    .tag {
      display: inline-flex;
      align-items: center;
      border-radius: 999px;
      padding: 4px 12px;
      font-size: 0.75rem;
      background: rgba(0, 212, 255, 0.1);
      border: 1px solid var(--border-color);
      color: var(--text-secondary);
      gap: 6px;
      white-space: nowrap;
    }

    .tag.dot::before {
      content: "";
      width: 7px;
      height: 7px;
      border-radius: 999px;
      background: var(--primary-cyan);
      box-shadow: 0 0 8px var(--primary-cyan);
    }

    .field-group {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
      gap: 14px;
      margin-bottom: 14px;
    }

    label {
      display: block;
      font-size: 0.8rem;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--text-secondary);
      margin-bottom: 6px;
      font-weight: 600;
    }

    input[type="text"],
    input[type="number"],
    select {
      width: 100%;
      padding: 10px 12px;
      border-radius: 10px;
      border: 1px solid var(--border-color);
      background: rgba(5, 8, 16, 0.7);
      color: var(--text-primary);
      font-size: 0.95rem;
      outline: none;
      transition: border 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
      font-family: var(--mono);
    }

    input[type="text"]:focus,
    input[type="number"]:focus,
    select:focus {
      border-color: var(--primary-cyan);
      box-shadow: 0 0 0 3px var(--accent-glow);
      background: rgba(5, 8, 16, 0.9);
    }

    input[readonly] {
      opacity: 0.7;
      cursor: not-allowed;
      background: rgba(5, 8, 16, 0.5);
    }

    select {
      cursor: pointer;
      appearance: none;
      background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2300d4ff' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
      background-repeat: no-repeat;
      background-position: right 12px center;
      padding-right: 36px;
    }

    .btn-row {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      margin-top: 8px;
      margin-bottom: 14px;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--primary-cyan), var(--secondary-blue));
      color: var(--dark-bg);
      box-shadow: 0 8px 20px rgba(0, 212, 255, 0.25);
      font-weight: 700;
    }

    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 12px 30px rgba(0, 212, 255, 0.35);
    }

    .btn-ghost {
      background: rgba(0, 212, 255, 0.08);
      color: var(--primary-cyan);
      border: 1px solid var(--border-color);
      font-weight: 600;
    }

    .btn-ghost:hover {
      border-color: var(--primary-cyan);
      background: rgba(0, 212, 255, 0.15);
      transform: translateY(-1px);
    }

    .output-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
      gap: 10px;
      margin-top: 14px;
    }

    .pill {
      padding: 10px 12px;
      border-radius: 12px;
      background: rgba(5, 8, 16, 0.7);
      border: 1px solid var(--border-color);
      font-size: 0.85rem;
      transition: transform 0.2s ease, box-shadow 0.2s ease;
    }

    .pill:hover {
      transform: translateY(-1px);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    }

    .pill strong {
      display: block;
      font-size: 0.7rem;
      text-transform: uppercase;
      letter-spacing: 0.1em;
      color: var(--text-secondary);
      margin-bottom: 6px;
      font-weight: 700;
    }

    .pill span {
      font-family: var(--mono);
      font-size: 0.9rem;
      word-break: break-all;
      color: var(--text-primary);
      display: block;
    }

    .pill.accent {
      border-color: var(--primary-cyan);
      background: rgba(0, 212, 255, 0.1);
      box-shadow: 0 0 20px rgba(0, 212, 255, 0.15);
    }

    .pill.large {
      grid-column: 1 / -1;
    }

    .error-text {
      color: #f87171;
      font-size: 0.85rem;
      margin-top: 8px;
      padding: 8px 12px;
      background: rgba(248, 113, 113, 0.1);
      border: 1px solid rgba(248, 113, 113, 0.3);
      border-radius: 8px;
    }

    .hidden {
      display: none;
    }

    table {
      width: 100%;
      border-collapse: collapse;
      margin-top: 10px;
      font-size: 0.85rem;
    }

    th,
    td {
      padding: 10px 8px;
      text-align: left;
      border-bottom: 1px solid var(--border-color);
    }

    th {
      font-size: 0.75rem;
      text-transform: uppercase;
      letter-spacing: 0.08em;
      color: var(--text-secondary);
      font-weight: 700;
    }

    tr:nth-child(even) td {
      background: rgba(0, 212, 255, 0.03);
    }

    tbody tr:hover td {
      background: rgba(0, 212, 255, 0.08);
    }

    .link-row {
      margin-top: 20px;
      font-size: 0.9rem;
      color: var(--text-secondary);
      text-align: center;
    }

    .link-row a {
      color: var(--primary-cyan);
      text-decoration: none;
      font-weight: 600;
    }

    .link-row a:hover {
      text-decoration: underline;
    }

    /* Card styling enhancement */
    .card {
      margin-bottom: 20px;
    }

    @media (max-width: 600px) {
      .field-group {
        grid-template-columns: 1fr;
      }
      
      .output-grid {
        grid-template-columns: 1fr;
      }
    }