/* ============================================ */
    /* MOBILE-FIRST LAYOUT CONTROL                */
    /* ============================================ */
    .mobile-layout {
      display: flex;
      flex-direction: column;
      height: 100vh;
      width: 100%;
    }

    .desktop-layout {
      display: none;
    }

    /* Character counter hidden state */
    .char-counter.hidden,
    .desktop-char-counter.hidden {
      opacity: 0;
      visibility: hidden;
    }

    /* Show character counter when input focused */
    .chat-input-wrapper:focus-within .char-counter,
    .desktop-input-wrapper:focus-within .desktop-char-counter {
      opacity: 1;
      visibility: visible;
    }

    /* Toggle label full width for better clickability */
    .menu-toggle-label,
    .toggle-label {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      cursor: pointer;
    }

    /* FIX: Remove rectangular border from input wrapper */
    .chat-input-wrapper,
    .desktop-input-wrapper {
      border: none !important;
      outline: none !important;
      box-shadow: none !important;
    }

    /* FIX: Mobile input positioning */
    .chat-input-container {
      padding-bottom: env(safe-area-inset-bottom, 0);
      margin-bottom: 0;
    }

    /* Customer Service Mode Button Styling */
    .menu-item-customer-service {
      background-color: var(--color-info);
      color: white;
      border-color: var(--color-info);
      box-shadow: var(--shadow-md);
      margin-bottom: 1rem;
    }

    .menu-item-customer-service:hover {
      background-color: #1c7ed6;
      transform: translateY(-2px);
      box-shadow: var(--shadow-lg);
    }

    .dashboard-btn-customer-service {
      background-color: var(--color-info);
      color: white;
      border-color: var(--color-info);
      box-shadow: var(--shadow-md);
    }

    .dashboard-btn-customer-service:hover {
      background-color: #1c7ed6;
      transform: translateY(-2px);
      box-shadow: var(--shadow-lg);
    }

    /* ============================================ */
    /* DESKTOP LAYOUT (≥ 1024px)                  */
    /* ============================================ */
    @media (min-width: 1024px) {
      .mobile-layout {
        display: none !important;
      }

      .desktop-layout {
        display: grid !important;
        grid-template-rows: auto 1fr auto;
        grid-template-columns: 280px 1fr 320px;
        min-height: 100vh;
        height: 100vh;
        gap: 0;
        overflow: hidden;
      }

      /* Header Styling */
      .desktop-layout .pmerit-header {
        grid-row: 1;
        grid-column: 1 / -1;
        height: var(--header-height, 70px);
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 0 1.5rem;
        background-color: var(--bg-card);
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow);
        z-index: 50;
      }

      .pmerit-logo {
        font-weight: 700;
        font-size: 1.5rem;
        color: var(--primary);
        display: flex;
        align-items: center;
        gap: 0.5rem;
      }

      .pmerit-logo::before {
        content: "🎓";
        font-size: 1.5rem;
      }

      .header-nav {
        display: flex;
        align-items: center;
        gap: 0.75rem;
      }

      .nav-btn {
        padding: 0.5rem 1rem;
        border-radius: 50px;
        font-weight: 500;
        font-size: 0.9rem;
        cursor: pointer;
        transition: var(--transition);
        border: 1px solid var(--border-color);
        background-color: var(--bg-card);
        color: var(--text-primary);
        min-height: 44px;
      }

      .nav-btn:hover {
        border-color: var(--primary);
        transform: translateY(-1px);
      }

      .nav-btn.primary {
        background-color: var(--primary);
        color: white;
        border-color: var(--primary);
      }

      .nav-btn.primary:hover {
        background-color: var(--primary-dark);
        transform: translateY(-2px);
        box-shadow: var(--shadow-lg);
      }

      /* Sidebars */
      .desktop-layout .left-sidebar,
      .desktop-layout .right-sidebar {
        grid-row: 2;
        background-color: var(--bg-secondary);
        padding: 1.5rem 1rem;
        overflow-y: auto;
        min-height: 0;
      }

      .desktop-layout .left-sidebar {
        grid-column: 1;
        border-right: 1px solid var(--border-color);
      }

      .desktop-layout .right-sidebar {
        grid-column: 3;
        border-left: 1px solid var(--border-color);
      }

      /* Center Panel */
      .desktop-layout .center-panel {
        grid-row: 2;
        grid-column: 2;
        background-color: var(--bg-primary);
        display: grid;
        grid-template-rows: 1fr auto;
        gap: 12px;
        min-height: 0;
        overflow: hidden;
        padding: 12px;
      }

      .desktop-layout .chat-stream {
        grid-row: 1;
        position: relative;
        overflow-y: auto;
        padding: 8px 12px 0;
        min-height: 0;
      }

      .desktop-chat-container {
        display: flex;
        flex-direction: column;
        gap: 1.5rem;
        padding: 1rem 0;
      }

      .desktop-chat-message {
        display: flex;
        gap: 1rem;
        align-items: flex-start;
      }

      .message-avatar {
        width: 40px;
        height: 40px;
        border-radius: 50%;
        background: var(--primary);
        color: white;
        display: flex;
        align-items: center;
        justify-content: center;
        flex-shrink: 0;
      }

      .message-content {
        background: var(--bg-card);
        border: 1px solid var(--border-color);
        border-radius: 12px;
        padding: 1rem;
        max-width: 80%;
        box-shadow: var(--shadow);
      }

      .message-header {
        margin-bottom: 0.5rem;
        color: var(--primary);
      }

      .message-content p {
        margin: 0;
        line-height: 1.6;
        color: var(--text-primary);
      }

      .desktop-layout .interaction-bar,
      .desktop-layout .desktop-chat-input-area {
        grid-row: 2;
        position: relative;
        padding: 8px 12px;
        border-top: 1px solid var(--border-color);
        background: var(--bg-card);
        border-radius: 12px;
      }

      /* Footer */
      .desktop-layout .pmerit-footer {
        grid-row: 3;
        grid-column: 1 / -1;
        padding: 0.75rem 1.5rem;
        background-color: var(--bg-card);
        border-top: 1px solid var(--border-color);
        box-shadow: 0 -1px 2px rgba(0, 0, 0, 0.05);
        min-height: auto;
        height: auto;
        line-height: 1.2;
      }
      
      .footer-container {
        max-width: 1400px;
        margin: 0 auto;
        padding: 0;
        display: flex;
        align-items: center;
        justify-content: space-between;
        gap: 1.5rem;
      }
      
      .footer-left {
        display: flex;
        align-items: center;
        gap: 0.5rem;
        font-weight: 500;
        font-size: 0.85rem;
        color: var(--text-primary);
      }
      
      .footer-left i {
        font-size: 0.75rem;
        color: var(--color-success);
      }
      
      .footer-status {
        color: var(--primary);
      }
      
      .footer-right {
        display: flex;
        align-items: center;
        gap: 1rem;
      }
      
      .footer-link {
        color: var(--text-secondary);
        text-decoration: none;
        font-size: 0.85rem;
        padding: 0.25rem 0.5rem;
        border-radius: 4px;
        transition: var(--transition-fast);
      }
      
      .footer-link:hover {
        color: var(--primary);
        background-color: var(--bg-secondary);
      }

      /* Sidebar Components */
      .pane-title {
        font-weight: 700;
        font-size: 1.1rem;
        color: var(--primary);
        margin-bottom: 1rem;
      }

      .toggle, .action {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 0.75rem;
        border-radius: 8px;
        margin-bottom: 0.5rem;
        cursor: pointer;
        transition: var(--transition);
        background-color: var(--bg-card);
        border: 1px solid var(--border-color);
        min-height: 44px;
      }

      .toggle:hover, .action:hover {
        border-color: var(--primary);
        transform: translateY(-1px);
        box-shadow: var(--shadow);
      }

      .icon {
        color: var(--primary);
        margin-right: 0.5rem;
      }

      /* Toggle Switch Component */
      .toggle-switch {
        position: relative;
        width: 40px;
        height: 20px;
        display: inline-block;
        flex-shrink: 0;
      }

      .toggle-switch input[type="checkbox"] {
        opacity: 0;
        width: 0;
        height: 0;
        position: absolute;
      }

      .toggle-slider {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: #ccc;
        border-radius: 34px;
        transition: .4s;
        cursor: pointer;
      }

      .toggle-slider::before {
        content: "";
        position: absolute;
        width: 16px;
        height: 16px;
        left: 2px;
        bottom: 2px;
        background-color: white;
        border-radius: 50%;
        transition: .4s;
      }

      .toggle-switch input[type="checkbox"]:checked + .toggle-slider {
        background-color: var(--primary);
      }

      .toggle-switch input[type="checkbox"]:checked + .toggle-slider::before {
        transform: translateX(20px);
      }

      /* Dashboard Button */
      .dashboard-btn {
        width: 100%;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
        padding: 0.75rem;
        border-radius: 8px;
        margin-bottom: 1rem;
        cursor: pointer;
        transition: var(--transition);
        border: 1px solid var(--border-color);
        background-color: var(--bg-card);
        font-weight: 600;
        min-height: 44px;
      }

      .dashboard-btn:hover {
        border-color: var(--primary);
        transform: translateY(-1px);
        box-shadow: var(--shadow);
      }

      .dashboard-btn-primary {
        background-color: var(--primary);
        color: white;
        border-color: var(--primary);
        box-shadow: var(--shadow-md);
      }

      .dashboard-btn-primary:hover {
        background-color: var(--primary-dark);
        transform: translateY(-2px);
        box-shadow: var(--shadow-lg);
      }

      /* Collapsible Component */
      .collapsible {
        border: 1px solid var(--border-color);
        border-radius: 8px;
        overflow: hidden;
        background-color: var(--bg-card);
        margin-bottom: 0.5rem;
      }

      .collapsible-header {
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 0.75rem;
        cursor: pointer;
        background-color: var(--bg-secondary);
        transition: var(--transition);
      }

      .collapsible-header:hover {
        background-color: var(--border-color);
      }

      .collapsible-body {
        display: none;
        padding: 0.75rem;
        background-color: var(--bg-card);
        border-top: 1px solid var(--border-color);
      }

      .collapsible.open .collapsible-body {
        display: block;
      }

      /* Support Cards */
      .support-card {
        background-color: var(--bg-card);
        border: 1px solid var(--border-color);
        border-radius: 8px;
        padding: 1rem;
        margin-bottom: 1rem;
      }

      .support-card h3 {
        margin-bottom: 0.5rem;
        color: var(--primary);
        font-size: 1rem;
      }

      .support-buttons {
        display: flex;
        gap: 0.5rem;
        margin-top: 1rem;
      }

      .support-btn {
        flex: 1;
        padding: 0.6rem;
        border-radius: 6px;
        border: 1px solid var(--border-color);
        background: var(--bg-card);
        color: var(--text-primary);
        cursor: pointer;
        transition: var(--transition);
        font-size: 0.85rem;
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 0.25rem;
      }

      .support-btn:hover {
        border-color: var(--color-info);
        background: var(--color-info);
        color: #FFFFFF;
        transform: translateY(-1px);
      }

      [data-theme="dark"] .support-btn:hover {
        background: #1c7ed6;
        border-color: #1c7ed6;
      }

      .support-btn i {
        font-size: 1.2rem;
        color: var(--color-info);
      }

      .support-btn:hover i {
        color: #FFFFFF;
      }

      /* CTA Button */
      .cta-large {
        width: 100%;
        background: var(--primary);
        color: white;
        padding: 0.75rem;
        border-radius: 8px;
        border: none;
        text-align: center;
        font-weight: 600;
        cursor: pointer;
        transition: var(--transition);
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 0.5rem;
      }

      .cta-large:hover {
        background: var(--primary-dark);
        transform: translateY(-2px);
        box-shadow: var(--shadow-lg);
      }
    }

    /* ============================================ */
    /* LARGER DESKTOP (≥ 1440px)                  */
    /* ============================================ */
    @media (min-width: 1440px) {
      .desktop-layout {
        grid-template-columns: 280px 1fr 360px;
      }
    }