/* CSS Reset and Base Styles */
        :root {
            --primary-color: #d8715a;
            --primary-hover: #904141;
            --background-color: #F7FAFC;
            --panel-background: #FFFFFF;
            --border-color: #E2E8F0;
            --text-primary: #2D3748;
            --text-secondary: #718096;
            --shadow-color: rgba(0, 0, 0, 0.1);
            --danger-color: #E53E3E;
        }

        /* Lightbox Overlay & Animation */
        .mindmap-lightbox-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            display: flex;
            justify-content: center;
            align-items: center;
            z-index: 999999999;
            backdrop-filter: blur(8px);
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.3s ease, visibility 0.3s ease;
        }

        .mindmap-lightbox-overlay.visible {
            opacity: 1;
            visibility: visible;
        }

        .mindmap-lightbox-content {
            background: var(--panel-background);
            border-radius: 24px;
            box-shadow: 0 20px 40px var(--shadow-color);
            width: 95%;
            height: 90%;
            max-width: 1600px;
            display: flex;
            overflow: hidden;
            position: relative;
            transform: scale(0.95);
            transition: transform 0.3s ease;
        }
        
        .mindmap-lightbox-overlay.visible .mindmap-lightbox-content {
            transform: scale(1);
        }

        .mindmap-close-btn {
            position: absolute;
            top: 20px;
            right: 25px;
            font-size: 2rem;
            color: var(--text-secondary);
            cursor: pointer;
            z-index: 1010;
            transition: color 0.2s;
        }
        .mindmap-close-btn:hover {
            color: var(--text-primary);
        }

        /* Left Input Panel */
        .mindmap-left-panel {
            flex-basis: 320px;
            flex-shrink: 0;
            padding: 40px;
            background: #FDFDFD;
            border-right: 1px solid var(--border-color);
            display: flex;
            flex-direction: column;
            overflow-y: auto;
        }
        
        .mindmap-left-panel h3 {
            margin-top: 0;
            color: var(--text-primary);
            font-size: 1.5rem;
        }

        .mindmap-left-panel p {
            font-size: 0.95rem;
            color: var(--text-secondary);
            line-height: 1.6;
            margin-bottom: 25px;
        }
        
        #mindmap-input, #mindmap-develop-input {
            width: 100%;
            border-radius: 12px;
            border: 1px solid var(--border-color);
            padding: 15px;
            font-size: 1rem;
            font-family: 'Inter', 'Noto Sans Sinhala', sans-serif;
            resize: none;
            margin-bottom: 40px;
            box-sizing: border-box;
            transition: border-color 0.2s, box-shadow 0.2s;
            background-color: #F7FAFC;
            flex-grow: 1;
            min-height: 200px;
        }
        /* Watermark for mindmap visualizer */
        #mindmap-visualizer::before {
            content: "apilage mind map";
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%) rotate(-30deg);
            font-size: 5rem;
            font-weight: 900;
            color: rgba(0, 0, 0, 0.08);
            user-select: none;
            pointer-events: none;
            z-index: 0;
            white-space: nowrap;
            text-shadow: 2px 2px 6px rgba(0,0,0,0.1);
        }
        
        #mindmap-input:focus, #mindmap-develop-input:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 3px rgba(90, 103, 216, 0.2);
            background-color: white;
        }
        
        .mindmap-button {
            padding: 15px 20px;
            border: none;
            background-image: linear-gradient(45deg, #ea8766 0%, #d8625a 100%);
            color: white;
            border-radius: 12px;
            font-size: 1rem;
            font-weight: 700;
            cursor: pointer;
            transition: transform 0.2s ease, box-shadow 0.2s ease;
            box-shadow: 0 4px 15px rgba(216, 98, 90, 0.3);
        }

        .mindmap-button:hover {
            transform: translateY(-2px);
            box-shadow: 0 7px 20px rgba(144, 65, 65, 0.4);
        }

        .ai-assistant {
            margin-top: 20px;
            border-top: 1px solid var(--border-color);
            padding-top: 20px;
        }
        
        /* Right Visualization Panel */
        .mindmap-right-panel {
            flex-grow: 1;
            position: relative;
            overflow: hidden;
            background-color: #F9F9F9;
            cursor: grab;
        }
        .mindmap-right-panel.connecting-mode {
            cursor: crosshair;
        }
        .mindmap-right-panel:active {
            cursor: grabbing;
        }

        #mindmap-visualizer {
            width: 100%;
            height: 100%;
            position: relative;
        }
        
        #mindmap-canvas {
            position: absolute;
            transform-origin: 0 0;
            width: 300%;
            height: 300%;
            top: -100%;
            left: -100%;
        }

        /* Mind Map Node Styles */
        .mindmap-node {
            position: absolute;
            padding: 12px 24px;
            border-radius: 12px;
            color: black;
            min-width: 60px;
            text-align: center;
            cursor: grab;
            user-select: none;
            box-shadow: 0 5px 15px rgba(0,0,0,0.08);
            transition: all 0.2s ease-out;
            font-weight: 500;
            border: 1px solid transparent;
        }
        .connecting-mode .mindmap-node {
            cursor: crosshair;
        }
        .mindmap-node.connection-start {
            box-shadow: 0 0 0 4px var(--primary-color);
        }

        .mindmap-node:active {
            cursor: grabbing;
            box-shadow: 0 10px 25px rgba(0,0,0,0.2);
            transform: scale(1.05);
            z-index: 10;
        }
        
        .mindmap-node.color-main { 
            background-color: #D6BCFA;
            color: black;
            border-color: #BF9CF7;
        }
        .mindmap-node.color-0 { background-color: #ff5d78; border-color: #ca112d;}
        .mindmap-node.color-1 { background-color: #f6ad4d; border-color: #b06707;}
        .mindmap-node.color-2 { background-color: #36f5d5; border-color: #0a7206;}
        .mindmap-node.color-3 { background-color: #377dee; border-color: #195bea;}
        
        .mindmap-node:focus {
            outline: 3px solid var(--primary-color);
            outline-offset: 2px;
        }

        /* Node Action Buttons */
        .node-actions {
            position: absolute;
            top: -8px;
            right: -8px;
            display: flex;
            opacity: 0;
            transform: scale(0.5);
            transition: all 0.2s ease;
        }
        .mindmap-node:hover .node-actions {
            opacity: 1;
            transform: scale(1);
        }
        .node-action-btn {
            width: 20px;
            height: 20px;
            color: white;
            border-radius: 50%;
            border: 2px solid white;
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 12px;
            font-weight: bold;
            cursor: pointer;
            margin-left: 4px;
        }
        .delete-node-btn { background: var(--danger-color); }
        .info-node-btn { background: var(--primary-color); }

        /* Node Note Style */
        .node-note {
            position: absolute;
            bottom: calc(100% + 10px);
            left: 50%;
            transform: translateX(-50%);
            width: 200px;
            background: white;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 10px;
            font-size: 0.9rem;
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
            z-index: 20;
            display: none; /* Hidden by default */
        }
        .node-note:focus {
            outline: 2px solid var(--primary-color);
        }

        /* Manual Text Block Style */
        .manual-text-block {
            position: absolute;
            padding: 10px;
            background: rgba(255, 255, 255, 0.7);
            border: 1px dashed var(--text-secondary);
            border-radius: 8px;
            cursor: move;
            z-index: 5;
            backdrop-filter: blur(2px);
        }
        .manual-text-block:focus {
            outline: 2px solid var(--primary-color);
        }
        .manual-text-block .delete-text-btn {
            position: absolute;
            top: -8px;
            right: -8px;
            width: 18px;
            height: 18px;
            background: var(--danger-color);
            color: white;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            font-size: 11px;
            cursor: pointer;
            opacity: 0;
            transition: opacity 0.2s;
        }
        .manual-text-block:hover .delete-text-btn {
            opacity: 1;
        }

        /* SVG Connection Lines */
        .mindmap-connector {
            stroke: black;
            stroke-width: 2.5px;
            fill: none;
            stroke-linecap: round;
            stroke-linejoin: round;
            animation: draw-line 0.8s ease-out forwards;
            pointer-events: auto; /* Allow clicks on connectors */
            cursor: pointer;
        }
        .mindmap-connector.selected {
            stroke: var(--primary-color);
            stroke-dasharray: 5, 5;
        }
        
        @keyframes draw-line {
            from { opacity: 0; }
            to { opacity: 1; }
        }
        
        /* Loader Animation */
        .mindmap-loader {
            position: absolute;
            inset: 0;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            background: rgba(255, 255, 255, 0.9);
            z-index: 20;
            transition: opacity 0.3s;
        }
        .mindmap-loader p {
            margin-top: 20px;
            font-size: 1.2rem;
            color: var(--text-primary);
            font-weight: 500;
        }
        .mindmap-spinner {
            width: 50px;
            height: 50px;
            border: 5px solid var(--border-color);
            border-top-color: var(--primary-color);
            border-radius: 50%;
            animation: mindmap-spin 1s linear infinite;
        }
        @keyframes mindmap-spin {
            to { transform: rotate(360deg); }
        }

        /* Toolbar for new buttons */
        .mindmap-toolbar {
            position: absolute;
            top: 20px;
            right: 70px;
            display: flex;
            gap: 10px;
            z-index: 10;
        }
        .mindmap-toolbar button {
            background: rgba(255, 255, 255, 0.8);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 8px 12px;
            cursor: pointer;
            backdrop-filter: blur(5px);
            transition: background 0.2s, box-shadow 0.2s;
        }
        .mindmap-toolbar button:hover {
            background: white;
        }
        .mindmap-toolbar button.active {
            background: var(--primary-color);
            color: white;
            box-shadow: 0 2px 8px rgba(90, 103, 216, 0.4);
        }

        /* Help text for new features */
        .help-text {
            position: absolute;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
            background: rgba(0,0,0,0.6);
            color: white;
            padding: 8px 15px;
            border-radius: 20px;
            font-size: 0.9rem;
            z-index: 10;
            user-select: none;
        }

        /* Context Menu */
        #context-menu {
            position: fixed;
            display: none;
            background: white;
            border-radius: 8px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.2);
            z-index: 100;
            padding: 5px 0;
        }
        .context-menu-item {
            padding: 8px 15px;
            cursor: pointer;
        }
        .context-menu-item:hover {
            background: #f0f0f0;
        }



/* Dark Mode Styles */
[data-theme="dark"] {
    --background-color: #1e1e1e;
    --panel-background: #252526;
    --border-color: #3c3c3c;
    --text-primary: #f3f3f3;
    --text-secondary: #c5c5c5;
    --shadow-color: rgba(0, 0, 0, 0.6);
}
[data-theme="dark"] .mindmap-left-panel {
    background: var(--panel-background);
}
[data-theme="dark"] #mindmap-input,
[data-theme="dark"] #mindmap-develop-input {
    background-color: #2d2d2d;
    border-color: var(--border-color);
    color: var(--text-primary);
}
[data-theme="dark"] #mindmap-input:focus,
[data-theme="dark"] #mindmap-develop-input:focus {
    background-color: #1e1e1e;
}
[data-theme="dark"] .mindmap-right-panel {
    background-color: #F9F9F9;
}
[data-theme="dark"] .mindmap-node {
    color: var(--text-primary);
    box-shadow: 0 5px 15px rgba(0,0,0,0.4);
}
[data-theme="dark"] .node-note {
    background: #2d2d2d;
    border-color: var(--border-color);
    color: var(--text-primary);
}
[data-theme="dark"] .mindmap-button {
    background-image: linear-gradient(45deg, #bb4c3a 0%, #a13a35 100%);
    box-shadow: 0 4px 15px rgba(161, 58, 53, 0.3);
}
[data-theme="dark"] .mindmap-toolbar button {
    background: rgba(50, 50, 50, 0.8);
    border-color: var(--border-color);
    color: var(--text-primary);
}
[data-theme="dark"] .mindmap-toolbar button.active {
    background: var(--primary-color);
    color: #fff;
}
/* =========================
   Responsive: Mobile & Small-screen Improvements
   (Add at end of file)
   ========================= */

/* Large tablets & small laptops: stack the panels vertically */
@media (max-width: 1200px) {
  .mindmap-lightbox-content {
    width: 98%;
    height: 94%;
    max-width: 1200px;
    border-radius: 18px;
    flex-direction: column; /* left panel becomes top, visualiser below */
  }

  .mindmap-left-panel {
    flex-basis: auto;
    width: 100%;
    max-height: 300px;
    padding: 20px;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
    overflow-y: auto;
  }

  .mindmap-right-panel {
    height: calc(100% - 300px);
    min-height: 320px;
  }

  /* Make the canvas fit the new layout */
  #mindmap-canvas {
    width: 100% !important;
    height: 100% !important;
    top: 0 !important;
    left: 0 !important;
    transform: none !important;
  }

  .mindmap-toolbar { top: 12px; right: 12px; left: auto; }
}

/* Tablets & large phones: increase tap targets & reduce clutter */
@media (max-width: 900px) {
  #mindmap-input, #mindmap-develop-input {
    min-height: 160px;
    padding: 12px;
    font-size: 0.95rem;
  }

  .mindmap-button {
    width: 100%;
    padding: 12px 14px;
    font-size: 1rem;
    border-radius: 10px;
  }

  .mindmap-close-btn {
    font-size: 1.6rem;
    top: 10px;
    right: 12px;
  }

  .mindmap-visualizer::before {
    font-size: 3.2rem;
    color: rgba(0,0,0,0.05);
  }

  .mindmap-node {
    padding: 10px 16px;
    font-size: 0.95rem;
    min-width: 54px;
  }

  .node-actions { top: -6px; right: -6px; transform: scale(0.95); }
}

/* Phones: full-screen lightbox, hide large watermark, improve touch UX */
@media (max-width: 480px) {
  .mindmap-lightbox-overlay {
    padding: 0;
    align-items: stretch;
  }

  .mindmap-lightbox-content {
    width: 100%;
    height: 100%;
    max-width: none;
    border-radius: 0;
    overflow: hidden;
  }

  /* Left panel becomes a scrollable top panel */
  .mindmap-left-panel {
    order: 2;
    width: 100%;
    max-height: 220px;
    padding: 12px 14px;
    border-bottom: 1px solid var(--border-color);
    overflow-y: auto;
  }

  .mindmap-right-panel { order: 1; height: calc(100% - 220px); }

  #mindmap-input, #mindmap-develop-input {
    min-height: 120px;
    padding: 10px;
    font-size: 0.95rem;
  }

  .mindmap-button { padding: 10px; font-size: 0.95rem; }

  /* Move toolbar to bottom-left for thumb reach */
  .mindmap-toolbar {
    top: auto;
    bottom: 12px;
    left: 12px;
    right: auto;
    gap: 8px;
  }

  .help-text { display: none; } /* reduce visual noise */
  .mindmap-node {
    padding: 8px 12px;
    font-size: 0.85rem;
    min-width: 44px;
  }

  /* Avoid aggressive scale when dragging on mobile */
  .mindmap-node:active { transform: none; }

  /* Hide the large watermark on tiny screens */
  #mindmap-visualizer::before { display: none; }

  /* Make node actions easier to tap */
  .node-actions { opacity: 1; transform: scale(1); }

  /* Reduce clutter */
  .manual-text-block .delete-text-btn { display: none; }
  .mindmap-loader { padding: 10px; }
}

/* Touch-first adjustments: larger tap targets & reduced hover-dependence */
@media (hover: none) and (pointer: coarse) {
  .mindmap-toolbar button { min-width: 44px; height: 44px; padding: 8px; }
  .mindmap-button { padding: 12px; }
  .mindmap-node { -webkit-tap-highlight-color: rgba(0,0,0,0.03); touch-action: manipulation; }
  /* make actions visible on touch devices */
  .mindmap-node:hover .node-actions { opacity: 1; transform: scale(1); }
}

/* Small z-index / overlay fixes for mobile contexts */
@media (max-width: 768px) {
  #context-menu { z-index: 2000; }
  .mindmap-lightbox-overlay { z-index: 1000000; }
}

/* Respect reduced motion preference */
@media (prefers-reduced-motion: reduce) {
  .mindmap-lightbox-overlay, .mindmap-lightbox-content, .mindmap-node, .mindmap-connector {
    transition: none !important;
    animation: none !important;
  }
}