/* ============================================
   Canvas, Nodes & Connections
   ============================================ */

/* Canvas container */
#canvas-container {
    position: fixed;
    top: var(--toolbar-height);
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    background: var(--bg-primary);
    cursor: grab;
}

#canvas-container.panning {
    cursor: grabbing;
}

#canvas-container.space-held {
    cursor: grab;
}

#canvas-container.space-held.panning {
    cursor: grabbing;
}

/* Grid background pattern */
#canvas-container::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(circle, var(--bg-tertiary) 1px, transparent 1px);
    background-size: 30px 30px;
    opacity: 0.4;
    pointer-events: none;
    z-index: 0;
}

/* Canvas world - transformed layer */
#canvas-world {
    position: absolute;
    top: 0;
    left: 0;
    width: 0;
    height: 0;
    transform-origin: 0 0;
    z-index: var(--z-nodes);
}

/* SVG connections layer */
.connections-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: visible;
    pointer-events: none;
    z-index: var(--z-connections);
}

.connections-layer path {
    pointer-events: stroke;
    cursor: pointer;
}

.connections-layer path:hover {
    stroke: var(--connection-color-hover) !important;
    stroke-width: 2.5 !important;
}

/* ---- Nodes ---- */
.mind-node {
    position: absolute;
    background: var(--node-bg);
    border: 2px solid var(--node-border);
    border-radius: var(--radius-lg);
    padding: 10px 16px;
    min-width: 80px;
    max-width: 300px;
    cursor: pointer;
    transition: box-shadow var(--transition-fast), border-color var(--transition-fast);
    display: flex;
    flex-direction: column;
    gap: 6px;
    z-index: var(--z-nodes);
}

.mind-node:hover {
    background: var(--node-bg-hover);
    box-shadow: 0 0 0 1px var(--node-border-selected);
}

.mind-node.selected {
    border-color: var(--node-border-selected);
    box-shadow: 0 0 16px var(--node-shadow), 0 0 0 2px rgba(108, 92, 231, 0.25);
}

.mind-node.dragging {
    opacity: 0.7;
    z-index: 999;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    transition: none;
}

.mind-node.drop-target {
    border-color: var(--accent-secondary) !important;
    box-shadow: 0 0 20px rgba(0, 184, 148, 0.3) !important;
}

.mind-node.root-node {
    background: linear-gradient(135deg, var(--bg-tertiary), var(--bg-surface));
    border-color: var(--accent-primary);
    min-width: 120px;
}

.mind-node.root-node .node-content {
    font-size: 18px;
    font-weight: 600;
    text-align: center;
}

/* Node content (text) */
.node-content {
    color: var(--text-primary);
    font-size: var(--font-size-base);
    line-height: 1.5;
    word-wrap: break-word;
    outline: none;
    min-height: 1.5em;
    white-space: pre-wrap;
}

.node-content[contenteditable="true"] {
    cursor: text;
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-sm);
    padding: 2px 4px;
    margin: -2px -4px;
}

.node-content:empty::before {
    content: '輸入文字...';
    color: var(--text-muted);
    font-style: italic;
}

/* Node image */
.node-image {
    max-width: 100%;
    max-height: 200px;
    border-radius: var(--radius-sm);
    object-fit: contain;
    margin-top: 4px;
}

/* Collapse/Expand button */
.collapse-btn {
    position: absolute;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--bg-surface);
    border: 2px solid var(--node-border);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-collapse-btn);
    transition: background var(--transition-fast), border-color var(--transition-fast);
}

.collapse-btn:hover {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
}

.collapse-btn svg {
    width: 12px;
    height: 12px;
}

/* Child count badge on collapsed */
.collapse-btn .child-count {
    position: absolute;
    top: -8px;
    right: -8px;
    background: var(--accent-primary);
    color: white;
    font-size: 10px;
    font-weight: 600;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}

/* Box selection */
.box-selection {
    position: fixed;
    border: 1.5px dashed var(--accent-primary);
    background: rgba(108, 92, 231, 0.08);
    pointer-events: none;
    z-index: var(--z-box-selection);
}

/* Animated layout transition */
.mind-node.layout-animating {
    transition: left var(--transition-smooth), top var(--transition-smooth);
}

/* Drop indicator line */
.drop-indicator {
    position: absolute;
    height: 3px;
    background: var(--accent-secondary);
    border-radius: 2px;
    pointer-events: none;
    z-index: 998;
}

/* Cross-link label */
.crosslink-label {
    position: absolute;
    background: var(--bg-surface);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--node-border);
    cursor: pointer;
    z-index: var(--z-nodes);
    white-space: nowrap;
}

.crosslink-label[contenteditable="true"] {
    cursor: text;
    outline: 1px solid var(--accent-primary);
}