:root {
    --primary-bg: #0a0a0f;
    --secondary-bg: #141419;
    --card-bg: #1a1a24;
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-muted: rgba(255, 255, 255, 0.5);
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --sidebar-width: 220px;
    --header-height: 52px;
    --properties-width: 240px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--primary-bg);
    color: var(--text-primary);
    overflow: hidden;
    height: 100vh;
}

.app {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* Header */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--spacing-md);
    height: var(--header-height);
    background: var(--secondary-bg);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    flex-shrink: 0;
}

.header-left h1 {
    font-size: 1.1rem;
    font-weight: 600;
    white-space: nowrap;
}

.header-left h1 i {
    color: var(--accent-primary);
    margin-right: var(--spacing-xs);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.file-actions,
.edit-actions {
    display: flex;
    gap: var(--spacing-xs);
}

.header-btn {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.8rem;
    font-family: inherit;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

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

.header-btn.danger:hover {
    background: #ef4444;
    border-color: #ef4444;
}

.back-btn {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.8rem;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition-fast);
    white-space: nowrap;
}

.back-btn:hover {
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

/* Dropdown */
.dropdown {
    position: relative;
}

.dropdown-menu {
    display: none;
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 4px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    z-index: 200;
    min-width: 160px;
}

.dropdown-menu.show {
    display: block;
}

.dropdown-menu button {
    display: block;
    width: 100%;
    padding: 8px 14px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.85rem;
    text-align: left;
}

.dropdown-menu button:hover {
    background: var(--accent-primary);
    color: var(--text-primary);
}

/* Workspace */
.workspace {
    display: flex;
    flex: 1;
    overflow: hidden;
    position: relative;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--secondary-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    overflow-x: hidden;
    flex-shrink: 0;
    transition: width var(--transition-base), min-width var(--transition-base);
}

.sidebar.collapsed {
    width: 0;
    min-width: 0;
    border-right: none;
}

.sidebar.collapsed .sidebar-content {
    display: none;
}

.sidebar-toggle {
    position: absolute;
    left: var(--sidebar-width);
    top: 12px;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    cursor: pointer;
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.65rem;
    transition: left var(--transition-base), var(--transition-fast);
    transform: translateX(-50%);
}

.sidebar-toggle:hover {
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.sidebar.collapsed ~ .sidebar-toggle {
    left: 0;
    transform: translateX(4px);
}

.sidebar.collapsed ~ .sidebar-toggle i {
    transform: rotate(180deg);
}

.sidebar-content {
    padding: var(--spacing-sm);
}

.sidebar-section {
    margin-bottom: var(--spacing-md);
}

.sidebar-section h3 {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    padding: 0 var(--spacing-xs);
}

/* Tool buttons */
.tool-buttons {
    display: flex;
    gap: var(--spacing-xs);
}

.tool-btn {
    flex: 1;
    padding: 8px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition-fast);
}

.tool-btn:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

.tool-btn.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

/* Shape palette */
.shape-palette {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4px;
}

.shape-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 6px 4px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: grab;
    transition: var(--transition-fast);
    user-select: none;
}

.shape-item:hover {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.shape-item.active {
    border-color: var(--accent-primary);
    background: var(--accent-primary);
    color: var(--text-primary);
}

.shape-item:active {
    cursor: grabbing;
}

.shape-item svg {
    width: 40px;
    height: 30px;
    color: var(--text-secondary);
    margin-bottom: 2px;
}

.shape-item span {
    font-size: 0.6rem;
    color: var(--text-muted);
}

/* Canvas container */
.canvas-container {
    flex: 1;
    position: relative;
    overflow: hidden;
    background: var(--primary-bg);
    cursor: default;
}

.canvas-container:focus {
    outline: none;
}

#diagram-canvas {
    position: absolute;
    top: 0;
    left: 0;
}

.canvas-container.tool-pan {
    cursor: grab;
}

.canvas-container.tool-pan:active {
    cursor: grabbing;
}

.canvas-container.tool-connect {
    cursor: crosshair;
}

/* Text editor overlay */
.text-editor {
    position: absolute;
    background: var(--card-bg);
    color: var(--text-primary);
    border: 2px solid var(--accent-primary);
    border-radius: var(--radius-sm);
    padding: 4px 8px;
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    text-align: center;
    resize: none;
    outline: none;
    z-index: 50;
    overflow: hidden;
}

/* Zoom controls */
.zoom-controls {
    position: absolute;
    bottom: var(--spacing-md);
    left: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--secondary-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 4px;
    z-index: 10;
}

.zoom-controls button {
    width: 30px;
    height: 30px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    transition: var(--transition-fast);
}

.zoom-controls button:hover {
    background: var(--card-bg);
    color: var(--text-primary);
}

.zoom-controls span {
    font-size: 0.75rem;
    color: var(--text-muted);
    min-width: 40px;
    text-align: center;
}

/* Minimap */
.minimap {
    position: absolute;
    bottom: var(--spacing-md);
    right: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--secondary-bg);
    z-index: 10;
    opacity: 0.8;
}

.minimap:hover {
    opacity: 1;
}

/* Properties panel */
.properties-panel {
    width: var(--properties-width);
    background: var(--secondary-bg);
    border-left: 1px solid var(--border-color);
    padding: var(--spacing-md);
    overflow-y: auto;
    flex-shrink: 0;
}

.properties-panel h3 {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
}

.prop-group {
    margin-bottom: var(--spacing-md);
}

.prop-group label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.prop-group input[type="text"],
.prop-group input[type="number"],
.prop-group select {
    width: 100%;
    padding: 6px 10px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.85rem;
}

.prop-group input[type="color"] {
    width: 100%;
    height: 32px;
    padding: 2px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
}

.prop-group input[type="range"] {
    width: 100%;
    accent-color: var(--accent-primary);
}

.size-inputs {
    display: flex;
    align-items: center;
    gap: 6px;
}

.size-inputs input {
    width: 70px;
    padding: 6px 8px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.85rem;
}

.size-inputs span {
    color: var(--text-muted);
}

/* Modals */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 500;
}

.modal {
    background: var(--secondary-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    width: 90%;
    max-width: 400px;
}

.modal h3 {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-lg);
}

.modal .prop-group {
    margin-bottom: var(--spacing-lg);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-sm);
}

.btn-primary,
.btn-secondary {
    padding: 8px 18px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.85rem;
    transition: var(--transition-fast);
}

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

.btn-primary:hover {
    background: var(--accent-secondary);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-secondary);
}

.btn-secondary:hover {
    color: var(--text-primary);
}

/* Load list */
.load-list {
    max-height: 300px;
    overflow-y: auto;
    margin-bottom: var(--spacing-md);
}

.load-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 12px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    margin-bottom: 6px;
    cursor: pointer;
    transition: var(--transition-fast);
}

.load-item:hover {
    border-color: var(--accent-primary);
}

.load-item-name {
    font-size: 0.9rem;
}

.load-item-date {
    font-size: 0.7rem;
    color: var(--text-muted);
}

.load-item-actions {
    display: flex;
    gap: 6px;
}

.load-item-actions button {
    padding: 4px 8px;
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.7rem;
    transition: var(--transition-fast);
}

.load-item-actions button:hover {
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.load-item-actions button.delete-btn:hover {
    color: #ef4444;
    border-color: #ef4444;
}

.empty-message {
    text-align: center;
    color: var(--text-muted);
    padding: var(--spacing-lg);
    font-size: 0.85rem;
}

/* Saved list in sidebar */
.saved-list {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.saved-list-item {
    padding: 6px 8px;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.75rem;
    color: var(--text-secondary);
    transition: var(--transition-fast);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.saved-list-item:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

/* Grid background pattern drawn on canvas */

/* Selection box */

/* Responsive */
@media (max-width: 768px) {
    .header {
        padding: 0 var(--spacing-sm);
        gap: var(--spacing-xs);
    }

    .header-left h1 {
        font-size: 0.95rem;
    }

    .btn-label {
        display: none;
    }

    .header-btn {
        padding: 6px 8px;
    }

    .sidebar {
        width: 180px;
    }

    .sidebar.collapsed {
        width: 0;
    }

    .properties-panel {
        position: absolute;
        right: 0;
        top: 0;
        bottom: 0;
        z-index: 50;
        box-shadow: -4px 0 20px rgba(0, 0, 0, 0.3);
    }

    .minimap {
        display: none;
    }

    .back-btn {
        display: none;
    }
}

@media (max-width: 480px) {
    .sidebar {
        position: absolute;
        left: 0;
        top: 0;
        bottom: 0;
        z-index: 50;
        box-shadow: 4px 0 20px rgba(0, 0, 0, 0.3);
        width: 180px;
    }

    .edit-actions {
        display: none;
    }
}