/* ===== CSS Reset & Variables ===== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg-dark: #0d0d0f;
    --bg-sidebar: #141418;
    --bg-canvas: #1a1a1f;
    --bg-card: #1e1e24;
    --bg-hover: #2a2a32;
    --border-color: #2d2d35;
    --text-primary: #f0f0f2;
    --text-secondary: #8a8a95;
    --text-hint: #5a5a65;
    --accent: #6366f1;
    --accent-hover: #818cf8;
    --accent-glow: rgba(99, 102, 241, 0.3);
    --danger: #ef4444;
    --danger-hover: #f87171;
    --success: #22c55e;
    --grid-color: rgba(255, 255, 255, 0.05);
    --grid-major-color: rgba(255, 255, 255, 0.1);
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

html,
body {
    height: 100%;
    font-family: var(--font-main);
    background: var(--bg-dark);
    color: var(--text-primary);
    overflow: hidden;
}

/* ===== App Layout ===== */
.app-container {
    display: grid;
    grid-template-columns: 280px 1fr 260px;
    height: 100vh;
    gap: 1px;
    background: var(--border-color);
}

/* ===== Sidebar ===== */
.sidebar {
    background: var(--bg-sidebar);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-header {
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.upload-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    width: 100%;
    padding: 10px 16px;
    background: linear-gradient(135deg, var(--accent), #4f46e5);
    border: none;
    border-radius: 8px;
    color: white;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px var(--accent-glow);
}

.upload-btn:hover {
    background: linear-gradient(135deg, var(--accent-hover), #6366f1);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--accent-glow);
}

.upload-btn input {
    display: none;
}

.asset-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    align-content: start;
}

.asset-list::-webkit-scrollbar {
    width: 6px;
}

.asset-list::-webkit-scrollbar-track {
    background: transparent;
}

.asset-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 40px 20px;
    color: var(--text-hint);
}

.empty-state p {
    margin-bottom: 8px;
    font-size: 13px;
}

.empty-state .hint {
    font-size: 11px;
    color: var(--text-hint);
}

/* Asset Thumbnail Card */
.asset-thumb {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 8px;
    cursor: grab;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
}

.asset-thumb:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.asset-thumb:active {
    cursor: grabbing;
}

.asset-thumb-preview {
    width: 100%;
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background:
        linear-gradient(45deg, #2a2a32 25%, transparent 25%),
        linear-gradient(-45deg, #2a2a32 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #2a2a32 75%),
        linear-gradient(-45deg, transparent 75%, #2a2a32 75%);
    background-size: 8px 8px;
    background-position: 0 0, 0 4px, 4px -4px, -4px 0px;
    background-color: #1e1e24;
    border-radius: 4px;
    overflow: hidden;
}

.asset-thumb-preview img {
    max-width: 100%;
    max-height: 100%;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
}

.asset-thumb-label {
    font-size: 10px;
    color: var(--text-secondary);
    text-align: center;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    width: 100%;
}

.asset-thumb {
    position: relative;
    /* For absolute positioning of delete button */
}

/* Delete Button for Asset Thumb */
.asset-delete-btn {
    position: absolute;
    top: -6px;
    right: -6px;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--danger);
    color: white;
    border: 2px solid var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 14px;
    opacity: 0;
    transform: scale(0.8);
    transition: all 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
    z-index: 10;
}

.asset-thumb:hover .asset-delete-btn {
    opacity: 1;
    transform: scale(1);
}

.asset-delete-btn:hover {
    background: var(--danger-hover);
    transform: scale(1.1);
}

/* ===== Main Canvas Area ===== */
.canvas-area {
    background: var(--bg-dark);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.toolbar {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 10px 16px;
    background: var(--bg-sidebar);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.toolbar-group {
    display: flex;
    align-items: center;
    gap: 6px;
}

.tool-btn {
    padding: 6px 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s ease;
}

.tool-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
}

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

.tool-btn.danger:hover {
    background: var(--danger);
    border-color: var(--danger);
}

.zoom-display {
    min-width: 50px;
    text-align: center;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
}

.canvas-size-label {
    font-size: 12px;
    color: var(--text-secondary);
}

.size-input {
    width: 60px;
    padding: 4px 8px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 12px;
    text-align: center;
}

.size-input:focus {
    outline: none;
    border-color: var(--accent);
}

.canvas-wrapper {
    flex: 1;
    overflow: auto;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
}

.canvas-container {
    position: relative;
    width: 800px;
    height: 600px;
    background:
        linear-gradient(45deg, #252530 25%, transparent 25%),
        linear-gradient(-45deg, #252530 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #252530 75%),
        linear-gradient(-45deg, transparent 75%, #252530 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
    background-color: #1e1e24;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    overflow: hidden;
}

.canvas-container.show-grid {
    background:
        repeating-linear-gradient(0deg, transparent, transparent 15px, var(--grid-color) 15px, var(--grid-color) 16px),
        repeating-linear-gradient(90deg, transparent, transparent 15px, var(--grid-color) 15px, var(--grid-color) 16px),
        repeating-linear-gradient(0deg, transparent, transparent 79px, var(--grid-major-color) 79px, var(--grid-major-color) 80px),
        repeating-linear-gradient(90deg, transparent, transparent 79px, var(--grid-major-color) 79px, var(--grid-major-color) 80px),
        linear-gradient(45deg, #252530 25%, transparent 25%),
        linear-gradient(-45deg, #252530 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #252530 75%),
        linear-gradient(-45deg, transparent 75%, #252530 75%);
    background-size: 16px 16px, 16px 16px, 80px 80px, 80px 80px, 16px 16px, 16px 16px, 16px 16px, 16px 16px;
    background-color: #1e1e24;
}

/* Smart Guides */
#guides-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 10000;
}

.guide-line {
    position: absolute;
    background-color: #f43f5e;
    /* Rose-500 */
    box-shadow: 0 0 4px rgba(0, 0, 0, 0.5);
}

.guide-line.vertical {
    width: 1px;
    height: 100%;
    /* Can be clamped in JS, but full height is safer for now */
    border-left: 1px dashed #f43f5e;
    background: transparent;
}

.guide-line.horizontal {
    height: 1px;
    width: 100%;
    border-top: 1px dashed #f43f5e;
    background: transparent;
}

.distance-marker {
    position: absolute;
    background: rgba(244, 63, 94, 0.1);
    border: 1px dashed rgba(244, 63, 94, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #f43f5e;
    font-size: 10px;
    font-weight: 700;
    pointer-events: none;
    z-index: 10001;
}

.distance-label {
    background: #1e1e24;
    padding: 2px 4px;
    border-radius: 4px;
    border: 1px solid #f43f5e;
}

/* Placed Assets on Canvas */
.canvas-asset {
    position: absolute;
    cursor: move;
    user-select: none;
    transition: box-shadow 0.15s ease;
}

.canvas-asset img {
    display: block;
    image-rendering: pixelated;
    image-rendering: crisp-edges;
    pointer-events: none;
}

.canvas-asset:hover {
    box-shadow: 0 0 0 2px var(--accent);
}

.canvas-asset.selected {
    box-shadow: 0 0 0 2px var(--accent), 0 0 12px var(--accent-glow);
}

/* ===== Controls Panel ===== */
.controls-panel {
    background: var(--bg-sidebar);
    padding: 16px;
    overflow-y: auto;
}

.controls-panel h3 {
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.no-selection {
    text-align: center;
    padding: 20px;
    color: var(--text-hint);
    font-size: 13px;
}

.selection-controls {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-size: 11px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-secondary);
}

.position-inputs {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--text-secondary);
}

.pos-input {
    width: 60px;
    padding: 6px 8px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 12px;
}

.pos-input:focus {
    outline: none;
    border-color: var(--accent);
}

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

#scale-value {
    font-size: 12px;
    color: var(--text-primary);
    font-weight: 600;
}

.layer-buttons {
    display: flex;
    gap: 8px;
}

.layer-buttons .tool-btn {
    flex: 1;
    font-size: 11px;
    padding: 8px;
}

/* Lock & Clip Controls */
.lock-btn {
    width: 100%;
}

.lock-btn.active {
    background: var(--success);
    border-color: var(--success);
}

.lock-hint {
    font-size: 10px;
    color: var(--text-hint);
    margin: 0;
}

.clip-controls {
    background: var(--bg-card);
    padding: 12px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.clip-row {
    display: flex;
    align-items: center;
    gap: 8px;
}

.clip-row input[type="range"] {
    flex: 1;
}

#clip-value {
    font-size: 12px;
    font-weight: 600;
    color: var(--accent);
    min-width: 40px;
}

.clip-select {
    width: 100%;
    padding: 8px;
    background: var(--bg-dark);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    font-size: 12px;
    cursor: pointer;
}

.clip-select:focus {
    outline: none;
    border-color: var(--accent);
}

.control-divider {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 4px 0;
}

/* Locked Asset Indicator */
.canvas-asset.locked::after {
    content: '🔒';
    position: absolute;
    top: -8px;
    right: -8px;
    font-size: 12px;
    background: var(--success);
    border-radius: 50%;
    width: 18px;
    height: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Drag Over State */
body.drag-over::before {
    content: 'Drop PNG files to add assets';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(99, 102, 241, 0.15);
    border: 4px dashed var(--accent);
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 600;
    color: var(--accent);
    pointer-events: none;
}

/* Responsive */
@media (max-width: 1200px) {
    .app-container {
        grid-template-columns: 220px 1fr 200px;
    }
}

@media (max-width: 900px) {
    .app-container {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr auto;
    }

    .sidebar,
    .controls-panel {
        max-height: 200px;
    }
}