:root {
    --bg-color: #1a1a1a;
    --panel-bg: #252525;
    --text-color: #e0e0e0;
    --accent-color: #4a90e2;
    --accent-hover: #357abd;
    --border-color: #333;
}

body {
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

header {
    background-color: var(--panel-bg);
    padding: 1rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    z-index: 10;
}

h1 {
    margin: 0;
    font-size: 1.2rem;
    font-weight: 600;
    color: #fff;
    display: flex;
    align-items: center;
    gap: 10px;
}

.controls {
    display: flex;
    gap: 1rem;
    align-items: center;
}

button,
.file-upload-label {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s, transform 0.1s;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
}

button:hover,
.file-upload-label:hover {
    background-color: var(--accent-hover);
}

button:active,
.file-upload-label:active {
    transform: scale(0.98);
}

button:disabled {
    background-color: #555;
    cursor: not-allowed;
    opacity: 0.7;
}

input[type="file"] {
    display: none;
}

/* Main Canvas Container - Figma Style */
#main-container {
    flex: 1;
    overflow: hidden;
    position: relative;
    background-image: radial-gradient(#333 1px, transparent 1px);
    background-size: 20px 20px;
    cursor: default;
}

#main-container.panning {
    cursor: grab;
}

#main-container.panning:active {
    cursor: grabbing;
}

/* Canvas Viewport for Konva Stage */
#canvas-viewport {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* Konva canvas 样式 */
#canvas-viewport canvas {
    display: block;
}

.status-bar {
    background-color: var(--panel-bg);
    padding: 0.5rem 2rem;
    font-size: 0.85rem;
    color: #aaa;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    visibility: hidden;
    opacity: 0;
    transition: opacity 0.3s;
}

.loading-overlay.active {
    visibility: visible;
    opacity: 1;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

/* Settings Panel */
.settings {
    display: flex;
    gap: 10px;
    align-items: center;
    background: rgba(255, 255, 255, 0.05);
    padding: 5px 10px;
    border-radius: 4px;
}

.settings label {
    font-size: 0.8rem;
    color: #ccc;
}

.settings input[type="number"] {
    background: #333;
    border: 1px solid #444;
    color: white;
    padding: 2px 5px;
    border-radius: 3px;
    width: 50px;
}

/* Auto Fill Toggle */
.auto-fill-toggle {
    display: flex;
    align-items: center;
    gap: 5px;
    cursor: pointer;
    padding: 4px 8px;
    background: #333;
    border-radius: 4px;
    border: 1px solid #444;
}

.auto-fill-toggle input[type="checkbox"] {
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.auto-fill-toggle span {
    font-size: 0.8rem;
    color: #ccc;
}

.drag-over {
    position: relative;
}

.drag-over::after {
    content: '释放以导入图片';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(74, 144, 226, 0.2);
    border: 4px dashed var(--accent-color);
    z-index: 999;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2rem;
    color: white;
    pointer-events: none;
    backdrop-filter: blur(2px);
}

/* Preview Container */
#preview-container {
    background-color: white;
    box-shadow: 0 0 30px rgba(0, 0, 0, 0.5);
    position: absolute;
    top: 0;
    left: 0;
}

.img-item {
    position: absolute;
    transition: transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    cursor: grab;
    user-select: none;
    overflow: hidden;
    border: 2px solid transparent;
    box-sizing: border-box;
}

.img-item:hover {
    border-color: rgba(74, 144, 226, 0.5);
}

.img-item.selected {
    border-color: var(--accent-color);
    box-shadow: 0 0 10px rgba(74, 144, 226, 0.5);
}

.img-item:active {
    cursor: grabbing;
    z-index: 100;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
    transition: none;
}

.img-item.dragging {
    opacity: 0.3;
    z-index: 1000;
    /* transform: scale(1.05); Removed to prevent blocking view */
    border: 2px dashed var(--accent-color);
}

.img-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    pointer-events: none;
    image-rendering: -webkit-optimize-contrast;
    image-rendering: crisp-edges;
}

/* Placeholder slot for empty positions */
.img-placeholder {
    position: absolute;
    background: rgba(74, 144, 226, 0.1);
    border: 2px dashed rgba(74, 144, 226, 0.3);
    box-sizing: border-box;
    transition: all 0.2s ease;
}

.img-placeholder.drag-over-slot {
    background: rgba(74, 144, 226, 0.3);
    border-color: var(--accent-color);
}

select {
    background-color: #333;
    color: white;
    border: 1px solid #444;
    padding: 0.5rem;
    border-radius: 6px;
    font-size: 0.9rem;
    outline: none;
}

/* Zoom Indicator */
.zoom-indicator {
    position: fixed;
    bottom: 60px;
    right: 20px;
    background: var(--panel-bg);
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.85rem;
    color: var(--text-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    opacity: 0;
    transition: opacity 0.3s;
    z-index: 100;
    display: flex;
    align-items: center;
    gap: 10px;
    border: 1px solid var(--border-color);
}

.zoom-indicator.visible {
    opacity: 1;
}

.zoom-indicator button {
    padding: 4px 8px;
    font-size: 0.75rem;
    min-width: 28px;
}

.zoom-indicator span {
    min-width: 50px;
    text-align: center;
}

/* Navigation Hint */
.nav-hint {
    position: fixed;
    bottom: 60px;
    left: 20px;
    background: var(--panel-bg);
    padding: 10px 16px;
    border-radius: 8px;
    font-size: 0.75rem;
    color: #888;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    z-index: 100;
    border: 1px solid var(--border-color);
    line-height: 1.6;
}

.nav-hint kbd {
    background: #444;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: monospace;
    margin: 0 2px;
    font-size: 0.7rem;
}

/* Placeholder */
#placeholder-text {
    color: #666;
    text-align: center;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* ========== 虚拟渲染样式 (Figma-like) ========== */
.img-item.out-of-view {
    visibility: hidden;
    content-visibility: hidden;
}

.img-item.out-of-view img {
    content-visibility: hidden;
}

/* 拖拽目标视觉提示 */
.img-item.drag-over-target {
    border-color: var(--accent-color) !important;
    box-shadow: 0 0 15px rgba(74, 144, 226, 0.6);
}