:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #10b981;
    --secondary-hover: #059669;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;

    --bg-gradient: linear-gradient(135deg, #fdfbfb 0%, #ebedee 100%);
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.1);

    --text-main: #1e293b;
    --text-muted: #64748b;

    --border-radius: 16px;
    --sidebar-width: 250px;
}

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

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

/* Base App Layout */
.app-container {
    display: flex;
    height: 100vh;
    padding: 20px;
    gap: 20px;
    background-image:
        radial-gradient(at 40% 20%, hsla(28, 100%, 74%, 1) 0px, transparent 50%),
        radial-gradient(at 80% 0%, hsla(189, 100%, 56%, 1) 0px, transparent 50%),
        radial-gradient(at 0% 50%, hsla(355, 100%, 93%, 1) 0px, transparent 50%),
        radial-gradient(at 80% 50%, hsla(340, 100%, 76%, 1) 0px, transparent 50%),
        radial-gradient(at 0% 100%, hsla(22, 100%, 77%, 1) 0px, transparent 50%),
        radial-gradient(at 80% 100%, hsla(242, 100%, 70%, 1) 0px, transparent 50%),
        radial-gradient(at 0% 0%, hsla(343, 100%, 76%, 1) 0px, transparent 50%);
}

/* Glassmorphism Panel Utilities */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    box-shadow: var(--glass-shadow);
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    min-width: 150px;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    box-shadow: var(--glass-shadow);
    overflow: hidden;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.sidebar-header h2 {
    font-size: 1.2rem;
    font-weight: 600;
}

.thumbnails-container {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    align-items: center;
}

.thumbnails-container::-webkit-scrollbar {
    width: 6px;
}

.thumbnails-container::-webkit-scrollbar-thumb {
    background: rgba(0, 0, 0, 0.1);
    border-radius: 10px;
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 10px;
    opacity: 0.5;
}

/* Thumbnail Items */
.thumbnail-wrapper {
    position: relative;
    width: 100%;
    background: white;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: all 0.2s ease;
    border: 2px solid transparent;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 5px;
}

.thumbnail-wrapper.selected {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

.thumbnail-wrapper.drag-over-top {
    border-top: 4px solid var(--primary-color);
}

.thumbnail-wrapper.drag-over-bottom {
    border-bottom: 4px solid var(--primary-color);
}

.thumbnail-wrapper:hover:not(.selected) {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.thumbnail-wrapper canvas {
    max-width: 100%;
    height: auto;
    display: block;
    border-radius: 4px;
}

.page-number {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    font-size: 0.75rem;
    padding: 2px 6px;
    border-radius: 12px;
}

/* Resizer */
.resizer {
    width: 6px;
    cursor: col-resize;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: transparent;
    transition: background-color 0.2s ease;
    border-radius: 3px;
    flex-shrink: 0;
}

.resizer:hover,
.resizer.dragging {
    background-color: var(--primary-color);
    opacity: 0.5;
}

/* Main Content Area */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
    min-width: 0;
}

/* Toolbar */
.toolbar {
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 20px;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    box-shadow: var(--glass-shadow);
    transition: opacity 0.3s ease;
}

.toolbar.disabled {
    opacity: 0.5;
    pointer-events: none;
}

.toolbar-group {
    display: flex;
    gap: 10px;
}

button {
    border: none;
    background: white;
    color: var(--text-main);
    height: 40px;
    padding: 0 16px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: all 0.2s ease;
}

button i {
    font-size: 1rem;
}

button:hover {
    background: #f8fafc;
    transform: translateY(-1px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

button:active {
    transform: translateY(1px);
}

button.primary {
    background: var(--primary-color);
    color: white;
}

button.primary:hover {
    background: var(--primary-hover);
}

button.secondary {
    background: var(--secondary-color);
    color: white;
}

button.secondary:hover {
    background: var(--secondary-hover);
}

button.danger {
    color: var(--danger-color);
}

button.danger:hover {
    background: #fef2f2;
}

.extract-input {
    height: 40px;
    padding: 0 12px;
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.8);
    color: var(--text-main);
    font-size: 0.9rem;
    font-family: inherit;
    width: 120px;
    transition: all 0.2s ease;
}

.extract-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2);
}

.extract-input:disabled {
    background: rgba(200, 200, 200, 0.5);
    cursor: not-allowed;
}

/* Workspace */
.workspace {
    flex: 1;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    box-shadow: var(--glass-shadow);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

/* Dropzone */
.dropzone {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border: 3px dashed rgba(99, 102, 241, 0.4);
    border-radius: calc(var(--border-radius) - 2px);
    transition: all 0.3s ease;
    cursor: pointer;
}

.dropzone:not(.active) {
    display: none;
}

.dropzone.dragover {
    background: rgba(99, 102, 241, 0.05);
    border-color: var(--primary-color);
}

.dropzone-content {
    text-align: center;
    pointer-events: none;
}

.dropzone-content i {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 20px;
    opacity: 0.8;
}

.dropzone-content h3 {
    font-size: 1.5rem;
    margin-bottom: 8px;
}

.dropzone-content p {
    color: var(--text-muted);
}

/* Main Viewer */
.main-viewer {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    padding: 20px;
    background: rgba(0, 0, 0, 0.02);
    overflow: hidden;
    /* We handle scrolling/panning via JS transform on a container */
}

.main-viewer.hidden {
    display: none;
}

.viewer-canvas-container {
    flex: 1;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    /* Hide overflow to allow panning */
    position: relative;
    cursor: grab;
}

.viewer-canvas-container:active {
    cursor: grabbing;
}

.main-viewer canvas {
    max-width: none;
    max-height: none;
    object-fit: contain;
    background: white;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    transform-origin: center center;
    transition: transform 0.1s ease-out;
    /* Smooth zooming */
    position: absolute;
}

.page-info {
    margin-top: 15px;
    background: white;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
    z-index: 10;
}

/* Navigation Buttons */
.nav-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--text-main);
    z-index: 20;
    transition: all 0.2s ease;
    padding: 0;
}

.nav-btn:hover:not(:disabled) {
    background: white;
    transform: translateY(-50%) scale(1.05);
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
}

.nav-btn:active:not(:disabled) {
    transform: translateY(-50%) scale(0.95);
}

.prev-btn {
    left: 20px;
}

.next-btn {
    right: 20px;
}

.nav-btn:disabled {
    opacity: 0.3;
    pointer-events: none;
    background: rgba(200, 200, 200, 0.3);
    box-shadow: none;
}

/* Loading Overlay */
.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 100;
    border-radius: var(--border-radius);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.loading-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(99, 102, 241, 0.2);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 10px;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}