:root {
    /* Color Palette */
    --bg-color: #0f172a;
    --sidebar-bg: #1e293b;
    --panel-bg: #334155;
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #3b82f6;
    --danger-color: #ef4444;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #475569;
    --success-color: #10b981;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    
    /* Shadows & Border Radius */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.2), 0 4px 6px -2px rgba(0,0,0,0.1);
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
}

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

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

.hidden {
    display: none !important;
}

/* Layout */
.app-container {
    display: flex;
    width: 100%;
    height: 100%;
}

/* Sidebar */
.sidebar {
    width: 320px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    z-index: 10;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.logo ion-icon {
    font-size: 2rem;
    color: #a855f7;
}

.logo h2 {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Upload Group */
.upload-group {
    margin-bottom: 1.5rem;
}

.upload-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 1rem;
    background: rgba(99, 102, 241, 0.1);
    border: 2px dashed var(--primary-color);
    border-radius: var(--radius-lg);
    color: var(--text-main);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-btn:hover {
    background: rgba(99, 102, 241, 0.2);
    transform: translateY(-2px);
}

.upload-btn ion-icon {
    font-size: 1.5rem;
}

.file-info {
    margin-top: 0.75rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    text-align: center;
    word-break: break-all;
}

/* Controls */
.control-section {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    transition: opacity 0.3s ease;
}

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

/* Tabs */
.tabs {
    display: flex;
    background-color: var(--panel-bg);
    border-radius: var(--radius-md);
    padding: 0.25rem;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s ease;
}

.tab-btn.active {
    background-color: var(--sidebar-bg);
    color: var(--text-main);
    box-shadow: var(--shadow-sm);
}

.tab-panel {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-muted);
}

.control-group select, .control-group input[type="number"] {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--panel-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-main);
    font-family: inherit;
    font-size: 0.9rem;
    outline: none;
    transition: border-color 0.2s ease;
}

.control-group select:focus, .control-group input[type="number"]:focus {
    border-color: var(--primary-color);
}

/* Slider */
.slider-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#quality-val {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary-color);
}

input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 6px;
    background: var(--panel-bg);
    border-radius: 3px;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: transform 0.1s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* Row Inputs */
.row-inputs {
    flex-direction: row;
    gap: 1rem;
}

.input-col {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

/* Checkbox */
.checkbox-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    accent-color: var(--primary-color);
    width: 16px;
    height: 16px;
    cursor: pointer;
}

.checkbox-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
    cursor: pointer;
}

/* Buttons */
.action-buttons {
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    outline: none;
}

.btn-primary {
    width: 100%;
    padding: 0.85rem;
    background: var(--gradient-primary);
    color: white;
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    width: 100%;
    padding: 0.75rem;
    background: var(--panel-bg);
    color: var(--text-main);
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: all 0.2s ease;
}

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

.btn-danger {
    width: 100%;
    padding: 0.75rem;
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--danger-color);
    transition: all 0.2s ease;
}

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

/* Main Area */
.preview-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    background-color: var(--bg-color);
    position: relative;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.preview-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Stats */
.stats {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--sidebar-bg);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.stat-badge {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.85rem;
    font-weight: 500;
}

.stat-badge.original {
    color: var(--text-muted);
}

.stat-badge.compressed {
    color: var(--primary-color);
}

.stat-badge.saving {
    background: rgba(16, 185, 129, 0.15);
    color: var(--success-color);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    margin-left: 0.5rem;
}

.stat-arrow {
    color: var(--text-muted);
}

/* Canvas Container */
.canvas-container {
    flex: 1;
    background: var(--sidebar-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

/* Checkerboard pattern for transparent images */
.canvas-container::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background-image: 
        linear-gradient(45deg, #1e293b 25%, transparent 25%), 
        linear-gradient(-45deg, #1e293b 25%, transparent 25%), 
        linear-gradient(45deg, transparent 75%, #1e293b 75%), 
        linear-gradient(-45deg, transparent 75%, #1e293b 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    opacity: 0.3;
    z-index: 0;
}

.upload-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    color: var(--text-muted);
    z-index: 1;
}

.upload-placeholder ion-icon {
    font-size: 4rem;
    color: var(--border-color);
}

#image-preview {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    z-index: 1;
    transition: opacity 0.3s ease;
}

.back-link {
    position: absolute;
    bottom: 1.5rem;
    right: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s ease;
    background: var(--sidebar-bg);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    z-index: 10;
}

.back-link:hover {
    color: var(--text-main);
}

/* Cropper Customization */
.cropper-view-box,
.cropper-face {
    border-radius: 0;
}
.cropper-line {
    background-color: var(--primary-color);
}
.cropper-point {
    background-color: var(--primary-color);
}