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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #f8fafc;
    --surface-color: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --transition: 150ms ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

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

/* Header */
.header {
    background: var(--surface-color);
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-color);
    text-align: center;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo-img {
    width: 40px;
    height: 40px;
    object-fit: contain;
}

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
}

.tagline {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Main Content */
.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    padding: 2rem;
    max-width: 1600px;
    margin: 0 auto;
    width: 100%;
}

/* Controls Panel */
.controls-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.controls-panel h2,
.controls-panel h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

/* Shadows List Section */
.shadows-list-section {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

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

.section-header h2 {
    margin-bottom: 0;
}

.shadows-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-height: 200px;
    overflow-y: auto;
}

.shadow-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background: var(--bg-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition);
    border: 2px solid transparent;
}

.shadow-item:hover {
    background: #f1f5f9;
}

.shadow-item.active {
    border-color: var(--primary-color);
    background: #eef2ff;
}

.shadow-item .color-indicator {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    flex-shrink: 0;
}

.shadow-item .shadow-name {
    flex: 1;
    font-size: 0.9rem;
    font-weight: 500;
}

.shadow-item .visibility-btn,
.shadow-item .delete-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    transition: all var(--transition);
    font-size: 1rem;
}

.shadow-item .visibility-btn:hover {
    color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.shadow-item .delete-btn:hover {
    color: var(--danger-color);
    background: rgba(239, 68, 68, 0.1);
}

.shadow-item.hidden-shadow {
    opacity: 0.5;
}

/* Shadow Controls */
.shadow-controls {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.control-group {
    margin-bottom: 1.25rem;
}

.control-group:last-child {
    margin-bottom: 0;
}

.control-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.slider-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.slider-container input[type="range"] {
    flex: 1;
    height: 6px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--border-color);
    border-radius: 3px;
    outline: none;
    cursor: pointer;
}

.slider-container input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: transform var(--transition);
}

.slider-container input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.slider-container input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

.slider-container input[type="number"] {
    width: 70px;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    text-align: center;
    outline: none;
    transition: border-color var(--transition);
}

.slider-container input[type="number"]:focus {
    border-color: var(--primary-color);
}

.slider-container .unit {
    color: var(--text-secondary);
    font-size: 0.875rem;
    min-width: 20px;
}

/* Color Container */
.color-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.color-container input[type="color"] {
    width: 50px;
    height: 40px;
    padding: 0;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    overflow: hidden;
}

.color-container input[type="color"]::-webkit-color-swatch-wrapper {
    padding: 2px;
}

.color-container input[type="color"]::-webkit-color-swatch {
    border: none;
    border-radius: 3px;
}

.color-container input[type="text"] {
    flex: 1;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-family: monospace;
    outline: none;
    text-transform: uppercase;
}

.color-container input[type="text"]:focus {
    border-color: var(--primary-color);
}

/* Checkbox Group */
.checkbox-group label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    margin-bottom: 0;
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

.checkbox-group span {
    font-size: 0.9rem;
    color: var(--text-primary);
}

/* CSS Output Section */
.css-output-section {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.css-output-container {
    position: relative;
}

.css-output {
    background: #1e293b;
    color: #e2e8f0;
    padding: 1.25rem;
    border-radius: var(--radius-md);
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-all;
    min-height: 80px;
}

/* Buttons */
.btn {
    padding: 0.625rem 1.25rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
}

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

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

.btn-copy {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    background: rgba(255, 255, 255, 0.1);
    color: #e2e8f0;
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
}

.btn-copy:hover {
    background: rgba(255, 255, 255, 0.2);
}

.btn-copy.copied {
    background: var(--success-color);
}

.btn-copy .copied-text {
    display: none;
}

.btn-copy.copied .copy-text {
    display: none;
}

.btn-copy.copied .copied-text {
    display: inline;
}

/* Preview Panel */
.preview-panel {
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.preview-panel h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.preview-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 400px;
}

.preview-background {
    width: 100%;
    height: 100%;
    min-height: 400px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #f0f0f0;
    transition: background-color var(--transition);
}

.preview-box {
    width: 200px;
    height: 200px;
    background: #ffffff;
    border-radius: var(--radius-md);
    transition: box-shadow 0.2s ease;
}

.preview-options {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.preview-options label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.preview-options input[type="color"] {
    width: 40px;
    height: 32px;
    padding: 0;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
}

/* Footer */
.footer {
    background: var(--surface-color);
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition);
}

.footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr;
        padding: 1.5rem;
    }

    .preview-panel {
        order: -1;
    }

    .preview-container {
        min-height: 300px;
    }

    .preview-background {
        min-height: 300px;
    }
}

@media (max-width: 640px) {
    .header {
        padding: 1rem;
    }

    .header h1 {
        font-size: 1.35rem;
    }

    .main-content {
        padding: 1rem;
        gap: 1rem;
    }

    .shadows-list-section,
    .shadow-controls,
    .css-output-section,
    .preview-panel {
        padding: 1rem;
    }

    .section-header {
        flex-direction: column;
        gap: 0.75rem;
        align-items: flex-start;
    }

    .slider-container {
        flex-wrap: wrap;
    }

    .slider-container input[type="range"] {
        width: 100%;
        order: 3;
        margin-top: 0.5rem;
    }

    .preview-box {
        width: 150px;
        height: 150px;
    }

    .preview-options {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .css-output {
        font-size: 0.75rem;
        padding: 1rem;
    }

    .footer {
        padding: 1rem;
    }
}

/* Scrollbar Styling */
.shadows-list::-webkit-scrollbar {
    width: 6px;
}

.shadows-list::-webkit-scrollbar-track {
    background: var(--bg-color);
    border-radius: 3px;
}

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

.shadows-list::-webkit-scrollbar-thumb:hover {
    background: #cbd5e1;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
}

.empty-state p {
    font-size: 0.9rem;
}