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

:root {
    --primary-color: #00D4AA;
    --secondary-color: #667eea;
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --dark-bg: #1a1a2e;
    --card-bg: #ffffff;
    --text-primary: #2d3748;
    --text-secondary: #718096;
    --border-color: #e2e8f0;
    --shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 15px 50px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1600px;
    margin: 0 auto;
}

header {
    text-align: center;
    color: white;
    margin-bottom: 40px;
    animation: fadeInDown 0.6s ease;
}

header h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 10px;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.2);
}

header .subtitle {
    font-size: 1.2rem;
    opacity: 0.95;
    font-weight: 300;
}

.main-content {
    display: grid;
    grid-template-columns: 400px 1fr;
    gap: 30px;
    animation: fadeIn 0.8s ease;
}

@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 1fr;
    }
}

.controls-panel {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 30px;
    box-shadow: var(--shadow);
    max-height: calc(100vh - 200px);
    overflow-y: auto;
}

.controls-panel::-webkit-scrollbar {
    width: 8px;
}

.controls-panel::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 10px;
}

.controls-panel::-webkit-scrollbar-thumb {
    background: var(--secondary-color);
    border-radius: 10px;
}

.panel-section {
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 2px solid var(--border-color);
}

.panel-section:last-of-type {
    border-bottom: none;
}

.panel-section h2 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    font-weight: 600;
}

.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f8fafc;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: #f0fdf4;
    transform: translateY(-2px);
}

.upload-placeholder {
    pointer-events: none;
}

.upload-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 10px;
}

.upload-placeholder p {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.upload-placeholder small {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.preview-thumb {
    margin-top: 15px;
    text-align: center;
}

.preview-thumb img {
    max-width: 100%;
    max-height: 150px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.input-group input[type="text"],
.input-group input[type="number"],
.input-group select {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
    font-family: inherit;
}

.input-group input[type="text"]:focus,
.input-group input[type="number"]:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.1);
}

.input-group input[type="range"] {
    width: calc(100% - 60px);
    margin-right: 10px;
    vertical-align: middle;
}

.input-group span {
    display: inline-block;
    min-width: 50px;
    text-align: right;
    font-weight: 600;
    color: var(--primary-color);
}

.color-picker-row {
    display: flex;
    gap: 10px;
}

.color-picker-row input[type="color"] {
    width: 60px;
    height: 45px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
}

.color-picker-row input[type="text"] {
    flex: 1;
}

.size-inputs {
    display: flex;
    gap: 10px;
    align-items: center;
}

.size-inputs input {
    flex: 1;
}

.size-inputs span {
    font-weight: 600;
    color: var(--text-secondary);
}

.action-buttons {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 30px;
}

.btn {
    padding: 15px 25px;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: inherit;
}

.btn span {
    font-size: 1.2rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), #00a886);
    color: white;
    box-shadow: 0 4px 15px rgba(0, 212, 170, 0.3);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 170, 0.4);
}

.btn-secondary {
    background: linear-gradient(135deg, var(--secondary-color), #5568d3);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.btn-secondary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-tertiary {
    background: white;
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-tertiary:hover {
    background: #f8fafc;
    border-color: var(--text-secondary);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.preview-panel {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 30px;
    box-shadow: var(--shadow);
    min-height: 600px;
}

.preview-container {
    height: 100%;
    display: flex;
    flex-direction: column;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.preview-header h3 {
    font-size: 1.3rem;
    color: var(--text-primary);
    font-weight: 600;
}

.preview-actions {
    display: flex;
    gap: 8px;
}

.icon-btn {
    padding: 8px 12px;
    border: 2px solid var(--border-color);
    background: white;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.icon-btn:hover {
    background: #f8fafc;
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.canvas-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(45deg, #f0f0f0 25%, transparent 25%),
                linear-gradient(-45deg, #f0f0f0 25%, transparent 25%),
                linear-gradient(45deg, transparent 75%, #f0f0f0 75%),
                linear-gradient(-45deg, transparent 75%, #f0f0f0 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
    border-radius: 15px;
    padding: 20px;
    overflow: auto;
}

#coverCanvas {
    max-width: 100%;
    max-height: 100%;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    border-radius: 10px;
    transition: transform 0.3s ease;
}

footer {
    text-align: center;
    color: white;
    margin-top: 30px;
    padding: 20px;
    font-size: 0.95rem;
    opacity: 0.9;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Loading Animation */
.loading {
    position: relative;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 30px;
    height: 30px;
    margin: -15px 0 0 -15px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Toggle Switches */
.section-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.toggle-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.toggle-item {
    display: flex;
    align-items: center;
    cursor: pointer;
    padding: 10px;
    border-radius: 8px;
    transition: background 0.2s ease;
}

.toggle-item:hover {
    background: #f8fafc;
}

.toggle-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    margin-right: 12px;
    accent-color: var(--primary-color);
}

.toggle-label {
    font-size: 0.95rem;
    color: var(--text-primary);
    user-select: none;
}

/* Quick Presets */
.preset-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 15px;
}

.preset-btn {
    padding: 10px;
    background: linear-gradient(135deg, #f8fafc, #e2e8f0);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-primary);
}

.preset-btn:hover {
    background: linear-gradient(135deg, #e2e8f0, #cbd5e0);
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.preset-btn.active {
    background: linear-gradient(135deg, var(--primary-color), #00a886);
    color: white;
    border-color: var(--primary-color);
}

/* URL Input Group */
.url-input-group {
    display: flex;
    gap: 10px;
}

.url-input-group input {
    flex: 1;
}

.btn-small {
    padding: 12px 20px;
    background: linear-gradient(135deg, var(--primary-color), #00a886);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
    white-space: nowrap;
}

.btn-small:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 212, 170, 0.3);
}

.btn-small:active {
    transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    header h1 {
        font-size: 2rem;
    }

    header .subtitle {
        font-size: 1rem;
    }

    .controls-panel,
    .preview-panel {
        padding: 20px;
    }

    .main-content {
        gap: 20px;
    }
    
    .preset-buttons {
        grid-template-columns: 1fr;
    }
}