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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 40px;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* Main */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* Upload Section */
.upload-section {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
}

.upload-area {
    background: var(--card-bg);
    border: 2px dashed var(--border-color);
    border-radius: 16px;
    padding: 60px 40px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background-color: #f5f3ff;
}

.upload-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.upload-text {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.click-text {
    color: var(--primary-color);
    font-weight: 600;
}

.upload-hint {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Processing Section */
.processing-section {
    text-align: center;
    padding: 60px;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    margin: 0 auto 24px;
    animation: spin 1s linear infinite;
}

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

.processing-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.processing-hint {
    color: var(--text-secondary);
}

/* Result Section */
.result-section {
    width: 100%;
}

.preview-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 32px;
}

.preview-box {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow);
}

.preview-box h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-secondary);
}

.image-wrapper {
    width: 100%;
    aspect-ratio: 1;
    border-radius: 8px;
    overflow: hidden;
    background-color: var(--bg-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-wrapper img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.checkerboard {
    background-image:
        linear-gradient(45deg, #e2e8f0 25%, transparent 25%),
        linear-gradient(-45deg, #e2e8f0 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, #e2e8f0 75%),
        linear-gradient(-45deg, transparent 75%, #e2e8f0 75%);
    background-size: 20px 20px;
    background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

.action-buttons {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    padding: 14px 28px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

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

.btn-download:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: white;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

/* Error Section */
.error-section {
    text-align: center;
    padding: 60px;
}

.error-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.error-text {
    font-size: 1.1rem;
    color: #ef4444;
    margin-bottom: 24px;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
}

.privacy-notice {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background-color: #ecfdf5;
    color: #059669;
    padding: 10px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    margin-bottom: 16px;
}

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

/* Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.75rem;
    }

    .preview-container {
        grid-template-columns: 1fr;
    }

    .upload-area {
        padding: 40px 20px;
    }

    .action-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .btn {
        justify-content: center;
    }
}