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

:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --text-color: #1f2937;
    --text-muted: #6b7280;
    --bg-color: #f9fafb;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

.header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
    flex-wrap: wrap;
    gap: 12px;
}

.site-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 16px;
}

.download-count {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.95rem;
    color: var(--text-muted);
}

.download-count strong {
    color: var(--primary-color);
    font-size: 1.1rem;
}

.icon {
    width: 20px;
    height: 20px;
}

.icon-sm {
    width: 16px;
    height: 16px;
}

.icon-large {
    width: 64px;
    height: 64px;
    color: var(--text-muted);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 10px 20px;
    font-size: 0.95rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

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

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

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

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

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

.btn-danger:hover {
    background: #dc2626;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.85rem;
}

.btn-block {
    width: 100%;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.main {
    flex: 1;
    padding: 24px 0;
}

.image-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.image-card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.image-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.image-preview {
    aspect-ratio: 16/10;
    background: var(--bg-color);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.image-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.image-placeholder {
    color: var(--text-muted);
}

.image-info {
    padding: 16px;
}

.image-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.image-desc {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 12px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.image-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

.empty-state p {
    margin-top: 16px;
    font-size: 1.1rem;
}

.footer {
    background: var(--card-bg);
    border-top: 1px solid var(--border-color);
    padding: 20px 0;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.admin-link {
    color: var(--text-muted);
    text-decoration: none;
}

.admin-link:hover {
    color: var(--primary-color);
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 16px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-sm {
    max-width: 400px;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
    line-height: 1;
}

.modal-close:hover {
    color: var(--text-color);
}

.modal-body {
    padding: 20px;
}

.task-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.task-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    background: var(--bg-color);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.task-item.completed {
    opacity: 0.6;
    background: #f0fdf4;
    border-color: var(--success-color);
}

.task-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    flex-shrink: 0;
}

.task-icon svg {
    width: 20px;
    height: 20px;
}

.task-info {
    flex: 1;
    min-width: 0;
}

.task-info h4 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 2px;
}

.task-info p {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.task-reward {
    display: inline-block;
    font-size: 0.75rem;
    color: var(--success-color);
    font-weight: 500;
    margin-top: 4px;
}

.task-action {
    flex-shrink: 0;
}

.task-done {
    color: var(--success-color);
    font-size: 0.85rem;
    font-weight: 500;
}

.qrcode-placeholder {
    background: var(--bg-color);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 40px 20px;
    text-align: center;
    margin-bottom: 16px;
}

.qrcode-placeholder .hint {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 8px;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 6px;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    font-size: 0.95rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--card-bg);
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.toast {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-color);
    color: white;
    padding: 12px 24px;
    border-radius: var(--radius);
    font-size: 0.9rem;
    z-index: 2000;
    opacity: 0;
    transition: all 0.3s;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--danger-color);
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .site-title {
        font-size: 1.25rem;
    }
    
    .user-info {
        width: 100%;
        justify-content: center;
    }
    
    .image-grid {
        grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
        gap: 16px;
    }
    
    .task-item {
        flex-direction: column;
        text-align: center;
    }
    
    .task-info {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .image-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        margin: 8px;
    }
}