/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

/* CSS Custom Properties (Variables) */
:root {
    /* Colors */
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    
    /* Neutral Colors */
    --white: #ffffff;
    --light: #f8f9fa;
    --dark: #343a40;
    --text-color: #333333;
    --text-muted: #6c757d;
    --border-color: #dee2e6;
    --bg-color: #ffffff;
    --bg-light: #f8f9fa;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15), 0 10px 10px rgba(0, 0, 0, 0.04);
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
    
    /* Layout */
    --container-max-width: 1200px;
    --header-height: 80px;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --text-color: #e9ecef;
        --text-muted: #adb5bd;
        --border-color: #495057;
        --bg-color: #1a1a1a;
        --bg-light: #2d2d2d;
        --white: #212529;
        --light: #343a40;
    }
}

/* Container */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    width: 100%;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
}

/* Links */
a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-color);
    opacity: 0.8;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 38px;
    white-space: nowrap;
}

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

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

.btn-primary:hover:not(:disabled) {
    background-color: #0056b3;
    border-color: #0056b3;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover:not(:disabled) {
    background-color: var(--light);
    border-color: var(--secondary-color);
}

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

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

.btn-danger:hover:not(:disabled) {
    background-color: #c82333;
    border-color: #c82333;
}

/* Header */
.main-header {
    background-color: var(--white);
    border-bottom: 2px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.app-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--primary-color);
    font-size: 1.5rem;
    margin: 0;
}

.app-title .icon {
    font-size: 1.75rem;
}

/* Connection Status */
.connection-status {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    color: var(--text-muted);
}

.status-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--secondary-color);
    animation: pulse 2s infinite;
}

.status-indicator.connected {
    background-color: var(--success-color);
    animation: none;
}

.status-indicator.disconnected {
    background-color: var(--danger-color);
    animation: none;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* Navigation */
.main-nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    color: var(--text-muted);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 40px;
}

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

.nav-btn.active {
    color: var(--primary-color);
    background-color: var(--light);
    border-color: var(--primary-color);
}

.nav-btn .icon {
    font-size: 1rem;
}

/* Main Content */
.main-content {
    padding: var(--spacing-xl) 0;
    min-height: calc(100vh - var(--header-height));
}

/* Content Sections */
.content-section {
    display: none;
}

.content-section.active {
    display: block;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-xl);
    gap: var(--spacing-lg);
}

.section-header h2 {
    margin: 0;
    color: var(--text-color);
}

.section-header p {
    color: var(--text-muted);
    margin: var(--spacing-xs) 0 0 0;
}

/* Form Elements */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    transition: border-color var(--transition-fast);
    background-color: var(--white);
    color: var(--text-color);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

/* Checkbox */
.checkbox-label {
    display: flex !important;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: auto;
    margin: 0;
}

.checkmark {
    position: relative;
    display: inline-block;
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.checkbox-label input[type="checkbox"]:checked + .checkmark::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--white);
    font-size: 12px;
    font-weight: bold;
}

/* Loading Spinner */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    text-align: center;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--spacing-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(4px);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.modal-content {
    background-color: var(--white);
    border-radius: var(--radius-lg);
    max-width: 90vw;
    max-height: 90vh;
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
}

.modal-header h3 {
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

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

.modal-body {
    padding: var(--spacing-lg);
    max-height: 70vh;
    overflow-y: auto;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    border-top: 2px solid var(--border-color);
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: calc(var(--header-height) + var(--spacing-md));
    right: var(--spacing-md);
    z-index: 1100;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    background-color: var(--white);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    min-width: 300px;
    max-width: 400px;
    box-shadow: var(--shadow-lg);
    animation: toastSlideIn 0.3s ease-out;
    position: relative;
    overflow: hidden;
}

.toast::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background-color: var(--info-color);
}

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

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-xs);
}

.toast-title {
    font-weight: 600;
    font-size: 0.875rem;
    margin: 0;
}

.toast-close {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    font-size: 1.2rem;
    padding: 0;
    line-height: 1;
}

.toast-body {
    font-size: 0.875rem;
    color: var(--text-muted);
    line-height: 1.4;
}

/* Utility Classes */
.text-muted { color: var(--text-muted); }
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.d-none { display: none !important; }
.d-block { display: block !important; }
.d-flex { display: flex !important; }
.d-inline-flex { display: inline-flex !important; }

.justify-content-center { justify-content: center; }
.justify-content-between { justify-content: space-between; }
.align-items-center { align-items: center; }

.mt-0 { margin-top: 0 !important; }
.mt-1 { margin-top: var(--spacing-xs) !important; }
.mt-2 { margin-top: var(--spacing-sm) !important; }
.mt-3 { margin-top: var(--spacing-md) !important; }
.mt-4 { margin-top: var(--spacing-lg) !important; }

.mb-0 { margin-bottom: 0 !important; }
.mb-1 { margin-bottom: var(--spacing-xs) !important; }
.mb-2 { margin-bottom: var(--spacing-sm) !important; }
.mb-3 { margin-bottom: var(--spacing-md) !important; }
.mb-4 { margin-bottom: var(--spacing-lg) !important; }

.p-0 { padding: 0 !important; }
.p-1 { padding: var(--spacing-xs) !important; }
.p-2 { padding: var(--spacing-sm) !important; }
.p-3 { padding: var(--spacing-md) !important; }
.p-4 { padding: var(--spacing-lg) !important; }

/* Additional Photo Grid Styles */
.photo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.photo-item {
    background-color: var(--white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    cursor: pointer;
    position: relative;
}

.photo-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.photo-thumbnail {
    position: relative;
    width: 100%;
    height: 200px;
    overflow: hidden;
}

.photo-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.photo-item:hover .photo-thumbnail img {
    transform: scale(1.05);
}

.private-badge {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    background-color: rgba(220, 53, 69, 0.9);
    color: white;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    z-index: 2;
}

.photo-info {
    padding: var(--spacing-md);
}

.photo-title {
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-color);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.photo-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
}

.photo-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tag {
    background-color: var(--primary-color);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.65rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.tag-more {
    background-color: var(--secondary-color);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: 0.65rem;
    font-weight: 500;
}

.no-photos {
    grid-column: 1 / -1;
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--text-muted);
}

.no-photos-content {
    max-width: 300px;
    margin: 0 auto;
}

.no-photos-icon {
    font-size: 4rem;
    display: block;
    margin-bottom: var(--spacing-lg);
    opacity: 0.5;
}

/* Pagination Styles */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xl);
    flex-wrap: wrap;
}

.pagination-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 40px;
    height: 40px;
    padding: var(--spacing-sm);
    border: 2px solid var(--border-color);
    background-color: var(--white);
    color: var(--text-color);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.pagination-btn:hover:not(:disabled) {
    background-color: var(--primary-color);
    color: var(--white);
    border-color: var(--primary-color);
    transform: translateY(-1px);
}

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

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

.pagination-ellipsis {
    padding: var(--spacing-sm);
    color: var(--text-muted);
}

/* Modal Photo Info Styles */
.info-section {
    margin-bottom: var(--spacing-lg);
}

.info-section h4 {
    margin-bottom: var(--spacing-md);
    color: var(--text-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: var(--spacing-sm);
}

.info-grid {
    display: grid;
    gap: var(--spacing-sm);
}

.info-item {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--bg-light);
}

.info-item:last-child {
    border-bottom: none;
}

.info-label {
    font-weight: 500;
    color: var(--text-muted);
    min-width: 100px;
}

.info-value {
    color: var(--text-color);
    text-align: right;
    flex: 1;
    word-break: break-word;
}

.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

/* Stats Styles */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.stat-card {
    background-color: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    text-align: center;
    transition: all var(--transition-normal);
    border: 2px solid var(--border-color);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.stat-card h3 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    display: block;
    line-height: 1;
}

.stats-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.stats-section {
    background-color: var(--white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 2px solid var(--border-color);
}

.stats-section h3 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: var(--spacing-sm);
}

.tag-cloud {
    line-height: 2;
}

.tag-cloud-item {
    display: inline-block;
    margin: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--bg-light);
    color: var(--text-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid var(--border-color);
}

.tag-cloud-item:hover {
    background-color: var(--primary-color);
    color: var(--white);
    transform: translateY(-1px);
}

.uploader-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--bg-light);
}

.uploader-item:last-child {
    border-bottom: none;
}

.uploader-name {
    font-weight: 500;
    color: var(--text-color);
}

.uploader-count {
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Toast Animation */
@keyframes toastSlideOut {
    from {
        opacity: 1;
        transform: translateY(0);
    }
    to {
        opacity: 0;
        transform: translateY(-20px);
    }
}