:root {
    /* Color System */
    --primary: #0066CC;
    --primary-light: #4D94DF;
    --primary-dark: #004C99;
    --secondary: #6C757D;
    --secondary-light: #ADB5BD;
    --secondary-dark: #495057;
    --accent: #FF9500;
    --accent-light: #FFBF66;
    --accent-dark: #CC7A00;
    --success: #34C759;
    --warning: #FFCC00;
    --error: #FF3B30;
    --neutral-50: #F9FAFB;
    --neutral-100: #F3F4F6;
    --neutral-200: #E5E7EB;
    --neutral-300: #D1D5DB;
    --neutral-400: #9CA3AF;
    --neutral-500: #6B7280;
    --neutral-600: #4B5563;
    --neutral-700: #374151;
    --neutral-800: #1F2937;
    --neutral-900: #111827;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;

    /* Spacing */
    --spacing-0: 0;
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;
    --spacing-24: 6rem;
    --spacing-32: 8rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Borders */
    --border-radius-sm: 0.125rem;
    --border-radius: 0.25rem;
    --border-radius-md: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 0.75rem;
    --border-radius-2xl: 1rem;
    --border-radius-3xl: 1.5rem;
    --border-radius-full: 9999px;
}

/* General Styles */
body {
    font-family: var(--font-family);
    color: var(--neutral-800);
    background-color: var(--neutral-100);
    line-height: 1.5;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--primary-dark);
    text-decoration: none;
}

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

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

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

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

/* Header */
.header {
    margin-bottom: var(--spacing-16);
}

.navbar {
    background-color: white;
    box-shadow: var(--shadow);
    padding: var(--spacing-3) 0;
    transition: all 0.3s ease;
}

.navbar-brand {
    font-weight: 600;
    color: var(--neutral-900);
    display: flex;
    align-items: center;
}

.navbar-brand:hover {
    color: var(--primary);
}

.nav-links {
    color: var(--neutral-700);
    font-weight: 500;
    padding: var(--spacing-2) var(--spacing-4);
    border-radius: var(--border-radius);
    transition: all 0.2s ease;
}

.nav-links:hover {
    color: var(--primary);
    background-color: var(--neutral-100);
}

.nav-links.active {
    color: var(--primary);
    background-color: var(--neutral-100);
}

.search-container {
    position: relative;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: var(--spacing-3);
    color: var(--neutral-400);
}

.search-input {
    padding-left: var(--spacing-8);
    border-radius: var(--border-radius-full);
    border: 1px solid var(--neutral-300);
    transition: all 0.2s ease;
}

.search-input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(0, 102, 204, 0.1);
}

.nav-icons {
    display: flex;
}

.icon-link {
    color: var(--neutral-600);
    font-size: 1.25rem;
    padding: var(--spacing-2);
    border-radius: var(--border-radius-full);
    transition: all 0.2s ease;
}

.icon-link:hover {
    color: var(--primary);
    background-color: var(--neutral-100);
}

/* Main Content */
.main-content {
    padding-top: 5rem;
    min-height: calc(100vh - 15rem);
}

/* Welcome Banner */
.welcome-banner {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-8);
    margin-bottom: var(--spacing-8);
    box-shadow: var(--shadow);
}

.welcome-banner h1 {
    color: var(--neutral-900);
    font-weight: 600;
    margin-bottom: var(--spacing-2);
}

.welcome-banner p {
    color: var(--neutral-600);
    margin-bottom: var(--spacing-4);
}

.welcome-banner img {
    border-radius: var(--border-radius-lg);
    max-height: 200px;
    object-fit: cover;
}

/* Stats Section */
.stats-section {
    margin-bottom: var(--spacing-8);
}

.stat-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    height: 100%;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--border-radius-full);
    background-color: rgba(0, 102, 204, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: var(--spacing-4);
}

.stat-icon i {
    font-size: 1.5rem;
    color: var(--primary);
}

.stat-info h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-1);
}

.stat-info p {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    margin: 0;
}

/* Categories Section */
.categories-section, .recent-discussions, .featured-members {
    margin-bottom: var(--spacing-8);
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-4);
}

.section-header h2 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    color: var(--neutral-900);
    margin: 0;
}

.view-all {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--primary);
}

.view-all i {
    transition: transform 0.2s ease;
}

.view-all:hover i {
    transform: translateX(2px);
}

.category-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    height: 100%;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.category-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--border-radius-full);
    background-color: rgba(0, 102, 204, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: var(--spacing-4);
    flex-shrink: 0;
}

.category-icon i {
    font-size: 1.75rem;
    color: var(--primary);
}

.category-info {
    flex: 1;
}

.category-info h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-1);
}

.category-info p {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    margin-bottom: var(--spacing-2);
}

.category-stats {
    display: flex;
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.category-stats span {
    display: flex;
    align-items: center;
    margin-right: var(--spacing-3);
}

.category-stats i {
    margin-right: var(--spacing-1);
}

/* Discussion Cards */
.discussion-list {
    margin-bottom: var(--spacing-4);
}

.discussion-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    box-shadow: var(--shadow);
    display: flex;
    margin-bottom: var(--spacing-4);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.discussion-card-left {
    margin-right: var(--spacing-4);
}

.discussion-card-middle {
    flex: 1;
    min-width: 0; /* Helps with text truncation */
}

.discussion-card-right {
    margin-left: var(--spacing-4);
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    justify-content: space-between;
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: var(--border-radius-full);
    object-fit: cover;
}

.discussion-card h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-1);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.discussion-meta {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
    margin-bottom: var(--spacing-2);
}

.discussion-meta span {
    margin-right: var(--spacing-3);
}

.discussion-excerpt {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    margin: 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.discussion-stats {
    display: flex;
    gap: var(--spacing-3);
    margin-bottom: var(--spacing-2);
}

.stat {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--neutral-800);
}

.stat-label {
    display: block;
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.discussion-time {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

/* Member Cards */
.member-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    box-shadow: var(--shadow);
    text-align: center;
    height: 100%;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.member-avatar {
    width: 80px;
    height: 80px;
    border-radius: var(--border-radius-full);
    object-fit: cover;
    margin: 0 auto var(--spacing-3);
}

.member-card h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-1);
}

.member-title {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    margin-bottom: var(--spacing-2);
}

.member-stats {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

/* Footer */
.footer {
    background-color: white;
    padding: var(--spacing-8) 0 var(--spacing-4);
    box-shadow: 0 -1px 3px rgba(0, 0, 0, 0.05);
    margin-top: var(--spacing-16);
}

.footer h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-4);
}

.footer p {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    margin-bottom: var(--spacing-4);
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: var(--spacing-2);
}

.footer-links a {
    font-size: var(--font-size-sm);
    color: var(--neutral-600);
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: var(--primary);
}

.social-links {
    display: flex;
    gap: var(--spacing-3);
    margin-top: var(--spacing-4);
}

.social-link {
    width: 36px;
    height: 36px;
    border-radius: var(--border-radius-full);
    background-color: var(--neutral-100);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-600);
    transition: all 0.2s ease;
}

.social-link:hover {
    background-color: var(--primary);
    color: white;
}

.footer-bottom {
    margin-top: var(--spacing-8);
    padding-top: var(--spacing-4);
    border-top: 1px solid var(--neutral-200);
    text-align: center;
}

.footer-bottom p {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
    margin: 0;
}

/* Thread Page Styles */
.breadcrumb {
    margin-bottom: var(--spacing-4);
}

.thread-header {
    margin-bottom: var(--spacing-6);
}

.thread-header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-2);
}

.thread-meta {
    display: flex;
    justify-content: space-between;
    font-size: var(--font-size-sm);
    color: var(--neutral-500);
}

.thread-category a {
    color: var(--primary);
    font-weight: 500;
}

.thread-stats i {
    margin-right: var(--spacing-1);
}

.original-post, .replies-section {
    margin-bottom: var(--spacing-8);
}

.post-card, .reply-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-6);
    box-shadow: var(--shadow);
    margin-bottom: var(--spacing-4);
}

.post-author {
    display: flex;
    margin-bottom: var(--spacing-4);
}

.author-avatar {
    width: 64px;
    height: 64px;
    border-radius: var(--border-radius-full);
    object-fit: cover;
    margin-right: var(--spacing-4);
}

.author-info h4 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-1);
}

.author-title {
    font-size: var(--font-size-sm);
    color: var(--primary);
    display: block;
    margin-bottom: var(--spacing-1);
}

.author-stats {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.author-stats span {
    margin-right: var(--spacing-3);
}

.post-content {
    font-size: var(--font-size-base);
    color: var(--neutral-800);
    margin-bottom: var(--spacing-4);
}

.post-content p {
    margin-bottom: var(--spacing-4);
}

.post-content ul, .post-content ol {
    margin-bottom: var(--spacing-4);
    padding-left: var(--spacing-6);
}

.post-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-4);
    border-top: 1px solid var(--neutral-200);
}

.post-meta {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.nested-replies {
    margin-top: var(--spacing-4);
    margin-left: var(--spacing-10);
}

.nested-reply {
    background-color: var(--neutral-50);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    margin-bottom: var(--spacing-3);
    border-left: 3px solid var(--primary-light);
}

.nested-reply .post-author {
    margin-bottom: var(--spacing-2);
}

.nested-reply .author-avatar {
    width: 40px;
    height: 40px;
}

.reply-form-section {
    margin-bottom: var(--spacing-8);
}

.reply-form-section h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-4);
}

.form-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
}

/* Topic Page Styles */
.category-header {
    display: flex;
    align-items: center;
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-6);
    box-shadow: var(--shadow);
    margin-bottom: var(--spacing-6);
}

.category-icon-large {
    width: 80px;
    height: 80px;
    border-radius: var(--border-radius-full);
    background-color: rgba(0, 102, 204, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: var(--spacing-6);
    flex-shrink: 0;
}

.category-icon-large i {
    font-size: 2.5rem;
    color: var(--primary);
}

.category-info-large {
    flex: 1;
}

.category-info-large h1 {
    font-size: var(--font-size-3xl);
    font-weight: 600;
    color: var(--neutral-900);
    margin-bottom: var(--spacing-1);
}

.category-info-large p {
    font-size: var(--font-size-lg);
    color: var(--neutral-600);
    margin-bottom: var(--spacing-2);
}

.category-stats {
    display: flex;
    flex-wrap: wrap;
    font-size: var(--font-size-sm);
    color: var(--neutral-500);
}

.category-stats span {
    display: flex;
    align-items: center;
    margin-right: var(--spacing-4);
}

.category-stats i {
    margin-right: var(--spacing-1);
}

.category-actions {
    margin-left: var(--spacing-4);
}

.category-filters {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-4);
}

.filter-actions {
    display: flex;
}

.threads-list {
    margin-bottom: var(--spacing-8);
}

.thread-card {
    background-color: white;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-4);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    margin-bottom: var(--spacing-4);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.thread-status {
    margin-right: var(--spacing-4);
}

.status-badge {
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-full);
    background-color: var(--neutral-200);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-600);
}

.status-badge.hot {
    background-color: rgba(255, 59, 48, 0.1);
    color: var(--error);
}

.status-badge.pinned {
    background-color: rgba(52, 199, 89, 0.1);
    color: var(--success);
}

.status-badge.new {
    background-color: rgba(0, 122, 255, 0.1);
    color: var(--primary);
}

.status-badge.solved {
    background-color: rgba(52, 199, 89, 0.1);
    color: var(--success);
}

.thread-info {
    flex: 1;
    min-width: 0; /* Helps with text truncation */
}

.thread-title {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin-bottom: var(--spacing-1);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.thread-meta {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.thread-meta span {
    margin-right: var(--spacing-3);
}

.thread-tag {
    display: inline-block;
    background-color: var(--neutral-100);
    padding: 0 var(--spacing-2);
    border-radius: var(--border-radius);
    font-size: var(--font-size-xs);
    color: var(--neutral-600);
    height: fit-content;
}

.thread-stats {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    margin: 0 var(--spacing-6);
}

.thread-last-post {
    display: flex;
    align-items: center;
}

.avatar-sm {
    width: 32px;
    height: 32px;
    border-radius: var(--border-radius-full);
    object-fit: cover;
    margin-right: var(--spacing-2);
}

.last-post-info {
    font-size: var(--font-size-xs);
}

.last-post-info a {
    display: block;
    font-weight: 500;
}

.last-post-time {
    color: var(--neutral-500);
}

.load-more {
    margin: var(--spacing-6) 0;
}

.category-statistics {
    margin-top: var(--spacing-8);
}

.contributor-list, .stats-list, .thread-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.contributor-list li, .stats-list li {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-2) 0;
    border-bottom: 1px solid var(--neutral-200);
}

.contributor-list li:last-child, .stats-list li:last-child, .thread-list li:last-child {
    border-bottom: none;
}

.contributor-name {
    font-weight: 500;
    margin-right: auto;
    margin-left: var(--spacing-2);
}

.contributor-count {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

.stat-label {
    color: var(--neutral-600);
}

.thread-list li {
    display: flex;
    flex-direction: column;
    padding: var(--spacing-2) 0;
    border-bottom: 1px solid var(--neutral-200);
}

.thread-list a {
    font-weight: 500;
    margin-bottom: var(--spacing-1);
}

.thread-metric {
    font-size: var(--font-size-xs);
    color: var(--neutral-500);
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

.welcome-banner, .stat-card, .category-card, .discussion-card, .member-card {
    animation: slideUp 0.5s ease forwards;
}

.discussion-card:nth-child(1) { animation-delay: 0.1s; }
.discussion-card:nth-child(2) { animation-delay: 0.2s; }
.discussion-card:nth-child(3) { animation-delay: 0.3s; }
.discussion-card:nth-child(4) { animation-delay: 0.4s; }

.category-card:nth-child(1) { animation-delay: 0.1s; }
.category-card:nth-child(2) { animation-delay: 0.2s; }
.category-card:nth-child(3) { animation-delay: 0.3s; }
.category-card:nth-child(4) { animation-delay: 0.4s; }

.member-card:nth-child(1) { animation-delay: 0.1s; }
.member-card:nth-child(2) { animation-delay: 0.2s; }
.member-card:nth-child(3) { animation-delay: 0.3s; }
.member-card:nth-child(4) { animation-delay: 0.4s; }

/* Hover effects */
.btn, .nav-link, .icon-link, .social-link {
    transition: all 0.2s ease;
}

.btn:hover {
    transform: translateY(-1px);
}

.btn:active {
    transform: translateY(1px);
}

/* Responsive styles */
@media (max-width: 992px) {
    .thread-stats {
        display: none;
    }
    
    .category-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .category-icon-large {
        margin-bottom: var(--spacing-4);
    }
    
    .category-actions {
        margin-left: 0;
        margin-top: var(--spacing-4);
        align-self: flex-start;
    }
    
    .thread-last-post {
        display: none;
    }
}

@media (max-width: 768px) {
    .discussion-card {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .discussion-card-left {
        margin-bottom: var(--spacing-3);
    }
    
    .discussion-card-right {
        width: 100%;
        margin-left: 0;
        margin-top: var(--spacing-3);
        flex-direction: row;
        justify-content: space-between;
    }
    
    .category-filters {
        flex-direction: column;
    }
    
    .search-filter {
        margin-top: var(--spacing-3);
    }
    
    .form-actions {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
    
    .submit-buttons {
        margin-top: var(--spacing-3);
        width: 100%;
        display: flex;
        justify-content: flex-end;
    }
    .post-meta{
        display: flex;
        align-items: center;
        justify-content: space-between;
    }
    .maintime{
        width: 100%;
    }
}