:root {
    --bg-color: #F5F5F7;
    --card-bg: #FFFFFF;
    --text-primary: #1D1D1F;
    --text-secondary: #86868B;
    --accent-color: #0071E3;
    --accent-hover: #0077ED;
    --border-radius: 20px;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
    --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

body {
    font-family: var(--font-stack);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 0 20px;
}

.top-nav {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.top-nav-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 56px;
}

.top-nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text-primary);
}

.top-nav-logo-icon {
    height: 40px;
}

.top-nav-logo-text {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: -0.01em;
    background: linear-gradient(135deg, #1D1D1F 0%, #434344 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.top-nav-links {
    display: flex;
    gap: 4px;
}

.top-nav-link {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    padding: 6px 12px;
    border-radius: 8px;
    position: relative;
}

.top-nav-link:hover {
    background: rgba(0, 0, 0, 0.04);
}

.top-nav-link.active {
    color: var(--accent-color);
    background: rgba(0, 113, 227, 0.08);
}

.header {
    background: white;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 0;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    text-decoration: none;
    background: linear-gradient(135deg, #1D1D1F 0%, #434344 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav {
    display: flex;
    gap: 30px;
}

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--accent-color);
}

.activity-detail-page {
    padding: 60px 0 40px 0;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-secondary);
    margin-top: 30px;
    margin-bottom: 30px;
    font-size: 14px;
    font-weight: 500;
}

.back-link:hover {
    color: var(--accent-color);
}

.page-content {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 32px;
    align-items: start;
}

.left-content {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.activity-header {
    background: transparent;
    border-radius: var(--border-radius);
    padding: 0;
}

.activity-title-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.activity-title {
    font-size: 28px;
    font-weight: 700;
    line-height: 1.3;
}

.activity-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 24px;
    align-items: center;
}

.activity-status {
    background: #86868B;
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.activity-status.active {
    background: #0071E3;
}

.activity-type.养虾记 {
    background: transparent;
    color: #0071E3;
}

.activity-type.社群 {
    background: transparent;
    color: #8B5CF6;
}

.activity-type.线上活动 {
    background: transparent;
    color: #22C55E;
}

.activity-type.线下活动 {
    background: transparent;
    color: #F59E0B;
}

.activity-type.直播活动 {
    background: transparent;
    color: #EF4444;
}

.activity-type {
    font-size: 14px;
    font-weight: 500;
    background: transparent;
}

.activity-info {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--text-secondary);
}

.activity-actions {
    display: flex;
    gap: 12px;
}

.action-btn {
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.primary-btn {
    background: var(--accent-color);
    color: white;
    border: none;
}

.primary-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.secondary-btn {
    background: white;
    color: var(--text-primary);
    border: 1px solid #e0e0e0;
}

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

.activity-main {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.content-section {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.section-title {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.section-content {
    color: var(--text-primary);
    line-height: 1.6;
}

.section-content p {
    margin-bottom: 16px;
}

.section-content ul {
    margin-bottom: 16px;
    padding-left: 24px;
}

.section-content li {
    margin-bottom: 8px;
}

.activity-flow {
    list-style: none;
    padding: 0;
}

.activity-flow li {
    display: flex;
    margin-bottom: 16px;
    padding-bottom: 16px;
    border-bottom: 1px solid #f0f0f0;
}

.activity-flow li:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.activity-flow time {
    min-width: 100px;
    font-weight: 600;
    color: var(--accent-color);
}

.activity-flow span {
    flex: 1;
}

.right-content {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.activity-sidebar {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.poster-container {
    width: 100%;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 100%);
}

.poster-container img {
    width: 100%;
    height: auto;
    display: block;
}

.sidebar-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.sidebar-card h3 {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.sidebar-info {
    color: var(--text-secondary);
    font-size: 14px;
}

.sidebar-info-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
}

.sidebar-info-label {
    font-weight: 500;
    color: var(--text-primary);
}

.sidebar-info-value {
    flex: 1;
    text-align: right;
}

footer {
    background: var(--bg-color);
    color: var(--text-secondary);
    padding: 32px 0;
    margin-top: 24px;
}

.poster-container img,
.sidebar-info img {
    cursor: zoom-in;
    transition: opacity 0.3s ease;
}

.poster-container img:hover,
.sidebar-info img:hover {
    opacity: 0.9;
}

.photo-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.photo-item {
    border-radius: 12px;
    overflow: hidden;
    cursor: pointer;
    transition: all 0.3s ease;
    aspect-ratio: 4 / 3;
    position: relative;
}

.photo-item::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0);
    transition: background 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.photo-item:hover::after {
    background: rgba(0, 0, 0, 0.15);
}

.photo-item:hover {
    transform: scale(1.03);
    box-shadow: var(--shadow-md);
}

.photo-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.lightbox {
    display: none;
    position: fixed;
    z-index: 2000;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.92);
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

.lightbox.active {
    display: flex;
}

.lightbox-img-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    padding: 60px 80px;
    position: relative;
}

.lightbox-img-wrapper img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    border-radius: 8px;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.lightbox.active .lightbox-img-wrapper img {
    transform: scale(1);
}

.lightbox-close {
    position: absolute;
    top: 20px;
    right: 24px;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.15);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 24px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.3s ease;
    z-index: 10;
}

.lightbox-close:hover {
    background: rgba(255, 255, 255, 0.3);
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    background: rgba(255, 255, 255, 0.15);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 24px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.3s ease;
    z-index: 10;
}

.lightbox-nav:hover {
    background: rgba(255, 255, 255, 0.3);
}

.lightbox-prev {
    left: 20px;
}

.lightbox-next {
    right: 20px;
}

.lightbox-counter {
    color: rgba(255, 255, 255, 0.7);
    font-size: 14px;
    padding: 12px 0 20px;
    text-align: center;
}

.image-modal {
    display: none;
    position: fixed;
    z-index: 2000;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    cursor: zoom-out;
    padding: 40px;
    align-items: center;
    justify-content: center;
}

.image-modal.active {
    display: flex;
}

.image-modal img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    border-radius: 8px;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.5);
    transform: scale(0.9);
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.image-modal.active img {
    transform: scale(1);
}

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

.handout-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 20px;
    background: var(--bg-color);
    border-radius: 12px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.handout-item:hover {
    background: #E8E8ED;
    transform: translateX(4px);
}

.handout-icon {
    width: 40px;
    height: 40px;
    background: rgba(0, 113, 227, 0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-color);
    flex-shrink: 0;
}

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

.handout-title {
    font-size: 15px;
    font-weight: 500;
    margin-bottom: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.handout-meta {
    font-size: 13px;
    color: var(--text-secondary);
}

.handout-link-icon {
    width: 18px;
    height: 18px;
    color: var(--text-secondary);
    flex-shrink: 0;
}

@media (max-width: 960px) {
    .page-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .activity-title {
        font-size: 24px;
    }

    .activity-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .activity-actions {
        flex-direction: column;
    }

    .action-btn {
        width: 100%;
        justify-content: center;
    }

    .content-section {
        padding: 24px;
    }
}