/* ============================================
   海洋之心 - 心血管文献检索平台
   学术医学风 (NEJM/Lancet)
   深海蓝 #1a3a5c + 医学红 #c41e3a
   ============================================ */

/* CSS Variables */
:root {
    --color-primary: #1a3a5c;
    --color-primary-light: #2a5a8c;
    --color-primary-dark: #0f2a4c;
    --color-accent: #c41e3a;
    --color-accent-light: #e84258;
    --color-bg: #f8f9fa;
    --color-text: #1a1a2e;
    --color-text-light: #4a5568;
    --color-muted: #8896a8;
    --color-border: #e2e8f0;
    --color-tag-bg: #e0ecf4;
    --color-card: #ffffff;
    --font-serif: 'Noto Serif SC', Georgia, 'Times New Roman', serif;
    --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
    --radius: 10px;
    --radius-sm: 8px;
    --radius-xs: 6px;
    --transition: all 0.3s ease;
    --max-width: 1200px;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
    color: var(--color-accent);
}

ul, ol {
    list-style-position: inside;
}

/* Container */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

.content-wrapper {
    min-height: calc(100vh - 220px);
    padding: 24px 20px;
}

/* ============================================
   Header
   ============================================ */
.header {
    background-color: var(--color-primary);
    color: #ffffff;
    padding: 16px 0;
    box-shadow: 0 2px 8px rgba(26, 58, 92, 0.15);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    color: #ffffff;
}

.logo:hover {
    color: #ffffff;
}

.logo-svg {
    flex-shrink: 0;
}

.logo-text {
    font-family: var(--font-serif);
    font-size: 24px;
    font-weight: 700;
    letter-spacing: 2px;
}

/* Nav */
.nav {
    display: flex;
    gap: 6px;
    align-items: center;
}

.nav-link {
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
    font-weight: 500;
    padding: 6px 14px;
    border-radius: 20px;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--color-primary);
    background-color: #ffffff;
}

.nav-link.active {
    color: var(--color-primary);
    background-color: #ffffff;
    font-weight: 600;
}

.nav-rss {
    color: rgba(255, 200, 100, 0.9);
    font-weight: 600;
}

.nav-rss:hover {
    background-color: rgba(255, 200, 100, 0.2);
    color: #ffd700;
}

/* User Area */
.user-area {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-email {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
}

.btn-login,
.btn-logout {
    color: #ffffff;
    font-size: 13px;
    padding: 6px 16px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 20px;
    transition: var(--transition);
    white-space: nowrap;
}

.btn-login:hover,
.btn-logout:hover {
    background-color: #ffffff;
    color: var(--color-primary);
    border-color: #ffffff;
}

/* ============================================
   Search Section
   ============================================ */
.search-section {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    margin-bottom: 24px;
}

.search-form {
    width: 100%;
}

.search-box {
    display: flex;
    gap: 0;
    margin-bottom: 16px;
}

.search-input {
    flex: 1;
    padding: 12px 20px;
    font-size: 15px;
    border: 2px solid var(--color-border);
    border-right: none;
    border-radius: var(--radius) 0 0 var(--radius);
    outline: none;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.search-input:focus {
    border-color: var(--color-primary);
}

.search-btn {
    padding: 12px 32px;
    background-color: var(--color-primary);
    color: #ffffff;
    border: none;
    border-radius: 0 var(--radius) var(--radius) 0;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

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

.filters {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.filter-select {
    padding: 8px 14px;
    font-size: 13px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    background-color: #ffffff;
    color: var(--color-text);
    cursor: pointer;
    outline: none;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.filter-select:focus {
    border-color: var(--color-primary);
}

/* Search History */
.search-history {
    margin-top: 16px;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
}

.history-label {
    font-size: 13px;
    color: var(--color-muted);
}

.history-tag {
    font-size: 12px;
    color: var(--color-primary);
    background-color: var(--color-tag-bg);
    padding: 4px 12px;
    border-radius: 20px;
    transition: var(--transition);
}

.history-tag:hover {
    background-color: var(--color-primary);
    color: #ffffff;
}

/* ============================================
   Stats Grid
   ============================================ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.stat-card {
    background-color: var(--color-card);
    padding: 25px;
    text-align: center;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border-top: 3px solid var(--color-primary);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-card:nth-child(odd) {
    border-top-color: var(--color-primary);
}

.stat-card:nth-child(even) {
    border-top-color: var(--color-accent);
}

.stat-number {
    font-family: var(--font-serif);
    font-size: 36px;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.2;
}

.stat-label {
    font-size: 13px;
    color: var(--color-muted);
    margin-top: 8px;
}

/* ============================================
   Section Header
   ============================================ */
.section-header {
    margin-bottom: 16px;
}

.section-title {
    font-family: var(--font-serif);
    font-size: 20px;
    font-weight: 600;
    color: var(--color-primary);
    border-left: 4px solid var(--color-accent);
    padding-left: 12px;
    line-height: 1.4;
}

/* ============================================
   Paper Card
   ============================================ */
.paper-card {
    background-color: var(--color-card);
    padding: 20px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 16px;
    transition: var(--transition);
}

.paper-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary);
}

.paper-card-header {
    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.batch-checkbox {
    margin-top: 4px;
    cursor: pointer;
    accent-color: var(--color-primary);
    flex-shrink: 0;
}

.paper-title {
    font-family: var(--font-serif);
    font-size: 16px;
    font-weight: 600;
    color: var(--color-primary);
    line-height: 1.4;
    flex: 1;
}

.paper-title a {
    color: inherit;
}

.paper-title a:hover {
    color: var(--color-accent);
}

.paper-title-cn {
    font-size: 14px;
    color: var(--color-text-light);
    margin: 6px 0 0 28px;
}

.paper-meta {
    font-size: 13px;
    color: var(--color-muted);
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    align-items: center;
    margin: 10px 0 10px 28px;
}

.meta-journal {
    font-weight: 500;
    font-style: italic;
}

.paper-tag {
    display: inline-block;
    font-size: 12px;
    background-color: var(--color-tag-bg);
    color: var(--color-primary);
    border-radius: 20px;
    padding: 3px 12px;
}

.paper-abstract {
    font-size: 14px;
    color: var(--color-text-light);
    line-height: 1.6;
    margin: 8px 0 12px 28px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.paper-actions {
    display: flex;
    gap: 8px;
    margin-left: 28px;
    flex-wrap: wrap;
    align-items: center;
}

/* Button Small */
.btn-sm {
    display: inline-block;
    padding: 4px 12px;
    font-size: 12px;
    border: 1px solid var(--color-border);
    border-radius: 15px;
    background-color: #ffffff;
    color: var(--color-text-light);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    font-family: var(--font-sans);
}

.btn-sm:hover {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
}

/* Favorite Button */
.btn-favorite {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 12px;
    font-size: 12px;
    border: 1px solid var(--color-border);
    border-radius: 15px;
    background-color: #ffffff;
    color: var(--color-text-light);
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

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

.btn-favorite.favorited {
    background-color: var(--color-accent);
    color: #ffffff;
    border-color: var(--color-accent);
}

/* ============================================
   Pagination
   ============================================ */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 4px;
    margin: 24px 0 8px;
    flex-wrap: wrap;
}
.pagination a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 10px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    color: var(--color-text-light);
    font-size: 14px;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
}
.pagination a:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
    background-color: rgba(26, 35, 126, 0.05);
}
.pagination a.active {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
    font-weight: 600;
}
.pagination a.page-nav {
    font-size: 16px;
    padding: 0 12px;
}
.pagination .page-dots {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 28px;
    height: 36px;
    color: var(--color-text-light);
    font-size: 14px;
    user-select: none;
}
.pagination-info {
    text-align: center;
    color: var(--color-text-light);
    font-size: 13px;
    margin-bottom: 16px;
}

/* ============================================
   Category List
   ============================================ */
.category-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 24px;
}

.category-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 16px;
    background-color: #ffffff;
    border: 1px solid var(--color-border);
    border-radius: 20px;
    font-size: 13px;
    color: var(--color-text-light);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.category-item:hover {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
}

.category-item.active {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
}

.category-count {
    font-size: 11px;
    background-color: rgba(255, 255, 255, 0.2);
    padding: 1px 8px;
    border-radius: 10px;
}

.category-item:not(.active) .category-count {
    background-color: var(--color-tag-bg);
    color: var(--color-primary);
}

/* ============================================
   Detail Page
   ============================================ */
.detail-section {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}

.detail-title {
    font-family: var(--font-serif);
    font-size: 24px;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1.4;
    margin-bottom: 8px;
}

.detail-title-cn {
    font-size: 16px;
    color: var(--color-text-light);
    margin-bottom: 16px;
}

.detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    font-size: 13px;
    color: var(--color-muted);
    padding: 12px 0;
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 20px;
}

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

.detail-meta-label {
    color: var(--color-muted);
}

.detail-meta-value {
    color: var(--color-text);
    font-weight: 500;
}

/* Authors */
.detail-authors {
    font-size: 14px;
    color: var(--color-text-light);
    margin-bottom: 16px;
    line-height: 1.8;
}

.detail-authors-label {
    font-weight: 600;
    color: var(--color-primary);
}

/* Tags */
.detail-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

/* Cite Section */
.cite-section {
    margin: 20px 0;
}

.cite-tabs {
    display: flex;
    gap: 4px;
    flex-wrap: wrap;
}

.cite-tab {
    padding: 6px 14px;
    font-size: 13px;
    border: 1px solid var(--color-border);
    border-bottom: none;
    border-radius: 15px 15px 0 0;
    background-color: var(--color-bg);
    color: var(--color-muted);
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.cite-tab:hover {
    color: var(--color-primary);
}

.cite-tab.active {
    background-color: var(--color-primary);
    color: #ffffff;
    border-color: var(--color-primary);
}

.cite-box {
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 0 var(--radius-sm) var(--radius-sm) var(--radius-sm);
    padding: 15px;
}

.cite-content {
    display: none;
    font-family: 'Courier New', Consolas, monospace;
    font-size: 13px;
    line-height: 1.6;
    color: var(--color-text);
    white-space: pre-wrap;
    word-break: break-all;
}

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

.btn-copy {
    margin-top: 10px;
    padding: 6px 16px;
    background-color: var(--color-primary);
    color: #ffffff;
    border: none;
    border-radius: var(--radius-xs);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

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

/* Share */
.share-section {
    margin: 20px 0;
    padding: 15px;
    background-color: var(--color-bg);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    gap: 10px;
}

.share-label {
    font-size: 13px;
    color: var(--color-muted);
    flex-shrink: 0;
}

.share-url {
    flex: 1;
    padding: 6px 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: 13px;
    background-color: #ffffff;
    color: var(--color-text-light);
    outline: none;
}

/* Abstract */
.detail-abstract {
    font-size: 15px;
    line-height: 1.8;
    color: var(--color-text);
    margin: 20px 0;
}

.detail-abstract h4 {
    font-family: var(--font-serif);
    font-size: 16px;
    color: var(--color-primary);
    margin-bottom: 10px;
}

.detail-abstract p {
    margin-bottom: 12px;
}

/* AI Summary */
.ai-summary-section {
    margin: 24px 0;
}

.ai-summary-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.ai-summary-title {
    font-family: var(--font-serif);
    font-size: 16px;
    color: var(--color-primary);
    font-weight: 600;
}

.ai-summary-btn {
    padding: 6px 16px;
    background-color: var(--color-accent);
    color: #ffffff;
    border: none;
    border-radius: var(--radius-xs);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.ai-summary-btn:hover {
    background-color: #a01828;
}

.ai-summary-btn:disabled {
    background-color: var(--color-muted);
    cursor: not-allowed;
}

.ai-summary-box {
    border-left: 4px solid var(--color-accent);
    padding: 20px;
    background-color: #fafafa;
    border-radius: var(--radius-sm);
}

.ai-loading {
    color: var(--color-muted);
    font-size: 14px;
    padding: 10px 0;
}

.ai-content p {
    margin-bottom: 10px;
    line-height: 1.8;
    font-size: 14px;
}

.ai-content h4,
.ai-content h5 {
    font-family: var(--font-serif);
    color: var(--color-primary);
    margin: 12px 0 6px;
}

.ai-error {
    color: var(--color-accent);
    font-size: 14px;
    padding: 10px 0;
}

/* Reading Notes */
.notes-section {
    margin: 24px 0;
}

.notes-section h4 {
    font-family: var(--font-serif);
    font-size: 16px;
    color: var(--color-primary);
    margin-bottom: 10px;
}

.notes-textarea {
    width: 100%;
    min-height: 120px;
    padding: 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 14px;
    resize: vertical;
    outline: none;
    transition: var(--transition);
}

.notes-textarea:focus {
    border-color: var(--color-primary);
}

.notes-actions {
    margin-top: 10px;
    display: flex;
    gap: 8px;
}

.btn-primary {
    padding: 8px 20px;
    background-color: var(--color-primary);
    color: #ffffff;
    border: none;
    border-radius: var(--radius-xs);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

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

.btn-danger {
    padding: 8px 20px;
    background-color: #ffffff;
    color: var(--color-accent);
    border: 1px solid var(--color-accent);
    border-radius: var(--radius-xs);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.btn-danger:hover {
    background-color: var(--color-accent);
    color: #ffffff;
}

/* Related Grid */
.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 15px;
    margin-top: 16px;
}

.related-card {
    background-color: var(--color-bg);
    padding: 15px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    border: 1px solid transparent;
}

.related-card:hover {
    background-color: #ffffff;
    border-color: var(--color-border);
    box-shadow: var(--shadow-sm);
}

.related-card h4 {
    font-family: var(--font-serif);
    font-size: 14px;
    color: var(--color-primary);
    line-height: 1.4;
    margin-bottom: 8px;
    font-weight: 600;
}

.related-card h4 a {
    color: inherit;
}

.related-card h4 a:hover {
    color: var(--color-accent);
}

.related-card-meta {
    font-size: 12px;
    color: var(--color-muted);
}

/* Back Link */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    color: var(--color-muted);
    margin-bottom: 16px;
    transition: var(--transition);
}

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

/* ============================================
   Footer
   ============================================ */
.footer {
    background-color: var(--color-primary);
    color: #ffffff;
    padding: 30px 0;
    margin-top: 40px;
}

.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 30px;
}

.footer-title {
    font-family: var(--font-serif);
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.footer-section h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 10px;
    color: rgba(255, 255, 255, 0.9);
}

.footer-section p {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 4px;
}

.footer-section a {
    display: block;
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
    padding: 3px 0;
    transition: var(--transition);
}

.footer-section a:hover {
    color: #ffffff;
}

.footer-copy {
    margin-top: 8px !important;
    font-size: 12px !important;
    color: rgba(255, 255, 255, 0.5) !important;
}

/* ============================================
   Batch Bar
   ============================================ */
.batch-bar {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: var(--color-primary);
    z-index: 100;
    box-shadow: 0 -2px 12px rgba(0, 0, 0, 0.2);
    padding: 12px 0;
    display: none;
}

.batch-bar-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.batch-count {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.9);
}

.batch-count strong {
    color: #ffd700;
    font-size: 18px;
}

.batch-actions {
    display: flex;
    gap: 8px;
}

.btn-batch {
    padding: 6px 16px;
    background-color: rgba(255, 255, 255, 0.15);
    color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-xs);
    font-size: 13px;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

.btn-batch:hover {
    background-color: #ffffff;
    color: var(--color-primary);
}

.btn-clear {
    background-color: rgba(196, 30, 58, 0.3);
    border-color: rgba(196, 30, 58, 0.5);
}

.btn-clear:hover {
    background-color: var(--color-accent);
    color: #ffffff;
}

/* ============================================
   Toast
   ============================================ */
.toast {
    position: fixed;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background-color: var(--color-text);
    color: #ffffff;
    padding: 10px 24px;
    border-radius: var(--radius-xs);
    font-size: 14px;
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
    pointer-events: none;
}

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

/* ============================================
   About Page
   ============================================ */
.about-section {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}

.about-section h2 {
    font-family: var(--font-serif);
    font-size: 22px;
    color: var(--color-primary);
    margin-bottom: 16px;
    border-left: 4px solid var(--color-accent);
    padding-left: 12px;
}

.about-section p {
    font-size: 15px;
    line-height: 1.8;
    color: var(--color-text-light);
    margin-bottom: 12px;
}

.about-section ul {
    margin: 12px 0 12px 20px;
    line-height: 2;
}

.about-section li {
    font-size: 14px;
    color: var(--color-text-light);
}

.feature-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 16px;
    margin-top: 16px;
}

.feature-item {
    padding: 16px;
    background-color: var(--color-bg);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--color-primary);
}

.feature-item:nth-child(even) {
    border-left-color: var(--color-accent);
}

.feature-item h4 {
    font-family: var(--font-serif);
    font-size: 15px;
    color: var(--color-primary);
    margin-bottom: 6px;
}

.feature-item p {
    font-size: 13px;
    color: var(--color-muted);
    margin: 0;
    line-height: 1.6;
}

/* ============================================
   Stats Page
   ============================================ */
.stats-chart-section {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}

.stats-chart-section h2 {
    font-family: var(--font-serif);
    font-size: 20px;
    color: var(--color-primary);
    margin-bottom: 20px;
    border-left: 4px solid var(--color-accent);
    padding-left: 12px;
}

.bar-chart {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.bar-item {
    display: flex;
    align-items: center;
    gap: 12px;
}

.bar-label {
    width: 180px;
    font-size: 13px;
    color: var(--color-text-light);
    text-align: right;
    flex-shrink: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.bar-track {
    flex: 1;
    height: 24px;
    background-color: var(--color-bg);
    border-radius: 4px;
    overflow: hidden;
}

.bar-fill {
    height: 100%;
    background-color: var(--color-primary);
    border-radius: 4px;
    transition: width 0.6s ease;
    min-width: 2px;
}

.bar-item:nth-child(even) .bar-fill {
    background-color: var(--color-accent);
}

.bar-value {
    width: 60px;
    font-size: 13px;
    color: var(--color-muted);
    flex-shrink: 0;
    font-weight: 500;
}

/* ============================================
   Forms (Subscribe, Login)
   ============================================ */
.subscribe-form {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
}

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

.form-label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: 6px;
}

.form-input {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: 14px;
    font-family: var(--font-sans);
    outline: none;
    transition: var(--transition);
}

.form-input:focus {
    border-color: var(--color-primary);
}

.form-select {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: 14px;
    background-color: #ffffff;
    outline: none;
    cursor: pointer;
    font-family: var(--font-sans);
}

.form-textarea {
    width: 100%;
    min-height: 80px;
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: 14px;
    font-family: var(--font-sans);
    resize: vertical;
    outline: none;
    transition: var(--transition);
}

.form-textarea:focus {
    border-color: var(--color-primary);
}

.btn-submit {
    padding: 10px 28px;
    background-color: var(--color-primary);
    color: #ffffff;
    border: none;
    border-radius: var(--radius-xs);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
}

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

/* RSS List */
.rss-list {
    list-style: none;
}

.rss-list li {
    padding: 10px 0;
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.rss-list li:last-child {
    border-bottom: none;
}

.rss-list li span {
    font-size: 14px;
    color: var(--color-text-light);
}

.rss-list li a {
    font-size: 13px;
    color: var(--color-primary);
    font-family: 'Courier New', Consolas, monospace;
}

/* ============================================
   Login / Register
   ============================================ */
.auth-container {
    max-width: 460px;
    margin: 40px auto;
}

.auth-tabs {
    display: flex;
    gap: 0;
    margin-bottom: 24px;
    border-bottom: 2px solid var(--color-border);
}

.auth-tab {
    padding: 10px 24px;
    font-size: 15px;
    font-weight: 500;
    color: var(--color-muted);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: var(--transition);
    background: none;
    border-top: none;
    border-left: none;
    border-right: none;
    font-family: var(--font-sans);
}

.auth-tab.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.auth-form {
    background-color: var(--color-card);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}

.auth-form h2 {
    font-family: var(--font-serif);
    font-size: 20px;
    color: var(--color-primary);
    margin-bottom: 20px;
}

.auth-error {
    background-color: #fee;
    color: var(--color-accent);
    padding: 10px 14px;
    border-radius: var(--radius-xs);
    font-size: 13px;
    margin-bottom: 16px;
    border: 1px solid #fcc;
}

.auth-link {
    display: block;
    text-align: center;
    margin-top: 16px;
    font-size: 13px;
    color: var(--color-muted);
}

.auth-link a {
    color: var(--color-primary);
    font-weight: 500;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--color-muted);
    font-size: 15px;
}

/* Select All */
.select-all-wrapper {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    padding: 10px 16px;
    background-color: var(--color-card);
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
}

.select-all-wrapper label {
    font-size: 14px;
    color: var(--color-text-light);
    cursor: pointer;
}

.select-all-wrapper input {
    accent-color: var(--color-primary);
    cursor: pointer;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
    .header-inner {
        flex-direction: column;
        gap: 12px;
    }

    .nav {
        flex-wrap: wrap;
        justify-content: center;
        gap: 4px;
    }

    .nav-link {
        padding: 4px 10px;
        font-size: 13px;
    }

    .user-area {
        font-size: 13px;
    }

    .content-wrapper {
        padding: 16px 12px;
    }

    .search-section {
        padding: 20px 15px;
    }

    .search-box {
        flex-direction: column;
        gap: 8px;
    }

    .search-input {
        border-right: 2px solid var(--color-border);
        border-radius: var(--radius);
    }

    .search-btn {
        border-radius: var(--radius);
    }

    .filters {
        flex-direction: column;
    }

    .filter-select {
        width: 100%;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .stat-card {
        padding: 16px;
    }

    .stat-number {
        font-size: 28px;
    }

    .paper-card {
        padding: 15px;
    }

    .paper-card-header {
        gap: 8px;
    }

    .paper-title-cn,
    .paper-meta,
    .paper-abstract,
    .paper-actions {
        margin-left: 0;
    }

    .detail-section {
        padding: 20px 15px;
    }

    .detail-title {
        font-size: 20px;
    }

    .detail-meta {
        gap: 12px;
    }

    .cite-tabs {
        overflow-x: auto;
        flex-wrap: nowrap;
        -webkit-overflow-scrolling: touch;
    }

    .footer-inner {
        grid-template-columns: 1fr;
        gap: 20px;
        text-align: center;
    }

    .related-grid {
        grid-template-columns: 1fr;
    }

    .batch-bar-inner {
        flex-direction: column;
        gap: 8px;
    }

    .bar-label {
        width: 100px;
        font-size: 12px;
    }

    .auth-container {
        margin: 20px auto;
    }

    .auth-form {
        padding: 20px;
    }

    .feature-list {
        grid-template-columns: 1fr;
    }

    .share-section {
        flex-wrap: wrap;
    }
}