/* ========================================
   学术论文筛选器 — Apple 学术风格
   色调：纯白/浅灰背景 + 深色文字 + 蓝色强调
   ======================================== */

/* --- 基础重置 --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-bg: #FAFAFA;
  --color-surface: #FFFFFF;
  --color-border: #E5E5E5;
  --color-border-light: #F0F0F0;
  --color-text-primary: #1D1D1F;
  --color-text-secondary: #6E6E73;
  --color-text-tertiary: #999;
  --color-accent: #0071E3;
  --color-accent-hover: #0077ED;
  --color-accent-bg: rgba(0, 113, 227, 0.06);
  --color-green: #34C759;
  --color-orange: #FF9500;
  --color-purple: #AF52DE;
  --color-red: #FF3B30;
  --color-teal: #5AC8FA;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: 'Noto Serif SC', 'Georgia', serif;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.08);
  --shadow-xl: 0 16px 48px rgba(0,0,0,0.1);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
}

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

/* --- 滚动条 --- */
* {
  scrollbar-width: thin;
  scrollbar-color: #D1D1D6 transparent;
}
*::-webkit-scrollbar { width: 6px; }
*::-webkit-scrollbar-track { background: transparent; }
*::-webkit-scrollbar-thumb { background: #D1D1D6; border-radius: 3px; }

/* --- 导航栏 --- */
#navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 0.5px solid var(--color-border);
}

.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 14px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-left {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* --- Tab导航 --- */
.nav-tabs {
  display: flex;
  gap: 4px;
  background: var(--color-bg);
  border-radius: 10px;
  padding: 3px;
}

.nav-tab {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 16px;
  border: none;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 500;
  font-family: var(--font-sans);
  color: var(--color-text-secondary);
  background: transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.nav-tab i {
  font-size: 14px;
}

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

.nav-tab.active {
  background: var(--color-surface);
  color: var(--color-text-primary);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

/* --- 页面切换 --- */
.page-content {
  display: none;
}

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

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--color-text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 18px;
}

.brand-text h1 {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
}

.brand-text p {
  font-size: 11px;
  color: var(--color-text-tertiary);
  letter-spacing: 0.02em;
}

.stats-bar {
  display: flex;
  align-items: center;
  gap: 20px;
}

.stats-bar.hidden {
  display: none;
}

.stat-item {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.stat-label {
  font-size: 12px;
  color: var(--color-text-tertiary);
}

.stat-value {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
}

.stat-value-accent {
  color: var(--color-accent);
}

.stat-divider {
  width: 1px;
  height: 20px;
  background: var(--color-border);
}

/* --- 主内容区 --- */
.main-content {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 22px;
}

/* --- 上传区域 --- */
.upload-section {
  padding-top: 80px;
  padding-bottom: 40px;
}

.upload-hero {
  text-align: center;
  margin-bottom: 48px;
}

.upload-eyebrow {
  font-size: 14px;
  font-weight: 500;
  color: var(--color-accent);
  letter-spacing: 0.04em;
  margin-bottom: 12px;
}

.upload-title {
  font-family: var(--font-serif);
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.15;
  color: var(--color-text-primary);
  margin-bottom: 16px;
}

.upload-desc {
  font-size: 17px;
  line-height: 1.65;
  color: var(--color-text-secondary);
  max-width: 540px;
  margin: 0 auto;
}

/* --- 拖放区 --- */
.drop-zone {
  position: relative;
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-xl);
  padding: 64px 40px;
  text-align: center;
  transition: all 0.3s ease;
  cursor: pointer;
  background: var(--color-surface);
  margin-bottom: 48px;
}

.drop-zone:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
}

.drop-zone.drop-active {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
  transform: scale(1.005);
}

.file-input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
  z-index: 10;
}

.drop-zone-content {
  pointer-events: none;
}

.drop-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  border-radius: 16px;
  background: var(--color-accent-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  color: var(--color-accent);
  transition: transform 0.3s ease;
}

.drop-zone:hover .drop-icon {
  transform: translateY(-2px);
}

.drop-title {
  font-size: 17px;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 4px;
}

.drop-hint {
  font-size: 14px;
  color: var(--color-text-tertiary);
}

/* --- 功能卡片 --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  transition: box-shadow 0.3s ease, transform 0.3s ease;
}

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

.feature-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  margin-bottom: 16px;
}

.feature-icon-blue {
  background: rgba(0, 113, 227, 0.08);
  color: var(--color-accent);
}

.feature-icon-purple {
  background: rgba(175, 82, 222, 0.08);
  color: var(--color-purple);
}

.feature-icon-green {
  background: rgba(52, 199, 89, 0.08);
  color: var(--color-green);
}

.feature-card h3 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--color-text-primary);
}

.feature-card p {
  font-size: 13px;
  line-height: 1.55;
  color: var(--color-text-secondary);
}

/* --- 加载动画 --- */
.loading-section {
  text-align: center;
  padding: 120px 0;
}

.loading-section.hidden { display: none; }

.loading-spinner {
  width: 32px;
  height: 32px;
  border: 2.5px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  margin: 0 auto 16px;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-text {
  font-size: 15px;
  color: var(--color-text-secondary);
}

/* --- 筛选工具栏 --- */
.filter-section {
  padding-top: 32px;
  padding-bottom: 8px;
}

.filter-section.hidden { display: none; }

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.filter-left {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.filter-label {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.filter-label i {
  margin-right: 4px;
}

.tag-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag-btn {
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
  border: 1px solid var(--color-border);
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.tag-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-bg);
}

.tag-btn.active {
  background: var(--color-text-primary);
  color: #fff;
  border-color: var(--color-text-primary);
}

.tag-btn .count {
  opacity: 0.5;
  margin-left: 4px;
}

.filter-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

.search-wrapper {
  position: relative;
}

.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 14px;
  color: var(--color-text-tertiary);
}

.search-input {
  width: 220px;
  padding: 8px 12px 8px 34px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--color-text-primary);
  background: var(--color-bg);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
  font-family: var(--font-sans);
}

.search-input::placeholder {
  color: var(--color-text-tertiary);
}

.search-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(0, 113, 227, 0.1);
}

.export-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--color-text-primary);
  color: #fff;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
  font-family: var(--font-sans);
}

.export-btn:hover {
  background: #333;
  transform: translateY(-1px);
}

.export-btn:active {
  transform: translateY(0);
}

/* --- 论文列表 --- */
.results-section {
  padding-top: 16px;
  padding-bottom: 60px;
}

.results-section.hidden { display: none; }

.paper-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.paper-card {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 20px 24px;
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: box-shadow 0.25s ease, transform 0.2s ease;
  animation: cardFadeIn 0.4s ease both;
}

.paper-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

@keyframes cardFadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.paper-index {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-tertiary);
  flex-shrink: 0;
  margin-top: 2px;
}

.paper-body {
  flex: 1;
  min-width: 0;
}

.paper-title {
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--color-text-primary);
  margin-bottom: 6px;
  transition: color 0.2s;
}

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

.paper-meta {
  font-size: 13px;
  color: var(--color-text-tertiary);
  margin-bottom: 10px;
}

.paper-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 10px;
}

.paper-abstract {
  font-size: 13px;
  line-height: 1.65;
  color: var(--color-text-secondary);
  margin-bottom: 12px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.paper-footer {
  display: flex;
  align-items: center;
  gap: 16px;
}

.confidence-indicator {
  display: flex;
  align-items: center;
  gap: 8px;
}

.confidence-label {
  font-size: 11px;
  color: var(--color-text-tertiary);
}

.confidence-bar {
  width: 80px;
  height: 3px;
  background: var(--color-border-light);
  border-radius: 2px;
  overflow: hidden;
}

.confidence-fill {
  height: 100%;
  border-radius: 2px;
  transition: width 0.6s ease;
}

.confidence-high { background: var(--color-green); }
.confidence-medium { background: var(--color-orange); }
.confidence-low { background: #D1D1D6; }

.paper-evidence-count {
  font-size: 11px;
  color: var(--color-text-tertiary);
}

.paper-links {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
  margin-top: 2px;
}

.paper-link-btn {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  border: 1px solid var(--color-border);
  background: transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-tertiary);
  font-size: 14px;
  text-decoration: none;
  transition: all 0.2s;
}

.paper-link-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-bg);
}

/* --- 方法标签 --- */
.method-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 12px;
  white-space: nowrap;
  letter-spacing: 0.01em;
}

/* 8色循环标签系统 */
.method-tag-0 { background: rgba(52, 199, 89, 0.1); color: #1B7A32; }
.method-tag-1 { background: rgba(255, 149, 0, 0.1); color: #C93400; }
.method-tag-2 { background: rgba(175, 82, 222, 0.1); color: #8944AB; }
.method-tag-3 { background: rgba(0, 113, 227, 0.1); color: #0055AA; }
.method-tag-4 { background: rgba(255, 59, 48, 0.1); color: #D70015; }
.method-tag-5 { background: rgba(90, 200, 250, 0.1); color: #0A7ACA; }
.method-tag-6 { background: rgba(255, 100, 130, 0.1); color: #C44060; }
.method-tag-7 { background: rgba(48, 176, 199, 0.1); color: #1A8A9E; }
.method-tag-default { background: rgba(142, 142, 147, 0.1); color: #636366; }

/* --- 学科选择器 --- */
.discipline-section {
  margin-bottom: 36px;
}

.discipline-section-title {
  text-align: center;
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-tertiary);
  margin-bottom: 20px;
}

.discipline-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
}

.discipline-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 20px;
  background: var(--color-surface);
  border: 2px solid var(--color-border-light);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.25s ease;
}

.discipline-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.discipline-card.selected {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
}

.discipline-card.selected .discipline-icon {
  background: var(--color-accent);
  color: white;
}

.discipline-icon {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
  transition: all 0.25s;
}

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

.discipline-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 2px;
}

.discipline-desc {
  font-size: 11px;
  color: var(--color-text-tertiary);
  line-height: 1.4;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.discipline-check {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 2px solid var(--color-border);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: transparent;
  transition: all 0.2s;
}

.discipline-card.selected .discipline-check {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: white;
}

.discipline-selected-hint {
  display: none;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  background: rgba(0, 113, 227, 0.04);
  border: 1px solid rgba(0, 113, 227, 0.12);
  border-radius: 10px;
  margin-top: 16px;
}

.discipline-selected-hint.visible {
  display: flex;
}

.discipline-selected-hint .hint-text {
  font-size: 13px;
  color: var(--color-text-secondary);
}

.discipline-selected-hint .hint-text strong {
  color: var(--color-accent);
  font-weight: 600;
}

/* 拖放区禁用态 */
.drop-zone.disabled {
  opacity: 0.45;
  pointer-events: none;
  border-color: var(--color-border-light);
}

/* 学科图标色 */
.disc-design .discipline-icon { background: rgba(175, 82, 222, 0.1); color: #8944AB; }
.disc-cs .discipline-icon { background: rgba(0, 113, 227, 0.1); color: #0071E3; }
.disc-psych .discipline-icon { background: rgba(255, 149, 0, 0.1); color: #C93400; }
.disc-edu .discipline-icon { background: rgba(52, 199, 89, 0.1); color: #248A3D; }
.disc-med .discipline-icon { background: rgba(255, 59, 48, 0.1); color: #D70015; }
.disc-soc .discipline-icon { background: rgba(90, 200, 250, 0.1); color: #0A7ACA; }

/* 阅读报告中的学科标签 */
.discipline-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: 10px;
  margin-top: 2px;
}

.discipline-tag-yes {
  background: rgba(52, 199, 89, 0.12);
  color: #248A3D;
}

.discipline-tag-no {
  background: rgba(142, 142, 147, 0.1);
  color: #636366;
}

/* --- 无结果 --- */
.no-results {
  text-align: center;
  padding: 80px 0;
}

.no-results.hidden { display: none; }

.no-results i {
  font-size: 48px;
  color: var(--color-border);
  margin-bottom: 12px;
  display: block;
}

.no-results p {
  font-size: 15px;
  color: var(--color-text-tertiary);
}

/* --- 弹窗 --- */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
}

.modal-overlay.hidden { display: none; }

.modal-overlay:not(.hidden) {
  animation: modalFadeIn 0.25s ease;
}

@keyframes modalFadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.modal-container {
  position: relative;
  width: 100%;
  max-width: 680px;
  max-height: 85vh;
  background: var(--color-surface);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 28px;
  border-bottom: 1px solid var(--color-border-light);
  flex-shrink: 0;
}

.modal-header h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text-primary);
}

.modal-close {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: none;
  background: var(--color-bg);
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 16px;
  transition: background 0.2s;
}

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

.modal-body {
  padding: 28px;
  overflow-y: auto;
  flex: 1;
}

/* 弹窗内部样式 */
.detail-title {
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.35;
  color: var(--color-text-primary);
  margin-bottom: 8px;
}

.detail-authors {
  font-size: 14px;
  color: var(--color-text-secondary);
  margin-bottom: 4px;
}

.detail-venue {
  font-size: 12px;
  color: var(--color-text-tertiary);
  margin-bottom: 20px;
}

.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 24px;
}

.detail-section {
  margin-bottom: 24px;
}

.detail-section-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-tertiary);
  margin-bottom: 10px;
}

.detail-abstract {
  font-size: 14px;
  line-height: 1.75;
  color: var(--color-text-secondary);
}

.highlight-match {
  background: rgba(255, 214, 0, 0.25);
  color: var(--color-text-primary);
  padding: 1px 3px;
  border-radius: 3px;
  font-weight: 500;
}

.evidence-block {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin-bottom: 12px;
}

.evidence-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.evidence-conf {
  font-size: 11px;
  color: var(--color-text-tertiary);
}

.evidence-item {
  font-size: 13px;
  color: var(--color-text-secondary);
  padding: 2px 0;
}

.evidence-item .source {
  color: var(--color-accent);
  font-weight: 500;
}

.evidence-item .term {
  color: var(--color-text-primary);
  font-weight: 500;
}

.detail-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.keyword-chip {
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 14px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

.detail-stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.detail-stat-card {
  background: var(--color-bg);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
}

.detail-stat-card .label {
  font-size: 11px;
  color: var(--color-text-tertiary);
  margin-bottom: 2px;
}

.detail-stat-card .value {
  font-size: 20px;
  font-weight: 600;
  color: var(--color-text-primary);
}

/* --- 页脚 --- */
.site-footer {
  text-align: center;
  padding: 32px 22px;
  font-size: 13px;
  color: var(--color-text-tertiary);
  border-top: 1px solid var(--color-border-light);
}

.site-footer a {
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
}

/* --- 隐藏工具类 --- */
.hidden {
  display: none !important;
}

/* --- 响应式 --- */
@media (max-width: 768px) {
  .upload-title {
    font-size: 28px;
  }

  .upload-desc {
    font-size: 15px;
  }

  .upload-desc br { display: none; }

  .features-grid,
  .discipline-grid {
    grid-template-columns: 1fr;
  }

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

  .nav-left {
    flex-direction: column;
    gap: 10px;
    width: 100%;
  }

  .nav-tabs {
    width: 100%;
    justify-content: center;
  }

  .stats-bar {
    gap: 12px;
  }

  .filter-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .filter-left, .filter-right {
    flex-direction: column;
    align-items: stretch;
  }

  .search-input {
    width: 100%;
  }

  .paper-card {
    flex-direction: column;
    gap: 12px;
    padding: 16px;
  }

  .paper-index {
    display: none;
  }

  .paper-links {
    flex-direction: row;
  }

  .modal-container {
    max-height: 90vh;
    border-radius: var(--radius-lg);
  }
}