/* ===== 刘昊学术主页 - 极简主义风格 ===== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;500;600;700&display=swap');
@import url('https://cdn.jsdelivr.net/npm/lxgw-wenkai-webfont@1.7.0/style.css');

:root {
  --text-primary: #1a1a1a;
  --text-secondary: #4a4a4a;
  --text-muted: #7a7a7a;
  --text-light: #a0a0a0;

  --accent-color: #1a1a1a;

  --bg-page: #faf9f7;
  --bg-content: rgba(255, 255, 255, 0.85);
  --bg-card: rgba(255, 255, 255, 0.6);

  --border-light: rgba(0, 0, 0, 0.06);
  --border-medium: rgba(0, 0, 0, 0.1);

  --font-serif: "Noto Serif SC", "Source Han Serif SC", "SimSun", serif;
  --font-kai: "LXGW WenKai", "KaiTi", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  --max-width: 920px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-padding-top: 88px;
}

body {
  font-family: var(--font-serif);
  color: var(--text-primary);
  line-height: 1.75;
  min-height: 100vh;
  background: var(--bg-page);
  position: relative;
}

/* 全局底纹背景 - COVER.jpg */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url('/COVER.jpg');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  opacity: 0.06;
  z-index: -2;
  pointer-events: none;
}

/* 纸质纹理叠加 */
body::after {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url("data:image/svg+xml,%3Csvg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.02'/%3E%3C/svg%3E");
  z-index: -1;
  pointer-events: none;
}

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

a:hover {
  color: var(--text-muted);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-8);
}

/* ===== 全局顶部导航栏 ===== */
.global-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-content);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-light);
  padding: var(--space-5) 0;
}

.global-nav-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
}

.nav-link {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  transition: color 0.2s var(--ease-out);
  white-space: nowrap;
  padding: var(--space-2) 0;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 1.5px;
  background: var(--text-primary);
  transform: scaleX(0);
  transition: transform 0.25s var(--ease-out);
}

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

.nav-link:hover::after {
  transform: scaleX(1);
}

.nav-link.active {
  color: var(--text-primary);
}

.nav-link.active::after {
  transform: scaleX(1);
}

.mobile-nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 20px;
  color: var(--text-primary);
  padding: var(--space-2) var(--space-3);
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
}

/* ===== 主页 Hero 区域 ===== */
.home-hero {
  padding: var(--space-16) 0 var(--space-12);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-10);
}

.hero-main {
  flex: 1;
  min-width: 0;
}

.home-hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  margin-bottom: var(--space-2);
  line-height: 1.2;
  color: var(--text-primary);
}

.home-hero .hero-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-8);
  letter-spacing: 0.02em;
  line-height: 1.6;
}

.hero-intro {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.9;
  max-width: 480px;
  margin-bottom: var(--space-8);
}

.hero-aside {
  flex-shrink: 0;
  width: 180px;
  text-align: center;
}

.hero-photo-wrapper {
  margin-bottom: var(--space-3);
}

.hero-photo-wrapper img {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 3px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
}

.photo-caption {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
  letter-spacing: 0.02em;
}

/* ===== 内容区块 ===== */
.section-block {
  padding: var(--space-12) 0;
  border-top: 1px solid var(--border-light);
}

.section-title {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.section-subtitle {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: var(--space-6);
}

/* ===== 快速导航链接 ===== */
.quick-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  max-width: 400px;
}

.quick-link-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.95rem;
  color: var(--text-primary);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border-light);
  transition: all 0.2s var(--ease-out);
  min-height: 44px;
}

.quick-link-item:hover {
  color: var(--text-primary);
  padding-left: var(--space-2);
  border-bottom-color: var(--text-primary);
}

.quick-link-item .link-icon {
  font-size: 0.85rem;
  opacity: 0.5;
  transition: transform 0.2s var(--ease-out);
}

.quick-link-item:hover .link-icon {
  transform: translateX(4px);
}

/* ===== 项目展示 ===== */
.project-card {
  display: flex;
  gap: var(--space-6);
  align-items: flex-start;
  padding: var(--space-6) 0;
  border-bottom: 1px solid var(--border-light);
}

.project-card:last-child {
  border-bottom: none;
}

.project-thumb {
  flex-shrink: 0;
  width: 160px;
}

.project-thumb img {
  width: 100%;
  border-radius: 3px;
  opacity: 0.9;
  transition: opacity 0.25s var(--ease-out), transform 0.25s var(--ease-out);
}

.project-thumb img:hover {
  opacity: 1;
  transform: scale(1.02);
}

.project-info h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: var(--space-2);
  line-height: 1.5;
  color: var(--text-primary);
}

.project-info p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: var(--space-3);
}

.project-link {
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  transition: gap 0.2s var(--ease-out);
}

.project-link:hover {
  gap: var(--space-2);
}

.project-links-group {
  display: flex;
  gap: var(--space-4);
  margin-top: var(--space-2);
}

/* ===== 课程列表 ===== */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 0;
}

.course-card {
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--border-light);
}

.course-card-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: var(--space-2);
  gap: var(--space-3);
}

.course-card-header h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.course-semester-tag {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

.course-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-2);
}

.course-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.course-enter {
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
}

.current-semester .course-card {
  border-left: 2px solid var(--text-primary);
  padding-left: var(--space-4);
}

/* ===== 分类标题 ===== */
.category-heading {
  font-size: 1rem;
  font-weight: 600;
  margin: var(--space-8) 0 var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
}

.category-heading:first-child {
  margin-top: 0;
}

/* ===== 课程页面专用样式 ===== */
.course-entry {
  padding: var(--space-5) 0;
  border-bottom: 1px solid var(--border-light);
}

.course-entry:last-child {
  border-bottom: none;
}

.course-entry-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
  flex-wrap: wrap;
}

.course-entry-header h3 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
}

.course-tag {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
  padding: var(--space-1) var(--space-2);
  background: rgba(0, 0, 0, 0.04);
  border-radius: 2px;
}

.course-tag.current {
  color: var(--text-primary);
  background: rgba(0, 0, 0, 0.08);
  font-weight: 500;
}

.course-entry-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
  margin-bottom: var(--space-2);
}

.course-entry-meta {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.course-entry-link {
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--text-primary);
}

.course-entry-link:hover {
  color: var(--text-secondary);
}

/* ===== 课程详情页专用样式 ===== */
.course-detail-page {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-8);
}

.course-detail-header {
  padding: var(--space-10) 0;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: var(--space-6);
}

.course-detail-header h1 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}

.course-detail-header .course-meta {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.course-detail-section {
  margin-bottom: var(--space-8);
}

.course-detail-section h2 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--border-light);
}

.course-detail-section p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-3);
}

.course-detail-section ul {
  list-style: none;
  padding: 0;
  margin-bottom: var(--space-2);
}

.syllabus-list li {
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border-light);
}

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

.course-detail-section .info-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.course-detail-section .info-item {
  padding: var(--space-3);
  }

.course-detail-section .info-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: var(--space-1);
}

.course-detail-section .info-value {
  font-size: 0.95rem;
  font-weight: 500;
}

.course-detail-section .week-item {
  display: flex;
  gap: var(--space-3);
  align-items: baseline;
}

.course-detail-section .week-number {
  font-weight: 600;
  color: var(--text-primary);
  min-width: 80px;
  flex-shrink: 0;
}

.course-detail-section .week-content {
  flex: 1;
}

.course-detail-section .reading-item {
  padding: var(--space-2) 0;
  font-size: 0.9rem;
  position: relative;
  padding-left: var(--space-4);
}

.course-detail-section .reading-item::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

/* ===== 资源/链接列表 ===== */
.resource-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.resource-item {
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border-light);
  min-height: 44px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

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

.resource-title {
  font-weight: 500;
  margin-bottom: var(--space-1);
  font-size: 0.95rem;
}

.resource-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ===== 信息列表 ===== */
.info-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.info-list li {
  display: flex;
  gap: var(--space-3);
  align-items: baseline;
  font-size: 0.92rem;
  color: var(--text-secondary);
  padding: var(--space-2) 0;
  min-height: 44px;
}

.info-list .label {
  font-weight: 500;
  color: var(--text-primary);
  min-width: 88px;
  flex-shrink: 0;
}

.info-list .value a {
  color: var(--text-secondary);
}

.info-list .value a:hover {
  color: var(--text-primary);
}

/* ===== 页脚 ===== */
footer {
  padding: var(--space-10) 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-light);
  margin-top: var(--space-8);
}

footer p + p {
  margin-top: var(--space-2);
}

footer a {
  color: var(--text-muted);
}

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

/* ===== 内页通用样式 ===== */
.page-header {
  padding: var(--space-12) 0 var(--space-8);
  text-align: left;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-2);
  color: var(--text-primary);
}

.page-header .page-meta {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.page-body {
  padding: var(--space-5) 0 var(--space-12);
  max-width: 680px;
}

/* 内页两栏布局 */
.two-col-layout {
  display: flex;
  gap: var(--space-10);
  margin-top: var(--space-8);
}

.layout-sidebar {
  width: 140px;
  flex-shrink: 0;
  position: sticky;
  top: 96px;
  align-self: flex-start;
}

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.sidebar-nav-item {
  font-size: 0.85rem;
  color: var(--text-secondary);
  padding: var(--space-3);
  border-left: 2px solid transparent;
  transition: all 0.2s var(--ease-out);
  min-height: 44px;
  display: flex;
  align-items: center;
}

.sidebar-nav-item:hover {
  color: var(--text-primary);
  border-left-color: var(--border-medium);
}

.sidebar-nav-item.active {
  color: var(--text-primary);
  border-left-color: var(--text-primary);
  font-weight: 500;
}

.layout-main {
  flex: 1;
  min-width: 0;
}

.content-section {
  margin-bottom: var(--space-10);
  scroll-margin-top: 104px;
}

.content-section h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
}

.content-section h3 {
  font-size: 1rem;
  font-weight: 600;
  margin: var(--space-6) 0 var(--space-3);
  color: var(--text-primary);
}

.content-section ul {
  list-style: none;
  padding: 0;
}

.content-section li {
  padding: var(--space-2) 0 var(--space-2) var(--space-4);
  position: relative;
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.75;
}

.content-section li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

.content-section p {
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.85;
  margin-bottom: var(--space-3);
}

.pub-entry {
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--border-light);
}

.pub-entry:last-child {
  border-bottom: none;
}

.pub-title {
  font-weight: 500;
  font-size: 0.94rem;
  margin-bottom: var(--space-1);
  line-height: 1.6;
  color: var(--text-primary);
}

.pub-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ===== 响应式设计 ===== */

@media (max-width: 900px) {
  .container {
    padding: 0 var(--space-6);
  }

  .home-hero {
    flex-direction: column-reverse;
    align-items: center;
    text-align: center;
    padding: var(--space-10) 0 var(--space-8);
  }

  .hero-aside {
    width: 140px;
  }

  .hero-intro {
    max-width: 100%;
  }

  .quick-links {
    max-width: 100%;
    align-items: center;
  }

  .global-nav-inner {
    gap: var(--space-5);
  }

  .nav-link {
    font-size: 0.75rem;
  }

  .two-col-layout {
    flex-direction: column;
    gap: var(--space-6);
  }

  .layout-sidebar {
    width: 100%;
    position: static;
  }

  .sidebar-nav {
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--space-2);
  }

  .sidebar-nav-item {
    border-left: none;
    border-bottom: 2px solid transparent;
    padding: var(--space-2) var(--space-3);
    font-size: 0.85rem;
  }

  .sidebar-nav-item.active {
    border-left-color: transparent;
    border-bottom-color: var(--text-primary);
  }
}

@media (max-width: 640px) {
  html {
    font-size: 15px;
  }

  .container {
    padding: 0 var(--space-4);
  }

  .global-nav {
    padding: var(--space-3) 0;
  }

  .global-nav-inner {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-content);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-light);
    padding: var(--space-4);
    gap: 0;
    z-index: 99;
  }

  .global-nav-inner.open {
    display: flex;
  }

  .mobile-nav-toggle {
    display: flex;
    position: absolute;
    right: var(--space-4);
    top: 50%;
    transform: translateY(-50%);
  }

  .nav-link {
    font-size: 0.9rem;
    letter-spacing: 0.05em;
    padding: var(--space-3) 0;
    text-align: left;
    border-bottom: none;
    min-height: 48px;
    display: flex;
    align-items: center;
    width: 100%;
  }

  .nav-link::after {
    display: none;
  }

  .nav-link.active {
    font-weight: 600;
  }

  .home-hero {
    padding: var(--space-8) 0 var(--space-6);
  }

  .home-hero h1 {
    font-size: 1.9rem;
    letter-spacing: 0.1em;
  }

  .hero-intro {
    font-size: 0.9rem;
  }

  .section-block {
    padding: var(--space-8) 0;
  }

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

  .project-card {
    flex-direction: column;
    gap: var(--space-4);
  }

  .project-thumb {
    width: 100%;
    max-width: 320px;
  }

  .project-links-group {
    flex-direction: column;
    gap: var(--space-2);
  }
}

@media (max-width: 400px) {
  .container {
    padding: 0 var(--space-3);
  }

  .home-hero h1 {
    font-size: 1.6rem;
  }

  .hero-aside {
    width: 120px;
  }
}

/* ===== 选择文本样式 ===== */
::selection {
  background: rgba(0, 0, 0, 0.1);
  color: inherit;
}

/* ===== 滚动条 ===== */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: rgba(0, 0, 0, 0.12);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(0, 0, 0, 0.2);
}

/* ===== 焦点状态 (无障碍) ===== */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--text-primary);
  outline-offset: 2px;
}

/* ===== 课程页面专用样式 ===== */

/* 课程页面导航栏 - 与主页保持一致 */
.course-page .global-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-content);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-light);
  padding: var(--space-5) 0;
}

.course-page .global-nav-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
}

/* 课程页面内容区域 */
.course-page .container {
  padding-top: var(--space-6);
}

/* 课程页面标题区域 - 移除背景图片，使用简洁样式 */
.course-header {
  padding: var(--space-12) 0 var(--space-8);
  text-align: center;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: var(--space-8);
}

.course-header h1 {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-3);
  color: var(--text-primary);
}

.course-header .subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

/* 课程页面链接加粗 */
.course-page a {
  font-weight: 600;
}

.course-page .nav-link {
  font-weight: 600;
}

/* 课程条目样式优化 */
.course-entry {
  padding: var(--space-6) 0;
  border-bottom: 1px solid var(--border-light);
  line-height: 1.8;
}

.course-entry:last-child {
  border-bottom: none;
}

.course-entry-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
}

.course-entry-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.5;
}

.course-tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
  padding: var(--space-1) var(--space-3);
  background: rgba(0, 0, 0, 0.04);
  border-radius: 2px;
}

.course-tag.current {
  color: var(--text-primary);
  background: rgba(0, 0, 0, 0.08);
}

.course-entry-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.85;
  margin-bottom: var(--space-3);
}

.course-entry-meta {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
  line-height: 1.6;
}

/* 进入课程链接 - 加粗醒目 */
.course-entry-link {
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  color: var(--text-primary);
  padding: var(--space-2) 0;
  position: relative;
}

.course-entry-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--text-primary);
  transform: scaleX(0);
  transition: transform 0.25s var(--ease-out);
}

.course-entry-link:hover {
  color: var(--text-primary);
}

.course-entry-link:hover::after {
  transform: scaleX(1);
}

/* 课程章节样式优化 */
.course-section {
  margin-bottom: var(--space-12);
}

.course-section h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
  letter-spacing: 0.02em;
}

.course-section h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: var(--space-6) 0 var(--space-4);
  color: var(--text-primary);
  line-height: 1.5;
}

.course-section p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.9;
  margin-bottom: var(--space-4);
}

.course-section ul {
  list-style: none;
  padding: 0;
  margin-bottom: var(--space-4);
}

.course-section li {
  padding: var(--space-3) 0 var(--space-3) var(--space-5);
  position: relative;
  color: var(--text-secondary);
  font-size: 0.94rem;
  line-height: 1.85;
}

.course-section li::before {
  content: "·";
  position: absolute;
  left: var(--space-2);
  color: var(--text-muted);
  font-weight: 700;
}

/* 课程大纲周次样式 */
.syllabus-week {
  padding: var(--space-6) 0;
  border-bottom: 1px solid var(--border-light);
}

.syllabus-week:last-child {
  border-bottom: none;
}

.week-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
  line-height: 1.5;
}

.week-content {
  padding-left: var(--space-2);
}

.week-content h4 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: var(--space-4) 0 var(--space-3);
}

.week-content ul {
  list-style: none;
  padding: 0;
}

.week-content li {
  padding: var(--space-2) 0 var(--space-2) var(--space-4);
  position: relative;
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.8;
}

.week-content li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--text-muted);
}

/* 资源列表链接加粗 */
.resource-list a {
  font-weight: 700;
}

/* 分页导航样式 */
.pagination {
  display: flex;
  justify-content: space-between;
  padding: var(--space-8) 0;
  border-top: 1px solid var(--border-light);
  margin-top: var(--space-8);
}

.pagination a {
  font-weight: 700;
  font-size: 0.9rem;
}

/* 信息列表样式优化 */
.info-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.info-list li {
  display: flex;
  gap: var(--space-4);
  align-items: baseline;
  font-size: 0.95rem;
  color: var(--text-secondary);
  padding: var(--space-2) 0;
  min-height: 44px;
  line-height: 1.7;
}

.info-list .label {
  font-weight: 700;
  color: var(--text-primary);
  min-width: 100px;
  flex-shrink: 0;
}

.info-list .value a {
  font-weight: 700;
}

/* 减少动画偏好 ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}