/* CSS变量定义 */
:root {
  /* 颜色系统 - 日间模式 */
  --primary-color: #4F46E5;
  --primary-hover: #4338CA;
  --primary-color-alpha: rgba(79, 70, 229, 0.1);
  --secondary-color: #f16920;
  --accent-color: #06B6D4;
  --success-color: #10B981;
  --warning-color: #F59E0B;
  --error-color: #EF4444;
  
  /* 背景颜色 */
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8FAFC;
  --bg-tertiary: #F1F5F9;
  --bg-card: #FFFFFF;
  --bg-overlay: rgba(0, 0, 0, 0.5);
  
  /* 文字颜色 */
  --text-primary: #1E293B;
  --text-secondary: #64748B;
  --text-tertiary: #94A3B8;
  --text-inverse: #FFFFFF;
  
  /* 边框颜色 */
  --border-color: #E2E8F0;
  --border-hover: #CBD5E1;
  --border-focus: #4F46E5;
  
  /* 阴影 */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --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);
  
  /* 间距 */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-x: 1.25rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* 字体 */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 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;
  
  /* 圆角 */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* 过渡 */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
}

/* 夜间模式 */
[data-theme="dark"] {
  --primary-color-alpha: rgba(79, 70, 229, 0.2);
  --bg-primary: #0F172A;
  --bg-secondary: #1E293B;
  --bg-tertiary: #334155;
  --bg-card: #1E293B;
  --bg-overlay: rgba(0, 0, 0, 0.8);
  
  --text-primary: #F8FAFC;
  --text-secondary: #CBD5E1;
  --text-tertiary: #94A3B8;
  
  --border-color: #334155;
  --border-hover: #475569;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

/* 容器 */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--spacing-xl);
  }
}

/* 按钮样式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: 500;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

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

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: transparent;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
}

.btn-secondary:hover {
  background-color: var(--primary-color);
  color: var(--text-inverse);
  transform: translateY(-1px);
}

.btn-outline {
  background-color: transparent;
  color: var(--text-primary);
  border: 2px solid var(--border-color);
}

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


/* 按钮图标样式 */
.btn-icon {
  width: 8px !important;
  height: 8px !important;
  object-fit: contain;
  margin-right: var(--spacing-xs);
  flex-shrink: 0; /* 防止图标被压缩 */
  display: inline-block;
  vertical-align: middle;
}

/* 呼吸效果动画 */
.breathing-btn {
  animation: breathing 3s ease-in-out infinite;
  transition: all 0.3s ease;
}

@keyframes breathing {
  0%, 100% {
    transform: scale(1);
    box-shadow: 0 4px 8px rgba(79, 70, 229, 0.3);
  }
  50% {
    transform: scale(1.08);
    box-shadow: 0 12px 24px rgba(79, 70, 229, 0.5);
  }
}

/* 为secondary按钮的呼吸效果调整阴影颜色 */
.btn-secondary.breathing-btn {
  animation: breathing-secondary 3s ease-in-out infinite;
  transition: all 0.3s ease;
}

@keyframes breathing-secondary {
  0%, 100% {
    transform: scale(1);
    box-shadow: 0 4px 8px rgba(107, 114, 128, 0.3);
  }
  50% {
    transform: scale(1.08);
    box-shadow: 0 12px 24px rgba(107, 114, 128, 0.4);
  }
}
}

.btn-full {
  width: 100%;
}

/* 头部导航 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background-color: var(--bg-card);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-normal);
}

.navbar {
  padding: 0;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1000px;
  margin: 0 auto;
  padding: 0;

}

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

.logo-icon {
  height: 40px;
  width: auto;
  max-width: 200px;
}

.logo-text {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--secondary-color);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}


.nav-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  text-decoration: none;
  color: var(--text-secondary);
  font-size: var(--font-size-lg);
  font-weight: 500;
  transition: all var(--transition-fast);
  position: relative;
  padding: var(--spacing-x) var(--spacing-x);
  border-radius: var(--radius-md);
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary-color);
  background-color: var(--primary-color-alpha);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background-color: var(--primary-color);
  border-radius: var(--radius-full);
}

.nav-icon {
  width: 18px;
  height: 18px;
  stroke-width: 2;
  transition: transform var(--transition-fast);
}

.nav-link:hover .nav-icon {
  transform: translateY(-1px);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.bookmark-btn,
.share-btn,
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: none;
  background-color: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.bookmark-btn:hover,
.share-btn:hover,
.theme-toggle:hover {
  background-color: var(--bg-tertiary);
  color: var(--primary-color);
}

.bookmark-btn svg,
.share-btn svg,
.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.theme-toggle .moon-icon {
  display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
  display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
  display: block;
}

.desktop-only {
  display: none;
}

@media (min-width: 768px) {
  .desktop-only {
    display: flex;
  }
}

.mobile-menu-btn {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  cursor: pointer;
}

@media (min-width: 768px) {
  .mobile-menu-btn {
    display: none;
  }
}

.mobile-menu-btn span {
  width: 20px;
  height: 2px;
  background-color: var(--text-primary);
  transition: all var(--transition-fast);
}

/* 主要内容 */
.main-content {
  margin-top: 80px;
}

/* 英雄区域 */
.hero-section {
  padding: var(--spacing-3xl) 0;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  opacity: 0.5;
}

.hero-content-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-3xl);
  position: relative;
  z-index: 1;
}

.hero-text-content {
  text-align: center;
  max-width: 800px;
}

@media (min-width: 768px) {
  .hero-content {
    grid-template-columns: 1fr 1fr;
  }
}

.hero-title {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--secondary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: center;
  gap: 12px;
}

.hero-title-icon {
  width: 1.2em;
  height: 1.2em;
  object-fit: contain;
  flex-shrink: 0;
}

@media (min-width: 768px) {
  .hero-title {
    font-size: var(--font-size-5xl);
  }
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

@media (min-width: 480px) {
  .hero-actions {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
  }
}

.hero-image {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-image a {
  display: inline-block;
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.hero-image a:hover {
  transform: scale(1.02);
}

/* 英雄区域预览图样式 */
.hero-preview-image {
  width: 100%;
  max-width: 1000px;
  height: auto;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  transition: transform var(--transition-slow);
  object-fit: cover;
}
/* 
.hero-preview-image:hover {
  transform: scale(1.05);
}
*/

.card-header {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
}

.card-dots {
  display: flex;
  gap: var(--spacing-xs);
}

.card-dots span {
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
}

.card-dots span:nth-child(1) {
  background-color: #EF4444;
}

.card-dots span:nth-child(2) {
  background-color: #F59E0B;
}

.card-dots span:nth-child(3) {
  background-color: #10B981;
}

.card-content {
  padding: var(--spacing-xl);
  height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.typing-animation {
  font-family: 'Courier New', monospace;
  font-size: var(--font-size-lg);
  color: var(--primary-color);
}

.cursor {
  animation: blink 1s infinite;
}

@keyframes blink {
  0%, 50% { opacity: 1; }
  51%, 100% { opacity: 0; }
}

/* 区域标题 */
.section-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

@media (min-width: 768px) {
  .section-title {
    font-size: var(--font-size-4xl);
  }
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* 功能特色区域 */
.features-section {
  padding: var(--spacing-3xl) 0;
  background-color: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
}

@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.feature-card {
  background-color: var(--bg-card);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
  border: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(79, 70, 229, 0.1), transparent);
  transition: left var(--transition-slow);
}

.feature-card:hover::before {
  left: 100%;
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
  border-color: var(--primary-color);
}

.feature-icon {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-lg);
  transition: transform var(--transition-normal);
}

.feature-card:hover .feature-icon {
  transform: scale(1.1) rotate(5deg);
}

.feature-icon svg {
  width: 28px;
  height: 28px;
  color: var(--text-inverse);
}

.feature-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.feature-description {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* 关于我们区域 */
.about-section {
  padding: var(--spacing-3xl) 0;
  background-color: var(--bg-secondary);
}

.about-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}



.about-description {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.7;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: var(--spacing-xs);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.about-image {
  display: flex;
  justify-content: center;
}

.about-card {
  width: 100%;
  max-width: 300px;
  height: 200px;
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-xl);
  display: flex;
  align-items: center;
  justify-content: center;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: var(--spacing-lg);
}

.progress-fill {
  width: 75%;
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-full);
  animation: progress 2s ease-in-out infinite;
}

@keyframes progress {
  0%, 100% { width: 75%; }
  50% { width: 85%; }
}

.text-lines {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.text-line {
  height: 12px;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-sm);
  animation: pulse 2s ease-in-out infinite;
}

.text-line:nth-child(1) {
  width: 100%;
}

.text-line:nth-child(2) {
  width: 60%;
}

.text-line:nth-child(3) {
  width: 80%;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* 联系我们区域 */
.contact-section {
  padding: var(--spacing-3xl) 0;
}

.contact-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-3xl);
}

@media (min-width: 768px) {
  .contact-content {
    grid-template-columns: 1fr 1fr;
  }
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.contact-icon {
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.contact-icon svg {
  width: 24px;
  height: 24px;
  color: var(--text-inverse);
}

.contact-details h3 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--text-primary);
}

.contact-details p {
  color: var(--text-secondary);
}

/* 表单样式 */
.form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-input,
.form-textarea {
  padding: var(--spacing-md);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  font-family: inherit;
  background-color: var(--bg-card);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

/* 页脚 */
.footer {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  border-top: 1px solid var(--border-color);
  color: #FFFFFF;
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
}

@media (min-width: 768px) {
  .footer-content {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

/* 移动端页脚布局优化 */
@media (max-width: 767px) {
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
  
  /* 三个板块在移动端一行显示 */
  .footer-sections-row {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-sm);
  }
  
  .footer-sections-row .footer-section {
    flex: 1;
    min-width: 0; /* 允许内容收缩 */
  }
  
  .footer-sections-row .footer-title {
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-sm);
  }
  
  .footer-sections-row .footer-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr)); /* 自动调整列数，每列最小100px，最大为剩余空间的一等份 */
    gap: 10px; /* 列与列之间的间距 */
    gap: var(--spacing-xs);
  }
  
  .footer-sections-row .footer-links a {
    font-size: var(--font-size-sm);
  }
}

/* 桌面端保持原有布局 */
@media (min-width: 768px) {
  .footer-sections-row {
    /* display: contents; /* 让子元素直接参与grid布局 */
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-sm);
  }
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
}

.footer-description {
  color: var(--text-inverse);
  line-height: 1.6;
}

.footer-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-inverse);
}

.footer-section {
  flex: 1;
  min-width: 360px; /* 允许内容收缩 */
}

.footer-links {
  
  list-style: none;
  display: flex;
  flex-direction: row;
  gap: var(--spacing-sm);  
}

.footer-links li {
  min-width: 130px;
}

.footer-links a {
  color: var(--text-inverse);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  align-items: center;
  justify-content: space-between;
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-color);

}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
  }
}

.footer-copyright {
  width: 100%;
  color: var(--text-inverse);
  font-size: var(--font-size-sm);
  text-align: center;
}

.footer-social {
  display: flex;
  gap: var(--spacing-md);
}

.social-link {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  border-radius: var(--radius-full);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.social-link:hover {
  background-color: var(--primary-color);
  color: var(--text-inverse);
  transform: translateY(-2px);
}

.social-link svg {
  width: 20px;
  height: 20px;
}

/* 滚动按钮 */
.scroll-buttons {
  position: fixed;
  right: var(--spacing-lg);
  bottom: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
  z-index: 1000;
}

.scroll-btn {
  width: 50px;
  height: 50px;
  background: linear-gradient(135deg, var(--primary-color), var(--primary-color));
  color: var(--text-inverse);
  border: none;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-fast);
  opacity: 0;
  visibility: hidden;
}

.scroll-btn.visible {
  opacity: 1;
  visibility: visible;
}

.scroll-btn:hover {
  transform: translateY(-2px) scale(1.1);
  box-shadow: var(--shadow-xl);
}

.scroll-btn svg {
  width: 24px;
  height: 24px;
}

/* 响应式设计 */
@media (max-width: 767px) {
  .hero-title {
    font-size: var(--font-size-2xl);
  }
  
  .section-title {
    font-size: var(--font-size-2xl);
  }
  
  .hero-actions {
    flex-direction: column;
  }
  
  .nav-container {
    padding: 0 var(--spacing-sm);
  }
  
  .scroll-buttons {
    right: var(--spacing-md);
    bottom: var(--spacing-md);
  }
  
  .scroll-btn {
    width: 45px;
    height: 45px;
  }
}

/* 动画和过渡效果 */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fadeInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.animate-fade-in-up {
  animation: fadeInUp 0.6s ease-out;
}

.animate-fade-in-left {
  animation: fadeInLeft 0.6s ease-out;
}

.animate-fade-in-right {
  animation: fadeInRight 0.6s ease-out;
}

/* 加载状态 */
.loading {
  opacity: 0.7;
  pointer-events: none;
}

/* 工具类 */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

.hidden {
  display: none;
}

.visible {
  display: block;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 论文写作基础样式 */
.basics-section {
  padding: var(--spacing-xl) 0;
  background: var(--bg-secondary);
}

.basics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.basics-card {
  background: var(--bg-primary);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
  text-align: center;
}

.basics-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
  border-color: var(--primary-color);
}

.basics-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--primary-color-alpha);
  border-radius: 50%;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  justify-content: center;
}

.basics-card h3 {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.basics-card p {
  color: var(--text-secondary);
  line-height: 1.6;
}



/* 响应式设计 */
@media (max-width: 768px) {
  .basics-grid,
  .methods-grid,
  .tips-grid {
    grid-template-columns: 1fr;
  }
  
  .resources-grid {
    grid-template-columns: 1fr;
  }
  
  .standards-item {
    flex-direction: column;
    text-align: center;
  }
  
  .standards-number {
    margin-bottom: var(--spacing-sm);
  }
  
  .tab-buttons {
    flex-wrap: wrap;
  }
}

/* 打印样式 */
@media print {
  .header,
  .scroll-buttons,
  .nav-actions {
    display: none;
  }
  
  .main-content {
    margin-top: 0;
  }
  
  * {
    box-shadow: none !important;
  }
}