```css
/* ===== 全局重置与基础 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-body);
  color: var(--text-primary);
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  line-height: 1.7;
  font-size: 16px;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

/* ===== 设计变量（亮色） ===== */
:root {
  --bg-body: #f8fafc;
  --bg-header: rgba(15, 23, 42, 0.92);
  --bg-footer: #0b1120;
  --bg-card: #ffffff;
  --bg-article: #ffffff;
  --bg-nav: rgba(15, 23, 42, 0.95);
  --text-primary: #1e293b;
  --text-secondary: #334155;
  --text-heading: #0f172a;
  --text-link: #1d4ed8;
  --text-muted: #64748b;
  --text-button: #ffffff;
  --border-light: #e2e8f0;
  --text-nav: #e2e8f0;
  --text-nav-hover: #ffffff;
  --faq-question: #1e293b;
  --faq-answer: #334155;
  --btn-bg: #3b82f6;
  --btn-bg-hover: #2563eb;
  --badge-bg: #e2e8f0;
  --badge-text: #1e293b;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.05);
  --glass-bg: rgba(255, 255, 255, 0.6);
  --glass-border: rgba(255, 255, 255, 0.4);
  --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --gradient-hero: linear-gradient(120deg, #1e293b 0%, #334155 50%, #475569 100%);
  --gradient-card: linear-gradient(180deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.02) 100%);
  --scrollbar-thumb: #cbd5e1;
  --scrollbar-track: transparent;
}

/* ===== 暗色模式变量 ===== */
body.dark-mode {
  --bg-body: #0f172a;
  --bg-header: rgba(2, 6, 23, 0.92);
  --bg-footer: #020617;
  --bg-card: #1e293b;
  --bg-article: #1e293b;
  --text-primary: #e2e8f0;
  --text-secondary: #cbd5e1;
  --text-heading: #f8fafc;
  --text-link: #93c5fd;
  --text-muted: #94a3b8;
  --border-light: #334155;
  --text-nav: #e2e8f0;
  --faq-question: #f1f5f9;
  --faq-answer: #e2e8f0;
  --btn-bg: #3b82f6;
  --btn-bg-hover: #60a5fa;
  --badge-bg: #334155;
  --badge-text: #f1f5f9;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.3);
  --shadow-xl: 0 20px 25px rgba(0,0,0,0.3);
  --glass-bg: rgba(30, 41, 59, 0.6);
  --glass-border: rgba(148, 163, 184, 0.3);
  --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
  --gradient-hero: linear-gradient(120deg, #020617 0%, #1e293b 50%, #334155 100%);
  --gradient-card: linear-gradient(180deg, rgba(0,0,0,0) 0%, rgba(0,0,0,0.1) 100%);
  --scrollbar-thumb: #475569;
}

/* ===== 滚动条 ===== */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 8px;
}

::-webkit-scrollbar-thumb:hover {
  background: #94a3b8;
}

/* ===== 通用容器 ===== */
.container {
  max-width: 1320px;
  margin: 0 auto;
  padding: 0 clamp(16px, 4vw, 40px);
}

/* ===== 通用标题 ===== */
.section-title {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 800;
  margin: clamp(2rem, 5vw, 4rem) 0 clamp(1.5rem, 3vw, 2.5rem);
  color: var(--text-heading);
  position: relative;
  padding-left: 1.25rem;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

.section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 6px;
  height: 70%;
  background: linear-gradient(180deg, #3b82f6, #8b5cf6);
  border-radius: 3px;
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.4);
}

/* ===== 头部导航 ===== */
.main-header {
  background: var(--bg-header);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid var(--border-light);
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.main-header:hover {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
}

.logo a {
  color: var(--text-nav-hover);
  font-size: clamp(1.4rem, 2vw, 1.8rem);
  font-weight: 800;
  text-decoration: none;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #60a5fa, #a78bfa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: transform 0.3s ease;
}

.logo a:hover {
  transform: scale(1.02);
}

.logo a::before {
  content: '🎬';
  font-size: 1.2em;
  -webkit-text-fill-color: initial;
}

.nav-menu {
  display: flex;
  gap: clamp(1rem, 2vw, 2rem);
  list-style: none;
  align-items: center;
  margin: 0;
  padding: 0;
}

.nav-menu a {
  color: var(--text-nav);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease, background-color 0.2s ease;
  font-size: 0.95rem;
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  position: relative;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6);
  transition: width 0.3s ease;
  border-radius: 2px;
}

.nav-menu a:hover {
  color: var(--text-nav-hover);
  background: rgba(255, 255, 255, 0.08);
}

.nav-menu a:hover::after {
  width: 60%;
}

.search-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
}

.search-toggle input {
  padding: 8px 16px;
  border-radius: 30px;
  border: 1px solid var(--border-light);
  background-color: var(--bg-body);
  color: var(--text-primary);
  outline: none;
  width: clamp(120px, 15vw, 200px);
  font-size: 0.9rem;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

.search-toggle input:focus {
  border-color: #3b82f6;
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
  width: clamp(140px, 18vw, 240px);
}

.search-toggle input::placeholder {
  color: var(--text-muted);
  opacity: 0.7;
}

.dark-toggle, .menu-toggle {
  background: transparent;
  border: 1px solid var(--border-light);
  color: var(--text-nav);
  padding: 8px 14px;
  border-radius: 30px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 6px;
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.05);
}

.dark-toggle:hover, .menu-toggle:hover {
  background-color: rgba(255, 255, 255, 0.15);
  border-color: #3b82f6;
  transform: translateY(-1px);
}

.mobile-menu {
  display: none;
}

/* ===== Hero Banner 毛玻璃+渐变 ===== */
.hero {
  background: var(--gradient-hero);
  color: #ffffff;
  padding: clamp(2.5rem, 6vw, 6rem) 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 50%, rgba(99, 102, 241, 0.2) 0%, transparent 50%),
              radial-gradient(circle at 70% 30%, rgba(139, 92, 246, 0.2) 0%, transparent 50%);
  animation: heroGlow 12s ease-in-out infinite;
  pointer-events: none;
}

@keyframes heroGlow {
  0%, 100% { opacity: 0.5; transform: scale(1); }
  50% { opacity: 0.8; transform: scale(1.05); }
}

.hero-content {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-text {
  animation: fadeInUp 1s ease-out;
}

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

.hero-text h1 {
  font-size: clamp(2rem, 4.5vw, 3.5rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1.2rem;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #ffffff 0%, #e2e8f0 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-text p {
  color: #e2e8f0;
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  margin-bottom: 2rem;
  max-width: 600px;
  line-height: 1.8;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  opacity: 0.9;
}

.btn-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn {
  background: var(--btn-bg);
  color: #ffffff;
  padding: 0.9rem 2.2rem;
  border-radius: 50px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-size: 1rem;
  position: relative;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s ease;
}

.btn:hover {
  background: var(--btn-bg-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
}

.btn:hover::before {
  left: 100%;
}

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

.btn-outline {
  background: transparent;
  border: 2px solid rgba(255, 255, 255, 0.6);
  color: #ffffff;
  backdrop-filter: blur(10px);
  box-shadow: none;
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: #ffffff;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.hero-poster {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  padding: 1rem;
  border-radius: 24px;
  text-align: center;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.3);
  transition: transform 0.5s ease, box-shadow 0.5s ease;
  animation: float 6s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.hero-poster:hover {
  transform: scale(1.02);
  box-shadow: 0 30px 60px -12px rgba(0, 0, 0, 0.4);
}

.hero-poster svg {
  width: 100%;
  max-width: 280px;
  height: auto;
  border-radius: 16px;
  display: block;
  margin: 0 auto;
}

/* ===== 卡片网格 ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: clamp(1rem, 2vw, 1.8rem);
  margin-bottom: 2rem;
}

.card {
  background: var(--bg-card);
  border-radius: 20px;
  padding: clamp(1.5rem, 2.5vw, 2.5rem);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-light);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(10px);
  animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6, #d946ef);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: transparent;
  background: var(--bg-card);
}

.card:hover::before {
  transform: scaleX(1);
}

.card h3 {
  color: var(--text-heading);
  font-size: clamp(1.2rem, 2vw, 1.5rem);
  margin-bottom: 0.8rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.card p {
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  font-size: 0.98rem;
  line-height: 1.8;
}

.card a {
  color: var(--text-link);
  font-weight: 600;
  text-decoration: none;
  position: relative;
  transition: color 0.2s ease;
}

.card a:hover {
  color: var(--btn-bg-hover);
}

.card a::after {
  content: '→';
  margin-left: 4px;
  transition: transform 0.3s ease;
  display: inline-block;
}

.card a:hover::after {
  transform: translateX(4px);
}

/* ===== 文章列表 ===== */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
}

.article-item {
  background: var(--bg-card);
  padding: clamp(1rem, 2vw, 1.5rem) clamp(1.2rem, 2.5vw, 2rem);
  border-radius: 16px;
  border: 1px solid var(--border-light);
  border-left: 4px solid transparent;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(8px);
  animation: fadeIn 0.5s ease-out;
}

.article-item:hover {
  border-left-color: #3b82f6;
  transform: translateX(8px);
  box-shadow: var(--shadow-lg);
  background: var(--bg-card);
}

.article-item h3 {
  color: var(--text-heading);
  font-size: clamp(1rem, 1.5vw, 1.2rem);
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.article-item .meta {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin: 0.5rem 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.article-item .meta::before {
  content: '📅';
  font-size: 0.9em;
}

.article-item p {
  color: var(--text-primary);
  margin-bottom: 0.8rem;
  line-height: 1.7;
  opacity: 0.9;
}

.article-item a {
  color: var(--text-link);
  font-weight: 500;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  transition: color 0.2s ease;
}

.article-item a:hover {
  color: var(--btn-bg-hover);
}

.article-item a::after {
  content: '→';
  transition: transform 0.3s ease;
}

.article-item a:hover::after {
  transform: translateX(4px);
}

/* ===== FAQ 手风琴样式 ===== */
.faq-item {
  background: var(--bg-card);
  border-radius: 16px;
  margin-bottom: 0.8rem;
  border: 1px solid var(--border-light);
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(8px);
  animation: fadeIn 0.5s ease-out;
}

.faq-item:hover {
  box-shadow: var(--shadow-md);
  border-color: #3b82f6;
}

.faq-item.active {
  border-color: #3b82f6;
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.15);
}

.faq-question {
  background: none;
  border: none;
  text-align: left;
  font-size: clamp(1rem, 1.5vw, 1.1rem);
  font-weight: 600;
  color: var(--faq-question);
  padding: 1.2rem 1.5rem;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: background-color 0.2s ease;
  gap: 1rem;
}

.faq-question:hover {
  background-color: rgba(59, 130, 246, 0.05);
}

.faq-question span {
  font-size: 1.4rem;
  font-weight: 300;
  transition: transform 0.3s ease;
  color: #3b82f6;
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.1);
}

.faq-item.active .faq-question span {
  transform: rotate(45deg);
  background: #3b82f6;
  color: white;
}

.faq-answer {
  color: var(--faq-answer);
  padding: 0 1.5rem 1.2rem;
  display: none;
  line-height: 1.8;
  font-size: 0.95rem;
  animation: slideDown 0.3s ease-out;
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

.faq-item.active .faq-answer {
  display: block;
}

/* ===== HowTo 教程 ===== */
.howto-box {
  background: var(--bg-card);
  padding: clamp(1.5rem, 3vw, 2.5rem);
  border-radius: 24px;
  border: 1px solid var(--border-light);
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(10px);
  position: relative;
  overflow: hidden;
}

.howto-box::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6, #d946ef);
}

.howto-box h3 {
  color: var(--text-heading);
  font-size: 1.3rem;
  margin: 1.5rem 0 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 10px;
}

.howto-box h3:first-child {
  margin-top: 0;
}

.howto-box h3::before {
  content: '';
  width: 8px;
  height: 8px;
  background: linear-gradient(135deg, #3b82f6, #8b5cf6);
  border-radius: 50%;
  display: inline-block;
}

.howto-box p {
  color: var(--text-primary);
  line-height: 1.8;
  margin-bottom: 0.5rem;
}

.step-list {
  color: var(--text-primary);
  padding-left: 1.5rem;
  counter-reset: step-counter;
  list-style: none;
}

.step-list li {
  margin-bottom: 1rem;
  color: var(--text-secondary);
  line-height: 1.8;
  position: relative;
  padding-left: 2.5rem;
  counter-increment: step-counter;
}

.step-list li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 28px;
  height: 28px;
  background: linear-gradient(135deg, #3b82f6, #8b5cf6);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

/* ===== 底部 ===== */
.main-footer {
  background: var(--bg-footer);
  color: #cbd5e1;
  padding: clamp(2.5rem, 5vw, 4rem) 0 2rem;
  margin-top: clamp(3rem, 6vw, 5rem);
  position: relative;
  overflow: hidden;
}

.main-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.5), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: clamp(1.5rem, 3vw, 2.5rem);
}

.footer-grid h4 {
  color: #f1f5f9;
  margin-bottom: 1.2rem;
  font-weight: 600;
  font-size: 1.1rem;
  position: relative;
  padding-bottom: 0.5rem;
}

.footer-grid h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background: linear-gradient(90deg, #3b82f6, #8b5cf6);
  border-radius: 2px;
}

.footer-grid a {
  color: #94a3b8;
  text-decoration: none;
  display: block;
  margin-bottom: 0.6rem;
  transition: all 0.2s ease;
  font-size: 0.95rem;
}

.footer-grid a:hover {
  color: #ffffff;
  transform: translateX(4px);
}

.copyright {
  border-top: 1px solid rgba(148, 163, 184, 0.2);
  padding-top: 1.5rem;
  margin-top: 2.5rem;
  color: #94a3b8;
  text-align: center;
  font-size: 0.9rem;
}

.copyright p {
  margin-bottom: 0.3rem;
}

/* ===== 返回顶部 ===== */
.to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: linear-gradient(135deg, #3b82f6, #8b5cf6);
  color: #ffffff;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  transition: all 0.3s ease;
  border: none;
  font-size: 1.4rem;
  z-index: 100;
  box-shadow: 0 4px 15px rgba(59, 130, 246, 0.4);
  transform: translateY(20px);
}

.to-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.to-top:hover {
  transform: translateY(-4px) scale(1.1);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.5);
}

.to-top:active {
  transform: translateY(0) scale(0.95);
}

/* ===== 滚动动画 ===== */
@keyframes reveal {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.card, .article-item, .faq-item, .howto-box, .hero-poster {
  animation: reveal 0.6s ease-out both;
}

.card:nth-child(2), .article-item:nth-child(2), .faq-item:nth-child(2) {
  animation-delay: 0.1s;
}

.card:nth-child(3), .article-item:nth-child(3), .faq-item:nth-child(3) {
  animation-delay: 0.2s;
}

.card:nth-child(4), .article-item:nth-child(4), .faq-item:nth-child(4) {
  animation-delay: 0.3s;
}

.card:nth-child(5), .article-item:nth-child(5), .faq-item:nth-child(5) {
  animation-delay: 0.4s;
}

.card:nth-child(6), .article-item:nth-child(6), .faq-item:nth-child(6) {
  animation-delay: 0.5s;
}

/* ===== 响应式适配 ===== */
@media (max-width: 900px) {
  .nav-menu {
    display: none;
  }

  .mobile-menu {
    display: block;
  }

  .hero-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-text p {
    margin-left: auto;
    margin-right: auto;
  }

  .btn-group {
    justify-content: center;
  }

  .hero-poster {
    max-width: 400px;
    margin: 0 auto;
  }

  .footer-grid {
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  }

  .search-toggle input {
    width: 100px;
  }
}

@media (max-width: 600px) {
  .nav-wrapper {
    flex-wrap: wrap;
    gap: 10px;
  }

  .logo {
    flex: 1;
  }

  .search-toggle {
    order: 3;
    width: 100%;
    justify-content: center;
  }

  .search-toggle input {
    flex: 1;
    width: auto;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-grid h4::after {
    left: 50%;
    transform: translateX(-50%);
  }

  .footer-grid a:hover {
    transform: translateY(-2px);
  }

  .to-top {
    bottom: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }

  .card {
    padding: 1.2rem;
  }

  .section-title {
    padding-left: 1rem;
  }
}

/* ===== 移动菜单展开 ===== */
.nav-menu.mobile-open {
  display: flex;
  flex-direction: column;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--bg-header);
  padding: 1rem;
  border-radius: 0 0 16px 16px;
  box-shadow: var(--shadow-lg);
  z-index: 999;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  animation: slideDownMenu 0.3s ease-out;
}

@keyframes slideDownMenu {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

.nav-menu.mobile-open a {
  padding: 0.8rem 1rem;
  border-radius: 8px;
}

.nav-menu.mobile-open a:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* ===== 打印样式 ===== */
@media print {
  .main-header, .to-top, .btn-group, .search-toggle, .hero-poster {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  .card, .article-item, .faq-item, .howto-box {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
  }
}

/* ===== 无障碍 ===== */
:focus-visible {
  outline: 3px solid #3b82f6;
  outline-offset: 2px;
  border-radius: 4px;
}

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

/* ===== 动画性能优化 ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}
```