```css
/* ===== 桃花视频 - 温暖治愈系情感内容平台 ===== */
/* 版本: 1.0 | 最后更新: 2025-02-20 */

/* ===== CSS变量与主题 ===== */
:root {
  /* 品牌色系 */
  --primary: #c4455c;
  --primary-dark: #a52d4d;
  --primary-light: #ffb3c1;
  --primary-soft: #ffe0e6;
  --secondary: #f8a5b0;
  --accent: #f05b72;

  /* 中性色 */
  --bg: #fff5f7;
  --bg-card: #ffffff;
  --text: #2d2a2a;
  --text-light: #5f3e42;
  --text-muted: #888888;
  --text-dark: #333333;

  /* 功能色 */
  --border: #ffd9e0;
  --border-light: #f0d0d6;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.08);

  /* 布局 */
  --radius-sm: 12px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 40px;

  /* 渐变 */
  --gradient-hero: linear-gradient(135deg, #ffe0e6 0%, #ffb3c1 100%);
  --gradient-card: linear-gradient(145deg, #fff 0%, #fff5f7 100%);

  /* 间距 */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 32px;
  --space-xl: 48px;

  /* 字体 */
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.15rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-hero: 2.8rem;

  /* 动效 */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* ===== 暗色模式变量 ===== */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1e1e1e;
    --bg-card: #2a2a2a;
    --text: #e0e0e0;
    --text-light: #cccccc;
    --text-muted: #999999;
    --text-dark: #dddddd;
    --border: #3a3a3a;
    --border-light: #3a3a3a;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.5);
    --gradient-hero: linear-gradient(135deg, #3a2a2e 0%, #4a2c34 100%);
    --gradient-card: linear-gradient(145deg, #2a2a2a 0%, #333333 100%);
    --primary-soft: #3a2a2e;
  }
}

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

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

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

img,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

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

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input {
  font-family: inherit;
}

/* ===== 容器与布局 ===== */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-sm);
  }
}

/* ===== 吸顶导航 ===== */
.navbar {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

@media (prefers-color-scheme: dark) {
  .navbar {
    background: rgba(30, 30, 30, 0.95);
    border-bottom-color: #3a3a3a;
  }
}

.navbar.scrolled {
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
  gap: var(--space-md);
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: bold;
  font-size: 1.5rem;
  color: var(--primary-dark);
  white-space: nowrap;
  transition: transform var(--transition-fast);
}

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

.logo svg {
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  gap: 32px;
  font-weight: 500;
}

.nav-links a {
  color: var(--text-dark);
  font-size: var(--font-size-base);
  position: relative;
  padding: 4px 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width var(--transition-base);
}

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

.nav-links a:hover::after {
  width: 100%;
}

@media (prefers-color-scheme: dark) {
  .nav-links a {
    color: #ddd;
  }
  .nav-links a:hover {
    color: var(--primary-light);
  }
}

.search-box {
  display: flex;
  align-items: center;
  background: #f1f1f1;
  border-radius: 30px;
  padding: 8px 16px;
  transition: background var(--transition-base), box-shadow var(--transition-base);
}

.search-box:focus-within {
  box-shadow: 0 0 0 2px var(--primary-light);
  background: #fff;
}

@media (prefers-color-scheme: dark) {
  .search-box {
    background: #333;
  }
  .search-box:focus-within {
    background: #3a3a3a;
    box-shadow: 0 0 0 2px var(--primary);
  }
}

.search-box input {
  border: none;
  background: transparent;
  width: 140px;
  outline: none;
  font-size: 0.9rem;
  color: var(--text);
  transition: width var(--transition-base);
}

.search-box input:focus {
  width: 180px;
}

.search-box svg {
  color: var(--text-muted);
  margin-left: 8px;
  flex-shrink: 0;
}

.mobile-menu {
  display: none;
  font-size: 1.8rem;
  cursor: pointer;
  color: var(--text);
  padding: 4px 8px;
  border-radius: 8px;
  transition: background var(--transition-fast);
}

.mobile-menu:hover {
  background: var(--primary-soft);
}

@media (max-width: 900px) {
  .nav-links {
    display: none;
  }
  .mobile-menu {
    display: block;
  }
  .search-box {
    display: none;
  }
}

/* ===== 首屏Banner ===== */
.hero {
  background: var(--gradient-hero);
  border-radius: 0 0 60px 60px;
  padding: 60px 0;
  position: relative;
  overflow: hidden;
  transition: background var(--transition-base);
}

@media (max-width: 768px) {
  .hero {
    border-radius: 0 0 30px 30px;
    padding: 40px 0;
  }
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.3) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 8s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-20px) scale(1.05); }
}

.hero-content {
  display: flex;
  align-items: center;
  gap: 40px;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.hero-text {
  flex: 1;
  min-width: 280px;
}

.hero-text h1 {
  font-size: var(--font-size-hero);
  color: var(--primary-dark);
  margin-bottom: 20px;
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -0.02em;
}

@media (max-width: 768px) {
  .hero-text h1 {
    font-size: 2rem;
  }
}

@media (prefers-color-scheme: dark) {
  .hero-text h1 {
    color: var(--primary-light);
  }
}

.hero-text p {
  font-size: 1.2rem;
  color: var(--text-light);
  margin-bottom: 30px;
  max-width: 480px;
  line-height: 1.7;
}

@media (prefers-color-scheme: dark) {
  .hero-text p {
    color: #ccc;
  }
}

.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 12px 32px;
  border-radius: var(--radius-full);
  text-decoration: none;
  font-weight: 600;
  font-size: var(--font-size-base);
  transition: all var(--transition-base);
  box-shadow: 0 4px 15px rgba(196, 69, 92, 0.3);
  border: 2px solid transparent;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: width 0.5s ease, height 0.5s ease;
}

.btn:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(196, 69, 92, 0.4);
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

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

.hero-slider {
  flex: 1;
  min-width: 280px;
  display: flex;
  justify-content: center;
}

.slider-box {
  width: 100%;
  max-width: 480px;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 20px;
  box-shadow: 0 20px 30px rgba(0, 0, 0, 0.05);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  animation: slideIn 0.8s ease-out;
}

.slider-box:hover {
  transform: translateY(-5px);
  box-shadow: 0 25px 40px rgba(0, 0, 0, 0.1);
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.slider-item {
  text-align: center;
  padding: 20px 10px;
}

.slider-item svg {
  width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  transition: transform var(--transition-base);
}

.slider-item:hover svg {
  transform: scale(1.02);
}

/* ===== 通用区块 ===== */
section {
  padding: 50px 0;
  position: relative;
}

@media (max-width: 768px) {
  section {
    padding: 40px 0;
  }
}

.section-title {
  font-size: var(--font-size-2xl);
  color: var(--primary-dark);
  margin-bottom: 20px;
  text-align: center;
  position: relative;
  font-weight: 700;
  letter-spacing: -0.01em;
}

@media (prefers-color-scheme: dark) {
  .section-title {
    color: var(--primary-light);
  }
}

.section-title:after {
  content: '';
  display: block;
  width: 80px;
  height: 4px;
  background: var(--primary-light);
  margin: 12px auto 0;
  border-radius: 4px;
  transition: width var(--transition-base);
}

.section-title:hover:after {
  width: 120px;
}

/* ===== 网格布局 ===== */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
}

@media (max-width: 768px) {
  .grid-2 {
    grid-template-columns: 1fr;
    gap: 20px;
  }
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

@media (max-width: 900px) {
  .grid-4 {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 600px) {
  .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* ===== 卡片组件 ===== */
.card {
  background: var(--gradient-card);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  box-shadow: var(--shadow);
  transition: all var(--transition-base);
  border: 1px solid rgba(255, 255, 255, 0.5);
  position: relative;
  overflow: hidden;
}

@media (prefers-color-scheme: dark) {
  .card {
    background: var(--bg-card);
    border-color: #3a3a3a;
  }
}

.card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--primary-light), var(--primary), var(--primary-light));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}

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

.card h3 {
  color: var(--primary-dark);
  margin-bottom: 10px;
  font-size: 1.1rem;
  font-weight: 600;
}

@media (prefers-color-scheme: dark) {
  .card h3 {
    color: var(--primary-light);
  }
}

.card p {
  color: var(--text-light);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* ===== FAQ ===== */
.faq-item {
  margin-bottom: 15px;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  padding: 0 20px;
  box-shadow: var(--shadow);
  transition: all var(--transition-base);
  border: 1px solid transparent;
}

.faq-item:hover {
  border-color: var(--primary-light);
  box-shadow: var(--shadow-hover);
}

.faq-item.open {
  border-color: var(--primary-light);
  box-shadow: 0 4px 20px rgba(196, 69, 92, 0.1);
}

.faq-q {
  font-weight: 600;
  padding: 18px 0;
  cursor: pointer;
  border-bottom: 1px solid var(--border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
  transition: color var(--transition-fast);
}

.faq-q::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--primary);
  transition: transform var(--transition-base);
  flex-shrink: 0;
  margin-left: 12px;
}

.faq-item.open .faq-q::after {
  transform: rotate(45deg);
}

.faq-q:hover {
  color: var(--primary);
}

.faq-a {
  padding: 0 0 18px;
  color: var(--text-light);
  display: none;
  line-height: 1.7;
}

@media (prefers-color-scheme: dark) {
  .faq-a {
    color: #bbb;
  }
}

.faq-item.open .faq-a {
  display: block;
  animation: fadeIn 0.3s ease;
}

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

/* ===== 文章卡片 ===== */
.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.article-card svg {
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  transition: transform var(--transition-base);
}

.article-card:hover svg {
  transform: scale(1.03);
}

.article-card h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
  transition: color var(--transition-fast);
}

.article-card:hover h3 {
  color: var(--primary);
}

.article-meta {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 8px;
}

.article-card p:last-of-type {
  flex: 1;
  font-size: 0.9rem;
  line-height: 1.6;
}

/* ===== 内容知识库 ===== */
#articles .card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

#articles .card h3 {
  font-size: 1rem;
  line-height: 1.4;
}

#articles .card p {
  font-size: 0.9rem;
  flex: 1;
}

#articles .card a {
  margin-top: auto;
  font-weight: 500;
  display: inline-block;
  transition: all var(--transition-fast);
}

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

/* ===== HowTo ===== */
#howto .card {
  background: var(--gradient-card);
  padding: 30px;
}

@media (prefers-color-scheme: dark) {
  #howto .card {
    background: var(--bg-card);
  }
}

#howto .card p {
  margin-bottom: 10px;
  line-height: 1.8;
}

#howto .card strong {
  color: var(--primary);
}

/* ===== 联系我们 ===== */
#contact .card {
  height: 100%;
}

#contact .card p {
  margin-bottom: 8px;
}

#contact .card a {
  margin: 0 4px;
  display: inline-block;
}

/* ===== 页脚 ===== */
footer {
  background: #2d2a2a;
  color: #f0f0f0;
  padding: 40px 0 20px;
  margin-top: 40px;
}

@media (prefers-color-scheme: dark) {
  footer {
    background: #1a1a1a;
  }
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  margin-bottom: 30px;
}

@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 600px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
}

.footer-grid h4 {
  color: var(--primary-light);
  margin-bottom: 15px;
  font-size: 1.05rem;
  position: relative;
  padding-bottom: 8px;
}

.footer-grid h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 30px;
  height: 2px;
  background: var(--primary);
}

.footer-grid a {
  color: #ccc;
  display: block;
  text-decoration: none;
  margin-bottom: 8px;
  transition: all var(--transition-fast);
  font-size: 0.9rem;
}

.footer-grid a:hover {
  color: var(--primary-light);
  transform: translateX(4px);
}

.footer-bottom {
  text-align: center;
  border-top: 1px solid #444;
  padding-top: 20px;
  font-size: 0.9rem;
  color: #aaa;
}

.footer-bottom p {
  margin-bottom: 4px;
}

/* ===== 返回顶部按钮 ===== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  font-size: 24px;
  border: none;
  cursor: pointer;
  z-index: 999;
  box-shadow: 0 4px 15px rgba(196, 69, 92, 0.3);
  transition: all var(--transition-base);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

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

.back-to-top:hover {
  background: var(--primary-dark);
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(196, 69, 92, 0.4);
}

/* ===== 滚动动画 ===== */
.scroll-animate {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.scroll-animate.animated {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .nav-links {
    display: none;
  }
  .mobile-menu {
    display: block;
  }
  .hero-content {
    flex-direction: column;
    text-align: center;
  }
  .hero-text p {
    margin-left: auto;
    margin-right: auto;
  }
  .hero-slider {
    width: 100%;
  }
  .slider-box {
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .hero-text h1 {
    font-size: 2rem;
  }
  .hero-text p {
    font-size: 1rem;
  }
  .btn {
    padding: 10px 24px;
    font-size: 0.95rem;
  }
  .section-title {
    font-size: 1.6rem;
  }
  .back-to-top {
    width: 44px;
    height: 44px;
    font-size: 20px;
    bottom: 20px;
    right: 20px;
  }
}

@media (max-width: 480px) {
  .hero {
    border-radius: 0 0 20px 20px;
    padding: 30px 0;
  }
  .hero-content {
    gap: 20px;
  }
  .slider-box {
    padding: 12px;
  }
  .card {
    padding: 16px;
  }
  .faq-item {
    padding: 0 14px;
  }
  .faq-q {
    font-size: 0.95rem;
  }
}

/* ===== 无障碍与可访问性 ===== */
:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
}

@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;
  }
}

/* ===== 打印样式 ===== */
@media print {
  .navbar,
  .hero,
  .back-to-top,
  .mobile-menu {
    display: none !important;
  }
  body {
    background: #fff;
    color: #000;
  }
  .card {
    box-shadow: none;
    border: 1px solid #ddd;
  }
  section {
    padding: 20px 0;
  }
}

/* ===== 动画关键帧 ===== */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.6;
  }
}

@keyframes shimmer {
  0% {
    background-position: -200% center;
  }
  100% {
    background-position: 200% center;
  }
}

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

.mt-1 { margin-top: var(--space-xs); }
.mt-2 { margin-top: var(--space-sm); }
.mt-3 { margin-top: var(--space-md); }
.mt-4 { margin-top: var(--space-lg); }

.mb-1 { margin-bottom: var(--space-xs); }
.mb-2 { margin-bottom: var(--space-sm); }
.mb-3 { margin-bottom: var(--space-md); }
.mb-4 { margin-bottom: var(--space-lg); }

.hidden {
  display: none !important;
}

.visible {
  display: block !important;
}
```