/* ============================================
   91 品牌蜜桃网站 - 全局样式表
   设计主题：现代工业风 + 高性能汽车文化
   色彩方案：深灰(#1a1a1a) + 橙色(#ff6600) + 白色(#ffffff)
   ============================================ */

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', 'PingFang SC', sans-serif;
  background-color: #ffffff;
  color: #333333;
  line-height: 1.6;
  overflow-x: hidden;
}

/* ============================================
   排版系统
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 1rem;
  color: #1a1a1a;
}

h1 {
  font-size: 3.5rem;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 2.5rem;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 1.875rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1rem;
}

p {
  margin-bottom: 1rem;
  font-size: 1rem;
}

a {
  color: #ff6600;
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: #e55a00;
  text-decoration: underline;
}

/* ============================================
   容器与布局
   ============================================ */

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 2rem;
}

@media (max-width: 768px) {
  .container {
    padding: 0 1rem;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  h3 {
    font-size: 1.25rem;
  }
}

/* ============================================
   头部导航
   ============================================ */

header {
  background-color: #1a1a1a;
  color: #ffffff;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 2rem;
  max-width: 1280px;
  margin: 0 auto;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: #ff6600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo img {
  height: 40px;
  width: auto;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}

nav a {
  color: #ffffff;
  font-weight: 500;
  transition: color 0.3s ease;
}

nav a:hover {
  color: #ff6600;
  text-decoration: none;
}

.search-box {
  display: flex;
  align-items: center;
  background-color: #333333;
  border-radius: 4px;
  padding: 0.5rem 1rem;
  gap: 0.5rem;
}

.search-box input {
  background: transparent;
  border: none;
  color: #ffffff;
  outline: none;
  width: 200px;
  font-size: 0.9rem;
}

.search-box input::placeholder {
  color: #999999;
}

.search-box button {
  background: none;
  border: none;
  color: #ff6600;
  cursor: pointer;
  font-size: 1rem;
}

@media (max-width: 768px) {
  .header-content {
    padding: 0 1rem;
  }
  
  nav ul {
    gap: 1rem;
    font-size: 0.9rem;
  }
  
  .search-box {
    display: none;
  }
}

/* ============================================
   Banner 区域
   ============================================ */

.banner {
  position: relative;
  height: 600px;
  background: linear-gradient(135deg, #1a1a1a 0%, #333333 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.banner-bg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.6;
  z-index: 1;
}

.banner-content {
  position: relative;
  z-index: 2;
  text-align: center;
  color: #ffffff;
  max-width: 800px;
}

.banner-content h1 {
  color: #ffffff;
  font-size: 3.5rem;
  margin-bottom: 1rem;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.banner-content .subtitle {
  font-size: 1.5rem;
  color: #ff6600;
  margin-bottom: 2rem;
  font-weight: 600;
}

.banner-content .description {
  font-size: 1.1rem;
  color: #e0e0e0;
  margin-bottom: 2rem;
  line-height: 1.8;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 0.75rem 2rem;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
  text-decoration: none;
  display: inline-block;
}

.btn-primary {
  background-color: #ff6600;
  color: #ffffff;
}

.btn-primary:hover {
  background-color: #e55a00;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(255, 102, 0, 0.3);
}

.btn-secondary {
  background-color: transparent;
  color: #ffffff;
  border: 2px solid #ff6600;
}

.btn-secondary:hover {
  background-color: #ff6600;
  color: #1a1a1a;
}

@media (max-width: 768px) {
  .banner {
    height: 400px;
  }
  
  .banner-content h1 {
    font-size: 2rem;
  }
  
  .banner-content .subtitle {
    font-size: 1.2rem;
  }
  
  .cta-buttons {
    flex-direction: column;
  }
}

/* ============================================
   内容区域
   ============================================ */

section {
  padding: 4rem 0;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title h2 {
  position: relative;
  display: inline-block;
}

.section-title h2::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background-color: #ff6600;
}

.section-title p {
  color: #666666;
  font-size: 1.1rem;
  margin-top: 1rem;
}

/* ============================================
   视频卡片
   ============================================ */

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 3rem;
}

.video-card {
  background-color: #f5f5f5;
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
}

.video-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.video-thumbnail {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  background-color: #000000;
  overflow: hidden;
}

.video-thumbnail img,
.video-thumbnail video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.play-button {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 60px;
  height: 60px;
  background-color: #ff6600;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 10;
}

.play-button::after {
  content: '▶';
  color: #ffffff;
  font-size: 1.5rem;
  margin-left: 4px;
}

.video-card:hover .play-button {
  opacity: 1;
}

.video-info {
  padding: 1.5rem;
}

.video-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #1a1a1a;
}

.video-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  color: #666666;
  margin-bottom: 1rem;
}

.video-stats {
  display: flex;
  gap: 1rem;
  font-size: 0.85rem;
  color: #999999;
}

.video-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.tag {
  display: inline-block;
  background-color: #f0f0f0;
  color: #666666;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
}

/* ============================================
   FAQ 区域
   ============================================ */

.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  margin-bottom: 1.5rem;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  overflow: hidden;
}

.faq-question {
  background-color: #f5f5f5;
  padding: 1.5rem;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  transition: background-color 0.3s ease;
}

.faq-question:hover {
  background-color: #efefef;
}

.faq-icon {
  color: #ff6600;
  font-size: 1.5rem;
  transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

.faq-answer {
  display: none;
  padding: 1.5rem;
  background-color: #fafafa;
  color: #555555;
  line-height: 1.8;
}

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

/* ============================================
   评论区域
   ============================================ */

.reviews-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.review-card {
  background-color: #f9f9f9;
  padding: 2rem;
  border-radius: 8px;
  border-left: 4px solid #ff6600;
  transition: transform 0.3s ease;
}

.review-card:hover {
  transform: translateY(-4px);
}

.review-stars {
  color: #ff6600;
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

.review-text {
  color: #555555;
  margin-bottom: 1rem;
  font-style: italic;
}

.review-author {
  font-weight: 600;
  color: #1a1a1a;
  font-size: 0.95rem;
}

.review-role {
  color: #999999;
  font-size: 0.85rem;
}

/* ============================================
   专家展示
   ============================================ */

.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.expert-card {
  text-align: center;
  background-color: #f5f5f5;
  padding: 2rem;
  border-radius: 8px;
  transition: transform 0.3s ease;
}

.expert-card:hover {
  transform: translateY(-8px);
}

.expert-avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  margin: 0 auto 1.5rem;
  background-color: #e0e0e0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  overflow: hidden;
}

.expert-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.expert-name {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.expert-title {
  color: #ff6600;
  font-weight: 600;
  margin-bottom: 1rem;
}

.expert-bio {
  color: #666666;
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.expert-links {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.expert-links a {
  display: inline-block;
  padding: 0.5rem 1rem;
  background-color: #ff6600;
  color: #ffffff;
  border-radius: 4px;
  font-size: 0.9rem;
  transition: background-color 0.3s ease;
}

.expert-links a:hover {
  background-color: #e55a00;
  text-decoration: none;
}

/* ============================================
   合作品牌
   ============================================ */

.brands-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 2rem;
  align-items: center;
  justify-items: center;
}

.brand-logo {
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #f5f5f5;
  border-radius: 8px;
  padding: 1rem;
  transition: transform 0.3s ease;
}

.brand-logo:hover {
  transform: scale(1.05);
}

.brand-logo img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

/* ============================================
   页脚
   ============================================ */

footer {
  background-color: #1a1a1a;
  color: #e0e0e0;
  padding: 3rem 0 1rem;
  margin-top: 4rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-section h4 {
  color: #ffffff;
  margin-bottom: 1rem;
  font-size: 1.1rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 0.5rem;
}

.footer-section a {
  color: #e0e0e0;
  transition: color 0.3s ease;
}

.footer-section a:hover {
  color: #ff6600;
  text-decoration: none;
}

.footer-contact {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.footer-contact a {
  display: inline-block;
  padding: 0.5rem 1rem;
  background-color: #333333;
  border-radius: 4px;
  font-size: 0.9rem;
}

.footer-contact a:hover {
  background-color: #ff6600;
  color: #1a1a1a;
}

.footer-qrcode {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

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

.qrcode-item img {
  width: 100px;
  height: 100px;
  border-radius: 4px;
}

.qrcode-label {
  font-size: 0.85rem;
  margin-top: 0.5rem;
}

.footer-bottom {
  border-top: 1px solid #333333;
  padding-top: 1.5rem;
  text-align: center;
  font-size: 0.9rem;
  color: #999999;
}

.footer-bottom p {
  margin: 0.5rem 0;
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
  }
  
  .footer-qrcode {
    justify-content: center;
  }
}

/* ============================================
   响应式设计
   ============================================ */

@media (max-width: 1024px) {
  .container {
    padding: 0 1.5rem;
  }
  
  h1 {
    font-size: 2.5rem;
  }
  
  h2 {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  body {
    font-size: 14px;
  }
  
  nav ul {
    flex-direction: column;
    gap: 0.5rem;
  }
  
  .video-grid {
    grid-template-columns: 1fr;
  }
  
  .reviews-container {
    grid-template-columns: 1fr;
  }
  
  .expert-grid {
    grid-template-columns: 1fr;
  }
  
  .brands-container {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.75rem;
  }
  
  h2 {
    font-size: 1.25rem;
  }
  
  h3 {
    font-size: 1.1rem;
  }
  
  .banner-content h1 {
    font-size: 1.5rem;
  }
  
  .banner-content .subtitle {
    font-size: 1rem;
  }
  
  section {
    padding: 2rem 0;
  }
  
  .btn {
    padding: 0.6rem 1.5rem;
    font-size: 0.9rem;
  }
}

/* ============================================
   动画与过渡
   ============================================ */

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

.fade-in {
  animation: fadeIn 0.6s ease-out;
}

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

.slide-in-left {
  animation: slideInLeft 0.6s ease-out;
}

/* ============================================
   工具类
   ============================================ */

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

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

.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }
.mt-4 { margin-top: 4rem; }

.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }
.mb-3 { margin-bottom: 3rem; }
.mb-4 { margin-bottom: 4rem; }

.hidden {
  display: none;
}

.visible {
  display: block;
}