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

:root {
  --primary: #e8380d;
  --primary-dark: #c42f0a;
  --primary-light: #ff5c33;
  --text: #1a1a1a;
  --text-secondary: #666;
  --text-light: #999;
  --bg: #ffffff;
  --bg-gray: #f5f6f7;
  --bg-dark: #1a1a2e;
  --border: #e8e8e8;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  --radius: 8px;
  --max-width: 1200px;
  --header-height: 64px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  max-width: 100%;
  display: block;
}

ul {
  list-style: none;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
}

.logo img {
  width: 32px;
  height: 32px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav a {
  font-size: 15px;
  color: var(--text-secondary);
  transition: color 0.2s;
}

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

.btn-download {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 28px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 24px;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.2s;
}

.btn-download:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

.btn-download-lg {
  padding: 14px 40px;
  font-size: 17px;
  border-radius: 28px;
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 28px;
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
  border-radius: 24px;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-outline:hover {
  background: var(--primary);
  color: #fff;
}

/* Hero */
.hero {
  padding: calc(var(--header-height) + 80px) 0 100px;
  background: linear-gradient(180deg, #fff5f2 0%, #ffffff 60%);
  text-align: center;
}

.hero h1 {
  font-size: 48px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 20px;
  color: var(--text);
}

.hero h1 span {
  color: var(--primary);
}

.hero-desc {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 40px;
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Section */
.section {
  padding: 80px 0;
}

.section-gray {
  background: var(--bg-gray);
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
  text-align: center;
  max-width: 600px;
  margin: 0 auto 48px;
  line-height: 1.8;
}

/* Feature Grid */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.feature-card {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 36px 28px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
}

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

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 20px;
  background: linear-gradient(135deg, #fff0eb, #ffe0d6);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
}

.feature-card h3 {
  font-size: 20px;
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Split Section */
.split-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.split-content h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 20px;
}

.split-content p {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
}

.split-visual {
  background: linear-gradient(135deg, #fff0eb, #f5f6f7);
  border-radius: 16px;
  height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 80px;
}

/* Platform Download */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.platform-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 20px;
  text-align: center;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.platform-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

.platform-icon {
  font-size: 40px;
  margin-bottom: 16px;
}

.platform-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
}

.platform-card p {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 16px;
}

.platform-card .btn-download {
  padding: 8px 20px;
  font-size: 13px;
}

/* Article List */
.article-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.article-card {
  background: var(--bg);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.3s;
}

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

.article-thumb {
  height: 180px;
  background: linear-gradient(135deg, #fff0eb, #ffe8e0);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 48px;
}

.article-body {
  padding: 24px;
}

.article-body h3 {
  font-size: 18px;
  margin-bottom: 10px;
  line-height: 1.4;
}

.article-body p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}

.article-meta {
  font-size: 12px;
  color: var(--text-light);
}

.read-more {
  color: var(--primary);
  font-size: 14px;
  font-weight: 500;
}

/* Article Page */
.article-page {
  padding: calc(var(--header-height) + 40px) 0 80px;
}

.article-header {
  max-width: 800px;
  margin: 0 auto 40px;
  text-align: center;
}

.article-header h1 {
  font-size: 36px;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 16px;
}

.article-header .article-meta {
  font-size: 14px;
  color: var(--text-light);
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
}

.article-content h2 {
  font-size: 24px;
  font-weight: 600;
  margin: 36px 0 16px;
  color: var(--text);
}

.article-content h3 {
  font-size: 20px;
  font-weight: 600;
  margin: 28px 0 12px;
}

.article-content p {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 16px;
}

.article-content ul,
.article-content ol {
  margin: 16px 0 16px 24px;
  color: var(--text-secondary);
}

.article-content li {
  font-size: 16px;
  line-height: 1.8;
  margin-bottom: 8px;
  list-style: disc;
}

.article-content ol li {
  list-style: decimal;
}

/* Download Page */
.download-hero {
  padding: calc(var(--header-height) + 60px) 0 60px;
  background: linear-gradient(180deg, #fff5f2 0%, #ffffff 100%);
  text-align: center;
}

.download-hero h1 {
  font-size: 40px;
  font-weight: 700;
  margin-bottom: 16px;
}

.download-hero p {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto 36px;
}

.download-main {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 48px;
  margin-bottom: 60px;
}

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

.download-info h2 {
  font-size: 28px;
  margin-bottom: 12px;
}

.download-info p {
  color: var(--text-secondary);
  margin-bottom: 8px;
  font-size: 15px;
}

.download-version {
  display: inline-block;
  background: #fff0eb;
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 13px;
  margin-bottom: 20px;
}

.download-requirements {
  max-width: 800px;
  margin: 0 auto;
}

.download-requirements h3 {
  font-size: 20px;
  margin-bottom: 20px;
  text-align: center;
}

.req-table {
  width: 100%;
  border-collapse: collapse;
}

.req-table th,
.req-table td {
  padding: 14px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}

.req-table th {
  background: var(--bg-gray);
  font-weight: 600;
}

/* Footer */
.footer {
  background: var(--bg-dark);
  color: #ccc;
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.8;
  margin-top: 12px;
  color: #999;
}

.footer h4 {
  color: #fff;
  font-size: 15px;
  margin-bottom: 16px;
}

.footer-links a {
  display: block;
  font-size: 14px;
  color: #999;
  margin-bottom: 10px;
  transition: color 0.2s;
}

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

.footer-bottom {
  border-top: 1px solid #333;
  padding-top: 24px;
  text-align: center;
  font-size: 13px;
  color: #666;
}

/* Breadcrumb */
.breadcrumb {
  padding: 16px 0;
  font-size: 14px;
  color: var(--text-light);
}

.breadcrumb a {
  color: var(--text-secondary);
}

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

.breadcrumb span {
  margin: 0 8px;
}

/* Mobile menu */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--text);
}

/* Responsive */
@media (max-width: 992px) {
  .feature-grid,
  .article-list {
    grid-template-columns: repeat(2, 1fr);
  }

  .platform-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .split-section {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    padding: 20px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
  }

  .nav.open {
    display: flex;
  }

  .menu-toggle {
    display: block;
  }

  .hero h1 {
    font-size: 32px;
  }

  .section-title {
    font-size: 28px;
  }

  .feature-grid,
  .article-list,
  .platform-grid {
    grid-template-columns: 1fr;
  }

  .download-main {
    flex-direction: column;
    text-align: center;
  }

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

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