/* 基础重置与变量 */
:root {
  --primary-color: #1a73e8;
  --primary-hover: #1557b0;
  --text-dark: #202124;
  --text-secondary: #5f6368;
  --bg-light: #f8f9fa;
  --border-color: #dadce0;
  --font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

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

body {
  font-family: var(--font-family);
  color: var(--text-dark);
  line-height: 1.6;
  background-color: #ffffff;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* 导航栏 */
header {
  border-bottom: 1px solid var(--border-color);
  background-color: #ffffff;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-dark);
  font-size: 22px;
  font-weight: 500;
}

.logo svg {
  width: 36px;
  height: 36px;
}

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

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 16px;
  position: relative;
  padding: 20px 0;
  transition: color 0.2s;
}

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

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

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background-color: var(--primary-color);
  border-radius: 3px 3px 0 0;
}

/* 按钮通用样式 */
.btn-primary {
  background-color: var(--primary-color);
  color: #fff;
  border: none;
  border-radius: 24px;
  padding: 12px 32px;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.2s, box-shadow 0.2s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 160px;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  box-shadow: 0 1px 3px rgba(60,64,67,0.3), 0 4px 8px 3px rgba(60,64,67,0.15);
}

.btn-primary:disabled {
  background-color: var(--border-color);
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  background-color: #fff;
  color: var(--primary-color);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 12px 32px;
  font-size: 16px;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.2s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-secondary:hover {
  background-color: var(--bg-light);
}

/* 主容器 */
main {
  flex: 1;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 80px 24px;
  background-color: #fff;
}

.hero h1 {
  font-size: 56px;
  font-weight: 500;
  letter-spacing: -0.5px;
  margin-bottom: 24px;
  line-height: 1.2;
}

.hero p {
  font-size: 20px;
  color: var(--text-secondary);
  max-width: 800px;
  margin: 0 auto 40px;
}

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

/* Section */
.section {
  padding: 80px 24px;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
}

.section-title {
  text-align: center;
  font-size: 36px;
  font-weight: 500;
  margin-bottom: 48px;
}

/* Grid Layout */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 40px;
}

.card {
  background: #fff;
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  text-align: center;
  border: 1px solid var(--border-color);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.card-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 24px;
  color: var(--primary-color);
}

.card h3 {
  font-size: 24px;
  margin-bottom: 16px;
  font-weight: 500;
}

.card p {
  color: var(--text-secondary);
  font-size: 16px;
}

/* FAQ */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border-color);
  padding: 24px 0;
}

.faq-question {
  font-size: 20px;
  font-weight: 500;
  margin-bottom: 12px;
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.faq-question svg {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  color: var(--primary-color);
}

.faq-answer {
  color: var(--text-secondary);
  padding-left: 36px;
}

/* Footer */
footer {
  background-color: var(--bg-light);
  border-top: 1px solid var(--border-color);
  padding: 40px 24px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
}

.footer-safe {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-bottom: 16px;
  font-weight: 500;
  color: #1e8e3e; /* Green color for safe */
}

/* Utilities */
.text-center { text-align: center; }
.mb-2 { margin-bottom: 16px; }
.mb-4 { margin-bottom: 32px; }
.mt-4 { margin-top: 32px; }

/* Spin Animation */
@keyframes spin { 
  from { transform: rotate(0deg); } 
  to { transform: rotate(360deg); } 
}

/* 响应式 */
@media (max-width: 768px) {
  .hero h1 { font-size: 40px; }
  .hero p { font-size: 18px; }
  .nav-links { display: none; } /* 移动端简单处理 */
  .section { padding: 48px 24px; }
}

/* SEO 页面文章样式 */
.article-content {
  max-width: 800px;
  margin: 0 auto;
  font-size: 18px;
  color: var(--text-dark);
}

.article-content h2 {
  font-size: 28px;
  margin: 40px 0 20px;
  font-weight: 500;
}

.article-content p {
  margin-bottom: 20px;
  color: var(--text-secondary);
  line-height: 1.8;
}

.article-content ul {
  margin-bottom: 20px;
  padding-left: 24px;
  color: var(--text-secondary);
}

.article-content li {
  margin-bottom: 10px;
}