/* 现代化简洁样式 */
:root {
  --primary-color: #ff6b35;
  --primary-dark: #e55a2b;
  --secondary-color: #ff8c42;
  --accent-color: #ff4d1f;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --text-light: #9ca3af;
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --bg-dark: #111827;
  --border-color: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

body {
  font-family: var(--font-sans);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }

.text-center { text-align: center; }
.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }

.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem 1.5rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.card {
  background-color: var(--bg-primary);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: all 0.2s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.navbar {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar-brand {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  text-decoration: none;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s ease;
}

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

.hero {
  padding: 4rem 0;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
  color: white;
  text-align: center;
}

.hero-title {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.25rem;
  opacity: 0.9;
  margin-bottom: 2rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.footer {
  background-color: var(--bg-dark);
  color: white;
  padding: 3rem 0 1rem;
}

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