/* ==========================================
   公共样式文件 - common.css
   包含全局样式变量、重置样式、通用工具类
   ========================================== */

/* CSS变量定义 */
:root {
  --primary-color: #0d6efd;
  --secondary-color: #6c757d;
  --success-color: #198754;
  --danger-color: #dc3545;
  --warning-color: #ffc107;
  --info-color: #0dcaf0;
  --light-color: #f8f9fa;
  --dark-color: #212529;
  
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  
  --transition-base: all 0.3s ease;
  --shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
  --shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
  
  --border-radius: 0.375rem;
  --border-radius-lg: 0.5rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  line-height: 1.6;
  color: #333;
  overflow-x: hidden;
}

/* 通用容器 */
.container-custom {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 15px;
}

/* 通用按钮样式 */
.btn-primary-custom {
  background-color: var(--primary-color);
  color: white;
  border: none;
  padding: 12px 30px;
  border-radius: var(--border-radius);
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition-base);
  text-decoration: none;
  display: inline-block;
}

.btn-primary-custom:hover {
  background-color: #0b5ed7;
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.btn-outline-custom {
  background-color: transparent;
  color: var(--primary-color);
  border: 2px solid var(--primary-color);
  padding: 10px 28px;
  border-radius: var(--border-radius);
  font-size: 1rem;
  cursor: pointer;
  transition: var(--transition-base);
  text-decoration: none;
  display: inline-block;
}

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

/* 通用标题样式 */
.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  text-align: left;
  margin-bottom: 0.75rem;
  color: #1a1a1a;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.section-subtitle {
  font-size: 1.1rem;
  color: #6b7280;
  text-align: left;
  margin-bottom: 3.5rem;
  line-height: 1.6;
}

/* 间距工具类 */
.mt-5-custom { margin-top: 5rem; }
.mb-5-custom { margin-bottom: 5rem; }
.py-5-custom { padding: 5rem 0; }

/* 响应式工具类 */
@media (max-width: 768px) {
  .section-title {
    font-size: 2rem;
  }
  
  .section-subtitle {
    font-size: 1rem;
  }
  
  .py-5-custom {
    padding: 3rem 0;
  }
}