/* ===========================
   CSS Variables - Design System
   =========================== */

:root {
  /* Primary Colors */
  --primary-color: #409EFF;
  --primary-dark: #2E7FD6;
  --primary-light: #66B1FF;

  /* Secondary Colors */
  --secondary-color: #67C23A;
  --accent-color: #E6A23C;
  --danger-color: #F56C6C;

  /* Neutral Colors */
  --text-primary: #303133;
  --text-regular: #606266;
  --text-secondary: #909399;
  --text-placeholder: #C0C4CC;

  --bg-white: #FFFFFF;
  --bg-light: #F5F7FA;
  --bg-gray: #E4E7ED;
  --border-color: #DCDFE6;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-size-base: 16px;
  --font-size-small: 14px;
  --font-size-large: 18px;
  --font-size-xlarge: 24px;
  --font-size-xxlarge: 32px;
  --font-size-hero: 48px;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 600;
  --font-weight-bolder: 700;

  --line-height-base: 1.6;
  --line-height-heading: 1.4;

  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-xxl: 64px;
  --spacing-xxxl: 96px;

  /* Layout */
  --container-width: 1200px;
  --container-padding: 20px;

  /* Border Radius */
  --radius-small: 4px;
  --radius-medium: 8px;
  --radius-large: 12px;
  --radius-xlarge: 16px;

  /* Shadows */
  --shadow-light: 0 2px 12px 0 rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 4px 16px 0 rgba(0, 0, 0, 0.12);
  --shadow-heavy: 0 8px 24px 0 rgba(0, 0, 0, 0.15);

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.4s ease;

  /* Z-index Layers */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* Dark Mode Support (Optional) */
@media (prefers-color-scheme: dark) {
  :root {
    --text-primary: #E5E7EB;
    --text-regular: #D1D5DB;
    --text-secondary: #9CA3AF;
    --bg-white: #1F2937;
    --bg-light: #111827;
    --bg-gray: #374151;
    --border-color: #4B5563;
  }
}