/**
 * 知帆设计系统 - CSS Variables
 * 统一管理颜色、间距、字体、阴影、圆角等设计 token
 */

:root {
  /* ===== 品牌色 ===== */
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-light: #e0e7ff;
  --color-primary-soft: #6366f1;

  /* ===== 功能色 ===== */
  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;
  --color-error: #ef4444;
  --color-error-light: #fee2e2;
  --color-error-bg: #fef2f2;
  --color-info: #3b82f6;
  --color-info-light: #dbeafe;

  /* ===== 中性色 ===== */
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-surface-raised: #ffffff;
  --color-border: #e2e8f0;
  --color-border-light: #f1f5f9;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-text-tertiary: #94a3b8;
  --color-text-muted: #cbd5e1;

  /* ===== 灰阶（用于脑图、边框等精细场景） ===== */
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;

  /* ===== 间距体系 ===== */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;

  /* ===== 圆角 ===== */
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-2xl: 16px;
  --radius-full: 9999px;

  /* ===== 阴影 ===== */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --shadow-node: 0 1px 3px rgba(0, 0, 0, 0.1), 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-node-selected: 0 4px 12px rgba(59, 130, 246, 0.25);

  /* ===== 字体 ===== */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.85rem;
  --font-size-base: 0.95rem;
  --font-size-lg: 1.05rem;
  --font-size-xl: 1.2rem;
  --font-size-2xl: 1.5rem;

  /* ===== 过渡 ===== */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s ease;

  /* ===== Z-Index 层级 ===== */
  --z-dropdown: 50;
  --z-sticky: 100;
  --z-modal: 1000;
  --z-toast: 2000;
  --z-drag-ghost: 10000;
}

/* ===== 工具类 ===== */
.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border-width: 0; }