:root{--color-bg: #f7f9fc;--color-surface: #ffffff;--color-border: #e3e8ef;--color-text: #1f2937;--color-text-muted: #6b7280;--color-primary: #2563eb;--color-primary-hover: #1d4ed8;--color-assistant-bg: #f3f4f6;--radius-sm: 6px;--radius-md: 10px;--radius-lg: 14px;--space-1: 4px;--space-2: 8px;--space-3: 12px;--space-4: 16px;--space-6: 24px;--font-sans: -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;--font-mono: "JetBrains Mono", Consolas, monospace}*{box-sizing:border-box}body{margin:0;font-family:var(--font-sans);background:var(--color-bg);color:var(--color-text);line-height:1.6}