:root{--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;--color-text-primary: #1a1a2e;--color-text-secondary: #555;--color-text-tertiary: #888;--color-background-primary: #ffffff;--color-background-secondary: #f5f5f7;--color-border-primary: #333;--color-border-secondary: #ddd;--color-border-tertiary: #e5e5e5;--border-radius-md: 8px;--border-radius-lg: 12px}*{margin:0;padding:0;box-sizing:border-box}body{font-family:var(--font-sans);background:var(--color-background-primary);color:var(--color-text-primary);max-width:720px;margin:0 auto;padding:16px;-webkit-font-smoothing:antialiased}a{color:inherit}button{font-family:inherit}