DESIGN.md and Brand Kit

• DESIGN.md : Comprehensive design system and brand guidelines for LongCipher.
• lc.svg : Pure logo without text or slogans.
• lc11.svg : 1:1 aspect ratio logo with pure logo and text.
• lc31.svg : 3:1 aspect ratio logo with logo, text, and slogan.
• lc43.svg : 4:3 aspect ratio logo with logo, text, and slogan.
• lc169.svg : 16:9 aspect ratio logo with logo, text, and slogan.

• https://vercel.com/design/guidelines
• https://github.com/VoltAgent/awesome-design-md/tree/main/design-md/vercel
• https://raw.githubusercontent.com/vercel-labs/web-interface-guidelines/main/command.md