Version 1.3.0

• Introduced a color system and several commands to define color styles flexibly.
• Split the progress bar into a seperate model.
• Changed the kernel of the petal model and made it for more complicated uses.
• Added a dark mode for our project by using \usecolorstyle{dark}.
• Fixed a bug which caused abnormal shifting in the first page (titlepage).
• Updated color settings for enumerate environments.
• Changed some examples in our demo document.