Lithium Pro is an advanced upgrade package for the free Lithium app, designed specifically for book enthusiasts who want enhanced functionality and customization options. This app unlocks premium features within the main Lithium application, offering users a more personalized reading experience.

Key features include cloud synchronization through Google Drive, allowing readers to maintain consistency across multiple devices. The app also provides extensive theme customization, enabling users to tailor their reading interface with unique color schemes. Additionally, it expands annotation capabilities by providing more highlight color options. These professional tools make Lithium Pro particularly valuable for dedicated readers who need cross-device access and customized visualization of their digital library.

The Lithium Pro upgrade brings several professional enhancements to the reading experience. Its most notable feature is the automatic synchronization function, which uses Google Drive to keep reading progress and library organization consistent across all user devices. While book files themselves aren't synced, the reading data maintains perfect harmony between devices.

Another significant advantage is the custom themes capability. Users can create and modify their display themes, adjusting background colors, text shades, and hyperlink appearances. This level of personalization allows for optimal readability and comfort. The app also expands annotation options by providing additional highlight colors, making it easier to categorize and organize notes within texts.

All these features are seamlessly integrated into the main Lithium application's interface. Users can access these premium features through intuitive menus, particularly through the display settings where they can manage and switch between their custom themes effortlessly.

When it comes to e-books, the size of the library and the authenticity of copyrights are crucial factors for any avid reader. Lithium Pro ensures that users have access to a vast array of books, all while maintaining the integrity of copyright laws. This app works in tandem with the free version of Lithium, enhancing it with Pro features once installed.

The application leverages Google Drive to keep your data backed up and synchronized across multiple devices, ensuring you never lose your place in your digital library. While the books themselves aren't currently included in this sync, the convenience of accessing your reading material from any device is a significant advantage.

By choosing Lithium Pro, you're not just getting access to more books; you're also supporting authors and publishers by ensuring that the content you consume respects proper copyright procedures. This commitment to legal compliance provides peace of mind for users who value ethical consumption of literature.

Format compatibility is essential for readers who switch between devices or prefer certain formats for their e-books. Lithium Pro excels in this area, offering support for various e-book formats, which makes it versatile and user-friendly. Once you've installed this Pro license alongside the free Lithium app, you unlock an enhanced reading experience tailored to your needs.

In addition to its format flexibility, Lithium Pro allows users to customize themes, giving them control over page background color, text color, and link colors. This level of personalization ensures that no matter the format of the book, it will always look as per your preference when you read.

With additional features like more highlight colors and future updates on the horizon, Lithium Pro demonstrates its dedication to providing comprehensive format support without compromising on quality or readability. Users can expect an uninterrupted flow of their favorite stories in whichever format they choose.