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 application works as a Pro license that unlocks exclusive features in the free version when both are installed on your device. The app offers seamless synchronization of your reading data across multiple devices via Google Drive, ensuring you never lose your place or personal settings. With specialized tools tailored for the Books & Reference category, Lithium Pro provides users with an enriched reading experience through extensive customization and cloud backup solutions.

One of the standout features of Lithium Pro is its ability to sync user data such as bookmarks and preferences using Google Drive, although book files themselves aren't included in this process. Additionally, it allows for custom themes where readers can personalize their page backgrounds, text colors, and link colors according to their preference. These capabilities make it ideal for users who appreciate a personalized reading environment while maintaining consistency across various devices they own.

Lithium Pro stands out in the Books & Reference category by offering unique features that enhance the overall reading experience. One of the key functionalities is the synchronization feature which uses Google Drive to keep your reading data up-to-date across all your devices. This ensures that whether you're switching from your phone to a tablet, your progress and settings remain consistent without any manual intervention required.

In addition to syncing capabilities, Lithium Pro also provides extensive customization options. Users can create, delete, and edit custom themes that allow them to adjust background colors, text colors, and link colors within their reading interface. This level of personalization helps cater to individual preferences and improves readability based on different environments or moods. Furthermore, access to more highlight colors adds another layer of interaction with the content being read, making annotations more visually distinct and organized.

The combination of these features not only makes managing digital libraries easier but also significantly enhances user engagement by providing tools that adapt to specific needs and workflows. Whether it's adjusting visual settings for better comfort during long reading sessions or organizing notes effectively, Lithium Pro equips users with everything necessary to optimize their reference material consumption efficiently.

When it comes to e-books, the size of the library and the authenticity of copyrights are crucial factors for readers. Lithium Pro ensures that users have access to a vast collection of e-books while maintaining strict copyright compliance.

The app leverages Google Drive to keep your data backed up and in sync across devices, ensuring that your library is always up-to-date and accessible wherever you are. This feature not only enhances convenience but also guarantees that your collection remains personal and secure.

While the app itself does not directly host books, its seamless integration with the free version of Lithium allows users to activate Pro features, which may include additional resources or advanced management options for their e-books.

By focusing on copyright authenticity, Lithium Pro provides peace of mind, assuring users that their extensive library is legally sound and ethically sourced.

Format compatibility is essential for an optimal reading experience, allowing users to access various types of e-books without limitations. Lithium Pro excels in this area by supporting multiple formats, thus catering to diverse user preferences.

After upgrading, users can customize themes, adjusting page background color, text color, and link colors. This flexibility extends to the ability to create, delete, and edit themes, offering a personalized reading environment that supports different document formats.

In addition to custom themes, Lithium Pro offers more highlight colors, as seen in the screenshots. This feature enriches the reading experience by enabling users to annotate and emphasize text in a way that suits their style, regardless of the e-book format.

With ongoing updates and more features anticipated in the future, Lithium Pro is committed to expanding its format compatibility, ensuring that every reader finds their perfect match within its ecosystem.