You can Register and Log In with PD3.gg account or you can login directly with your Steam account.
If you register a PD3.gg account, you can connect your Steam account by clicking on the Connected accounts menu in the Profile page.
The benefit of having an account is that you can save your Skill builds, tracked and completed Challenges and Achievements (and other things in the future), and be sure that your progress will not be lost.
Otherwise, if you are not logged in, the progress of Challenges and Achievements will be saved in your browser's local storage.
Completed Achievements can be obtained only if you sign in through or connect your Steam account. (Epic Games coming soon)
Challenges
Added Challenges section where you can filter by many parameters, track and mark complete.
Achievements
Added Achievements section where you can filter by many parameters and track specific achievements.
If you are on the Achivements page and you are logged in or have connected Steam account, your progress will be updated automatically every few minutes.
Skill Builder
If you are signed in, you have the option to Save or Load a build from a list of previously saved builds.
The list with your saved builds can be found at Skills page on Save / Load tab or in your Profile page.
Others
Added C-Stacks reset countdown in the side bar of Home and some other pages.