[FROM] Padding to margin

Resolves: x
Releases: x
[CODE-STYLE] Change code style

Resolves: x
Releases: x
[TASK] Add toggleable indicator on the main icon

Resolves: x
Releases: x
[BUGFIX] Fix the issue of autoshowing the slide-leftpane on smaller screen devices.
And also fix the loading anim align center bug.

Resolves: #38, #39
Releases: 1.2.12