[FEATURE] Different Style for TOC

The max-width: 800px setting on the article element leaves a lot of blank space on a wide screen. The position and margin of TOC and article need some redesigns.

Different styles can be left as a setting which can be switched by the user manually for each post or entire site, or it can be adjusted by the reader with a button.

[HEIGE-PCloud]

Possible layout 1

.page {
    margin-left: 10%;
    margin-right: auto;
    max-width: initial;
    width: 70%;
}

[HEIGE-PCloud]

Possible layout 4

Add a button to switch toc between auto-toc and static-toc. Should be quite easy to implement.