I was able to figure out how to increase the shortcuts again, I'm still looking for a way to recover pinned posts:
As of update 141, more than 8 shorcuts no longer works this way:
"Increase the number of rows with browser.newtabpage.activity-stream.topSitesRows in about:config and then increase the width of the shortcuts section with the following userContent.css:
@-moz-document url(about:home), url(about:newtab) {
@media (min-width: 1800px) {
.ds-outer-wrapper-breakpoint-override main {
width: 1700px !important;
}
}
}
"
Per u/jscher2000 on FirefoxCSS subreddit, we can use this instead:
The page now uses grid layout. There is a hardcoded number of columns based on page width. You can tweak these rules to get more columns [on the userContent.css file]:
/** Grid column count Override Fx141 **/
.top-sites-list {
grid-template-columns: repeat(4, 1fr) !important;
}
@media (min-width: 680px) {
.top-sites-list {
grid-template-columns: repeat(6, 1fr) !important;
}
}
@media (min-width: 920px) {
.top-sites-list {
grid-template-columns: repeat(8, 1fr) !important;
}
}
@media (min-width: 1080px) {
.top-sites-list {
grid-template-columns: repeat(10, 1fr) !important;
}
}
@media (min-width: 1360px) {
.top-sites-list {
grid-template-columns: repeat(12, 1fr) !important;
}
}