A css snippet to make the left panel and toc display a horizontal scrollbar:

[SiriusXT]

Left panel:

.tree-wrapper.component .tree{
    overflow-x: auto;
    position: relative;
}
.tree-wrapper.component #ft-id-1{
    position: absolute;
}

.tree-wrapper.component .tree-actions{
    bottom: 12px;
    right: 12px;
}

::-webkit-scrollbar {
    height: 12px;
}

Toc:

#right-pane div.card-body div.toc-widget span.toc li{
    overflow: visible;
}

Tip: Hold down the shift key and the scroll wheel to quickly scroll horizontally

[Nriver]

This CSS works great! The shift key trick is quite useful, thank you!

I believe this CSS snippet significantly enhances the mobile experience, particularly when dealing with multiple levels of note trees and lengthy note titles. It greatly simplifies note tree navigation, making it much more intuitive and user-friendly.

[tuxgirl]

Sorry for the stupid question, but... How do I turn this on?

[eliandoran]

See https://docs.triliumnotes.org/User%20Guide/User%20Guide/Theme%20development/Custom%20app-wide%20CSS.html.