Hide "Site Contents" Link from SharePoint 2013 Quick Launch Navigation

Requirement: Hide site content link from left navigation SharePoint server 2013

How to hide site contents in SharePoint 2013 quick launch?
We can use CSS to hide "Site Contents" link from SharePoint 2013 quick launch navigation.

Hide all site content from quick launch SharePoint 2013 with CSS
Edit your SharePoint Master page, Insert a "Script Editor" web part and add the below code in it. 

<style>
#sideNavBox a[href$="/_layouts/15/viewlsts.aspx"]
 {
    display: none;
 }
</style>

To remove site content from quick launch of SharePoint 2013 sites, Add this CSS to master page, Or you can have it in Alternate CSS sheet.
Save and Publish your master page.

Remove Site Contents from SharePoint 2013 (Not recommended)
If you want to remove "Site Contents" link permanently, You can: Click on "Edit Links" under Quick Launch, edit and remove the "Site Contents" link. Same can be done by: Go To Site Settings >> Quick Launch >> site content  >> click on edit icon >> Delete.
The above methods works on SharePoint 2016 as well!

Related Post: How to Hide View All Site content & Recycle Bin Links in SharePoint 2010/MOSS 2007?