In SP 2013 , any plain html file can be turned in to SP 2013 master page.This is so cool..
This is to keep the distance in html and SharePoint master page controls in master page
Any change made to html is synced to masterpage without actually modifying the masterpage (will write a post on this soon..)
To work with Notepad++
1)Open up the SP site in Internet Explorer and Login with required credentials other wise mapping of the network drive would not be possible
2)In server,Click on Computers Icon-->Map network drive-->provide url to SP site
Once the drive is successfully created , you can open any files in site in any editor like notepad++/notepad/Visual studio etc
3)Under Design Manager -->Edit Master pages , upload any plain html file (initially I would suggest to create html file just having head and body tag in it)
4)You would observe that corresponding master page is automatically created, open both html and corresponding master page (but do not modify anything is master page)
Any change saved to html, will prompt you to reload the master page, (for the first time if it doesn't ask, then in notepad++-->Files-->Reload from disk)
Now your playground is ready , you could learn about how branding works in SharePoint 2013 with this.If you would like to share your leanings , please update it in comments.
Once this works fine try this with some freely available html5, css 3 templates and turn it to SP Master page in few minutes
Please comment your queries under this blog post