An error occurred while saving the commentAdrian Puescu commented
1. In your 'Theme Editor', create a new snippet with your html code for, let's say, a fixed header:
You can also write it as custom html in the 'HTML' tab, but it will not zoom along with the rest of the presentation if you're going to use the responsive version.
2. In your 'Deck Editor', add the snippet onto any slide (reload the deck page if it was already open before editing the theme).
3. In the same 'Deck Editor', click on the 'Style' button in the left menu - the one with the brush icon.
4. Now click on the 'Custom CSS' and enter the following:
content: 'Your master header text';
That's it! Now the snippet will have the same content on any slide and if you want to clone the deck and change the text, you will only have to do it once, in that 'Custom CSS' editor.
Using the same "hack" you can add a logo or create a footer as well.