I'm making a simple responsive "About" page with Muse CC 2017 that currently consists of a menu widget at the top of the page, an SVG logo graphic under the menu, a text box under the logo graphic and a menu widget in the footer. I'm testing it in Chrome, Explorer, Firefox and Safari. In Firefox and Chrome, the logo graphic, which is pinned to the left side of the page set to not resize, moves to the left in relation to the menu and the text box (pinned to the page center) moves up the page until the first two lines of text are over the bottom of the logo. It looks really wack in Safari, the logo shrinks vertically to less than half it's height as well as moving to the left like in the other browsers and the text also moves up.
The menus and the logo are part of the master page. The menus are the full width of the page and are set to "Responsive Width." The top menu is pinned to the top center of the browser and the bottom one is pinned to the bottom of the browser with "footer" box checked.
I've done several tutorials making pages many times more complicated than this and I hope to do more with this page when I get past this problem. I can't believe that I'm having a problem with something so simple.
So many words – and a simple link would show exactly, what you mean. You can pulbish a free temporary site by using Busines Catalyst (-> look into the "Publish" menu top right of Muse's application window).
The issues, you are encountering, normally are resolvable, if ineknows, how Muse is working, but because there can be tons of reasons, there is only one way to get assistance without endless guessing: Give us a .muse file with as less as possible elements, which demonstrate your issues. Upload your .muse file to Dropbox or a similar file sharing service and give us the download link, then we can assist.