Take a copy with the Pulse extension, open it here, then drag, resize and restyle until it is right. Nothing reaches your server. With Pulse you take away the edited file and a list of what changed.
Drop a .html copy here, or choose one. The Pulse browser extension makes them: open it on any page, press Layout, then Copy this page.
The copy is opened in this browser. It is not uploaded, and nothing in it can run — every script was removed when it was taken.
What it will not do: invent a section that is not there. It adjusts a page you already have. And a saved file only replaces a page on a site that IS a file — hand-written or static. If the site is generated by a CMS or a theme, the change list is the one to use, because replacing a template with a frozen rendering of one page loses every other page.
Keys: V select · M move · P parent · arrows nudge 1px, Shift 10px · + / − / 0 zoom · F full screen · Ctrl+Z undo · Esc deselect.