Unlike Pages ’09 v4.3 which wrote its documents out as zipped directories with a .pages extension — which Dropbox and Google filesystems understood as a single document — Pages v5(.2) writes out directories that only the OS X Finder helps Pages open as a Package file. These new Pages documents are incompatible with Dropbox and Google, unless they are first manually zipped (right-click and choose compress) to transform the directory structure into a single compressed document.
You can view your iCloud Pages documents in the Finder, but I would not recommend accessing them for edits directly:
Finder > [login directory] > Library > Mobile Documents > com~apple~Pages > Documents
If your local Library folder is not visible, open a Finder window and press command + J — then check Show Library Folder.