[download] Download a working local copy of a webpage

wget is capable of doing what you are asking. Just try the following:

wget -p -k http://www.example.com/

The -p will get you all the required elements to view the site correctly (css, images, etc). The -k will change all links (to include those for CSS & images) to allow you to view the page offline as it appeared online.

From the Wget docs:

‘-k’
‘--convert-links’
After the download is complete, convert the links in the document to make them
suitable for local viewing. This affects not only the visible hyperlinks, but
any part of the document that links to external content, such as embedded images,
links to style sheets, hyperlinks to non-html content, etc.

Each link will be changed in one of the two ways:

    The links to files that have been downloaded by Wget will be changed to refer
    to the file they point to as a relative link.

    Example: if the downloaded file /foo/doc.html links to /bar/img.gif, also
    downloaded, then the link in doc.html will be modified to point to
    ‘../bar/img.gif’. This kind of transformation works reliably for arbitrary
    combinations of directories.

    The links to files that have not been downloaded by Wget will be changed to
    include host name and absolute path of the location they point to.

    Example: if the downloaded file /foo/doc.html links to /bar/img.gif (or to
    ../bar/img.gif), then the link in doc.html will be modified to point to
    http://hostname/bar/img.gif. 

Because of this, local browsing works reliably: if a linked file was downloaded,
the link will refer to its local name; if it was not downloaded, the link will
refer to its full Internet address rather than presenting a broken link. The fact
that the former links are converted to relative links ensures that you can move
the downloaded hierarchy to another directory.

Note that only at the end of the download can Wget know which links have been
downloaded. Because of that, the work done by ‘-k’ will be performed at the end
of all the downloads.