Mixed Content: The page at https://query.wikidata.org/ was loaded over HTTPS, but requested an insecure favicon http://www.wikidata.org/static/favicon/testwikidata.ico. This content should also be served over HTTPS.
As a result, the lock is not green in Chrome and other modern browsers.
Also, assuming the wdq2sparql tool works fine over HTTPS, update its link to use HTTPS as well:
<li> <a href="http://tools.wmflabs.org/wdq2sparql/w2s.php">WDQ syntax translator</a>