As of midnight Wednesday, D.C.’s marijuana decriminalization law is officially in effect. The new law — approved by the D.C. Council, signed by Mayor Gray, [caption id="attachment_7876" align="alignright" width="187"] Mayor Vincent Gray[/caption] and submitted to Congress for a 60-day review — replaces misdemeanor criminal charges for possession of up to one ounce of marijuana with a civil violation, costing the offender $25. Now D.C. has the third-least punitive marijuana laws in the country, behind…