According to the State Council document, May 19-May 21 are designated as national days of mourning. During this period, flags will be flown at half-mast across the country and at all overseas institutions, public entertainment activities will be suspended, and the Ministry of Foreign Affairs and Chinese embassies and consulates abroad will set up condolence books. At 14:28 on May 19th, the entire nation will observe three minutes of silence, during which cars, trains, ships will sound their horns and air-raid sirens will wail. Admin5 and many grassroots websites will change the entire site to a plain design. It is also recommended that all Chinese websites switch to a plain appearance.
To facilitate mourning by websites, CSS filter code is provided as an expression of condolences.