白裙依旧青衫如故
[bái qún yī jiù qīng shān rú gù]
'Bai Qun Yi Jiu Qing Shan Ru Gu' (White Dress Remains Unchanged, Blue Robe Still As Old): This refers to the unchanged or lingering nature of the past. White dress and blue robe can denote different statuses in ancient times, thus the phrase signifies something staying old-fashioned despite the time changes or someone remains as loyal/unchanged towards an ideal/person as ever.