Certainly the mourning customs at the Russian court were very similar to European customs of the period. Greg King's 'At the court of the last Tsar' goes into some of the rituals at the time of the death of Alexander III in 1893 and they seem very much the sort of thing Queen Victoria would have approved of. There was much 'draping', i.e. hanging of black cloth over windows and doorways, swathing chandeliers in black tulle. Servants were dressed in mourning liveries and uniforms. Normal clothing was black, gradually lightening to lavenders and greys. Black-bordered writing-paper was used (when you see QV's letters reproduced they are frequently written on paper with a deep black border, so the Russians were following general European customs). The court mourned for a year, when there were no festivities or balls or other public indulgence in pleasurable activities, and it is clear from Tuxen's painting of Nicholas II's wedding which occurred the week after Alexander's funeral, the women universally wore white and silver, the acceptable alternative to black for such an event, but no other colours. So even though mourning had been relaxed for Maria Feodorovna's birthday this did not mean that mourning was relaxed very much at all. There was no wedding reception or any other festivity to mark the event and everyone went back into black immediately afterwards. None of this would have been much different for a ruler in any other European capital and although when Queen Victoria died Edward VII truncated the extent of court mourning - for example I don't think much draping was done - and length of time it lasted, it nevertheless was firmly carried out and due respect was paid (mourning for Edward VII in his turn was even shorter, though I love the 'black Ascot' where everyone went to the races but did so in black. A clear case of having their cake and eating it!). I would imagine that just as elsewhere in Europe, the aristocracy and the middle classes in Russia followed the court customs in mourning as far as money and practicalities allowed. The very poor did what they could to show some respect, and the only really different customs would have been in remote or rather primitive communities where much older traditions prevailed (I am thinking of wakes in Ireland, sin-eating, etc. - I have no idea if anything similar happened in Russia).