当黑暗吞没了最后一丝光明
[dāng hēi àn tūn méi le zuì hòu yī sī guāng míng]
This is a rather dramatic phrase that translates as 'When darkness swallows the last ray of light'. It paints a vivid picture of absolute despair and complete defeat or loss, expressing a profoundly negative outlook where there seems no positive element remaining whatsoever.