I am working on a WordPress website built on custom theme in which I want to ignore some specific CSS codes coming from wordpress plugin style sheet.
Your additional CSS has still got priority but the plugin stylesheet (/plugins/gravityview/templates/css/table-view.css I guess) classes are more specific and therefore win, for example:
.gv-table-view tr td from the plugin wins over your .gv-container-2777 td you could just copy their css or change yours to be more specific e.g .gv-container-2777 tr td