Bootstrap v3 Gradient Mixins. Drop this wherever your overrides are. It reuses the namespace to make usage more consistent.

gradient-mixins

#gradient {
  .vertical-alpha(@start-color: #555; @start-alpha: 0; @start-percent: 0%; @end-color: #333; @end-alpha: 1; @end-percent: 100%) {
		background-color: transparent !important;
	    @start-alpha-color: hsla(hue(@start-color), saturation(@start-color), lightness(@start-color), 0);
	    @end-alpha-color: hsla(hue(@end-color), saturation(@end-color), lightness(@end-color), @end-alpha);
	    #gradient .vertical(@start-alpha-color; @start-percent; @end-alpha-color; @end-percent);
	}

	.horizontal-three-colors-alpha(@start-color: #00b3ee; @start-alpha: 1; @mid-color: #7a43b6; @mid-alpha: 1; @color-stop: 50%; @end-color: #c3325f; @end-alpha: 1;) {
		background-color: transparent !important;
		@start-alpha-color: hsla(hue(@start-color), saturation(@start-color), lightness(@start-color), @start-alpha);
		@mid-alpha-color: hsla(hue(@mid-color), saturation(@mid-color), lightness(@mid-color), @mid-alpha);
		@end-alpha-color: hsla(hue(@end-color), saturation(@end-color), lightness(@end-color), @end-alpha);
		#gradient .horizontal-three-colors(@start-alpha-color, @mid-alpha-color, @color-stop, @end-alpha-color);
	}

	.vertical-three-colors-alpha(@start-color: #00b3ee; @start-alpha: 1; @mid-color: #7a43b6; @mid-alpha: 1; @color-stop: 50%; @end-color: #0026ff; @end-alpha: 1) {
		background-color: transparent !important;
	    @start-alpha-color: hsla(hue(@start-color), saturation(@start-color), lightness(@start-color), @start-alpha);
	    @mid-alpha-color: hsla(hue(@mid-color), saturation(@mid-color), lightness(@mid-color), @mid-alpha);
	    @end-alpha-color: hsla(hue(@end-color), saturation(@end-color), lightness(@end-color), @end-alpha);
	    #gradient .vertical-three-colors(@start-alpha-color, @mid-alpha-color, @color-stop, @end-alpha-color);
	}
}