Progress bar widget

$gbc-ProgressBarWidget-color

Type: color

Default value: $mt-progress-color

Computed value: #1e88e5

$gbc-ProgressBarWidget-percentage-background-color

Background color of the ProgressBar percentage

Type: color

Default value: $rgba(255, 255, 255, 0.88)

Computed value: rgba(255, 255, 255, 0.88)