Block Width
Some pre-defined responsive width CSS classes you could use for applying certain maximum width where applicable.
Use CLASS width-500 for restricting the block width to maximum 500 px.
Use CLASS width-550 for restricting the block width to maximum 550 px.
Use CLASS width-600 for restricting the block width to maximum 600 px.
Use CLASS width-700 for restricting the block width to maximum 700 px.
Use CLASS width-center along with above classes like width-550 width-center for aligning the block to center.