Center Button on Image Block

Site URL: https://amphibian-porcupine-6hk9.squarespace.com/interior-design-services-1

Hi! 

How can I center the button on the collage photo blocks? So that the button is bottom center of the block.

Website: https://amphibian-porcupine-6hk9.squarespace.com/interior-design-services-1

Add to Design > Custom CSS

.image-block-collage-text-alignment-left .sqs-block-image .design-layout-collage .image-card .image-button-wrapper {
    text-align: center !important;
}