By default, the shopping cart tells you to go "Back" but what does "Back" mean? Does it mean you go back to your gallery? Does it mean that you cancel and lose the items in your shopping cart? "Back" is a confusing term. Really they mean "Return to Gallery" or "Continue Shopping". The items in your cart remain in your cart when you click back. If you would like to change the Back button text, use the following CSS code:

/* Customize the "Back" (return to gallery) button in the shopping cart */
/* Hide the "Back" text */
#itemsPanel #cartContinue .sm-button-label { display: none !important; }
/* Add custom "Return to Gallery" text */
#itemsPanel #cartContinue.sm-button:after {
  content: 'Continue Shopping';
}

/* Fix the < and > buttons at the bottom of the shopping cart so they line up properly
#itemsPanel .sm-fonticon-AngleBracketLeftSlim:before, 
#itemsPanel .sm-fonticon-AngleBracketRightSlim:before {
  top: 3px !important;
  position: relative !important;
}