Use the .align-items-*-start classes to align single rows of items from the start on different screens.
Resize the browser window to see the effect. Note: align-items-stretch is default.
.align-items-start:
.align-items-start
.align-items-sm-start:
.align-items-sm-start
.align-items-md-start:
.align-items-md-start
.align-items-lg-start:
.align-items-lg-start
.align-items-xl-start:
.align-items-xl-start