For Containers:
justify-content: how the flex items will be aligned along main axis
options: flex-start | flex-end | center | space-between | space-around | space-evenlyalign-items: how the flex items will be aligned along cross axis
options: flex-start | flex-end | center | baseline | stretchalign-content: which only applies when there is more one row of flex items,
in that case, align-content controls how the rows aligned along cross axis if there are some empty space. options: flex-start | flex-end | center | space-between | space-around | stretch