Flex-box: Align last row to grid

Question

I have a simple flex-box layout with a container like:

.grid {
  display: flex;
  flex-flow: row wrap;
  justify-content: space-between;
}

Answer 1

I modified the example presented by Dan Andreasson by using a right border on elements to create a faux gutter. You can then use nth-child to remove the border on the last-child of the column grid count you need. here is a demo https://codepen.io/JacobLett/pen/mdVoroM

/* demo only */
body {
margin:0;
padding:0;
max-width:1024px;
margin:0 auto;
}
.block-list {
background: #ccc;
  border:1px solid #ccc;
}

.block-list .block-list__item {
background: #eee;
}
/* demo only */




.block-list .block-list__item {
   min-height: 100px;
   margin-bottom: 1rem;
}

@media only screen and (min-width: 900px) {
   .block-list {
      display: -webkit-box;
      display: flex;
      flex-wrap: wrap;
      -webkit-box-pack: justify;
      justify-content: space-between;
      background-color: #ffffff;
      margin: 1em auto;
   }

   .block-list:after {
      content: "";
      -webkit-box-flex: 1;
      flex: auto;
   }

   .block-list__item {
      height: 10em;
      width: 25%;
      box-sizing: border-box;
      border-right: 10px solid white;
   }

   .block-list-2 .block-list__item {
      width: 50%;
   }

   .block-list-2 .block-list__item:nth-child(2n) {
      border: none;
   }

   .block-list-3 .block-list__item {
      width: 33.3%;
   }

   .block-list-3 .block-list__item:nth-child(3n) {
      border: none;
   }

   .block-list-4 .block-list__item {
      width: 25%;
   }

   .block-list-4 .block-list__item:nth-child(4n) {
      border: none;
   }
   
   .block-list-5 .block-list__item {
      width: 20%;
   }

   .block-list-5 .block-list__item:nth-child(5n) {
      border: none;
   }
   
   .block-list-6 .block-list__item {
      width: 16.66%;
   }

   .block-list-6 .block-list__item:nth-child(6n) {
      border: none;
   }
}

2 column

   
1
   
   
2
   
   
3
   
   
4
   
   
5
   
   
6
   

3 column

   
1
   
   
2
   
   
3
   
   
4
   
   
5
   
   
6
   


4 column

   
1
   
   
2
   
   
3
   
   
4
   
   
5
   
   
6
   

5 column

   
1
   
   
2
   
   
3
   
   
4
   
   
5
   
   
6
   

6 column

   
1
   
   
2
   
   
3
   
   
4
   
   
5
   
   
6