/* -- Copyright © Microsoft Corporation. All rights reserved. */
#collection
{
    width: 50%;
    border: 1px solid black;

    /* Specifies that the toolbar contents will be laid out according to Flexbox rules. */
    display: -ms-flexbox;

    /* Specifies that the flexbox will lay out its children in multiple lines*/
    -ms-flex-flow: row wrap;

    /* Specifies that the flexbox will position its children at the top of the container in LTR mode*/
    -ms-flex-align: start;
}
.itemClass1
{
    background-color: red;
    border: 3px solid magenta;
    margin: 5px;
}
.itemClass2
{
    background-color: blue;
    border: 3px solid cyan;
    margin: 5px;
    font-size: 2em;
}
.itemClass3
{
    background-color: green;
    border: 3px solid grey;
    margin: 5px;
}