tags fixed height

/* CSS PART  */
.tags-container {
    width:540px;
    box-sizing:border-box;
}

.tags-row {
    display:flex;
    align-items: baseline;
    justify-content: space-evenly;
    flex-wrap: wrap;
    padding: 4px;

}

/* MAIN TITLES  */
.title {
    padding: 2px;
    text-align:center;
    text-transform:uppercase;
}


/* EACH BOX TAGS  */
.tags {
    width:120px;  /* change width and height for the size of each tag box  */
    height:200px;
    margin:15px 5px;
    /* delete both overflow if you don't want scroll  */
    overflow-y:scroll;
    overflow-x:hidden;
}

.list-item {
    padding: 6px;
}

.list-item ul {
    text-align:center;
    padding: 0;
    margin: 0;
}

.list-item ul li {
    list-style:none;
}

.list-item li {
    padding:2px 0;
    margin:5px 0;
}


/* GROUP TAGS 1  */
.tags-item1 {
    border: 1px solid red;
}

.title1 {
    color: white;
    background-color: red;
}


/* GROUP TAGS 2  */
.tags-item2 {
    border: 1px solid yellow;
}

.title2 {
    color: black;
    background-color: yellow;
}

/* GROUP TAGS 3  */
.tags-item3 {
    border: 1px solid blue;
}

.title3 {
    color: white;
    background-color: blue;
}


/* GROUP TAGS 4  */
.tags-item4 {
    border: 1px solid green;
}

.title4 {
    color: white;
    background-color: green;
}


/* GROUP TAGS 5  */
.tags-item5 {
    border: 1px solid purple;
}

.title5 {
    color: white;
    background-color: purple;
}


/* GROUP TAGS 6  */
.tags-item6 {
    border: 1px solid orange;
}

.title6 {
    color: white;
    background-color: orange;
}











<!-- > HTML PART <-->
<div class="tags-container">
    <div class="tags-row">

            <!-- > GROUP TAGS 1 <-->
        <div class="tags tags-item1">
            <div class="title title1">
                group one
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>


            <!-- > GROUP TAGS 2 <-->
        <div class="tags tags-item2">
            <div class="title title2">
                group two
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>

            <!-- > GROUP TAGS 3 <-->
         <div class="tags tags-item3">
            <div class="title title3">
                group three
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>

            <!-- > GROUP TAGS 4 <-->
        <div class="tags tags-item4">
            <div class="title title4">
                group four
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>

            <!-- > GROUP TAGS 5 <-->
        <div class="tags tags-item5">
            <div class="title title5">
                group five
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>

            <!-- > GROUP TAGS 6 <-->
        <div class="tags tags-item6">
            <div class="title title6">
                group six
            </div>
            <div class="list-item">
                <ul>
                    <li>tag</li>
                    <li>tag</li>
                    <li>tag</li>
                </ul>
            </div>
        </div>

    </div> <!-- > don't delete/touch <-->
</div> <!-- > don't delete/touch <-->