I am trying to get blue container in the middle of pink one, however seems vertical-align: middle;
doesn\'t do the job in that case.
Use flex blox in your absoutely positioned div to center its content.
See example https://plnkr.co/edit/wJIX2NpbNhO34X68ZyoY?p=preview
.some-absolute-div {
display: -webkit-box;
display: -webkit-flex;
display: -moz-box;
display: -moz-flex;
display: -ms-flexbox;
display: flex;
-webkit-box-pack: center;
-ms-flex-pack: center;
-webkit-justify-content: center;
-moz-justify-content: center;
justify-content: center;
-webkit-box-align: center;
-ms-flex-align: center;
-webkit-align-items: center;
-moz-align-items: center;
align-items: center;
}