Centre Date Picker Modal

Question

Hello i'm trying to make this popup visible, whenever the date modal appears but, this seems to only appear if I am on the centre of page, link here

I also attached some CSS that influences the modal, the goal is get it centred whenever the date modal appears.

If you need more details please free to ask me.

I've tried changing some CSS code and playing with the z-index value

     /* ==========================================================================
   $BASE-PICKER
   ========================================================================== */
/**
 * Note: the root picker element should *NOT* be styled more than what’s here.
 */
.picker {
  font-size: 16px;
  text-align: left;
  line-height: 1.2;
  color: #000000;
  position: absolute;
  z-index: 10000;
  -webkit-user-select: none;
     -moz-user-select: none;
      -ms-user-select: none;
          user-select: none;
}
/**
 * The picker input element.
 */
.picker__input {
  cursor: default;
}
/**
 * When the picker is opened, the input element is “activated”.
 */
.picker__input.picker__input--active {
  border-color: #0089ec;
}
/**
 * The holder is the only “scrollable” top-level container element.
 */
.picker__holder {
  width: 100%;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

/*!
 * Default mobile-first, responsive styling for pickadate.js
 * Demo: http://amsul.github.io/pickadate.js
 */
/**
 * Note: the root picker element should *NOT* be styled more than what’s here.
 */
/**
 * Make the holder and frame fullscreen.
 */
.picker__holder,
.picker__frame {
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  -webkit-transform: translateY(100%);
      -ms-transform: translateY(100%);
          transform: translateY(100%);
}
/**
 * The holder should overlay the entire screen.
 */
.picker__holder {
  position: fixed;
  transition: background 0.15s ease-out, -webkit-transform 0s 0.15s;
  transition: background 0.15s ease-out, transform 0s 0.15s;
  -webkit-backface-visibility: hidden;
}
/**
 * The frame that bounds the box contents of the picker.
 */
.picker__frame {
  position: absolute;
  margin: 0 auto;
  min-width: 256px;
  max-width: 666px;
  width: 100%;
  -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=0)";
  filter: alpha(opacity=0);
  -moz-opacity: 0;
  opacity: 0;
  transition: all 0.15s ease-out;
}
@media (min-height: 33.875em) {
  .picker__frame {
    overflow: visible;
    top: auto;
    bottom: -100%;
    max-height: 100%;
  }
}
@media (min-height: 40.125em) {
  .picker__frame {
    margin-bottom: 7.5%;
  }
}
/**
 * The wrapper sets the stage to vertically align the box contents.
 */
.picker__wrap {
  display: table;
  width: 100%;
  height: 100%;
}
@media (min-height: 33.875em) {
  .picker__wrap {
    display: block;
  }
}
/**
 * The box contains all the picker contents.
 */
.picker__box {
  background: #ffffff;
  display: table-cell;
  vertical-align: middle;
}
@media (min-height: 26.5em) {
  .picker__box {
    font-size: 1.25em;
  }
}
@media (min-height: 33.875em) {
  .picker__box {
    display: block;
    font-size: 1.33em;
    border: 1px solid #777777;
    border-top-color: #898989;
    border-bottom-width: 0;
    border-radius: 5px 5px 0 0;
    box-shadow: 0 12px 36px 16px rgba(0, 0, 0, 0.24);
  }
}
@media (min-height: 40.125em) {
  .picker__box {
    font-size: 1.5em;
    border-bottom-width: 1px;
    border-radius: 5px;
  }
}
/**
 * When the picker opens...
 */
.picker--opened .picker__holder {
  -webkit-transform: translateY(0);
      -ms-transform: translateY(0);
          transform: translateY(0);
  background: transparent;
  -ms-filter: "progid:DXImageTransform.Microsoft.gradient(startColorstr=#1E000000,endColorstr=#1E000000)";
  zoom: 1;
  background: rgba(0, 0, 0, 0.32);
  transition: background 0.15s ease-out;
}
.picker--opened .picker__frame {
  -webkit-transform: translateY(0);
      -ms-transform: translateY(0);
          transform: translateY(0);
  -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
  filter: alpha(opacity=100);
  -moz-opacity: 1;
  opacity: 1;
}
@media (min-height: 33.875em) {
  .picker--opened .picker__frame {
    top: auto;
    bottom: 0;
  }
}