Absolute bottom positioning does not work properly in Edge and IE

Question

I have an icon that is absolute, located in bottom: 50px, while this works fine in every browser, exceptions and IE are exceptions. I understand that Microsoft browsers have a lot of problems and how they look different. Here I see that the browser treats the midpoint of the section 100vhas the bottom. I need help to put the icon in IE and Edge in the same way as in Chrome, Opera and Firefox. Thank.

IE and Edge

Chrome, Firefox, Opera

HTML

.content1 {
  height: 100vh;
  width: 100%;
  position: relative;
  top: 0;
  z-index: 99;
}


/* this is the icon I was talking about */

.dropdown_blue1 {
  width: 25px;
  padding: 20px;
  position: absolute;
  margin: auto;
  z-index: 99;
  left: 0;
  right: 0;
  bottom: 50px;
}

<div class="content1"><img class="dropup_blue1" src="../assets/dropup_blue.png" alt=""><img class="dropdown_blue1" src="../assets/dropdown_blue.png" alt=""></div>

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Answer 1

, margin: auto; margin: 0 auto;

.content1 {
      height: 100vh;
      width: 100%;
      position: relative;
      top: 0;
      z-index: 99;
}
.dropdown_blue1 {
      width: 25px;
      padding: 20px;
      position: absolute;
      margin:0 auto; /* change here */
      z-index: 99;
      left: 0;
      right: 0;
      bottom: 50px;
}

<div class="content1">
   <img class="dropdown_blue1" src="../assets/dropdown_blue.png" alt="">
</div>

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Answer 2

! margin-left: auto; margin-right: auto; margin: auto;

Answer 3

I had a similar problem with two browsers, the absolute position was crazy. In the styles section I had.

td.Cir  {width:7in; height:7in; background-image:url('clock.png'); 
  background-size: 45%; background-position: center; 
  background-repeat:no-repeat; position:relative; font-size:28pt;
  min-width:7in; max-width:7in; text-shadow: -1px 0 blue, 0 1px blue,
  1px 0 blue, 0 -1px blue;}

In the table I had

</td></tr><tr><td class='Cir'>...</td><td>...</td></tr>

I changed the code to

<table><tr><td class='Cir'>...</td><td>...</td></tr></table>

and Edge and IE are now working fine