<!DOCTYPE html>
<style>
.flexbox {
    display: flex;
}
.inline-flexbox {
    display: inline-flex;
}
.flex-one {
    flex: 1;
}
.inline-block { display: inline-block; }
.flexbox, .inline-flexbox { background-color: lightgrey; }
.border { border: 11px solid pink; }
.padding { padding: 13px; }
.margin { margin: 8px 0; }
.flexbox > div {
    min-width: 0;
    min-height: 0;
}
</style>
<div>
before text
<div class="border" style="display: inline-block; background-color: lightgrey">
<div class="flexbox" style="height: 30px; margin-top: 7px; padding-top: 10px;">
  baseline
</div>
</div>
after text
</div>

<div>
Should align
<div class="inline-block border">
  <div class="flexbox padding" style="width: 50px; height: 50px; background-color: pink">
      <div class="flex-one" style="background-color: lightgrey"></div>
  </div>
</div>
with the
<div class="inline-block margin">
  <div class="flexbox border" style="width: 50px; height: 50px; background-color: pink">
      <div class="flex-one" style="background-color: lightgrey"></div>
  </div>
</div>
bottom of
<div class="inline-block padding" style="padding-left: 0; padding-right: 0">
  <div class="flexbox margin border" style="width: 50px; height: 50px; background-color: pink">
      <div class="flex-one" style="background-color: lightgrey;"></div>
  </div>
</div>
the grey box.
</div>

<div>
Should align with the
<div class="inline-block">
  <div class="flexbox" style="background-color: white">
      <div class="flex-one border padding margin" style="background-color: lightgrey;"></div>
  </div>
</div>
bottom of the pink box.
</div>

<div>
Should align 8px
<div class="inline-flexbox margin border" style="width: 30px; height: 30px;"></div>
below the bottom
<div class="inline-flexbox margin border padding"></div>
of the pink box.
</div>
