<div id="percentage_width_height" style="width: 200px; height: 200px; flex-direction: row;">
  <div style="width: 30%; height: 30%;"></div>
</div>

<div id="percentage_position_left_top" style="width: 400px; height: 400px; flex-direction: row;">
  <div style="width: 45%; height: 55%; left: 10%; top: 20%"></div>
</div>

<div id="percentage_position_bottom_right" style="width: 500px; height: 500px; flex-direction: row;">
  <div style="width: 55%; height: 15%; bottom: 10%; right: 20%"></div>
</div>

<div id="p