Test

You should see a grid with perfectly straight black lines. If not, please consider installing some MathML fonts.

Test grid

<div style="width: 540px; height: 540px; background: #eef;">
  <div style="position: absolute;">
    <div style="position: absolute; left: 20px; top: 20px;">
      <div style="position: absolute;">
        <div style="position: absolute; top: 0; left: 0;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 30px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 60px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 90px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 120px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 150px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 180px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 210px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 240px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 270px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 300px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 330px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 360px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 390px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 420px;">
          <math><mo minsize="500px"></mo></math></div>
        <div style="position: absolute; top: 0; left: 450px;">
          <math><mo minsize="500px"></mo></math></div>
      </div>
      <div style="position: absolute;">
        <div style="position: absolute; top: 0; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 30px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 60px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 90px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 120px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 150px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 180px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 210px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 240px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 270px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 300px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 330px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 360px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 390px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 420px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
        <div style="position: absolute; top: 450px; left: 0;">
          <math> <mover><mo></mo><mspace width="500px"></mspace></mover> </math></div>
      </div>
      <div style="position: absolute;">
        <div style="position: absolute; background: #eef; top: -20px; height: 40px; width: 500px;">
           </div>
        <div style="position: absolute; background: #eef; top: 480px; height: 40px; width: 500px;">
           </div>
      </div>
      <div style="position: absolute;">
        <div style="position: absolute; background: #eef; left: -20px; width: 40px; height: 500px;">
           </div>
        <div style="position: absolute; background: #eef; left: 480px; width: 40px; height: 500px;">
           </div>
      </div>
    </div>
  </div>
</div>