<div class="border_rounded">
<table>
    <tr>
      <th>&nbsp;</th>
      <th>th</th>
      <th>th</th>
      <th>th</th>
      <th>th</th>
    </tr> 

    <tr>
      <td rowspan="2">td</td>
      <td>td</td>
      <td >td</td>
      
      <td>td</td>
      <td>td</td>
    </tr>
    <tr>
      <td>th</td>
      <td>td</td>
      <td>td</td>
      <td>td</td>
    </tr>
    <tr>
      <td>th</td>
      <td>td</td>
      <td colspan="2">td</td>
      <td>td</td>
    </tr>
</table>
</div>
body{
  padding:30px;
}
.border_rounded{
  border:1px solid #aaa;
  display:inline-block;
  border-radius:10px;
  overflow:hidden;
}

table {
  border-collapse: collapse;
  th,td{
    padding: .6em 3em;
    border:1px solid #aaa;
    &:first-child{
      border-left:none;
    }
    &:last-child{
      border-right:none;
    }
  }
  th {
    background: #ddd;
  }

  td {
    background: #fff;
  }
  tr{
    &:first-child{
      th,td {
        border-top:none;
      }
    }
    &:last-child{
      th,td{
        border-bottom:none;
      }
    }

  }
}
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