How To Make A Table Cell To Stick On Top And Most Left Side Of Table At Same Time?

I have created table with sticky header using position property position:sticky; top:0;initially and then overwriting it for the first in first column using position:sticky; **l

Solution 1:

Keep z-index only for that cell:

.tableFixHead thead th:nth-child(1) {
  z-index: 1;
}

.tableFixHead {
  overflow-y: auto;
  max-height: 300px;
  margin-left: -15px;
  margin-right: -15px;
  margin-bottom: 100px;
}

.tableFixHead thead th {
  position: sticky;
  top: 0;
}


.tableFixHead,
.tableFixHead td {
  box-shadow: inset 1px -1px #293033;
}

.tableFixHead th {
  box-shadow: inset 1px 1px #293033, 0 1px #293033;
}

table {
  border-spacing: 0;
   font-size: 14px;
}

th {
  padding: 8px;
  color: #e9ecef;
  background-color: #1e2324;
  font-weight: 500;
  font-size: 14px;
}

thead {
  text-align: center;
}

td {
  background-color: #041230;
  text-align: center;
  padding: 10px;
  color: #e9ecef;
  min-width: 150px;
  font-size: 13px;
  word-spacing: 2px;
}

td:nth-child(1) {
  min-width: 50px;
  max-width: 50px;
  font-weight: bold;
  color: #66FCF1;
  position: sticky;
  left: 0;
  background: 
    linear-gradient(#041230, #041230) center/calc(100% - 2px) calc(100% - 2px) no-repeat, 
    red;
}

.tableFixHead thead th:nth-child(1) {
  color: #66FCF1;
  left: 0;
  background: 
    linear-gradient(#041230, #041230) center/calc(100% - 2px) calc(100% - 2px) no-repeat, 
    red;
  z-index: 1; /* added */
}

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.11.2/css/all.min.css">
<meta name="viewport" content="width=device-width, initial-scale=1">

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="resCSS.css">

<div class="container">

  <div class="tableFixHead">
    <table class="tablecolor2">
      <thead>
        <tr>
          <th>#</th>
          <th>Header 2</th>
          <th>Header 3</th>
          <th>Header 4</th>
          <th>Header 5</th>
          <th>Header 6</th>
          <th>Header 7</th>
          <th>Header 8</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td>row 1, cell 1</td>
          <td>row 1, cell 2</td>
          <td>row 1, cell 3</td>
          <td>row 1, cell 4</td>
          <td>row 1, cell 5</td>
          <td>row 1, cell 6</td>
          <td>row 1, cell 7</td>
          <td>row 1, cell 8</td>
        </tr>
        <tr>
          <td>row 2, cell 1</td>
          <td>row 2, cell 2</td>
          <td>row 2, cell 3</td>
          <td>row 2, cell 4</td>
          <td>row 2, cell 5</td>
          <td>row 2, cell 6</td>
          <td>row 2, cell 7</td>
          <td>row 2, cell 8</td>
        </tr>
        <tr>
          <td>row 3, cell 1</td>
          <td>row 3, cell 2</td>
          <td>row 3, cell 3</td>
          <td>row 3, cell 4</td>
          <td>row 3, cell 5</td>
          <td>row 3, cell 6</td>
          <td>row 3, cell 7</td>
          <td>row 3, cell 8</td>
        </tr>
        <tr>
          <td>row 4, cell 1</td>
          <td>row 4, cell 2</td>
          <td>row 4, cell 3</td>
          <td>row 4, cell 4</td>
          <td>row 4, cell 5</td>
          <td>row 4, cell 6</td>
          <td>row 4, cell 7</td>
          <td>row 4, cell 8</td>
        </tr>
        <tr>
          <td>row 1, cell 1</td>
          <td>row 1, cell 2</td>
          <td>row 1, cell 3</td>
          <td>row 1, cell 4</td>
          <td>row 1, cell 5</td>
          <td>row 1, cell 6</td>
          <td>row 1, cell 7</td>
          <td>row 1, cell 8</td>
        </tr>
        <tr>
          <td>row 2, cell 1</td>
          <td>row 2, cell 2</td>
          <td>row 2, cell 3</td>
          <td>row 2, cell 4</td>
          <td>row 2, cell 5</td>
          <td>row 2, cell 6</td>
          <td>row 2, cell 7</td>
          <td>row 2, cell 8</td>
        </tr>
        <tr>
          <td>row 3, cell 1</td>
          <td>row 3, cell 2</td>
          <td>row 3, cell 3</td>
          <td>row 3, cell 4</td>
          <td>row 3, cell 5</td>
          <td>row 3, cell 6</td>
          <td>row 3, cell 7</td>
          <td>row 3, cell 8</td>
        </tr>
        <tr>
          <td>row 4, cell 1</td>
          <td>row 4, cell 2</td>
          <td>row 4, cell 3</td>
          <td>row 4, cell 4</td>
          <td>row 4, cell 5</td>
          <td>row 4, cell 6</td>
          <td>row 4, cell 7</td>
          <td>row 4, cell 8</td>
        </tr>
        <tr>
          <td>row 1, cell 1</td>
          <td>row 1, cell 2</td>
          <td>row 1, cell 3</td>
          <td>row 1, cell 4</td>
          <td>row 1, cell 5</td>
          <td>row 1, cell 6</td>
          <td>row 1, cell 7</td>
          <td>row 1, cell 8</td>
        </tr>
        <tr>
          <td>row 2, cell 1</td>
          <td>row 2, cell 2</td>
          <td>row 2, cell 3</td>
          <td>row 2, cell 4</td>
          <td>row 2, cell 5</td>
          <td>row 2, cell 6</td>
          <td>row 2, cell 7</td>
          <td>row 2, cell 8</td>
        </tr>
        <tr>
          <td>row 3, cell 1</td>
          <td>row 3, cell 2</td>
          <td>row 3, cell 3</td>
          <td>row 3, cell 4</td>
          <td>row 3, cell 5</td>
          <td>row 3, cell 6</td>
          <td>row 3, cell 7</td>
          <td>row 3, cell 8</td>
        </tr>
        <tr>
          <td>row 4, cell 1</td>
          <td>row 4, cell 2</td>
          <td>row 4, cell 3</td>
          <td>row 4, cell 4</td>
          <td>row 4, cell 5</td>
          <td>row 4, cell 6</td>
          <td>row 4, cell 7</td>
          <td>row 4, cell 8</td>
        </tr>
        <tr>
          <td>row 1, cell 1</td>
          <td>row 1, cell 2</td>
          <td>row 1, cell 3</td>
          <td>row 1, cell 4</td>
          <td>row 1, cell 5</td>
          <td>row 1, cell 6</td>
          <td>row 1, cell 7</td>
          <td>row 1, cell 8</td>
        </tr>
        <tr>
          <td>row 2, cell 1</td>
          <td>row 2, cell 2</td>
          <td>row 2, cell 3</td>
          <td>row 2, cell 4</td>
          <td>row 2, cell 5</td>
          <td>row 2, cell 6</td>
          <td>row 2, cell 7</td>
          <td>row 2, cell 8</td>
        </tr>
        <tr>
          <td>row 3, cell 1</td>
          <td>row 3, cell 2</td>
          <td>row 3, cell 3</td>
          <td>row 3, cell 4</td>
          <td>row 3, cell 5</td>
          <td>row 3, cell 6</td>
          <td>row 3, cell 7</td>
          <td>row 3, cell 8</td>
        </tr>
        <tr>
          <td>row 4, cell 1</td>
          <td>row 4, cell 2</td>
          <td>row 4, cell 3</td>
          <td>row 4, cell 4</td>
          <td>row 4, cell 5</td>
          <td>row 4, cell 6</td>
          <td>row 4, cell 7</td>
          <td>row 4, cell 8</td>
        </tr>
      </tbody>
    </table>
  </div>
  <!-- Table Dormant / Discontinued -->
</div>
<!--  container -->