i don't know why the shadow is drawn under the other next element removing this line:
tr:nth-child(odd){background-color: #f2f2f2}
solves the problem
tested on Firefox and Brave :
tr{background-color:white;width:100%}
tr:nth-child(odd){background-color: #f2f2f2}
tr:nth-child(2){box-shadow : 0px 0px 5px 5px rgba(56,186,180,0.6);}
table{
border-collapse: collapse;
}
th, td {
text-align: left;
padding: 8px;
border-right: 1px solid #f2f2f2;
}
th {
background-color: #f5c000;
color: white;
}
#tr:first-child{
width:10px;
}<!DOCTYPE html>
<html>
<body>
<table>
<tr>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
</tr>
<tr>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
</tr>
<tr>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
<td>
Lorem ipsum
</td>
</tr>
</table>
</body>
</html>i want to use the shadow to indicate the selected element