How to apply colors to the column in the matrix field

Hi in my form the matrix shown in the image have to be understand as different columns as 1 and 2 

inside a,b,c,d

Here i would like to give pale colours that almost same for a and b and another pale color almost same for c and d 

so that all the 4 columns shoul under the particular column headings . i injected css not worked

Hi,

Remove first the CSS codes you injected to your form for that particular matrix field and use the following.

/*D*/

#cid_682 .form-matrix-table tr td:nth-child(n+23) {

background: #F2ACFD;

}

/*C*/

#cid_682 .form-matrix-table tr td:nth-child(n+16) {

background: #D360D3;

}

/*B*/

#cid_682 .form-matrix-table tr td:nth-child(n+9) {

background: #5656FF;

}

/*A*/

#cid_682 .form-matrix-table tr td:nth-child(n+1) {

background-color: #A3B2FF;

}

As you can see, I have labeled each code with their column names so you can easily identify which column is it for. Feel free to change the colors (bold text) to your preference.

Result:

Hope this helps. Thanks!