Another easy stego challenge. The challenge consists of a HTML file. Opening it up, reveals that there is a table present. There were various cells present with nearly-same background color.

Original file link here - glasses.tar.gz.

A sample from the original HTML file.

<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 255);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 255);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 254);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 254);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 255);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 255);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 255);"></td>
<td style="width: 7.75757575757576px; background-color: rgb(255, 255, 254);"></td>

There is a subtle difference in the background colors of the cells. But they only had two values, either (255, 255, 255)  or (255, 255, 254). Replacing (255, 255, 255) with (0, 0,0) and then replacing (255, 255, 254) with (0, 0, 255) (blue), gives us the following.

result

It is a QR code and the decoded result gives the flag

8febb919bc0fc08e3e1108b1b6bfef37