Remove line in monthly archives

Please share your URL if possible.

The web is under development.

Urls:
https://pro-it.no-ip.info/pro-it.es/2016/01/
https://pro-it.no-ip.info/pro-it.es/category/redes-sociales/
https://pro-it.no-ip.info/pro-it.es/tag/outlook-com/

Thanks.

Hi,
I changed css code:

.mainSection header {
border-bottom: 0px;
}

html {
    -webkit-text-size-adjust: auto;
}

But, sometihngs, the excerpt list appears on the right side, showing a longer top line: https://pro-it.no-ip.info/pro-it.es/2013/04/

Best Regards.

Hi,
The origin of showing a longer line was because the entry does not find the highlighted image. Sorry.
Thanks for everything.
Best Regards.