Overlined Navigation. How to remove it?

Hello everyone! 

I have an overlined navigation when hover, on my new website, I don't know how it happened.

I already have this CSS code there:

body:not(.header--menu-open) .header-nav-item--active a {
  background: none !important;
  font-weight: bold;
}

.sqs-block-html a,
.image-title-wrapper a,
.image-subtitle-wrapper a,
.sqs-image-caption a,
.image-caption a,
.sqs-block-newsletter a,
.list-item-content__description a,
.list-section-title a {
  text-decoration: none !important;
}

But still appears anyway. Can someone help me?

Thank you

Can you share site url? We can check problem easier