line header problem

Hello,

This line appeared to me. could someone tell me if it's the fault of some css?

/* GeneratePress Site CSS */

button, html input[type="button"], input[type="reset"], input[type="submit"], a.button, a.button:visited {
	border-width: 1px;
	border-style: solid;
	border-color: inherit;
}

.mc4wp-form-fields input[type="email"] {
	margin-bottom: 10px;
	width: 100%;
}

.archive.category .site .inside-article, .blog .site .inside-article{
    background-color: #ffffff;
}

.entry-meta .byline a {
    color: #26a9d8;
}
.entry-meta span a {
    font-size: 18px;
}

.main-navigation:not(.toggled) li.menu-social > a,
.main-navigation:not(.toggled) li.search-item > a{
	padding: 0 10px;
}

.no-sidebar .entry-content {
	max-width: 1200px;
	margin-left: auto;
	margin-right: auto;
}

.page.no-sidebar .entry-title {
	text-align: center;
}

.top-bar .lsi-social-icons a,
.top-bar .lsi-social-icons a:focus,
.top-bar .lsi-social-iconsa:active,
.top-bar .lsi-social-icons a:hover{
    background: transparent !important;
}

.masonry-load-more {
    text-align: center;
}
.top-bar .lsi-social-icons li {
	margin-bottom: 0 !important;
} /* End GeneratePress Site CSS */

/*
 * Style Featured Posts on Home page
 * **********************************/

/* shadow style images */
.home .wp-show-posts-inner .wp-show-posts-image.wpsp-image-left img {
	box-shadow: 0px 2px 22px -6px rgba(0,0,0,0.5);
}

/* post title spacing */
.home .wp-show-posts-entry-header {
	margin-bottom: 0.25em;
}

/* adjustments for tablets */
@media all and (max-width:1023px) {
	.home .wp-show-posts-inner .wp-show-posts-image.wpsp-image-left {
	}
}

/* adjustments for mobile */
@media all and (max-width:767px) {
	.home .wp-show-posts-inner .wp-show-posts-image.wpsp-image-left {
	}
}

/* Related News after posts */
@media all and (min-width:768px) {
	#wpsp-1152.wp-show-posts-columns .wp-show-posts-inner {
		margin-bottom: 15px !important;
        overflow: hidden;
	}
}

.wp-show-posts-image a img {
    border-radius: 4px;
}

@media (max-width:768px) {
    article.wp-show-posts-single.post.type-post .wp-show-posts-inner {
      display:flex;
      flex-direction:row;
    }
    
    article.wp-show-posts-single.post.type-post .wp-show-posts-inner>*:last-child {
      flex:1 0 60%;
      padding-left:10px;
       
    }
    article.wp-show-posts-single.post.type-post .wp-show-posts-inner {
      display:flex;
      align-items:flex-start
    }
}

/* 
 * Sidebar 
 * *********************/
.widget-area.sidebar .rpwwt-widget ul li a {
    color: var(--contrast-2);
}

/* 
 * Style FluentForm in footer
 * ******************************/

.site-footer .fluentform form {
	display: grid;
	grid-template-columns: 3fr 1fr;
}

.site-footer .fluentform .ff-el-group:not(.ff_submit_btn_wrapper) {
	padding: 0;
	margin: 0;
	display: block;
	border: 0;
}

.site-footer .fluentform .ff-el-group.ff_submit_btn_wrapper {
	padding: 0;
	margin: 0;
	display: block;
}
.site-footer .fluentform .ff-el-group.ff_submit_btn_wrapper button {
	width: 100%;
}

.site-footer .fluentform .ff-el-group input, 
.site-footer .fluentform .ff-el-group button {
	font-size: 1rem;
	border: 0;
	margin: 0;
	padding: 10px 20px;
}

.site-footer .fluentform .ff-el-form-control {
	background-color: #162933;
	border: 0;
	border-radius: 0.5em;
	border-top-right-radius: 0;
	border-bottom-right-radius: 0;
}
.site-footer .fluentform .ff-el-form-control:focus {
	color: var(--contrast);
	background-color: var(--base);
}

.site-footer .fluentform .frm-fluent-form .ff-btn-submit {
	background: var(--accent);
	color: var(--contrast);
	font-weight: bold;
	border: 0;
	border-radius: 0.5em;
	border-top-left-radius: 0;
	border-bottom-left-radius: 0;
}

.rpwwt-widget ul li {
    padding-bottom: 15px;
    border-bottom: 1px solid rgb(240, 240, 240);
}

@media(min-width: 769px) and (pointer: fine) {

    .paging-navigation p a:hover,
    h2.wp-show-posts-entry-title a:hover,
    div#rpwwt-recent-posts-widget-with-thumbnails-2 ul li a:hover,
    .generate-columns-container article.post:hover h2 {
        text-decoration: underline;
    }

}

@media (min-width: 1025px) {
    form.search-form.navigation-search.nav-search-active {
        width: 30%;
        transform: translateX(-50%);
        left: 50%;
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
        form.search-form.navigation-search.nav-search-active {
        width: 35%;
        transform: translateX(-50%);
        left: 50%;
    }
}