A little help please getting a page validated

Error: Element a not allowed as child of element ul in this context. (Suppressing further errors from this subtree.)
 
    From line 94, column 4; to line 94, column 31
 
    info">↩			<a class="mobile_user_menu">↩				<
 
    Contexts in which element a may be used:
        Where phrasing content is expected.
    Content model for element ul:
        Zero or more li and script-supporting elements.
 
    Error: Element ul not allowed as child of element ul in this context. (Suppressing further errors from this subtree.)
 
    From line 98, column 6; to line 98, column 35
 
    </a>↩					<ul class="dropmenu menu_nav">↩					
 
    Contexts in which element ul may be used:
        Where flow content is expected.
    Content model for element ul:
        Zero or more li and script-supporting elements.

// Wrapper div now echoes permanently for better layout options. h1 a is now target for "Go up" links.
	echo '
	<div id="top_section">
		<div class="inner_wrap">
		<a href="https://mysite.com"><img src="https://mysite.com/Themes/default/images/banner.webp" alt="My banner" ></a> 
 
			<ul class="floatleft" id="top_info">
			<a class="mobile_user_menu">
				<span class="menu_icon"></span>
				<span class="text_menu">', $txt['mobile_user_menu'], '</span>
			</a>';

/* Box-shadow only on this one. */
#wrapper {
	clear: both;
		background: linear-gradient(#d28b02, #aa660a);
 }
 
/* Set maximum width limit for content */
#top_section .inner_wrap, #wrapper, #header, #footer .inner_wrap {
	margin: 0 auto;
	width: 90%;
}
 
/* The framing graphics */
/* The top bar. */
#top_section {
	box-shadow: 0 1px 4px rgba(0, 0, 0, 0.16);
	background: #fff;
	clear: both;
}
#top_section::after {
	content: "";
	display: block;
	clear: both;
}
#top_info {
	padding: 5px 0;
	line-height: 1.3em;
	max-width: 100%;
 
#top_section {
	position: fixed;
    top: 0;
    width: 100vw;
    z-index: 10;