Theme Horse

Hi beth_almeida,

First of all create a child theme and paste the below code in your style.css
Add this below code in your style.css file

/*
Theme Name: Ambition Child Theme
Author: Self-Help WordPress User
Template: ambition
*/

@import url("../ambition/style.css"); 

@media only screen and (max-width: 1023px) {
.hgroup-right {
	padding-right: 0;
	min-width: inherit;
}
.search-toggle {
	display: none;
}

/* Responsive Navigation */
.menu-toggle {
	display: block;
	background-color: rgba(0, 0, 0, 0);
	font-size: 0;
	border: 0 none;
	padding: 0;
	color: #666;
	width: 30px;
	height: 21px;
	float: right;
	margin-top: 19px;
	cursor: pointer;
}
.menu-toggle:before {
	display: block;
	-webkit-font-smoothing: antialiased;
	-moz-osx-font-smoothing: grayscale;
	font-size: 25px;
	line-height: 0;
	font-family: 'Genericons';
	vertical-align: top;
	content: '\f419';
}
.hgroup-right {
	clear: both;
	float: none;
}
.nav-menu {
	display: none;
}
.toggled-on .nav-menu {
	display: block;
}
.main-navigation {
	float: none;
}
.main-navigation li {
	position: inherit;
	width: 100%;
	border-top: 1px solid rgba(0, 0, 0, 0.1);
	margin-left: 0;
}
.main-navigation a {
	float: none;
	padding: 10px 0;
	height: inherit;
}
/* Dropdown */
.main-navigation ul li ul,
.main-navigation ul li:hover ul ul,
.main-navigation ul ul li:hover ul ul,
.main-navigation ul ul ul li:hover ul ul,
.main-navigation ul ul ul ul li:hover ul ul {
	display: block;
}
.main-navigation ul li ul {
	position: inherit;
	top: 0;
	width: inherit;
}
.main-navigation ul li ul li a,
.main-navigation ul li.current-menu-item ul li a,
.main-navigation ul li ul li.current-menu-item a,
.main-navigation ul li.current_page_ancestor ul li a,
.main-navigation ul li.current-menu-ancestor ul li a,
.main-navigation ul li.current_page_item ul li a {
	padding: 10px 0 10px 15px;
}
.main-navigation ul li ul li a:hover,
.main-navigation ul li ul li:hover > a,
.main-navigation ul li.current-menu-item ul li a:hover {
	background-color: inherit;
}
.main-navigation ul li ul li ul {
	left: 0;
}
.main-navigation ul li ul li ul li a,
.main-navigation ul li.current-menu-item ul li ul li a,
.main-navigation ul li ul li.current-menu-item ul li a,
.main-navigation ul li.current_page_ancestor ul li ul li a,
.main-navigation ul li.current-menu-ancestor ul li ul li a,
.main-navigation ul li.current_page_item ul li ul li a {
	padding-left: 21px;
}
}

Thank you!