Sticky Menu with Elementor

Hi,

I have been trying to make a sticky menu. I could manage to set the z-index so that it always appears above the elements. However, when scrolling down, the menu bar background switches from black to white. How can I solve it ?

Site uses generatepress theme and menu bar has the following additional CSS;

.orjinmenu {
background: #222; /* Show a solid color for older browsers */
background: -moz-linear-gradient(#252525, #0a0a0a);
background: -o-linear-gradient(#252525, #0a0a0a);
background: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#252525), to(#0a0a0a)); /* older webkit syntax */
background: -webkit-linear-gradient(#252525, #0a0a0a);
-webkit-box-shadow: rgba(0, 0, 0, 0.4) 0px 1px 2px;
-moz-box-shadow: rgba(0, 0, 0, 0.4) 0px 1px 2px;
box-shadow: rgba(0, 0, 0, 0.4) 0px 1px 2px;
clear: both;
display: block;
float: left;
margin: 0 auto 6px;
width: 100%;
}
.orjinmenu ul {
font-size: 15px;
list-style: none;
margin: 0 0 0 -0.8125em;
padding-left: 0;
}
.orjinmenu li {
float: left;
position: relative;
}
.orjinmenu a {
color: #eee;
display: block;
line-height: 3.333em;
padding: 0 1.2125em;
text-decoration: none;
}
.orjinmenu ul ul {
-moz-box-shadow: 0 3px 3px rgba(0,0,0,0.2);
-webkit-box-shadow: 0 3px 3px rgba(0,0,0,0.2);
box-shadow: 0 3px 3px rgba(0,0,0,0.2);
display: none;
float: left;
margin: 0;
position: absolute;
top: 3.333em;
left: 0;
width: 188px;
z-index: 99999;
}
.orjinmenu ul ul ul {
left: 100%;
top: 0;
}
.orjinmenu ul ul a {
background: #f9f9f9;
border-bottom: 1px dotted #ddd;
color: #444;
font-size: 15px;
font-weight: normal;
height: auto;
line-height: 1.4em;
padding: 10px 10px;
width: 268px;
}
.orjinmenu li:hover > a,
.orjinmenu ul ul :hover > a,
.orjinmenu a:focus {
background: #efefef;
}
.orjinmenu li:hover > a,
.orjinmenu a:focus {
background: #f9f9f9; /* Show a solid color for older browsers */
background: -moz-linear-gradient(#f9f9f9, #e5e5e5);
background: -o-linear-gradient(#f9f9f9, #e5e5e5);
background: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#f9f9f9), to(#e5e5e5)); /* Older webkit syntax */
background: -webkit-linear-gradient(#f9f9f9, #e5e5e5);
color: #373737;
}
.orjinmenu ul li:hover > ul {
display: block;
}
.orjinmenu .current-menu-item > a,
.orjinmenu .current-menu-ancestor > a,
.orjinmenu .current_page_item > a,
.orjinmenu .current_page_ancestor > a {
font-weight: bold;
}

My second question is how I can make the menu bar lower ?

Thanks for the support in advance.