Hello,
1. The color for this menu can be changed from Theme Settings -> Styles & Colors as a primary color. If you want to change the color specifically for this menu you can use the following CSS code
header.header-categories .secondary-header .mega-navigation {
background: #8c7557;
}
As for the size, add the following code snippet to the Custom CSS in Theme Settings
header.header-categories .menu-opener {
font-size: 20px;
}
2. Use the following code
.page-title-default {
display:none;
}
Regards