Hi Sundar,
To change background-color and hover background-color color of drop-down menu Go to Appearance -> Theme Option -> Design Option Tab -> Custom CSS paste the following CSS code and Click on save all changes button:
#access ul li ul {
background-color: #fff;
border-color: #05A9C5;
}
#access ul li ul li a:hover,
#access ul li ul li:hover > a,
#access ul li.current-menu-item ul li a:hover {
background-color: #F9F9F9;
}
Note: Change above Hex color code #fff for drop-down background-color and #05A9C5 for border as well and change #F9F9F9 for hover background-color with your own Hex color code.
Thank you for using our theme.