/* Off Canvas width */
.main-navigation.offside {
    width: 80%;
}

/* Current Selected Menu */
.slideout-navigation.main-navigation .main-nav ul li[class*="current-menu-"] > a {
	font-weight: 600;
}

/* Category Space */
div.inside-navigation.grid-container.grid-parent {
	padding: 0px !important;
}

/* Category bottom line */
.main-navigation.offside ul li {
	border-bottom: 1px solid #505050;
}

/* Category Right Arrow */
.main-navigation.offside ul li::after {
	content: "›"; 
    position: absolute;
    right: 15px; /* right space */
    top: 50%;
    transform: translateY(-60%);
}

-------------------------------------

위 코드를 복사해서 CSS 창 빈 곳에 입력하면 됩니다.
감사합니다.

출처 : https://jamongspot.com/