/*
 * Enter any custom CSS here.
 * This file will not be overwritten by theme updates.
*/
/* Only target the TOP navigation bar */
nav {
  background-color: #000000 !important;
}

/* Keep nav text readable */
nav * {
  color: #ffffff !important;
}
/* Reset discount/code boxes */
[class*="code"],
[class*="discount"],
[class*="coupon"] {
  background: initial !important;
  color: initial !important;
}
<div class="topbar"> 
<div class="bg-dark">