notification row background

[Aligehri]

Does anyone know why my notification row background looks gray?

I think there is nothing wrong with my code:

.notification-row {
background: transparent;
border-radius: 12px;
padding: 2px;

}

.notification-row:focus,
.notification-row:hover {
background: transparent;
}

.notification {
border-radius: 12px;
margin: 6px 12px;
padding: 2px 2px 2px 2px;
background: rgba(0,0,0,0);
}

There's no any gray color in my css.