Migration from ionic 3 to ionic 5

I have migrated from ionic 3 to ionic 5 but i think none of my scss work.could any one help me please?
also i do not know where i put put my ionic 3 app.scss code to in the new ionic project so i put those scss code to ionic 5 global.scss file is this wrong?

this is one of my scss

.item-md {
padding: 0px;
}
.item-md.item-block .item-inner {
padding: 0px;
}
.label-md {
margin: 0px;
}
.item-ios {
padding: 0px;
}
.item-ios.item-block .item-inner {
padding: 0px;
}
.label-ios {
margin: 0px;
}
ion-content {
background: none;
background-image: url(’/…/…/assets/imgs/slide4.jpg’) no-repeat center
center / cover !important;

}
.Button_div {
	position: absolute;
	bottom: 12%;
	width: 100%;
	padding: 0 15px;
	z-index: 99999;
}
.select-md,
.select-ios {
	padding: 13px 12px 13px 10px;
	background: #606c81;
	font-size: 15px;
	color: #ffffff;
}
ion-select {
	max-width: 100%;
	width: 100%;
}
.select-md .select-icon .select-icon-inner,
.select-ios .select-icon .select-icon-inner {
	color: #ffffff;
	border-top: 8px solid;
	border-right: 6px solid transparent;
	border-left: 6px solid transparent;
	top: 45%;
}
.Next_btn_div {
	padding: 0 5px;
	margin-top: 10px;
}
ion-button {
	height: 40px !important;
	background: #0fc7ff;
}

these are my html and ts file