Set a Setting to all pages

Ionic Framework ionic-v3
1

HTML

ion-range min=“1” max=“3” snaps=“true” [(ngModel)]=“fontSize” class=“fontSize"
ion-label range-left class=“small-text” A /ion-label
ion-label range-right>A</ion-label
/ion-range
/ion-item
p class=“fontSize” [ngClass]=”{small: fontSize===1, medium: fontSize===2, big: fontSize===3}">text font size change /p

SCCS

.small {
font-size: 1em;
}
.medium {
font-size: 1.5em;
}
.big {
font-size: 2em;
}

OK! It works in texts on same pages of range. On my mind, it was just repeat into any page :
p class=“fontSize” [ngClass]="{small: fontSize===1, medium: fontSize===2, big: fontSize===3}" “text” /p
But doesn’t work properly,
Someone there could help me