criada a tela_historico.dart

lib/componentes/item_avisos.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:rkm_educa_app/componentes/text_custom.dart';
+import 'package:rkm_educa_app/utils/dimensoes.dart';
 import '../utils/cores.dart';
 
 class ItemAvisos extends StatelessWidget {
@@ -19,9 +20,6 @@ class ItemAvisos extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
 
-    double height = MediaQuery.of(context).size.height;
-    double width = MediaQuery.of(context).size.width;
-
     return GestureDetector(
       onTap: onTap,
       child: Container(
@@ -33,7 +31,7 @@ class ItemAvisos extends StatelessWidget {
               crossAxisAlignment: CrossAxisAlignment.center,
               children: [
                 Container(
-                  width: width*0.8,
+                  width: Dimensoes.width*0.8,
                   height: 65,
                   padding: const EdgeInsets.symmetric(horizontal: 20.0),
                   child: Column(