Created the custom text input for the task text

lib/src/App.dart

@@ -16,6 +16,7 @@ class App extends StatelessWidget {
         accentColor: Color(0xFF707070),
         canvasColor: Color.fromRGBO(23, 25, 29, 1.0),
         cardColor: Color.fromRGBO(36, 39, 44, 1.0),
+        cursorColor: Color.fromRGBO(112, 112, 112, 1),
         fontFamily: 'IBM Plex Sans',
       ),
     );

lib/src/screens/new_task_screen.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 
 import '../blocs/new_task_bloc.dart';
 import '../widgets/custom_app_bar.dart';
+import '../widgets/big_text_input.dart';
 
 class NewTaskScreen extends StatefulWidget {
   @override
@@ -16,6 +17,16 @@ class _NewTaskScreenState extends State<NewTaskScreen> {
       appBar: CustomAppBar(
         title: 'Add task',
       ),
+      body: Padding(
+        padding: const EdgeInsets.only(top: 15.0, left: 20.0, right: 20.0),
+        child: Column(
+          children: <Widget>[
+            BigTextInput(
+              height: 95,
+            ),
+          ],
+        ),
+      ),
     );
   }
 }

lib/src/widgets/big_text_input.dart

@@ -0,0 +1,50 @@
+import 'package:flutter/material.dart';
+
+class BigTextInput extends StatelessWidget {
+  final double height;
+  final double width;
+
+  BigTextInput({
+    this.height,
+    this.width,
+  });
+
+  Widget build(BuildContext context) {
+    return Material(
+      child: ConstrainedBox(
+        constraints: BoxConstraints(
+          minWidth: 100,
+          minHeight: 50,
+        ),
+        child: Container(
+          width: width,
+          height: height,
+          decoration: BoxDecoration(
+            color: Theme.of(context).cardColor,
+            borderRadius: BorderRadius.circular(8.0),
+          ),
+          child: TextField(
+            maxLines: 3,
+            maxLength: 220,
+            maxLengthEnforced: true,
+            cursorColor: Theme.of(context).cursorColor,
+            textInputAction: TextInputAction.done,
+            style: TextStyle(
+              color: Colors.white,
+              fontSize: 16,
+            ),
+            decoration: InputDecoration(
+              border: InputBorder.none,
+              contentPadding: EdgeInsets.only(left: 5.0, right: 5.0, top: 5.0),
+              counterStyle: TextStyle(color: Colors.white),
+              hintText: 'Do something...',
+              hintStyle: TextStyle(
+                color: Theme.of(context).cursorColor,
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}