TextFormField with side border

Morning guys, I’m newbie using Flutter and I’m facing a hard design question. The client asked for the login form to have a sideborder everytime the field is selected, as in the image below:

So far I managed to do this:

https://i.imgur.com/gsOQeZu.png (can’t post more than one image 'cause I’m a new user)

I’m usign a container to create this sideborder; this container has a certain height, but the TextFormField doesn’t follow this height. Here’s the code:

Container(
padding: EdgeInsets.only(left: 24.0),
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(20.0),
color: emailFocus
? Color(0xffE66970)
: Color(0xffEBEBEB),
),
height: 50,
child: TextFormField(
onTap: () {
setState(() {
emailFocus = true;
passwordFocus = false;
});
},
keyboardType: TextInputType.emailAddress,
autovalidateMode:
AutovalidateMode.onUserInteraction,
validator: (value) {
if (value.isEmpty) {
return 'Preencha seu email';
} else if (!EmailValidator.validate(value)) {
return 'Email inválido';
} else {
return null;
}
},
// validação do email acima
decoration: InputDecoration(
helperText: ' ',
fillColor: Color(0xffEBEBEB),
filled: true,
enabledBorder: UnderlineInputBorder(
borderRadius: BorderRadius.only(
topRight: Radius.circular(20.0),
bottomRight: Radius.circular(20.0)),
borderSide:
BorderSide(color: Colors.transparent),
),
focusedBorder: UnderlineInputBorder(
borderRadius: BorderRadius.only(
topRight: Radius.circular(20.0),
bottomRight: Radius.circular(20.0)),
borderSide:
BorderSide(color: Colors.transparent),
),
errorBorder: UnderlineInputBorder(
borderRadius: BorderRadius.only(
topRight: Radius.circular(20.0),
bottomRight: Radius.circular(20.0)),
borderSide:
BorderSide(color: Colors.transparent),
),
focusedErrorBorder: UnderlineInputBorder(
borderRadius: BorderRadius.only(
topRight: Radius.circular(20.0),
bottomRight: Radius.circular(20.0)),
borderSide:
BorderSide(color: Colors.transparent),
),
isDense: true),
textAlign: TextAlign.left,
style: TextStyle(
color: Color(0xff45237A), fontSize: 20.0),
),
)

Any tips? Thanks!