angular 5 material - form fields stuck at 180px

I've created a form in a dialog using material forms, but I can't seem to get the inputs to be wider than 180px despite following numerous examples including https://material.angular.io/components/input/example.

I'm sure this is a pretty standard CSS thing, but I don't have that sort of brain so I cant figure out the problem.

Does anyone have a serious / non-trivial example that works??

Here's mine:

<h1 mat-dialog-title>{{title}}</h1>
<mat-dialog-content>
  <form novalidate #f="ngForm" class="form-full-width">
    <mat-form-field class="input-full-width">
      <input type="text" [(ngModel)]="data.name" name="name" matInput placeholder="Name">
      <mat-hint>Enter a unique name.</mat-hint>
    </mat-form-field>
    <mat-form-field class="input-full-width">
      <textarea [(ngModel)]="data.description" name="description" matInput placeholder="Description"></textarea>
      <mat-hint>You should describe the purpose/use of this thing.</mat-hint>
    </mat-form-field>
  </form>
</mat-dialog-content>

CSS :

.form-full-width {
    min-width: 150px;
    max-width: 500px;
    width:100%;
}

.input-full-width {
    width:800px;
}

.mat-form-field.mat-form-field {
    width: auto;
}

Thanks.

can you try using

mat-form-field {
width: 100%;
}

I had the same issue in a mat-card, this worked for me.

Seems like it's something to do with View Encapsulation. This thread explains it: https://github.com/angular/material2/issues/4034 but changing encapsulation for the component causes all sorts of compile failures.

This article gave me the correct solution:https://material.angular.io/guide/customizing-component-styles

I'll move my style to global scope...

.formFieldWidth480 .mat-form-field-infix {
   width: 480px;
}

and in the component that opens the dialog:

this.newDialog = this.dialog.open(NewDialogComponent,
  {
    width: '650px', height: '550px',
    data : newThing,
    panelClass : "formFieldWidth480"
  });

I hope this saves someone else the day I lost...

Just like Jonesie said, this behavior is related to View Encapsulation. In this context .mat-form-field-infix takes 180px as default value probably beacause of this. The auto value lets the browser calculates the width instead of puting hardcoded value. The !important declarations forces the style override for this.
I am using !important since it complies with the rules for the use of this property. See docs

::ng-deep .mat-form-field-infix {
    width: auto !important;
}

It's that .mat-form-field.mat-form-field in the css that's causing an issue. As soon as I removed that, I could control the widths with .input-full-width width setting. I set up a demo here: StackBlitz.com

<h1 mat-dialog-title>{{title}}</h1>
<mat-dialog-content>
  <form novalidate #f="ngForm" class="form-full-width">
    <mat-form-field class="input-full-width">
      <input type="text" [(ngModel)]="data.name" name="name" matInput placeholder="Name">
      <mat-hint>Enter a unique name.</mat-hint>
    </mat-form-field>
    <mat-form-field class="input-full-width">
      <textarea [(ngModel)]="data.description" name="description" matInput placeholder="Description"></textarea>
      <mat-hint>You should describe the purpose/use of this thing.</mat-hint>
    </mat-form-field>
  </form>
</mat-dialog-content>

.form-full-width {
    min-width: 150px;
    max-width: 500px;
    width:100%;
}

.input-full-width {
    width:800px;
}

/* .mat-form-field.mat-form-field {
    width: auto;
} */

The solution I found was this one into general style.css

mat-form-field {
  margin-left: 2.5rem;
  width: calc(100% - 2.5rem);
}

::ng-deep .mat-form-field-infix {
  width:800px !important;
}

This should work fine.Not sure if it can be done without custom CSS.