chromium/chrome/browser/resources/omnibox/omnibox.css

/* Copyright 2012 The Chromium Authors
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file. */

html {
  height: 100%;
}

body {
  --action-color: rgb(66, 133, 244);
  --border-color: #ddd;

  background-color: #fcfcfc;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  height: 100%;
  margin: 0;
  min-width: 900px;
  padding: 8px;
}

omnibox-input {
  margin-bottom: 30px;
}