submit-social-housing-lettings-and-sales-data/app/frontend/styles/_button.scss

$app-button-shadow-size: $govuk-border-width-form-element;
$app-button-inverse-background-colour: govuk-colour("white");
$app-button-inverse-foreground-colour: $govuk-brand-colour;
$app-button-inverse-shadow-colour: govuk-shade(
  $app-button-inverse-foreground-colour,
  30%
);
$app-button-inverse-hover-background-colour: govuk-tint(
  $app-button-inverse-foreground-colour,
  90%
);

.app-button--inverse,
.app-button--inverse:link,
.app-button--inverse:visited {
  color: $app-button-inverse-foreground-colour;
  background-color: $app-button-inverse-background-colour;
  box-shadow: 0 $app-button-shadow-size 0 $app-button-inverse-shadow-colour;
}

.app-button--inverse:hover {
  color: $app-button-inverse-foreground-colour;
  background-color: $app-button-inverse-hover-background-colour;
}

.app-button--inverse:focus:not(:hover) {
  color: $govuk-focus-text-colour;
  background-color: $govuk-focus-colour;
}

.app-button--inverse:active,
.app-button--inverse:focus {
  border-color: $govuk-focus-colour;
  color: $app-button-inverse-foreground-colour;
  background-color: $app-button-inverse-hover-background-colour;
  box-shadow: inset 0 0 0 2px $govuk-focus-colour;
}

.submit-button-link {
  background: none;
  border: none;
  color: #1d70b8;
  text-decoration: underline;
  cursor: pointer;
}