nextcloud-server/apps/accessibility/css/highcontrast.scss

// SCSS variables
$color-main-text: #000;
$color-main-background: #fff;

$color-background-dark: darken($color-main-background, 30%);
$color-background-darker: darken($color-main-background, 30%);

$color-placeholder-light: darken($color-main-background, 30%);
$color-placeholder-dark: darken($color-main-background, 45%);

$color-text-maxcontrast: $color-main-text;
$color-text-light: $color-main-text;
$color-text-lighter: $color-main-text;

$color-loading-light: #ddd;
$color-loading-dark: #000;

$color-box-shadow: $color-main-text;

$color-border: darken($color-main-background, 50%);
$color-border-dark: darken($color-main-background, 50%);

[class^='icon-'], [class*=' icon-'],
.action,
#appmenu li a,
.menutoggle {
	opacity: 1 !important;
}