node_modules/@angular/material/stepper/_stepper-variables.scss

$mat-stepper-header-height: 72px !default;
// Minimum height for highest density stepper's is determined based on how much
// stepper headers can shrink until the step icon or step label exceed. We can't use
// a value below `42px` because the optional label for steps would otherwise exceed.
$mat-stepper-header-minimum-height: 42px !default;
$mat-stepper-header-maximum-height: $mat-stepper-header-height !default;

$mat-stepper-density-config: (
  height: (
    default: $mat-stepper-header-height,
    maximum: $mat-stepper-header-maximum-height,
    minimum: $mat-stepper-header-minimum-height,
  )
) !default;

// Note: These variables are not denoted with `!default` because they are used in the non-theme
// component styles. Modifying these variables does not have the desired effect for consumers.
$mat-stepper-label-header-height: 24px;
$mat-stepper-label-position-bottom-top-gap: 16px;
$mat-stepper-label-min-width: 50px;

$mat-vertical-stepper-content-margin: 36px;

$mat-stepper-side-gap: 24px;
$mat-stepper-line-width: 1px;
$mat-stepper-line-gap: 8px;

$mat-step-sub-label-font-size: 12px;
$mat-step-header-icon-size: 16px;