mdc-fab background mdc-theme-secondary

Have the following in my Head tag

<style>
:root {
--mdc-theme-primary: #64ba69;
--mdc-theme--primary-light: #96ed98;
--mdc-theme--primary-dark: #31893d;
--mdc-theme--secondary: #e55100;
--mdc-theme--secondary-light: #ff833a;
--mdc-theme--secondary-dark: #ab1a00;
}
</style>

I can see that primary works for below with computed results background-color: rgb(100, 186, 105); = #64ba69

.mdc-button--raised:not(:disabled), .mdc-button--unelevated:not(:disabled) {
background-color: var(--mdc-theme-primary, #3f51b5);
}

But secondary does not work for below mdc-fab as get computed results background-color:rgb(255, 64, 129); = #ff4081

.mdc-fab {
background-color: var(--mdc-theme-secondary, #ff4081);
}

Not sure why ?