Ok, for those looking for this, I found the answer in angular -material.modules.closure.button and angular -material.modules.js.button
.md-button.md-THEME_NAME-theme.md-primary.md-fab:not([disabled]):hover {
background-color: '{{primary-600}}'; }
.md-button.md-THEME_NAME-theme.md-primary.md-raised:not([disabled]).md-focused, .md-button.md-THEME_NAME-theme.md-primary.md-fab:not([disabled]).md-focused {
background-color: '{{primary-600}}'; }
This tells me what I need, namely that the focused buttons get primary-600.
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