Minor tweaks to catalog UI (#1176)

* Minor tweaks to catalog UI

* Review feedback

* Use styles instead

packages/core/src/layout/HeaderTabs/index.tsx

@@ -24,6 +24,7 @@ const useStyles = makeStyles(theme => ({
   tabsWrapper: {
     gridArea: 'pageSubheader',
     backgroundColor: theme.palette.background.paper,
+    paddingLeft: theme.spacing(3),
   },
   defaultTab: {
     padding: theme.spacing(3, 3),

packages/theme/src/baseTheme.ts

@@ -141,6 +141,7 @@ export function createThemeOverrides(theme: BackstageTheme): Overrides {
         color: theme.palette.link,
         minHeight: 24,
         textTransform: 'initial',
+        letterSpacing: '0.07em',
         '&:hover': {
           color: darken(theme.palette.link, 0.3),
           background: lighten(theme.palette.link, 0.95),