Fix button shadow on non-default themes

Author: zenoachtig

packages/gitbook/src/components/Header/HeaderLink.tsx

@@ -132,13 +132,15 @@ function HeaderItemButton(
                     'button-primary':
                         headerPreset != CustomizationHeaderPreset.Default &&
                         `bg-header-link dark:bg-header-link hover:bg-header-link dark:hover:bg-header-link
-                        text-header-background dark:text-header-background hover:text-header-background dark:hover:text-header-background`,
+                        text-header-background dark:text-header-background hover:text-header-background dark:hover:text-header-background
+                        shadow-none hover:shadow-none`,
                     'button-secondary': tcls(
                         headerPreset != CustomizationHeaderPreset.Default &&
                             `bg-header-link/2 dark:bg-header-link/2 hover:bg-header-link/3 dark:hover:bg-header-link/3 
                             text-header-link dark:text-header-link hover:text-header-link dark:hover:text-header-link
                             ring-header-link/4 dark:ring-header-link/4 hover:ring-header-link/5 dark:hover:ring-header-link/5
-                            contrast-more:ring-header-link contrast-more:bg-header-background contrast-more:text-header-link contrast-more:hover:ring-header-link`,
+                            contrast-more:ring-header-link contrast-more:bg-header-background contrast-more:text-header-link contrast-more:hover:ring-header-link
+                            shadow-none hover:shadow-none`,
                     ),
                 }[linkStyle],
             )}