Add zenburn theme (#2112)

src/shared/themes/zenburn/zenburn.ts

@@ -0,0 +1,28 @@
+import { AppThemeConfiguration } from '/@/shared/themes/app-theme-types';
+
+export const zenburn: AppThemeConfiguration = {
+    app: {
+        'overlay-header':
+            'linear-gradient(transparent 0%, rgb(40 44 52 / 85%) 100%), var(--theme-background-noise)',
+        'overlay-subheader':
+            'linear-gradient(180deg, rgb(40 44 52 / 5%) 0%, var(--theme-colors-background) 100%), var(--theme-background-noise)',
+        'scrollbar-handle-background': 'rgba(160, 160, 160, 20%)',
+        'scrollbar-handle-hover-background': 'rgba(160, 160, 160, 40%)',
+    },
+    colors: {
+        background: '#3f3f3f',
+        'background-alternate': '#313131',
+        black: '#313131',
+        foreground: '#dcdccc',
+        'foreground-muted': '#d9d9d9',
+        primary: '#95a4b2',
+        'state-error': '#dca3a3',
+        'state-info': '#95a4b2',
+        'state-success': '#7f9f7f',
+        'state-warning': '#efdcbc',
+        surface: '#636363',
+        'surface-foreground': '#95a4b2',
+        white: '#dcdccc',
+    },
+    mode: 'dark',
+};