this solves it

config/config.default.php

@@ -149,11 +149,16 @@ return [
     ],
 
     // Default theme, 1=style1.css
-    'theme'                   => env('THEME', 1),
+    'theme'                   => env('THEME', 18),
 
     // Supported themes
     // To disable a theme in the config.php, you can set its value to null
     'themes' => [
+        18 => [
+            'name' => 'Engelsystem IGERla 2024',
+            'type' => 'light',
+            'navbar_classes' => 'navbar-light',
+        ],
         17 => [
             'name' => 'Engelsystem 37c3 (2023)',
             'type' => 'dark',

resources/assets/themes/theme18.scss

@@ -0,0 +1,179 @@
+// IGERla 2024
+
+$color-background-0: #b3edf1;
+$color-background-100: #00c7ff;
+$color-link: #1ca800;
+
+//== changed Colors
+$body-color: #000;
+$gray-darker: #222;
+$gray-dark: #282828;
+$gray-light: #888;
+$gray-lighter: #adafae;
+
+$primary: #1d3099;
+$secondary: #ffd000;
+$success: #00a34f;
+$info: #34a1bf;
+$warning: #d1973b;
+$danger: #c23038;
+
+$text-muted: $gray-darker;
+$btn-link-disabled-color: $gray-darker;
+
+//== changed Forms
+
+// $input-bg: rgba(0, 0, 0, 0.5);
+// $input-bg-disabled: rgba(0, 0, 0, 0.6);
+// $input-group-addon-bg: rgba(0, 0, 0, 0.4);
+
+//== changed Pagination
+
+$pagination-hover-color: #fff;
+$pagination-active-color: #fff;
+
+//== changed Form states and alerts
+
+$state-success-text: #fff;
+$state-success-bg: $success;
+$state-success-border: darken($state-success-bg, 5%);
+
+$state-info-text: #fff;
+$state-info-bg: $info;
+$state-info-border: darken($state-info-bg, 7%);
+
+$state-warning-text: #fff;
+$state-warning-bg: $warning;
+$state-warning-border: darken($state-warning-bg, 3%);
+
+$state-danger-text: #fff;
+$state-danger-bg: $danger;
+$state-danger-border: darken($state-danger-bg, 3%);
+
+$headings-small-color: #fff;
+
+code {
+  background-color: $state-info-bg;
+  color: $state-info-text;
+}
+
+$alert-bg-scale: 0%;
+$alert-border-scale: 0%;
+$alert-color-scale: 0%;
+
+.alert {
+  color: #fff !important;
+
+  .text-danger,
+  .text-info {
+    color: #fff !important;
+  }
+}
+
+@import 'base';
+
+h1,
+h2,
+h3,
+h4,
+h5,
+h6,
+.h1,
+.h2,
+.h3,
+.h4,
+.h5,
+.h6 {
+  color: #000;
+}
+
+.form-control:disabled {
+  opacity: 0.7
+}
+
+.navbar {
+  background: $color-background-0 url('./theme18/bg_pattern_tiled.png') repeat;
+  border-bottom: 0 !important;
+}
+
+body > .container-fluid {
+  margin-bottom: 1em;
+}
+
+#footer {
+  padding-top: 1em;
+  background: #4d733b url('./theme18/bg_pattern_tiled.png') repeat;
+  color: white;
+
+  a {
+    color: inherit;
+  }
+
+  hr {
+    display: none;
+  }
+}
+
+body {
+  background: url('./theme18/bg_pattern_tiled.png') repeat, linear-gradient($color-background-0, $color-background-100) fixed;
+  min-height: 100vh;
+}
+
+[id='content'] a {
+  text-decoration: underline;
+
+  &.btn,
+  &.nav-link {
+    text-decoration: none;
+  }
+}
+
+.navbar {
+  --bs-navbar-color: black;
+
+  .icon-icon_angel {
+    background: black;
+  }
+
+  .nav-link {
+    color: black;
+
+    &:hover,
+    &.active {
+      color: black;
+      text-decoration: underline;
+    }
+  }
+}
+
+
+.text-success,
+.text-danger {
+  background: white;
+  border-radius: 3px;
+  padding: 1px;
+}
+
+td {
+  .text-success,
+  .text-danger {
+    background: transparent;
+    padding: 0;
+
+    .bi {
+      background: white;
+      border-radius: 3px;
+    }
+  }
+}
+
+.alert {
+  a {
+    color: inherit !important;
+  }
+
+  .text-success,
+  .text-danger {
+    background: transparent !important;
+  }
+}