properly align and center images in gallery as grid. also add github link to giessomat.

input/projects/giessomat.md

 ## Links
 
 You can find [all the source code for the device itself](https://git.xythobuz.de/thomas/giess-o-mat) (both the UI and the Controller) as well as the OpenSCAD [design files for the 3D printed parts](https://git.xythobuz.de/thomas/3d-print-designs/src/branch/master/giessomat) on my [Gitea instance](https://git.xythobuz.de).
+The project is also [mirrored on GitHub](https://github.com/xythobuz/giess-o-mat).
 
 ## License
 

static/css/style.css

     font-size: 0.6em;
 }
 
+.lightgallery {
+    display: flex;
+    justify-content: space-around;
+    align-items: center;
+    flex-wrap: wrap;
+}
+
 .border {
     overflow: hidden;
-    height: auto;
+    height: max-content;
     display: inline-block;
     border-radius: 10px;
     vertical-align: middle;