refactor(core): move CSS to external file

Declare styles for the main modal in the
main CSS file for the app instead of inline.

Closes #1258

apis_core/core/static/css/core.css

@@ -11,3 +11,8 @@ footer a:has(> img):hover,
 footer a:has(> span[class*="material-symbols"]):hover {
     text-decoration: none;
 }
+
+/* main modal in modal block */
+#modal .modal-dialog {
+    max-width: 800px;
+}

apis_core/core/templates/base.html

@@ -260,7 +260,7 @@
            tabindex="-1"
            aria-labelledby="modalLabel"
            aria-hidden="true">
-        <div class="modal-dialog" style="max-width: 800px;">
+        <div class="modal-dialog">
           <div id="modal-here" class="modal-content"></div>
         </div>
       </div>