login: Don't show an empty / undefined code of conduct.

core/auth.html

@@ -75,6 +75,10 @@
 								margin-bottom: 1em;
 								padding: 1em;
 							}
+							#code_of_conduct:has(>textarea:empty) {
+								display: none;
+								width: 100%;
+							}
 						</style>
 						<div style="display: flex; flex-direction: column; max-width: 1280px; margin: auto">
 							<h1 ?hidden=${this.name}>Welcome.</h1>
@@ -126,8 +130,10 @@
 								There is currently no administrator.  You will be made administrator.
 							</div>
 
-							<h2>Code of Conduct</h2>
-							<textarea readonly rows="20" cols="80" style="resize: none">${this.code_of_conduct}</textarea>
+							<div id="code_of_conduct">
+								<h2>Code of Conduct</h2>
+								<textarea readonly rows="20" style="resize: none; width: 100%">${this.code_of_conduct}</textarea>
+							</div>
 						</div>
 					`;
 				}