refactor: main-container>container and column improvements

frontend/src/App.vue

@@ -524,6 +524,12 @@ body {
 	}
 }
 
+.column {
+	display: flex;
+	flex: 1 1 0;
+	padding: 10px;
+}
+
 ul {
 	list-style: none;
 	margin: 0;
@@ -652,16 +658,19 @@ textarea {
 	display: flex;
 	flex-direction: column;
 
+	&.main-container-modal-active {
+		height: 100% !important;
+		overflow: hidden !important;
+	}
+
 	> .container {
+		position: relative;
 		flex: 1 0 auto;
+		margin: 0 auto;
+		max-width: 1200px;
 	}
 }
 
-.main-container.main-container-modal-active {
-	height: 100% !important;
-	overflow: hidden !important;
-}
-
 a {
 	color: var(--primary-color);
 	text-decoration: none;