browse: Polish error page

swh/web/static/css/style.css

@@ -437,10 +437,14 @@ fieldset[disabled] .btn-swh.active {
 .swh-http-error-desc {
     font-size: 12px;
     color: #647788;
+    text-align: center;
 }
 
 .swh-http-error-desc pre {
+    display: inline-block;
     text-align: left;
+    max-width: 800px;
+    white-space: pre-wrap;
 }
 
 .swh-table {
@@ -498,4 +502,4 @@ fieldset[disabled] .btn-swh.active {
 
 .pager a {
     outline: none;
-}
+}
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