show error color when link extraction failes

tubearchivist/static/css/dark.css

@@ -1,6 +1,7 @@
 :root {
     --main-bg: #00202f;
     --highlight-bg: #00293b;
+    --highlight-error: #990202;
     --highlight-bg-transparent: #00293baf;
     --main-font: #eeeeee;
     --accent-font-dark: #259485;

tubearchivist/static/css/light.css

@@ -1,19 +1,10 @@
 :root {
     --main-bg: #eeeeee;
     --highlight-bg: #d9e0d9;
+    --highlight-error: #f79c9c;
     --highlight-bg-transparent: #00293baf;
     --main-font: #00202f;
     --accent-font-dark: #259485;
     --accent-font-light: #35b399;
     --img-filter: invert(50%) sepia(9%) saturate(2940%) hue-rotate(122deg) brightness(94%) contrast(90%);
 }
-
-/* :root {
-    --main-bg: #00202f;
-    --highlight-bg: #00293b;
-    --highlight-bg-transparent: #00293baf;
-    --main-font: #eeeeee;
-    --accent-font-dark: #259485;
-    --accent-font-light: #97d4c8;
-    --img-filter: invert(50%) sepia(9%) saturate(2940%) hue-rotate(122deg) brightness(94%) contrast(90%);
-} */

tubearchivist/static/css/style.css

@@ -478,6 +478,13 @@ button:hover {
     padding: 30px 0 15px 0;
 }
 
+.download-progress.info {
+    background-color: var(--highlight-bg);
+}
+
+.download-progress.error {
+    background-color: var(--highlight-error);
+}
 
 /* settings */
 .settings-group {

tubearchivist/static/progress.js

@@ -54,6 +54,7 @@ function buildDownloadMessage(dlProgress) {
     var dlStatus = dlProgress['status'];
     var dlTitle = dlProgress['title'];
     var dlMessage = dlProgress['message'];
+    var dlLevel = dlProgress['level'];
     // animate
     if (dlStatus === 'rescan') {
         animate('rescan-icon', 'rotate-img');
@@ -64,6 +65,7 @@ function buildDownloadMessage(dlProgress) {
     var box = document.getElementById('downloadMessage');
     var message = document.createElement('div');
     message.classList.add('download-progress');
+    message.classList.add(dlLevel);
     message.id = 'progress';
     message.setAttribute('data', dlStatus);
     var title = document.createElement('h3');