Use css for darkmode

resources/problem.scss

@@ -234,6 +234,70 @@ ul.problem-list {
     .submit-bar {
         float: right;
     }
+
+    #submit-wrapper {
+        margin-top: 0.7em;
+    }
+
+    #submit-wrapper #editor, #submit-wrapper #language {
+        margin-top: 4px;
+    }
+
+    #id_language {
+        width: 100%;
+    }
+
+    #result-version-info {
+        border-bottom: 1px solid rgb(148, 148, 148);
+        margin: 0px 1em;
+        color: #757575;
+        font-weight: 600;
+        padding: 0.2em 0;
+        text-align: right;
+    }
+
+    #language-select2 .select2-results__message {
+        white-space: nowrap
+    }
+
+    #language-select2.select2-dropdown--above {
+        display: flex;
+        flex-direction: column-reverse;
+    }
+
+    #language-select2 .select2-results__option {
+        color: #757575 !important;
+        background: white !important;
+    }
+
+    #language-select2 .select2-results__option--highlighted {
+        text-decoration: underline;
+    }
+
+    #language-select2 .select2-results__option[aria-selected=true] {
+        font-weight: bold;
+        color: black !important;
+    }
+
+    #language-select2 .select2-results__option {
+        padding: 4px 0px;
+    }
+
+    #language-select2 .select2-results__options {
+        overflow-y: visible !important;
+    }
+
+    #language-select2 .select2-results__option {
+        break-inside: avoid-column;
+    }
+
+    #language-select2 .select2-results {
+        -webkit-columns: 10 7em;
+        -moz-columns: 10 7em;
+        columns: 10 7em;
+        padding-left: 1.5em;
+        padding-top: 0.5em;
+    }
 }
 
 @media (max-width: 550px) {
@@ -329,6 +393,40 @@ ul.problem-list {
     color: darkblue;
 }
 
+.problem-data-form {
+    .bad-file input, .bad-file .select2-selection {
+        border-color: red;
+    }
+}
+
+.problem-clarification {
+    border-bottom: 1px solid #ccc;
+    margin-top: 1em;
+    margin-bottom: 1em;
+}
+#clarification_header {
+    color: red;
+    cursor: pointer;
+}
+#clarification_header:hover {
+    color: orange;
+}
+
+#comment-announcement {
+    margin-top: 1em;
+    background-color: lightgray;
+    border-radius: 30px;
+    padding: 0.5em;
+    text-align: center;
+    cursor: pointer;
+    color: dimgrey;
+    font-weight: bold;
+}
+
+#comment-announcement:hover {
+    background-color: gray;
+}
+
 @media (max-width: 799px) {
     .problem-middle-right {
         display: flex;