diff --git a/default_environment/stylesheet/main.css b/default_environment/stylesheet/main.css
index b57d0db..b7af2a4 100644
--- a/default_environment/stylesheet/main.css
+++ b/default_environment/stylesheet/main.css
@@ -194,6 +194,9 @@ body {
         border-collapse: collapse;
         border: 1px solid var(--table-border-color);
         > tbody {
+            border-width: 1px 0;
+            border-style: solid;
+            border-color: var(--table-border-color);
             > tr {
                 > td {
                     padding: 0.2rem;
@@ -206,5 +209,16 @@ body {
                 background-color: var(--table-even-background-color);
             }
         }
+        > thead {
+            border-width: 1px 0;
+            border-style: solid;
+            border-color: var(--table-border-color);
+            > tr {
+                > th {
+                    padding: 0.2rem;
+                    font-weight: 600;
+                }
+            }
+        }
     }
 }