Update HTML styles for light mode support

- Changed body background and text color to use light mode variables for improved readability.
- Added styles for the header in light mode to ensure consistent design across themes.

Author: fr4iser90

scripts/html_utils.py

@@ -32,8 +32,8 @@ def html_header(title):
   --sev-bg-info-dark: #4a5568;
 }}
 body {{
-  background: var(--bg-dark);
-  color: var(--text-dark);
+  background: var(--bg-light);
+  color: var(--text-light);
   font-family: 'Segoe UI', Arial, sans-serif;
   margin: 0; padding: 0;
   transition: background 0.2s, color 0.2s;
@@ -56,6 +56,10 @@ def html_header(title):
   background: var(--bg-dark);
   border-bottom: 1px solid var(--table-border-dark);
 }}
+body.lightmode .header {{
+  background: var(--bg-light);
+  border-bottom: 1px solid var(--table-border);
+}}
 .toggle-btn {{
   background: var(--accent);
   color: #fff;