fix: remove Bootstrap .container from card styling

Fixed awkward appearance where Bootstrap .container elements were being
styled as cards with backgrounds, borders, and padding.

Changes:
- Removed .container from card/panel styling rule
- Added explicit .container reset to transparent background
- Removed .container from responsive design rule
- .container now maintains proper Bootstrap layout behavior

This fixes the "inner looks like a card" issue where main content areas
had unwanted card styling applied.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

asciinema/theme/custom.css

@@ -123,7 +123,6 @@ input[type="submit"]:active {
 /* Cards & Containers */
 .card,
 .panel,
-.container,
 .recording-item,
 article {
   background-color: var(--pivoine-bg-lighter) !important;
@@ -142,6 +141,15 @@ article {
   transform: translateY(-2px);
 }
 
+/* Don't style Bootstrap .container - it's a layout wrapper */
+.container {
+  background-color: transparent !important;
+  border: none !important;
+  box-shadow: none !important;
+  padding-left: 15px !important;
+  padding-right: 15px !important;
+}
+
 /* Forms & Inputs */
 input[type="text"],
 input[type="email"],
@@ -389,8 +397,7 @@ code {
 /* Responsive Design */
 @media (max-width: 768px) {
   .card,
-  .panel,
-  .container {
+  .panel {
     padding: 12px !important;
   }