Review tabset styling

Styling tabsets is currently minimal and I didn't do anything to officially reflect theme.

I added this to main.css:

/* Tabsets */
.panel-tabset {
  margin: 1.5rem 0;
}

.panel-tabset-tabby {
  display: flex;
  gap: 0.5rem;
  list-style: none;
  padding: 0;
  margin: 0 0 1rem 0;
  border-bottom: 1px solid var(--color-gray-200);
}

.dark .panel-tabset-tabby {
  border-bottom-color: var(--color-gray-700);
}

.panel-tabset-tabby li {
  margin: 0;
  padding: 0;
}

.panel-tabset-tabby li a {
  display: block;
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-gray-500);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.panel-tabset-tabby li a:hover {
  color: var(--color-gray-700);
}

.dark .panel-tabset-tabby li a {
  color: var(--color-gray-400);
}

.dark .panel-tabset-tabby li a:hover {
  color: var(--color-gray-200);
}

.panel-tabset-tabby li.active a,
.panel-tabset-tabby li a[aria-selected="true"] {
  color: var(--color-blue-600);
  border-bottom-color: var(--color-blue-600);
}

.dark .panel-tabset-tabby li.active a,
.dark .panel-tabset-tabby li a[aria-selected="true"] {
  color: var(--color-blue-400);
  border-bottom-color: var(--color-blue-400);
}

Some example posts that use tabsets:

• https://opensource.posit.co/blog/quarto/2025-10-13-1.8-release/#accessing-execution-information
• https://opensource.posit.co/blog/shiny/shinyswatch-0.7.0/
• https://opensource.posit.co/blog/shiny/shiny-r-1.8.0/