:root {
  --sidebar-width: 300px;
  --brand-color: #0d6efd;
}
.navbar-brand img {
  height: 30px;
  margin-right: 10px;
}
html, body {
  margin: 0; padding: 0; height: 100%; overflow: hidden;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
.main-container { display: flex; flex-direction: column; height: 100vh; }
.content-wrapper { display: flex; flex-grow: 1; overflow: hidden; }
#sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  overflow-y: auto;
  border-right: 1px solid #ddd;
  padding: 1rem;
}
#viewers-wrapper {
    flex-grow: 1;
    display: flex;
    background-color: #e0e0e0;
}
.viewer-pane {
    flex: 1;
    position: relative;
    height: 100%;
    display: flex;
    flex-direction: column;
    border-left: 1px solid #ccc;
}
.viewer-pane:first-child {
    border-left: none;
}
.viewer-header {
    text-align: center;
    padding: 4px;
    background-color: #f8f9fa;
    border-bottom: 1px solid #ddd;
    cursor: pointer;
    font-weight: bold;
    color: #6c757d;
    transition: all 0.2s ease-in-out;
}
.viewer-header.active {
    background-color: var(--brand-color);
    color: white;
    border-bottom-color: var(--brand-color);
}
.viewer-content {
    flex-grow: 1;
    position: relative;
}
#viewer-pane-right {
    display: none; /* Hidden by default */
}
body.comparison-mode #viewer-pane-right {
    display: flex; /* Shown in comparison mode */
}
model-viewer { width: 100%; height: 100%; display: block; background-color: #f0f2f5; }
.loader, .initial-prompt {
  position: absolute; top: 0; left: 0; width: 100%; height: 100%;
  display: flex; justify-content: center; align-items: center;
  text-align: center; z-index: 10;
}
.loader {
  background: rgba(255,255,255,0.9);
  flex-direction: column;
  font-size: 1.2rem; color: #333;
  display: none; /* Hidden by default */
}
.initial-prompt {
  color: #888; font-size: 1.5rem;
}
a.model-link {
  display: block; padding: .5rem .75rem; margin-bottom: .5rem;
  color: #333; text-decoration: none; border-radius: .25rem;
  transition: background-color .2s;
}
a.model-link:hover { background-color: #e9ecef; }
a.model-link.active { background: var(--brand-color); color: white; }
.settings-section { margin-top: 2rem; }
summary {
  font-weight: bold; cursor: pointer; padding: .5rem .75rem;
  border-radius: .25rem; margin-bottom: .25rem;
  transition: background-color .2s;
}
summary:hover { background-color: #e9ecef; }
#model-list ul { padding-left: 1rem; }