refine thinking accordion layout

packages/ui/src/styles/messaging/message-base.css

@@ -186,35 +186,108 @@
   @apply mt-4;
 }
 
-.reasoning-card-header {
-  @apply flex items-center justify-between;
+.message-reasoning-card {
+  background-color: var(--message-assistant-bg);
+  border-left: 4px solid var(--message-assistant-border);
+  margin-top: 0;
+  margin-bottom: 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 0;
 }
 
-.reasoning-card-header-right {
-  @apply flex items-center gap-2;
-}
-
-.reasoning-card-toggle {
-  @apply inline-flex items-center justify-center rounded border border-[var(--border-base)] text-[var(--text-muted)] bg-transparent px-3 py-0.5 text-xs font-semibold;
-}
-
-.reasoning-card-toggle:hover {
-  color: var(--accent-primary);
-  border-color: var(--accent-primary);
-}
-
-.reasoning-card-time {
-  @apply text-[11px] text-[var(--text-muted)];
-}
-
-.reasoning-card-body {
-  @apply pt-1;
-}
-
-.reasoning-card-text {
-  @apply whitespace-pre-wrap break-words leading-[1.1] text-[var(--text-muted)] text-sm;
-  font-family: inherit;
-  background: transparent;
+.message-reasoning-toggle {
+  width: 100%;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 0.65rem;
+  background: none;
   border: none;
+  padding: 0.25rem 0.6rem;
+  font: inherit;
+  color: inherit;
+  text-align: left;
+  cursor: pointer;
+  transition: background-color 0.2s ease, box-shadow 0.2s ease;
+}
+
+.message-reasoning-toggle:hover {
+  background-color: var(--surface-hover);
+}
+
+.message-reasoning-toggle:focus-visible {
+  outline: none;
+  box-shadow: 0 0 0 1px var(--accent-primary);
+}
+
+.message-reasoning-label {
+  font-size: 0.75rem;
+  font-weight: var(--font-weight-medium);
+  color: var(--message-assistant-border);
+}
+
+.message-reasoning-meta {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.5rem;
+}
+
+.message-reasoning-indicator {
+  line-height: 1;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 2.25rem;
+  height: 1.5rem;
+  padding: 0 0.65rem;
+  border: 1px solid var(--border-base);
+  border-radius: 0.375rem;
+  background-color: transparent;
+  color: var(--text-muted);
+  font-weight: var(--font-weight-semibold);
+  font-size: 0.85rem;
+  transition: color 0.2s ease, border-color 0.2s ease, background-color 0.2s ease, transform 0.2s ease;
+}
+
+.message-reasoning-toggle:hover .message-reasoning-indicator {
+  background-color: var(--surface-hover);
+  border-color: var(--accent-primary);
+  color: var(--accent-primary);
+}
+
+.message-reasoning-indicator:active {
+  transform: scale(0.97);
+}
+
+.message-reasoning-time {
+  font-size: 11px;
+  color: var(--text-muted);
+}
+
+.message-reasoning-expanded {
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+}
+
+.message-reasoning-divider {
+  width: 100%;
+  height: 1px;
+  background-color: var(--border-base);
+}
+
+.message-reasoning-body {
+  padding: 0.25rem 0.6rem 0.4rem;
+}
+
+.message-reasoning-text {
+  font-family: var(--font-family-mono);
+  font-size: var(--font-size-sm);
+  line-height: var(--line-height-tight);
+  color: var(--text-muted);
+  white-space: pre-wrap;
+  margin: 0;
 }