diff --git a/ui/src/components/session/SessionRail.vue b/ui/src/components/session/SessionRail.vue
index 2b387bf..f7dcd62 100644
--- a/ui/src/components/session/SessionRail.vue
+++ b/ui/src/components/session/SessionRail.vue
@@ -36,12 +36,12 @@ const emit = defineEmits(['open', 'goto-kg', 'goto-settings']);
 /* 兜底样式（类名按 UI_SPEC §3 / §7） */
 .collapsed-rail {
   display: flex;
-  flex-direction: column;
-  align-items: flex-start;  /* 展开态：图标靠左（原样图标，14px 对齐内容边距） */
+  flex-direction: row;       /* 展开态：三个图标横向一排 */
+  align-items: center;
   gap: 14px;
   width: 100%;
-  padding: 0 0 14px 14px;
-  margin-top: auto;          /* 沉底：与折叠态同一元素，切换时 Y 高度不变 */
+  padding: 0 14px 14px;
+  margin-top: auto;          /* 居底：与折叠态同一元素，切换时 Y 高度不变 */
 }
 .rail-item {
   display: inline-flex;
diff --git a/ui/src/styles/base.css b/ui/src/styles/base.css
index f468420..a41cb67 100644
--- a/ui/src/styles/base.css
+++ b/ui/src/styles/base.css
@@ -174,8 +174,9 @@ html.drawer-open { overflow: hidden; }
 .session-panel .inner { display: flex; flex-direction: column; min-height: 0; width: 260px; flex: 1; transition: opacity .2s var(--pa-ease); }
 .side-collapsed .session-panel .inner { opacity: 0; pointer-events: none; }
 .side-collapsed .session-panel .collapsed-rail {
-  align-items: center;   /* 折叠态：64px 轨内居中，图标原样 */
-  padding: 0 0 14px;     /* 折叠态：去掉展开态的左 14px（底 14px 两态一致） */
+  flex-direction: column; /* 折叠态：64px 窄轨纵向排布 */
+  align-items: center;    /* 折叠态：轨内居中，图标原样 */
+  padding: 0 0 14px;      /* 折叠态：去掉展开态的水平 14px（底 14px 两态一致） */
 }
 .rail-item {
   display: inline-flex; align-items: center; justify-content: center;