style(课表小组件): 下拉选中态改品牌色(#5979ea/#eef2ff)；表格限高 352px 只露 7 节、超出滚动、表头 sticky 常驻

- .cls-item.on 由 #2d8cf0/#f0f7ff 改为 var(--color-primary, #5979ea) / var(--color-primary-weak, #eef2ff)，
  与 WsToastLayer.vue 既有约定一致（CSS 变量 + 回退值）；hover 改 #f4f7ff
- 表格外套 .tt-scroll：max-height 352px（表头 44 + 7×44）+ overflow-y auto + 6px 细滚动条
- th 加 position sticky / top 0 / background #fff；因 sticky + border-collapse 会丢 cell border，
  分隔线由 border-bottom 改为 box-shadow inset 0 -1px 0 #e9edf1

src/components/widgets/SyllabusWidget.vue

@@ -34,22 +34,25 @@
             </Teleport>
 
             <div v-if="slots.length > 0" class="table-wrap">
-                <table class="tt">
-                    <thead>
-                        <tr>
-                            <th>节</th>
-                            <th v-for="day in dayCols" :key="day.index">{{ day.name }}</th>
-                        </tr>
-                    </thead>
-                    <tbody>
-                        <tr v-for="slot in slots" :key="slot.slotNo">
-                            <td class="sec">{{ cnNum(slot.slotNo) }}</td>
-                            <td v-for="day in dayCols" :key="day.index">
-                                <span class="sub" :title="subjectOf(slot, day.index)">{{ subjectOf(slot, day.index) }}</span>
-                            </td>
-                        </tr>
-                    </tbody>
-                </table>
+                <!-- 超过 7 节（表头 44 + 7×44 = 352px）纵向滚动，表头 sticky 常驻 -->
+                <div class="tt-scroll">
+                    <table class="tt">
+                        <thead>
+                            <tr>
+                                <th>节</th>
+                                <th v-for="day in dayCols" :key="day.index">{{ day.name }}</th>
+                            </tr>
+                        </thead>
+                        <tbody>
+                            <tr v-for="slot in slots" :key="slot.slotNo">
+                                <td class="sec">{{ cnNum(slot.slotNo) }}</td>
+                                <td v-for="day in dayCols" :key="day.index">
+                                    <span class="sub" :title="subjectOf(slot, day.index)">{{ subjectOf(slot, day.index) }}</span>
+                                </td>
+                            </tr>
+                        </tbody>
+                    </table>
+                </div>
             </div>
 
             <!-- 空态：模板内联 SVG，不依赖外部图片 / CSS 背景 -->
@@ -225,11 +228,11 @@ function reportHeight() {
     white-space: nowrap;
 
     &:hover {
-        background: #f5f8fb;
+        background: #f4f7ff;
     }
     &.on {
-        color: #2d8cf0;
-        background: #f0f7ff;
+        color: var(--color-primary, #5979ea);
+        background: var(--color-primary-weak, #eef2ff);
         font-weight: 600;
     }
 }
@@ -240,6 +243,24 @@ function reportHeight() {
 .table-wrap {
     padding: 8px 8px 10px;
 }
+/* 最多露出 7 节课（表头 44 + 7×44 = 352），再多则纵向滚动，表头 sticky 常驻 */
+.tt-scroll {
+    max-height: 352px;
+    overflow-y: auto;
+    scrollbar-width: thin;
+    scrollbar-color: #d5dbe3 transparent;
+
+    &::-webkit-scrollbar {
+        width: 6px;
+    }
+    &::-webkit-scrollbar-thumb {
+        background: #d5dbe3;
+        border-radius: 3px;
+    }
+    &::-webkit-scrollbar-track {
+        background: transparent;
+    }
+}
 .tt {
     width: 100%;
     border-collapse: collapse;
@@ -255,7 +276,12 @@ function reportHeight() {
         // 否则表头文字按基线对齐、偏上，视觉上像"贴住卡片 header"
         vertical-align: middle;
         border: 0;
-        border-bottom: 1px solid #e9edf1;
+        // sticky + border-collapse 时 cell 的 border 会随滚动丢失 ⇒ 用 inset box-shadow 画分隔线
+        box-shadow: inset 0 -1px 0 #e9edf1;
+        position: sticky;
+        top: 0;
+        z-index: 1;
+        background: #fff;
     }
     th:first-child,
     td:first-child {