style(docs): 为购买授权按钮添加折扣标签样式

添加首页 Hero 区和顶栏导航中购买授权按钮的折扣标签样式，使用红色背景和旋转效果突出显示

Author: pixelmaxQm

docs/.vitepress/theme/styles/global.scss

@@ -96,3 +96,44 @@ a{
 .dark .content {
     background-color: #1a1a1a;
 }
+
+/* 购买授权按钮与导航的折扣标签样式 */
+/* 首页 Hero 区的“购买授权”按钮 */
+a[href="/empower/index.html"] {
+  position: relative;
+}
+a[href="/empower/index.html"]::after {
+  content: "折扣";
+  position: absolute;
+  top: -8px;
+  right: -8px;
+  background: #ef4444; /* red-500 */
+  color: #fff;
+  font-size: 11px;
+  line-height: 1;
+  padding: 3px 8px;
+  border-radius: 9999px;
+  box-shadow: 0 2px 6px rgba(0,0,0,.15);
+  transform: rotate(8deg);
+  pointer-events: none;
+}
+
+/* 顶栏导航中的“购买授权” */
+.VPNavBar a[href="https://plugin.gin-vue-admin.com/license"] {
+  position: relative;
+}
+.VPNavBar a[href="https://plugin.gin-vue-admin.com/license"]::after {
+  content: "折扣";
+  position: absolute;
+  top: -6px;
+  right: -6px;
+  background: #ef4444; /* red-500 */
+  color: #fff;
+  font-size: 10px;
+  line-height: 1;
+  padding: 2px 6px;
+  border-radius: 9999px;
+  box-shadow: 0 2px 6px rgba(0,0,0,.15);
+  transform: rotate(8deg);
+  pointer-events: none;
+}