docs: explain stylesheet ownership, responsive rules and display boundaries

app/assets/styles/ConfigBandwidth.CWSH1WJZ.css

@@ -1,3 +1,5 @@
+/* 带宽配置：容量单位、滑块和说明文本。 */
+/* 导入方：app/components/config/ConfigBandwidth.vue、app/components/config/JyCloudConfig.vue、app/components/config/KkyEcsConfig.vue、app/components/config/MfCloudConfig.vue、app/components/instance/DcimManage.vue、app/components/instance/DcimUpgrade.vue、app/components/instance/InstanceBilling.vue、app/components/kkyecs/KkyUpgrade.vue、app/components/mfcloud/MfCloudResourceUpgrade.vue、app/pages/products/[id].vue、app/pages/products/cloud-server.vue。 */
 .bandwidth-field[data-v-45a9c613] {
   flex-direction: column;
   gap: 12px;
@@ -30,6 +32,7 @@
 .bandwidth-help > i[data-v-45a9c613] {
   font-size: 1rem;
 }
+/* 键盘操作的可见焦点：不要只保留鼠标 hover 效果而移除此反馈。 */
 .bandwidth-help[data-v-45a9c613]:focus-visible {
   outline: 2px solid var(--p-primary-color);
   outline-offset: 3px;
@@ -103,6 +106,7 @@
   height: 19px;
   box-shadow: 0 1px 2px #0000002e;
 }
+/* 键盘操作的可见焦点：不要只保留鼠标 hover 效果而移除此反馈。 */
 .bandwidth-slider[data-v-45a9c613]:focus-visible {
   outline: 2px solid var(--p-primary-color);
   outline-offset: 9px;
@@ -113,6 +117,7 @@
 .bandwidth-capacity.is-disabled[data-v-45a9c613] {
   opacity: 0.6;
 }
+/* 视口条件 (width<=639px) 下的响应式覆盖；保留相对基础规则的层叠顺序。 */
 @media (width<=639px) {
   .bandwidth-field[data-v-45a9c613] {
     max-width: none;