diff --git a/apps/web/src/shared/components/Login.vue b/apps/web/src/shared/components/Login.vue
index edaae34..ac19ba9 100644
--- a/apps/web/src/shared/components/Login.vue
+++ b/apps/web/src/shared/components/Login.vue
@@ -1,4 +1,6 @@
 <script setup lang="ts">
+import { STORAGE_KEY } from "utils/constants"
+import storage from "utils/storage"
 import { getClassUsernames, login } from "../api"
 import { storeToRefs } from "pinia"
 import { useAuthModalStore } from "../store/authModal"
@@ -15,59 +17,107 @@ const {
   loginLoading: isLoading,
   loginError: msg,
 } = storeToRefs(authStore)
-const loginRef = useTemplateRef("loginRef")
+
+// 学生页签走「班级 + 姓名」两个下拉，一个字都不用打；
+// 管理员页签只有用户名 + 密码，不拼班级前缀。
+const activeTab = ref<"student" | "admin">("student")
+const studentRef = useTemplateRef("studentRef")
+const adminRef = useTemplateRef("adminRef")
+const studentPasswordRef = useTemplateRef("studentPasswordRef")
 const classUserOptions = ref<SelectOption[]>([])
 const classUserLoading = ref(false)
-const isClassLogin = computed(() => Boolean(form.value.class))
+// 空串是「没有我所在的班级」，null 才是没选 —— 往届的班级毕业后会从后台配置里删掉，
+// 这一项是他们唯一的入口，写完整用户名登录
+const OTHER_CLASS = ""
 const classList = computed<SelectOption[]>(() => {
-  const defaults = [{ label: "没有我所在的班级", value: "" }]
   const configs =
     configStore.config?.classList.map((item) => ({
       label: `${item.slice(0, 2)}计算机${item.slice(2)}班`,
       value: `ks${item}`,
     })) ?? []
-  return [...defaults, ...configs]
+  return [...configs, { label: "没有我所在的班级", value: OTHER_CLASS }]
 })
-const rules: FormRules = {
+// 选了具体班级就是「选姓名」，选了「没有我所在的班级」就是「写用户名」
+const isClassLogin = computed(() => Boolean(form.value.class))
+const passwordRule: FormItemRule[] = [
+  { required: true, message: "密码必填", trigger: "blur" },
+  { min: 6, max: 20, message: "长度在 6 到 20 位之间", trigger: "input" },
+]
+const studentRules = computed<FormRules>(() => ({
+  class: [
+    {
+      validator: () => form.value.class !== null,
+      message: "班级必选",
+      trigger: ["blur", "change"],
+    },
+  ],
+  username: [
+    {
+      required: true,
+      message: isClassLogin.value ? "姓名必选" : "用户名必填",
+      trigger: ["blur", "change"],
+    },
+  ],
+  password: passwordRule,
+}))
+const adminRules: FormRules = {
   username: [
     { required: true, message: "用户名必填", trigger: ["blur", "change"] },
   ],
-  password: [
-    { required: true, message: "密码必填", trigger: "blur" },
-    { min: 6, max: 20, message: "长度在 6 到 20 位之间", trigger: "input" },
-  ],
+  password: passwordRule,
 }
 
-async function submit() {
-  loginRef.value!.validate(async (errors?: unknown) => {
-    if (!errors) {
-      try {
-        authStore.clearLoginError()
-        authStore.setLoginLoading(true)
-        const merged = {
-          username: form.value.username,
-          password: form.value.password,
-        }
-        if (form.value.class) {
-          merged.username = form.value.class + form.value.username
-        }
-        await login(merged)
-      } catch (err: any) {
-        // 判错误码而不是错误文案：文案在后端，改一个字这里就静默掉进「无法登录」
-        if (err.error === "account-disabled") {
-          authStore.setLoginError("此账号已被封禁")
-        } else if (err.error === "invalid-credentials") {
-          authStore.setLoginError("用户名或密码不正确")
-        } else {
-          authStore.setLoginError("无法登录")
-        }
-      } finally {
-        authStore.setLoginLoading(false)
+function resetForm() {
+  form.value.class = null
+  form.value.username = null
+  form.value.password = ""
+  classUserOptions.value = []
+  classUserLoading.value = false
+  authStore.clearLoginError()
+}
+
+function onTabChange(tab: "student" | "admin") {
+  resetForm()
+  studentRef.value?.restoreValidation()
+  adminRef.value?.restoreValidation()
+  // 切回学生页签把记住的班级填回去，别因为误点了一下管理员就得重选
+  if (tab === "student") restoreLastClass()
+}
+
+function submit() {
+  const formRef = activeTab.value === "student" ? studentRef : adminRef
+  formRef.value!.validate(async (errors?: unknown) => {
+    if (errors) return
+    try {
+      authStore.clearLoginError()
+      authStore.setLoginLoading(true)
+      const merged = {
+        username: form.value.username ?? "",
+        password: form.value.password,
       }
-      if (!msg.value) {
-        authStore.closeLoginModal()
-        await userStore.getMyProfile()
+      // 选了班级的只填了姓名，ks + 班级号的前缀这里补
+      if (activeTab.value === "student" && form.value.class) {
+        merged.username = form.value.class + merged.username
       }
+      await login(merged)
+    } catch (err: any) {
+      // 判错误码而不是错误文案：文案在后端，改一个字这里就静默掉进「无法登录」
+      if (err.error === "account-disabled") {
+        authStore.setLoginError("此账号已被封禁")
+      } else if (err.error === "invalid-credentials") {
+        authStore.setLoginError("用户名或密码不正确")
+      } else {
+        authStore.setLoginError("无法登录")
+      }
+    } finally {
+      authStore.setLoginLoading(false)
+    }
+    if (!msg.value) {
+      if (activeTab.value === "student") {
+        storage.set(STORAGE_KEY.LOGIN_CLASS, form.value.class)
+      }
+      authStore.closeLoginModal()
+      await userStore.getMyProfile()
     }
   })
 }
@@ -95,7 +145,7 @@ watch(
   () => form.value.class,
   (selectedClass) => {
     classUserOptions.value = []
-    form.value.username = ""
+    form.value.username = null
     if (!selectedClass) {
       classUserLoading.value = false
       return
@@ -104,8 +154,40 @@ watch(
   },
 )
 
+// 选完姓名直接跳到密码框，学生的手不用离开这一列
+function onUsernamePicked() {
+  nextTick(() => studentPasswordRef.value?.focus())
+}
+
+/**
+ * 机房电脑一台对一个班，班级记在本地下次自动填上；
+ * 姓名不记 —— 同一台机器换个人坐就是别人的名字了。
+ */
+function restoreLastClass() {
+  if (form.value.class !== null) return
+  const last = storage.get(STORAGE_KEY.LOGIN_CLASS)
+  if (
+    typeof last === "string" &&
+    classList.value.some((item) => item.value === last)
+  ) {
+    form.value.class = last
+  }
+}
+
+watch(classList, restoreLastClass)
+
+// 每次打开都从干净的表单开始，别把上一个人的姓名和密码留在框里
+watch(loginModalOpen, (open) => {
+  if (!open) return
+  resetForm()
+  studentRef.value?.restoreValidation()
+  adminRef.value?.restoreValidation()
+  restoreLastClass()
+})
+
 onMounted(() => {
   authStore.clearLoginError()
+  restoreLastClass()
 })
 </script>
 
@@ -115,85 +197,142 @@ onMounted(() => {
     v-model:show="loginModalOpen"
     preset="card"
     title="登录"
-    style="width: 400px"
+    style="width: 420px"
     :auto-focus="false"
   >
-    <n-form ref="loginRef" :model="form" :rules="rules" show-require-mark>
-      <n-alert :show-icon="false" class="tip">
-        关于【选择班级】的提醒：<br />
-        1. 如果是上课统一生成的账号，选择【相应班级】，用户名直接写自己的名字
-        <br />
-        2.
-        同样是上课用的号，但是没有你的班级。选择【没有我所在的班级】，用户名要写：ks班级+姓名，比如23计算机1班张三，就写ks231张三
-        <br />
-        3. 如果是自己注册的号，选择【没有我所在的班级】 <br />
-      </n-alert>
-      <n-form-item label="选择班级" path="class" :show-require-mark="false">
-        <n-select
-          v-model:value="form.class"
-          :options="classList"
-          clearable
-          name="class"
-          id="login-class"
-        />
-      </n-form-item>
-      <n-form-item label="用户名" path="username">
-        <n-select
-          v-if="form.class"
-          v-model:value="form.username"
-          :options="classUserOptions"
-          :loading="classUserLoading"
-          clearable
-          filterable
-          :name="isClassLogin ? 'class-username' : 'username'"
-          :id="isClassLogin ? 'login-class-username' : 'login-username'"
-          placeholder="请选择姓名"
-        />
-        <n-input
-          v-else
-          v-model:value="form.username"
-          autofocus
-          clearable
-          :name="isClassLogin ? 'class-username' : 'username'"
-          :id="isClassLogin ? 'login-class-username' : 'login-username'"
-          :autocomplete="isClassLogin ? 'off' : 'username'"
-        />
-      </n-form-item>
-      <n-form-item label="密码" path="password">
-        <n-input
-          v-model:value="form.password"
-          clearable
-          type="password"
-          :name="isClassLogin ? 'class-password' : 'password'"
-          :id="isClassLogin ? 'login-class-password' : 'login-password'"
-          :autocomplete="isClassLogin ? 'new-password' : 'current-password'"
-          @keyup.enter="submit"
-        />
-      </n-form-item>
-      <n-alert v-if="msg" type="error" :show-icon="false"> {{ msg }}</n-alert>
-      <n-form-item>
-        <n-flex style="width: 100%">
-          <n-button
-            type="primary"
-            :loading="isLoading"
-            @click="submit"
-            :style="{
-              flex: configStore.config?.allowRegister ? '0 0 auto' : '1',
-            }"
+    <n-tabs v-model:value="activeTab" @update:value="onTabChange">
+      <n-tab-pane name="student" tab="学生登录">
+        <n-form
+          ref="studentRef"
+          :model="form"
+          :rules="studentRules"
+          show-require-mark
+        >
+          <n-form-item label="班级" path="class">
+            <n-select
+              v-model:value="form.class"
+              :options="classList"
+              filterable
+              name="class"
+              id="login-class"
+              placeholder="选择班级"
+            />
+          </n-form-item>
+          <n-form-item
+            :label="isClassLogin ? '姓名' : '用户名'"
+            path="username"
           >
-            登录
-          </n-button>
-          <n-button v-if="configStore.config?.allowRegister" @click="goSignup">
-            没有账号？立即注册
-          </n-button>
-        </n-flex>
-      </n-form-item>
-    </n-form>
+            <n-select
+              v-if="isClassLogin"
+              v-model:value="form.username"
+              :options="classUserOptions"
+              :loading="classUserLoading"
+              filterable
+              name="class-username"
+              id="login-class-username"
+              placeholder="选择姓名"
+              @update:value="onUsernamePicked"
+            />
+            <n-input
+              v-else
+              v-model:value="form.username"
+              clearable
+              :disabled="form.class === null"
+              name="username"
+              id="login-username"
+              autocomplete="username"
+              placeholder="完整用户名，如 ks231张三"
+            />
+          </n-form-item>
+          <n-form-item label="密码" path="password">
+            <n-input
+              ref="studentPasswordRef"
+              v-model:value="form.password"
+              clearable
+              type="password"
+              :name="isClassLogin ? 'class-password' : 'password'"
+              :id="isClassLogin ? 'login-class-password' : 'login-password'"
+              :autocomplete="isClassLogin ? 'new-password' : 'current-password'"
+              @keyup.enter="submit"
+            />
+          </n-form-item>
+          <n-alert v-if="msg" type="error" :show-icon="false">{{
+            msg
+          }}</n-alert>
+          <n-form-item>
+            <n-flex style="width: 100%">
+              <n-button
+                type="primary"
+                :loading="isLoading"
+                @click="submit"
+                :style="{
+                  flex: configStore.config?.allowRegister ? '0 0 auto' : '1',
+                }"
+              >
+                登录
+              </n-button>
+              <n-button
+                v-if="configStore.config?.allowRegister"
+                @click="goSignup"
+              >
+                没有账号？立即注册
+              </n-button>
+            </n-flex>
+          </n-form-item>
+          <n-alert :show-icon="false" class="tip">
+            往届的班级、列表里找不到的班级、以及自己注册的账号，选【没有我所在的班级】，用户名要写完整，比如
+            23 计算机 1 班张三写 ks231张三。
+          </n-alert>
+        </n-form>
+      </n-tab-pane>
+
+      <n-tab-pane name="admin" tab="管理员登录">
+        <n-form
+          ref="adminRef"
+          :model="form"
+          :rules="adminRules"
+          show-require-mark
+        >
+          <n-form-item label="用户名" path="username">
+            <n-input
+              v-model:value="form.username"
+              clearable
+              name="username"
+              id="login-admin-username"
+              autocomplete="username"
+              placeholder="请输入用户名"
+            />
+          </n-form-item>
+          <n-form-item label="密码" path="password">
+            <n-input
+              v-model:value="form.password"
+              clearable
+              type="password"
+              name="password"
+              id="login-admin-password"
+              autocomplete="current-password"
+              @keyup.enter="submit"
+            />
+          </n-form-item>
+          <n-alert v-if="msg" type="error" :show-icon="false">{{
+            msg
+          }}</n-alert>
+          <n-form-item>
+            <n-button block type="primary" :loading="isLoading" @click="submit">
+              登录
+            </n-button>
+          </n-form-item>
+          <n-alert :show-icon="false" class="tip">
+            管理员和老师从这里登录，学生请走【学生登录】页签。
+          </n-alert>
+        </n-form>
+      </n-tab-pane>
+    </n-tabs>
   </n-modal>
 </template>
 
 <style scoped>
 .tip {
-  margin-bottom: 20px;
+  margin-top: 4px;
 }
 </style>
diff --git a/apps/web/src/shared/store/authModal.ts b/apps/web/src/shared/store/authModal.ts
index 5a8f42b..6016e2d 100644
--- a/apps/web/src/shared/store/authModal.ts
+++ b/apps/web/src/shared/store/authModal.ts
@@ -10,9 +10,11 @@ export const useAuthModalStore = defineStore("authModal", () => {
   const signupModalOpen = ref(false)
 
   // ==================== 登录表单状态 ====================
+  // class 为 null 表示还没选，别用空串 —— 空串是「没有我所在的班级」那一项的值。
+  // username 同理用 null：空串在 n-select 里是「选了一个空值」，占位符不显示。
   const loginForm = reactive({
-    class: "",
-    username: "",
+    class: null as string | null,
+    username: null as string | null,
     password: "",
   })
 
diff --git a/apps/web/src/shared/store/user.ts b/apps/web/src/shared/store/user.ts
index 1c77ec2..8272f09 100644
--- a/apps/web/src/shared/store/user.ts
+++ b/apps/web/src/shared/store/user.ts
@@ -82,7 +82,11 @@ export const useUserStore = defineStore("user", () => {
   function clearProfile() {
     profile.value = null
     demoMode.value = false
+    // 登录框记的班级要跨退登活下来：机房一台机器对一个班，下课登出、下节课再来
+    // 还是同一个班，清掉的话每个人都得重新选一遍。它是机器的属性，不是谁的隐私。
+    const loginClass = storage.get(STORAGE_KEY.LOGIN_CLASS)
     storage.clear()
+    if (loginClass !== null) storage.set(STORAGE_KEY.LOGIN_CLASS, loginClass)
   }
 
   // 退登的两步（吊销服务端会话、清本地状态）绑在一起：只清本地会留一个还活着
diff --git a/apps/web/src/utils/constants.ts b/apps/web/src/utils/constants.ts
index 3485ea4..0c73245 100644
--- a/apps/web/src/utils/constants.ts
+++ b/apps/web/src/utils/constants.ts
@@ -152,6 +152,7 @@ export const STORAGE_KEY = {
   ADMIN_PROBLEM: "adminProblem",
   ADMIN_PROBLEM_TAGS: "adminProblemTags",
   DEMO_MODE: "demoMode",
+  LOGIN_CLASS: "loginClass",
 }
 
 export const DIFFICULTY = {