diff --git a/frontend/src/views/Dashboard/Dashboard.test.js b/frontend/src/views/Dashboard/Dashboard.test.js
index 4d668dd..b3219d6 100644
--- a/frontend/src/views/Dashboard/Dashboard.test.js
+++ b/frontend/src/views/Dashboard/Dashboard.test.js
@@ -305,3 +305,62 @@ test("auditStatusRendering", async () => {
     assert.doesNotMatch(html, /danger/);
   }
 });
+
+
+test("domainModal.compilesAndRendersSanFieldsWithoutLiteralNewline", async () => {
+  const { readFile } = await import("node:fs/promises");
+  const { parse, compileScript, compileTemplate } = await import("@vue/compiler-sfc");
+  const { renderToString } = await import("@vue/server-renderer");
+  const Vue = await import("vue");
+  const source = await readFile(new URL("./DomainModal.vue", import.meta.url), "utf8");
+  const { descriptor, errors } = parse(source);
+  assert.deepEqual(errors, []);
+  assert.ok(compileScript(descriptor, { id: "domain-modal" }));
+  const compiled = compileTemplate({
+    source: descriptor.template.content,
+    filename: "DomainModal.vue",
+    id: "domain-modal",
+    compilerOptions: { mode: "function" },
+  });
+  assert.deepEqual(compiled.errors, []);
+  const render = new Function("Vue", compiled.code)(Vue);
+  for (const certificateType of ["single", "wildcard", "san"]) {
+    const app = Vue.createSSRApp({
+      render,
+      setup: () => ({
+        showForm: true,
+        formTitle: "test-domain",
+        closeForm: () => {},
+        saveDomain: () => {},
+        form: {
+          name: "example.test",
+          certificate_type: certificateType,
+          sans: "",
+          acme_environment: "staging",
+          dns_provider: "aliyun",
+          auto_renew: true,
+          server_ids: [],
+        },
+        dnsProviders: [],
+        servers: [],
+        displayLabel: (_, value) => value,
+        webServerLabels: {},
+        formError: "",
+        saving: false,
+      }),
+    });
+    app.component("HelpTip", {
+      setup: (_, { slots }) => () => Vue.h("span", { class: "test-help-tip" }, slots.default?.()),
+    });
+    const html = await renderToString(app);
+    assert.match(html, /class="modal-card domain-modal"/);
+    assert.match(html, /type="submit"/);
+    assert.match(html, /class="test-help-tip"/);
+    assert.doesNotMatch(html, /www\.example\.com\\napi/);
+    assert.equal(html.includes('id="domain-sans"'), certificateType === "san");
+    if (certificateType === "san") {
+      assert.match(html, /rows="2"/);
+      assert.ok(html.includes("www.example.com\napi.example.com"));
+    }
+  }
+});
diff --git a/frontend/src/views/Dashboard/Dashboard.vue b/frontend/src/views/Dashboard/Dashboard.vue
index b80113d..97362b1 100644
--- a/frontend/src/views/Dashboard/Dashboard.vue
+++ b/frontend/src/views/Dashboard/Dashboard.vue
@@ -2,6 +2,7 @@
 import ChangePassword from "../components/ChangePassword/ChangePassword.vue";
 import UserManagement from "../UserManagement/UserManagement.vue";
 import SettingsModal from "./SettingsModal.vue";
+import DomainModal from "./DomainModal.vue";
 import { useDashboard } from "./Dashboard.js";
 
 const dashboard = useDashboard();
@@ -466,143 +467,10 @@ const {
           </div>
         </form>
       </section>
-    </div>    <div v-if="showForm" class="modal-backdrop" @click.self="closeForm">
-      <section
-        class="modal-card"
-        role="dialog"
-        aria-modal="true"
-        :aria-label="formTitle"
-      >
-        <div class="modal-heading">
-          <div>
-            <p class="eyebrow">域名配置</p>
-            <h2>{{ formTitle }}</h2>
-          </div>
-          <button
-            class="close-button"
-            type="button"
-            aria-label="关闭"
-            @click="closeForm"
-          >
-            ×
-          </button>
-        </div>
-        <form @submit.prevent="saveDomain">
-          <label class="field" for="domain-name"
-            ><span>主域名</span
-            ><input
-              id="domain-name"
-              name="name"
-              v-model="form.name"
-              type="text"
-              placeholder="例如 example.com"
-              autocomplete="off"
-          /></label>
-          <label class="field" for="certificate-type"
-            ><span>证书类型</span
-            ><select
-              id="certificate-type"
-              name="certificate_type"
-              v-model="form.certificate_type"
-            >
-              <option value="single">单域名</option>
-              <option value="wildcard">泛域名</option>
-              <option value="san">SAN 多域名</option>
-            </select></label
-          >
-          <label
-            v-if="form.certificate_type === 'san'"
-            class="field"
-            for="domain-sans"
-            ><span>附加域名 <small>每行一个，也支持逗号分隔</small></span
-            ><textarea
-              id="domain-sans"
-              name="sans"
-              v-model="form.sans"
-              rows="4"
-              placeholder="www.example.com\napi.example.com"
-            ></textarea>
-          </label>
-          <div class="form-grid">
-            <label class="field" for="acme-environment"
-              ><span>ACME 环境</span
-              ><select
-                id="acme-environment"
-                name="acme_environment"
-                v-model="form.acme_environment"
-              >
-                <option value="staging">测试环境</option>
-                <option value="production">生产环境</option>
-              </select></label
-            >
-            <label class="field" for="dns-provider"
-              ><span>DNS 验证服务商</span
-              ><select
-                id="dns-provider"
-                name="dns_provider"
-                v-model="form.dns_provider"
-              >
-                <option value="">暂不选择</option>
-                <option
-                  v-for="provider in dnsProviders"
-                  :key="provider.value"
-                  :value="provider.value"
-                >
-                  {{ provider.label }}
-                </option>
-              </select></label
-            >
-          </div>
-          <label class="switch-field" for="auto-renew"
-            ><input
-              id="auto-renew"
-              name="auto_renew"
-              v-model="form.auto_renew"
-              type="checkbox"
-            /><span
-              ><strong>启用自动续期</strong
-              ><small>证书剩余有效期达到阈值时自动创建续期任务</small></span
-            ></label
-          >
-          <fieldset class="server-picker">
-            <legend>关联部署服务器</legend>
-            <label
-              v-for="server in servers"
-              :key="server.id"
-              class="server-option"
-              ><input
-                v-model="form.server_ids"
-                type="checkbox"
-                :value="server.id"
-              /><span
-                ><strong>{{ server.name }}</strong
-                ><small
-                  >{{ server.address }} ·
-                  {{ displayLabel(webServerLabels, server.web_server) }}</small
-                ></span
-              ></label
-            >
-            <p v-if="servers.length === 0" class="muted">
-              暂无服务器配置，可先保存域名后添加服务器。
-            </p>
-          </fieldset>
-          <p v-if="formError" class="form-error">{{ formError }}</p>
-          <div class="modal-actions">
-            <button
-              class="secondary-button"
-              type="button"
-              :disabled="saving"
-              @click="closeForm"
-            >
-              取消</button
-            ><button class="primary-button" type="submit" :disabled="saving">
-              {{ saving ? "保存中……" : "保存配置" }}
-            </button>
-          </div>
-        </form>
-      </section>
     </div>
 
+    <DomainModal v-if="showForm" :state="dashboard" />
+
     <div
       v-if="showServerForm"
       class="modal-backdrop"
diff --git a/frontend/src/views/Dashboard/DomainModal.css b/frontend/src/views/Dashboard/DomainModal.css
new file mode 100644
index 0000000..e4f9d8b
--- /dev/null
+++ b/frontend/src/views/Dashboard/DomainModal.css
@@ -0,0 +1,91 @@
+.modal-backdrop.domain-backdrop {
+  padding: 16px;
+}
+
+.domain-modal {
+  box-sizing: border-box;
+  width: min(100%, 1060px);
+  max-height: calc(100dvh - 32px);
+  padding: 22px 28px;
+}
+
+.domain-modal .modal-heading {
+  margin-bottom: 12px;
+  padding-bottom: 10px;
+}
+
+.domain-modal form {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 0 18px;
+}
+
+.domain-modal .domain-sans-field,
+.domain-modal .form-grid,
+.domain-modal .switch-field,
+.domain-modal .server-picker,
+.domain-modal .form-error,
+.domain-modal .modal-actions {
+  grid-column: 1 / -1;
+}
+
+.domain-modal .field {
+  min-width: 0;
+  margin-bottom: 9px;
+  gap: 5px;
+}
+
+.domain-modal .field input,
+.domain-modal .field select,
+.domain-modal .field textarea {
+  min-height: 36px;
+  padding: 8px 11px;
+}
+
+.domain-modal .field textarea {
+  min-height: 72px;
+}
+
+.domain-modal .field > span,
+.domain-modal .switch-field > span {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+}
+
+.domain-modal .switch-field {
+  align-items: center;
+  margin: 4px 0 10px;
+}
+
+.domain-modal .server-picker {
+  min-width: 0;
+  max-height: 130px;
+  overflow-y: auto;
+  margin: 4px 0 12px;
+  padding: 10px 12px;
+}
+
+.domain-modal .server-picker .muted {
+  margin: 8px 0;
+}
+
+.domain-modal .form-error {
+  margin-bottom: 8px;
+}
+
+.domain-modal .modal-actions {
+  padding-top: 10px;
+  border-top: 1px solid #dce6f1;
+}
+
+@media (max-width: 640px) {
+  .domain-modal {
+    padding: 18px;
+  }
+
+  .domain-modal form,
+  .domain-modal .form-grid {
+    grid-template-columns: minmax(0, 1fr);
+  }
+}
diff --git a/frontend/src/views/Dashboard/DomainModal.vue b/frontend/src/views/Dashboard/DomainModal.vue
new file mode 100644
index 0000000..0fabfed
--- /dev/null
+++ b/frontend/src/views/Dashboard/DomainModal.vue
@@ -0,0 +1,160 @@
+<script setup>
+import HelpTip from "../components/HelpTip/HelpTip.vue";
+
+const props = defineProps({ state: { type: Object, required: true } });
+const {
+  showForm,
+  formTitle,
+  closeForm,
+  saveDomain,
+  form,
+  dnsProviders,
+  servers,
+  displayLabel,
+  webServerLabels,
+  formError,
+  saving,
+} = props.state;
+</script>
+
+<template>
+    <div v-if="showForm" class="modal-backdrop domain-backdrop" @click.self="closeForm">
+      <section
+        class="modal-card domain-modal"
+        role="dialog"
+        aria-modal="true"
+        :aria-label="formTitle"
+      >
+        <div class="modal-heading">
+          <div>
+            <p class="eyebrow">域名配置</p>
+            <h2>{{ formTitle }}</h2>
+          </div>
+          <button
+            class="close-button"
+            type="button"
+            aria-label="关闭"
+            @click="closeForm"
+          >
+            ×
+          </button>
+        </div>
+        <form @submit.prevent="saveDomain">
+          <label class="field" for="domain-name"
+            ><span>主域名</span
+            ><input
+              id="domain-name"
+              name="name"
+              v-model="form.name"
+              type="text"
+              placeholder="例如 example.com"
+              autocomplete="off"
+          /></label>
+          <label class="field" for="certificate-type"
+            ><span>证书类型</span
+            ><select
+              id="certificate-type"
+              name="certificate_type"
+              v-model="form.certificate_type"
+            >
+              <option value="single">单域名</option>
+              <option value="wildcard">泛域名</option>
+              <option value="san">SAN 多域名</option>
+            </select></label
+          >
+          <label
+            v-if="form.certificate_type === 'san'"
+            class="field domain-sans-field"
+            for="domain-sans"
+            ><span>附加域名 <HelpTip>每行一个，也支持逗号分隔</HelpTip></span
+            ><textarea
+              id="domain-sans"
+              name="sans"
+              v-model="form.sans"
+              rows="2"
+              :placeholder="'www.example.com\napi.example.com'"
+            ></textarea>
+          </label>
+          <div class="form-grid">
+            <label class="field" for="acme-environment"
+              ><span>ACME 环境</span
+              ><select
+                id="acme-environment"
+                name="acme_environment"
+                v-model="form.acme_environment"
+              >
+                <option value="staging">测试环境</option>
+                <option value="production">生产环境</option>
+              </select></label
+            >
+            <label class="field" for="dns-provider"
+              ><span>DNS 验证服务商</span
+              ><select
+                id="dns-provider"
+                name="dns_provider"
+                v-model="form.dns_provider"
+              >
+                <option value="">暂不选择</option>
+                <option
+                  v-for="provider in dnsProviders"
+                  :key="provider.value"
+                  :value="provider.value"
+                >
+                  {{ provider.label }}
+                </option>
+              </select></label
+            >
+          </div>
+          <label class="switch-field" for="auto-renew"
+            ><input
+              id="auto-renew"
+              name="auto_renew"
+              v-model="form.auto_renew"
+              type="checkbox"
+            /><span
+              ><strong>启用自动续期</strong
+              ><HelpTip>证书剩余有效期达到阈值时自动创建续期任务</HelpTip></span
+            ></label
+          >
+          <fieldset class="server-picker">
+            <legend>关联部署服务器</legend>
+            <label
+              v-for="server in servers"
+              :key="server.id"
+              class="server-option"
+              ><input
+                v-model="form.server_ids"
+                type="checkbox"
+                :value="server.id"
+              /><span
+                ><strong>{{ server.name }}</strong
+                ><small
+                  >{{ server.address }} ·
+                  {{ displayLabel(webServerLabels, server.web_server) }}</small
+                ></span
+              ></label
+            >
+            <p v-if="servers.length === 0" class="muted">
+              暂无服务器配置，可先保存域名后添加服务器。
+            </p>
+          </fieldset>
+          <p v-if="formError" class="form-error">{{ formError }}</p>
+          <div class="modal-actions">
+            <button
+              class="secondary-button"
+              type="button"
+              :disabled="saving"
+              @click="closeForm"
+            >
+              取消</button
+            ><button class="primary-button" type="submit" :disabled="saving">
+              {{ saving ? "保存中……" : "保存配置" }}
+            </button>
+          </div>
+        </form>
+      </section>
+    </div>
+</template>
+
+<style scoped src="./Dashboard.css"></style>
+<style scoped src="./DomainModal.css"></style>