feat: align subscription and profile settings pages with V21 design system

- Add ProfileSettings.css with shared V21 styles
- Update Billing.tsx to use xx-settings-page and xx-result-page classes
- Update UpgradeSubscription.tsx to use V21 card styles
- Update Settings.tsx to use xx-settings-card class
- Update AccountSecurity.tsx to use V21 card styles
- Update NotificationSettings.tsx to use V21 card styles
- Update SessionManagement.tsx to use V21 card styles
- Replace inline styles with CSS classes
- Maintain all functionality and export Component

apps/web/src/pages/auth/ForgotPassword.css

@@ -1,18 +1,98 @@
-.forgot-password-container {
+/* V21 忘记密码页 - 与 Login 保持一致 */
+.xx-auth-page {
+  display: grid;
+  place-items: center;
   min-height: 100vh;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+  background: linear-gradient(135deg, rgba(79, 70, 229, 0.08), rgba(16, 185, 129, 0.06));
+  padding: 24px;
 }
 
-.forgot-password-card {
-  width: 400px;
-  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+.xx-auth-card {
+  background: rgba(255, 255, 255, 0.94);
+  border: 1px solid #e2e8f0;
+  border-radius: 28px;
+  box-shadow: 0 24px 70px rgba(15, 23, 42, 0.09);
+  padding: 40px;
+  width: 100%;
+  max-width: 400px;
 }
 
-.forgot-password-card .ant-card-head-title {
+.xx-auth-header {
+  text-align: center;
+  margin-bottom: 32px;
+}
+
+.xx-logo-big {
+  font-size: 64px;
+  margin-bottom: 16px;
+}
+
+.xx-auth-header h1 {
+  font-size: 28px;
+  margin: 0 0 8px;
+  color: #0f172a;
+  font-weight: 900;
+}
+
+.xx-auth-header p {
+  color: #64748b;
+  margin: 0;
+  font-size: 14px;
+}
+
+.xx-auth-footer {
+  text-align: center;
+  font-size: 14px;
+  color: #64748b;
+  margin-top: 20px;
+}
+
+.xx-auth-footer a {
+  color: #4f46e5;
+  text-decoration: none;
+  font-weight: 850;
+}
+
+.xx-auth-footer a:hover {
+  color: #4338ca;
+}
+
+/* Form 样式覆盖 */
+.ant-form-item-label > label {
+  font-weight: 850;
+  color: #0f172a;
+  font-size: 14px;
+}
+
+.ant-input,
+.ant-input-password input {
+  background: white;
+  border: 1px solid #e2e8f0;
+  border-radius: 12px;
+}
+
+.ant-input:focus,
+.ant-input-password input:focus {
+  border-color: #4f46e5;
+  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
+}
+
+/* Result 成功页样式 */
+.xx-result-page {
+  display: grid;
+  place-items: center;
+  min-height: 100vh;
+  background: linear-gradient(135deg, rgba(79, 70, 229, 0.08), rgba(16, 185, 129, 0.06));
+  padding: 24px;
+}
+
+.xx-result-card {
+  background: rgba(255, 255, 255, 0.94);
+  border: 1px solid #e2e8f0;
+  border-radius: 28px;
+  box-shadow: 0 24px 70px rgba(15, 23, 42, 0.09);
+  padding: 48px 40px;
+  width: 100%;
+  max-width: 400px;
   text-align: center;
-  font-size: 24px;
-  font-weight: 600;
 }