Fix login form card layout to hug content and align with Android.

Use content-driven card height with safe area insets so the form no longer stretches to the screen bottom.

Co-authored-by: Cursor <cursoragent@cursor.com>

suixinkan/UI/Login/LoginViewController.swift

@@ -61,6 +61,7 @@ final class LoginViewController: BaseViewController {
         topFormStack.axis = .vertical
         topFormStack.spacing = 0
         topFormStack.alignment = .fill
+        topFormStack.distribution = .fill
 
         loginButton.addTarget(self, action: #selector(loginButtonTapped), for: .touchUpInside)
         loginByCodeButton.addTarget(self, action: #selector(loginByCodeButtonTapped), for: .touchUpInside)
@@ -115,28 +116,24 @@ final class LoginViewController: BaseViewController {
 
         welcomeLabel.snp.makeConstraints { make in
             make.top.equalTo(view.safeAreaLayoutGuide).offset(48)
-            make.leading.trailing.equalToSuperview().inset(24)
+            make.leading.trailing.equalTo(view.safeAreaLayoutGuide).inset(24)
         }
 
         formCardShadowView.snp.makeConstraints { make in
             make.top.equalTo(welcomeLabel.snp.bottom).offset(48)
-            make.leading.trailing.equalToSuperview().inset(24)
+            make.leading.trailing.equalTo(view.safeAreaLayoutGuide).inset(24)
-            make.bottom.equalTo(view.safeAreaLayoutGuide).offset(-24)
+            make.bottom.lessThanOrEqualTo(view.safeAreaLayoutGuide).offset(-24)
         }
 
         formCardView.snp.makeConstraints { make in
             make.edges.equalToSuperview()
         }
 
-        topFormStack.snp.makeConstraints { make in
-            make.top.leading.trailing.equalToSuperview().inset(16)
-            make.bottom.equalToSuperview().inset(16)
-        }
-
         registerContainer.snp.makeConstraints { make in
             make.centerX.equalToSuperview()
-            make.bottom.equalToSuperview().inset(16)
         }
+
+        applyCardLayoutConstraints(showRegisterSection: false)
     }
 
     override func viewDidLayoutSubviews() {
@@ -230,15 +227,7 @@ final class LoginViewController: BaseViewController {
         let showRegisterSection = viewModel.enableRegister
         loginByCodeButton.isHidden = !showRegisterSection
         registerContainer.isHidden = !showRegisterSection
-
+        applyCardLayoutConstraints(showRegisterSection: showRegisterSection)
-        topFormStack.snp.remakeConstraints { make in
-            make.top.leading.trailing.equalToSuperview().inset(16)
-            if showRegisterSection {
-                make.bottom.lessThanOrEqualTo(registerContainer.snp.top).offset(-16)
-            } else {
-                make.bottom.equalToSuperview().inset(16)
-            }
-        }
 
         if let payload = viewModel.pendingAccountSelection {
             if let controller = accountSelectionController {
@@ -252,6 +241,27 @@ final class LoginViewController: BaseViewController {
         }
     }
 
+    /// 卡片高度随内容自适应，底部与屏幕 safeArea 至少保留 24pt 间距。
+    private func applyCardLayoutConstraints(showRegisterSection: Bool) {
+        if showRegisterSection {
+            topFormStack.snp.remakeConstraints { make in
+                make.top.leading.trailing.equalToSuperview().inset(16)
+            }
+            registerContainer.snp.remakeConstraints { make in
+                make.top.equalTo(topFormStack.snp.bottom).offset(16)
+                make.centerX.equalToSuperview()
+                make.bottom.equalToSuperview().inset(16)
+            }
+        } else {
+            registerContainer.snp.remakeConstraints { make in
+                make.centerX.equalToSuperview()
+            }
+            topFormStack.snp.remakeConstraints { make in
+                make.edges.equalToSuperview().inset(16)
+            }
+        }
+    }
+
     private func performLogin() {
         viewModel.normalizeUsernameCountryCodeIfNeeded()
         accountField.text = viewModel.normalizedUsername