Fix send flow UI issues on Android and add validation toasts

android/app/src/main/java/org/bitcoinppl/cove/flows/SendFlow/EnterAmountView.kt

@@ -121,7 +121,7 @@ fun EnterAmountView(
                     color = if (exceedsBalance) CoveColor.WarningOrange else MaterialTheme.colorScheme.onSurface,
                     fontWeight = FontWeight.Bold,
                     textAlign = TextAlign.Center,
-                    modifier = Modifier.fillMaxWidth().offset(x = amountOffset),
+                    modifier = Modifier.fillMaxWidth().padding(horizontal = 30.dp).offset(x = amountOffset),
                     onTextWidthChanged = { width -> textWidth = width },
                     onFocusChanged = { focused ->
                         isFocused = focused

android/app/src/main/java/org/bitcoinppl/cove/flows/SendFlow/SendFlowConfirmScreen.kt

@@ -167,7 +167,7 @@ fun SendFlowConfirmScreen(
                         text = stringResource(R.string.action_swipe_to_send),
                         sendState = sendState,
                         onComplete = onSwipeToSend,
-                        containerColor = MaterialTheme.colorScheme.surfaceVariant,
+                        containerColor = MaterialTheme.coveColors.swipeTrackBg,
                         targetContainerColor = MaterialTheme.coveColors.midnightBtn,
                         knobColor = MaterialTheme.coveColors.midnightBtn,
                         textColor = MaterialTheme.colorScheme.onSurface,

android/app/src/main/java/org/bitcoinppl/cove/flows/SendFlow/SendFlowContainer.kt

@@ -210,6 +210,7 @@ private fun SendFlowRouteToScreen(
             val exceedsBalance = sendFlowManager.rust.amountExceedsBalance()
             var previouslyExceeded by remember { mutableStateOf(false) }
             val snackbarHostState = remember { SnackbarHostState() }
+            val validationScope = rememberCoroutineScope()
 
             LaunchedEffect(exceedsBalance) {
                 if (exceedsBalance && !previouslyExceeded) {
@@ -229,8 +230,39 @@ private fun SendFlowRouteToScreen(
                 snackbarHostState = snackbarHostState,
                 onBack = { app.popRoute() },
                 onNext = {
-                    if (sendFlowManager.validate(displayAlert = true)) {
-                        sendFlowManager.dispatch(SendFlowManagerAction.FinalizeAndGoToNextScreen)
+                    val addressValid = sendFlowManager.rust.validateAddress()
+                    val amountValid = sendFlowManager.rust.validateAmount()
+                    val hasAddress = sendFlowManager.enteringAddress.isNotEmpty()
+                    val hasAmount = sendFlowManager.rust.amount().asSats() > 0uL
+
+                    when {
+                        !addressValid -> {
+                            // only show snackbar if address has content (not just empty)
+                            if (hasAddress) {
+                                validationScope.launch {
+                                    snackbarHostState.showSnackbar(
+                                        message = "Address not valid. Please try again.",
+                                        duration = SnackbarDuration.Short,
+                                    )
+                                }
+                            }
+                            presenter.focusField = SetAmountFocusField.ADDRESS
+                        }
+                        !amountValid -> {
+                            // only show snackbar if amount has content (not just empty/zero)
+                            if (hasAmount) {
+                                validationScope.launch {
+                                    snackbarHostState.showSnackbar(
+                                        message = "Amount not valid. Please try again.",
+                                        duration = SnackbarDuration.Short,
+                                    )
+                                }
+                            }
+                            presenter.focusField = SetAmountFocusField.AMOUNT
+                        }
+                        else -> {
+                            sendFlowManager.dispatch(SendFlowManagerAction.FinalizeAndGoToNextScreen)
+                        }
                     }
                 },
                 onScanQr = {

android/app/src/main/java/org/bitcoinppl/cove/ui/theme/Color.kt

@@ -33,6 +33,10 @@ object CoveColor {
     val coveBgDark = ComposeColor(0xFF191919)
     val midnightBtnDark = ComposeColor(0xFF4A4A4D)
 
+    // Swipe track background (matches iOS systemGray5)
+    val swipeTrackBgLight = ComposeColor(0xFFE5E5EA)
+    val swipeTrackBgDark = ComposeColor(0xFF2C2C2E)
+
     // Wallet colors - pastel palette (preferred)
     val beige = ComposeColor(0xFFFFB36E)
     val lightMint = ComposeColor(0xFFC5E5CD)
@@ -80,18 +84,21 @@ object CoveColor {
 data class CoveColorScheme(
     val midnightBtn: ComposeColor,
     val systemGreen: ComposeColor,
+    val swipeTrackBg: ComposeColor,
 )
 
 val LightCoveColors =
     CoveColorScheme(
         midnightBtn = CoveColor.midnightBlue, // #1C2536
         systemGreen = CoveColor.SystemGreenLight, // #34C759
+        swipeTrackBg = CoveColor.swipeTrackBgLight, // #E5E5EA (iOS systemGray5)
     )
 
 val DarkCoveColors =
     CoveColorScheme(
         midnightBtn = CoveColor.midnightBtnDark, // #4A4A4D
         systemGreen = CoveColor.SystemGreenDark, // #30D158
+        swipeTrackBg = CoveColor.swipeTrackBgDark, // #2C2C2E (iOS systemGray5)
     )
 
 val LocalCoveColors = staticCompositionLocalOf { LightCoveColors }

ios/Cove/Flows/SendFlow/SendFlowSetAmountScreen.swift

@@ -64,17 +64,51 @@ struct SendFlowSetAmountScreen: View {
 
     // MARK: Actions
 
-    // validate, create final psbt and send to next screen
     private func next() {
-        if validate(true) { sendFlowManager.dispatch(action: .finalizeAndGoToNextScreen) }
+        Task {
+            guard await performValidation() else { return }
+            sendFlowManager.dispatch(action: .finalizeAndGoToNextScreen)
+        }
     }
 
     private func dismissIfValid() {
-        if validate(true) {
+        Task {
+            guard await performValidation() else { return }
             presenter.focusField = .none
         }
     }
 
+    private func performValidation() async -> Bool {
+        if !validateAddress() {
+            if !address.wrappedValue.isEmpty {
+                await FloaterPopup(
+                    text: "Address not valid. Please try again.",
+                    backgroundColor: .orange,
+                    textColor: .white,
+                    iconColor: .white,
+                    icon: "exclamationmark.triangle"
+                ).dismissAfter(1).present()
+            }
+            presenter.focusField = .address
+            return false
+        }
+        if !validateAmount() {
+            let hasAmount = sendFlowManager.amount != nil && sendFlowManager.amount?.asSats() != 0
+            if hasAmount {
+                await FloaterPopup(
+                    text: "Amount not valid. Please try again.",
+                    backgroundColor: .orange,
+                    textColor: .white,
+                    iconColor: .white,
+                    icon: "exclamationmark.triangle"
+                ).dismissAfter(1).present()
+            }
+            presenter.focusField = .amount
+            return false
+        }
+        return true
+    }
+
     // doing it this way prevents an alert popping up when the user just goes back
     private func setAlertState(_ error: SendFlowError) {
         sendFlowManager.presenter.alertState = .init(.error(error))