diff --git a/app/src/main/java/ru/smkdmr/xlxclient/MainActivity.kt b/app/src/main/java/ru/smkdmr/xlxclient/MainActivity.kt
new file mode 100644
index 0000000..3c25ede
--- /dev/null
+++ b/app/src/main/java/ru/smkdmr/xlxclient/MainActivity.kt
@@ -0,0 +1,243 @@
+package ru.smkdmr.xlxclient
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Button
+import androidx.compose.material3.Card
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.ExposedDropdownMenuBox
+import androidx.compose.material3.ExposedDropdownMenuDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            SmkdmrTheme {
+                XlxConnectionScreen()
+            }
+        }
+    }
+}
+
+private val defaultRooms = listOf("A", "B", "C", "D", "E", "F", "G", "H")
+
+@Composable
+private fun SmkdmrTheme(content: @Composable () -> Unit) {
+    MaterialTheme(
+        colorScheme = lightColorScheme(),
+        typography = MaterialTheme.typography,
+        content = content
+    )
+}
+
+@Composable
+fun XlxConnectionScreen(modifier: Modifier = Modifier) {
+    var host by rememberSaveable { mutableStateOf("xlx.example.org") }
+    var port by rememberSaveable { mutableStateOf("40001") }
+    var room by rememberSaveable { mutableStateOf("A") }
+    var status by rememberSaveable { mutableStateOf("Введите параметры XLX-сервера") }
+
+    val portNumber = port.toIntOrNull()
+    val hostValid = host.trim().isNotEmpty()
+    val portValid = portNumber != null && portNumber in 1..65535
+    val roomValid = room.trim().isNotEmpty()
+    val canConnect = hostValid && portValid && roomValid
+
+    Scaffold { innerPadding ->
+        Surface(
+            modifier = modifier
+                .fillMaxSize()
+                .padding(innerPadding),
+            color = MaterialTheme.colorScheme.background
+        ) {
+            Column(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .padding(24.dp),
+                verticalArrangement = Arrangement.SpaceBetween
+            ) {
+                Column(verticalArrangement = Arrangement.spacedBy(18.dp)) {
+                    Header()
+
+                    Card(
+                        modifier = Modifier.fillMaxWidth(),
+                        elevation = CardDefaults.cardElevation(defaultElevation = 2.dp)
+                    ) {
+                        Column(
+                            modifier = Modifier.padding(18.dp),
+                            verticalArrangement = Arrangement.spacedBy(14.dp)
+                        ) {
+                            OutlinedTextField(
+                                value = host,
+                                onValueChange = { host = it.trim() },
+                                modifier = Modifier.fillMaxWidth(),
+                                label = { Text("IP или домен XLX") },
+                                singleLine = true,
+                                isError = !hostValid,
+                                supportingText = {
+                                    if (!hostValid) Text("Укажите адрес сервера")
+                                }
+                            )
+
+                            OutlinedTextField(
+                                value = port,
+                                onValueChange = { input ->
+                                    port = input.filter(Char::isDigit).take(5)
+                                },
+                                modifier = Modifier.fillMaxWidth(),
+                                label = { Text("Порт") },
+                                singleLine = true,
+                                keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
+                                isError = port.isNotBlank() && !portValid,
+                                supportingText = {
+                                    if (port.isNotBlank() && !portValid) Text("Порт должен быть от 1 до 65535")
+                                }
+                            )
+
+                            RoomPicker(
+                                selectedRoom = room,
+                                onRoomSelected = { room = it }
+                            )
+
+                            Spacer(modifier = Modifier.height(2.dp))
+
+                            Button(
+                                onClick = {
+                                    status = "Готово: ${host.trim()}:$port / комната ${room.trim().uppercase()}"
+                                },
+                                enabled = canConnect,
+                                modifier = Modifier.fillMaxWidth()
+                            ) {
+                                Text("Подключиться")
+                            }
+
+                            TextButton(
+                                onClick = {
+                                    host = "xlx.example.org"
+                                    port = "40001"
+                                    room = "A"
+                                    status = "Параметры сброшены"
+                                },
+                                modifier = Modifier.fillMaxWidth()
+                            ) {
+                                Text("Сбросить")
+                            }
+                        }
+                    }
+                }
+
+                StatusBlock(status = status)
+            }
+        }
+    }
+}
+
+@Composable
+private fun Header() {
+    Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
+        Text(
+            text = "SMKDMR XLX Client",
+            style = MaterialTheme.typography.headlineMedium
+        )
+        Text(
+            text = "Кастомный Android-клиент для выбора XLX-сервера, порта и комнаты.",
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun RoomPicker(
+    selectedRoom: String,
+    onRoomSelected: (String) -> Unit
+) {
+    var expanded by remember { mutableStateOf(false) }
+
+    ExposedDropdownMenuBox(
+        expanded = expanded,
+        onExpandedChange = { expanded = !expanded }
+    ) {
+        OutlinedTextField(
+            value = selectedRoom,
+            onValueChange = { value ->
+                onRoomSelected(value.take(1).uppercase())
+            },
+            modifier = Modifier
+                .menuAnchor()
+                .fillMaxWidth(),
+            label = { Text("Комната / модуль") },
+            singleLine = true,
+            trailingIcon = { ExposedDropdownMenuDefaults.TrailingIcon(expanded = expanded) },
+            supportingText = { Text("Например: A, B, C") }
+        )
+
+        ExposedDropdownMenu(
+            expanded = expanded,
+            onDismissRequest = { expanded = false }
+        ) {
+            defaultRooms.forEach { room ->
+                DropdownMenuItem(
+                    text = { Text(room) },
+                    onClick = {
+                        onRoomSelected(room)
+                        expanded = false
+                    }
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun StatusBlock(status: String) {
+    Card(modifier = Modifier.fillMaxWidth()) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            horizontalArrangement = Arrangement.SpaceBetween
+        ) {
+            Column(verticalArrangement = Arrangement.spacedBy(4.dp)) {
+                Text("Статус", style = MaterialTheme.typography.labelLarge)
+                Text(status, style = MaterialTheme.typography.bodyMedium)
+            }
+        }
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+private fun XlxConnectionScreenPreview() {
+    SmkdmrTheme {
+        XlxConnectionScreen()
+    }
+}