diff --git a/.idea/.name b/.idea/.name
new file mode 100644
index 0000000..050cf0c
--- /dev/null
+++ b/.idea/.name
@@ -0,0 +1 @@
+PianoTimeline
\ No newline at end of file
diff --git a/.idea/deploymentTargetSelector.xml b/.idea/deploymentTargetSelector.xml
new file mode 100644
index 0000000..ca16a99
--- /dev/null
+++ b/.idea/deploymentTargetSelector.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="deploymentTargetSelector">
+    <selectionStates>
+      <SelectionState runConfigName="app">
+        <option name="selectionMode" value="DROPDOWN" />
+        <DialogSelection />
+      </SelectionState>
+    </selectionStates>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index cdbc250..02c4aa5 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
   <component name="GradleSettings">
     <option name="linkedExternalProjectsSettings">
       <GradleProjectSettings>
diff --git a/.idea/inspectionProfiles/Project_Default.xml b/.idea/inspectionProfiles/Project_Default.xml
new file mode 100644
index 0000000..7061a0d
--- /dev/null
+++ b/.idea/inspectionProfiles/Project_Default.xml
@@ -0,0 +1,61 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="ComposePreviewDimensionRespectsLimit" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="ComposePreviewMustBeTopLevelFunction" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="ComposePreviewNeedsComposableAnnotation" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="ComposePreviewNotSupportedInUnitTestFiles" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="GlancePreviewDimensionRespectsLimit" enabled="true" level="WARNING" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="GlancePreviewMustBeTopLevelFunction" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="GlancePreviewNeedsComposableAnnotation" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="GlancePreviewNotSupportedInUnitTestFiles" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewAnnotationInFunctionWithParameters" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewApiLevelMustBeValid" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewDeviceShouldUseNewSpec" enabled="true" level="WEAK WARNING" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewFontScaleMustBeGreaterThanZero" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewMultipleParameterProviders" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewParameterProviderOnFirstParameter" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+    <inspection_tool class="PreviewPickerAnnotation" enabled="true" level="ERROR" enabled_by_default="true">
+      <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
+    </inspection_tool>
+  </profile>
+</component>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
index a4f09e2..74dd639 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="ExternalStorageConfigurationManager" enabled="true" />
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" project-jdk-name="jbr-21" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" default="true" project-jdk-name="jbr-21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">
diff --git a/.idea/planningMode.xml b/.idea/planningMode.xml
new file mode 100644
index 0000000..f58366e
--- /dev/null
+++ b/.idea/planningMode.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="PlanningModeManager">
+    <option name="approvalStates">
+      <map>
+        <entry key="20260623-075402-8a5368e9-a150-4048-aaa6-a07699e3c266" value="true" />
+      </map>
+    </option>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/studiobot.xml b/.idea/studiobot.xml
new file mode 100644
index 0000000..539e3b8
--- /dev/null
+++ b/.idea/studiobot.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="StudioBotProjectSettings">
+    <option name="shareContext" value="OptedIn" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 50b356d..04a8cf5 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -1,6 +1,8 @@
 plugins {
     alias(libs.plugins.android.application)
     alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.kotlin.serialization)
+    alias(libs.plugins.ksp)
 }
 
 android {
@@ -46,6 +48,41 @@ dependencies {
     implementation(libs.androidx.compose.ui.tooling.preview)
     implementation(libs.androidx.core.ktx)
     implementation(libs.androidx.lifecycle.runtime.ktx)
+
+    // Coroutines
+    implementation(libs.kotlinx.coroutines.android)
+
+    // JSON
+    implementation(libs.kotlinx.serialization.json)
+
+    // Networking
+    implementation(libs.retrofit)
+    implementation(libs.okhttp)
+    implementation(libs.okhttp.logging)
+    implementation(libs.retrofit.kotlinx.serialization)
+
+    // Room (local cache index)
+    implementation(libs.androidx.room.runtime)
+    implementation(libs.androidx.room.ktx)
+    ksp(libs.androidx.room.compiler)
+
+    // Media3 / ExoPlayer
+    implementation(libs.androidx.media3.exoplayer)
+    implementation(libs.androidx.media3.ui)
+    implementation(libs.androidx.media3.session)
+    implementation(libs.androidx.media3.common)
+
+    // DataStore (settings)
+    implementation(libs.androidx.datastore.preferences)
+
+    // ViewModel + Navigation for Compose
+    implementation(libs.androidx.lifecycle.viewmodel.compose)
+    implementation(libs.androidx.lifecycle.runtime.compose)
+    implementation(libs.androidx.navigation.compose)
+
+    // Coil (artwork, for later)
+    implementation(libs.coil.compose)
+
     testImplementation(libs.junit)
     androidTestImplementation(platform(libs.androidx.compose.bom))
     androidTestImplementation(libs.androidx.compose.ui.test.junit4)
@@ -53,4 +90,4 @@ dependencies {
     androidTestImplementation(libs.androidx.junit)
     debugImplementation(libs.androidx.compose.ui.test.manifest)
     debugImplementation(libs.androidx.compose.ui.tooling)
-}
\ No newline at end of file
+}
diff --git a/build.gradle.kts b/build.gradle.kts
index 18318be..1a95966 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,8 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
     alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.android) apply false
     alias(libs.plugins.kotlin.compose) apply false
-}
\ No newline at end of file
+    alias(libs.plugins.kotlin.serialization) apply false
+    alias(libs.plugins.ksp) apply false
+}
diff --git a/gradle.properties b/gradle.properties
index 99fc155..efcaaf9 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -16,4 +16,5 @@ org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
 # has changed. Additionally, Gradle applies performance optimizations to task execution.
 org.gradle.configuration-cache=true
 # Kotlin code style for this project: "official" or "obsolete":
-kotlin.code.style=official
\ No newline at end of file
+kotlin.code.style=official
+android.disallowKotlinSourceSets=false
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 394ece7..0a2b082 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -8,6 +8,19 @@ lifecycleRuntimeKtx = "2.6.1"
 activityCompose = "1.8.0"
 kotlin = "2.2.10"
 composeBom = "2026.02.01"
+# --- added for the data layer ---
+ksp = "2.2.10-2.0.2"
+kotlinxSerialization = "1.7.3"
+kotlinxCoroutines = "1.9.0"
+retrofit = "2.11.0"
+okhttp = "4.12.0"
+retrofitSerialization = "1.0.0"
+room = "2.8.4"
+media3 = "1.10.0"
+datastore = "1.1.1"
+lifecycleViewmodelCompose = "2.8.7"
+navigationCompose = "2.8.5"
+coil = "2.7.0"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
@@ -25,7 +38,44 @@ androidx-compose-ui-test-manifest = { group = "androidx.compose.ui", name = "ui-
 androidx-compose-ui-test-junit4 = { group = "androidx.compose.ui", name = "ui-test-junit4" }
 androidx-compose-material3 = { group = "androidx.compose.material3", name = "material3" }
 
+# --- Coroutines ---
+kotlinx-coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "kotlinxCoroutines" }
+
+# --- JSON serialization ---
+kotlinx-serialization-json = { group = "org.jetbrains.kotlinx", name = "kotlinx-serialization-json", version.ref = "kotlinxSerialization" }
+
+# --- Networking (Retrofit + OkHttp) ---
+retrofit = { group = "com.squareup.retrofit2", name = "retrofit", version.ref = "retrofit" }
+okhttp = { group = "com.squareup.okhttp3", name = "okhttp", version.ref = "okhttp" }
+okhttp-logging = { group = "com.squareup.okhttp3", name = "logging-interceptor", version.ref = "okhttp" }
+retrofit-kotlinx-serialization = { group = "com.jakewharton.retrofit", name = "retrofit2-kotlinx-serialization-converter", version.ref = "retrofitSerialization" }
+
+# --- Room (local cache index) ---
+androidx-room-runtime = { group = "androidx.room", name = "room-runtime", version.ref = "room" }
+androidx-room-ktx = { group = "androidx.room", name = "room-ktx", version.ref = "room" }
+androidx-room-compiler = { group = "androidx.room", name = "room-compiler", version.ref = "room" }
+
+# --- Media3 / ExoPlayer ---
+androidx-media3-exoplayer = { group = "androidx.media3", name = "media3-exoplayer", version.ref = "media3" }
+androidx-media3-ui = { group = "androidx.media3", name = "media3-ui", version.ref = "media3" }
+androidx-media3-session = { group = "androidx.media3", name = "media3-session", version.ref = "media3" }
+androidx-media3-common = { group = "androidx.media3", name = "media3-common", version.ref = "media3" }
+
+# --- DataStore (settings) ---
+androidx-datastore-preferences = { group = "androidx.datastore", name = "datastore-preferences", version.ref = "datastore" }
+
+# --- ViewModel + Navigation for Compose ---
+androidx-lifecycle-viewmodel-compose = { group = "androidx.lifecycle", name = "lifecycle-viewmodel-compose", version.ref = "lifecycleViewmodelCompose" }
+androidx-lifecycle-runtime-compose = { group = "androidx.lifecycle", name = "lifecycle-runtime-compose", version.ref = "lifecycleViewmodelCompose" }
+androidx-navigation-compose = { group = "androidx.navigation", name = "navigation-compose", version.ref = "navigationCompose" }
+
+# --- Coil (artwork / async image, for later) ---
+coil-compose = { group = "io.coil-kt", name = "coil-compose", version.ref = "coil" }
+
 [plugins]
 android-application = { id = "com.android.application", version.ref = "agp" }
 kotlin-compose = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
-
+# --- added for the data layer ---
+kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }