diff --git a/backend/DramaLing.Api/Controllers/FlashcardsController.cs b/backend/DramaLing.Api/Controllers/FlashcardsController.cs
index 8c29bc0..10887f0 100644
--- a/backend/DramaLing.Api/Controllers/FlashcardsController.cs
+++ b/backend/DramaLing.Api/Controllers/FlashcardsController.cs
@@ -62,6 +62,7 @@ public class FlashcardsController : BaseController
                         f.Example,
                         f.ExampleTranslation,
                         f.IsFavorite,
+                        f.Synonyms,
                         DifficultyLevelNumeric = f.DifficultyLevelNumeric,
                         CEFR = CEFRHelper.ToString(f.DifficultyLevelNumeric),
                         f.CreatedAt,
@@ -117,6 +118,7 @@ public class FlashcardsController : BaseController
                 Pronunciation = request.Pronunciation,
                 Example = request.Example,
                 ExampleTranslation = request.ExampleTranslation,
+                Synonyms = request.Synonyms, // 儲存 AI 生成的同義詞
                 DifficultyLevelNumeric = CEFRHelper.ToNumeric(request.CEFR ?? "A0"),
                 CreatedAt = DateTime.UtcNow,
                 UpdatedAt = DateTime.UtcNow
@@ -168,6 +170,7 @@ public class FlashcardsController : BaseController
                 flashcard.Example,
                 flashcard.ExampleTranslation,
                 flashcard.IsFavorite,
+                flashcard.Synonyms,
                 DifficultyLevelNumeric = flashcard.DifficultyLevelNumeric,
                 CEFR = CEFRHelper.ToString(flashcard.DifficultyLevelNumeric),
                 flashcard.CreatedAt,
@@ -402,5 +405,6 @@ public class CreateFlashcardRequest
     public string Pronunciation { get; set; } = string.Empty;
     public string Example { get; set; } = string.Empty;
     public string? ExampleTranslation { get; set; }
+    public string? Synonyms { get; set; } // AI 生成的同義詞 (JSON 字串)
     public string? CEFR { get; set; } = string.Empty;
 }
\ No newline at end of file
diff --git a/backend/DramaLing.Api/Data/DramaLingDbContext.cs b/backend/DramaLing.Api/Data/DramaLingDbContext.cs
index a9c7eab..9a3e174 100644
--- a/backend/DramaLing.Api/Data/DramaLingDbContext.cs
+++ b/backend/DramaLing.Api/Data/DramaLingDbContext.cs
@@ -129,6 +129,7 @@ public class DramaLingDbContext : DbContext
         flashcardEntity.Property(f => f.Pronunciation).HasColumnName("pronunciation");
         flashcardEntity.Property(f => f.Example).HasColumnName("example");
         flashcardEntity.Property(f => f.ExampleTranslation).HasColumnName("example_translation");
+        flashcardEntity.Property(f => f.Synonyms).HasColumnName("synonyms");
         // 已刪除的復習相關屬性配置
         // EasinessFactor, IntervalDays, NextReviewDate, MasteryLevel,
         // TimesReviewed, TimesCorrect, LastReviewedAt 已移除
diff --git a/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.Designer.cs b/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.Designer.cs
new file mode 100644
index 0000000..74063a7
--- /dev/null
+++ b/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.Designer.cs
@@ -0,0 +1,1346 @@
+// <auto-generated />
+using System;
+using DramaLing.Api.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace DramaLing.Api.Migrations
+{
+    [DbContext(typeof(DramaLingDbContext))]
+    [Migration("20251007093605_FixSynonymsColumn")]
+    partial class FixSynonymsColumn
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "8.0.10");
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.AudioCache", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Accent")
+                        .IsRequired()
+                        .HasMaxLength(2)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("accent");
+
+                    b.Property<int>("AccessCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("access_count");
+
+                    b.Property<string>("AudioUrl")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("audio_url");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<int?>("DurationMs")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("duration_ms");
+
+                    b.Property<int?>("FileSize")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("file_size");
+
+                    b.Property<DateTime>("LastAccessed")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("last_accessed");
+
+                    b.Property<string>("TextContent")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("text_content");
+
+                    b.Property<string>("TextHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("text_hash");
+
+                    b.Property<string>("VoiceId")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("voice_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("LastAccessed")
+                        .HasDatabaseName("IX_AudioCache_LastAccessed");
+
+                    b.HasIndex("TextHash")
+                        .IsUnique()
+                        .HasDatabaseName("IX_AudioCache_TextHash");
+
+                    b.ToTable("audio_cache", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.DailyStats", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<int>("AiApiCalls")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("ai_api_calls");
+
+                    b.Property<int>("CardsGenerated")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("cards_generated");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("date");
+
+                    b.Property<int>("SessionCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("session_count");
+
+                    b.Property<int>("StudyTimeSeconds")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("study_time_seconds");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.Property<int>("WordsCorrect")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("words_correct");
+
+                    b.Property<int>("WordsStudied")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("words_studied");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId", "Date")
+                        .IsUnique();
+
+                    b.ToTable("daily_stats", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ErrorReport", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<string>("AdminNotes")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("admin_notes");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("description");
+
+                    b.Property<Guid>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<string>("ReportType")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("report_type");
+
+                    b.Property<DateTime?>("ResolvedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("resolved_at");
+
+                    b.Property<Guid?>("ResolvedBy")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("resolved_by");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("status");
+
+                    b.Property<string>("StudyMode")
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("study_mode");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("FlashcardId");
+
+                    b.HasIndex("ResolvedBy");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("error_reports", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ExampleImage", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<int>("AccessCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("access_count");
+
+                    b.Property<string>("AltText")
+                        .HasMaxLength(200)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("alt_text");
+
+                    b.Property<string>("ContentHash")
+                        .HasMaxLength(64)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("content_hash");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<int?>("FileSize")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("file_size");
+
+                    b.Property<decimal?>("GeminiCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_cost");
+
+                    b.Property<string>("GeminiDescription")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_description");
+
+                    b.Property<string>("GeminiPrompt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_prompt");
+
+                    b.Property<int?>("ImageHeight")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("image_height");
+
+                    b.Property<int?>("ImageWidth")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("image_width");
+
+                    b.Property<string>("ModerationNotes")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("moderation_notes");
+
+                    b.Property<string>("ModerationStatus")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("moderation_status");
+
+                    b.Property<decimal?>("QualityScore")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("quality_score");
+
+                    b.Property<string>("RelativePath")
+                        .IsRequired()
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("relative_path");
+
+                    b.Property<decimal?>("ReplicateCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_cost");
+
+                    b.Property<string>("ReplicateModel")
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_model");
+
+                    b.Property<string>("ReplicatePrompt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_prompt");
+
+                    b.Property<string>("ReplicateVersion")
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_version");
+
+                    b.Property<decimal?>("TotalGenerationCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("total_generation_cost");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AccessCount");
+
+                    b.HasIndex("ContentHash")
+                        .IsUnique();
+
+                    b.ToTable("example_images", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Flashcard", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<string>("Definition")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("definition");
+
+                    b.Property<int>("DifficultyLevelNumeric")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("difficulty_level_numeric");
+
+                    b.Property<string>("Example")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("example");
+
+                    b.Property<string>("ExampleTranslation")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("example_translation");
+
+                    b.Property<bool>("IsArchived")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("is_archived");
+
+                    b.Property<bool>("IsFavorite")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("is_favorite");
+
+                    b.Property<string>("PartOfSpeech")
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("part_of_speech");
+
+                    b.Property<string>("Pronunciation")
+                        .HasMaxLength(255)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("pronunciation");
+
+                    b.Property<string>("Synonyms")
+                        .HasMaxLength(2000)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("synonyms");
+
+                    b.Property<string>("Translation")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("translation");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.Property<string>("Word")
+                        .IsRequired()
+                        .HasMaxLength(255)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("word");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("flashcards", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardExampleImage", b =>
+                {
+                    b.Property<Guid>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<Guid>("ExampleImageId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("example_image_id");
+
+                    b.Property<decimal?>("ContextRelevance")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("context_relevance");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<int>("DisplayOrder")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("display_order");
+
+                    b.Property<bool>("IsPrimary")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("is_primary");
+
+                    b.HasKey("FlashcardId", "ExampleImageId");
+
+                    b.HasIndex("ExampleImageId");
+
+                    b.ToTable("flashcard_example_images", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardReview", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<Guid>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<DateTime?>("LastReviewDate")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("last_review_date");
+
+                    b.Property<DateTime?>("LastSuccessDate")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("last_success_date");
+
+                    b.Property<DateTime>("NextReviewDate")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("next_review_date");
+
+                    b.Property<int>("SuccessCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("success_count");
+
+                    b.Property<int>("TotalCorrectCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("total_correct_count");
+
+                    b.Property<int>("TotalSkipCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("total_skip_count");
+
+                    b.Property<int>("TotalWrongCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("total_wrong_count");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("NextReviewDate")
+                        .HasDatabaseName("IX_FlashcardReviews_NextReviewDate");
+
+                    b.HasIndex("FlashcardId", "UserId")
+                        .IsUnique();
+
+                    b.HasIndex("UserId", "NextReviewDate")
+                        .HasDatabaseName("IX_FlashcardReviews_UserId_NextReviewDate");
+
+                    b.ToTable("flashcard_reviews", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardTag", b =>
+                {
+                    b.Property<Guid>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<Guid>("TagId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("tag_id");
+
+                    b.HasKey("FlashcardId", "TagId");
+
+                    b.HasIndex("TagId");
+
+                    b.ToTable("flashcard_tags", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ImageGenerationRequest", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<DateTime?>("CompletedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("completed_at");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<string>("FinalReplicatePrompt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("final_replicate_prompt");
+
+                    b.Property<Guid>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<DateTime?>("GeminiCompletedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_completed_at");
+
+                    b.Property<decimal?>("GeminiCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_cost");
+
+                    b.Property<string>("GeminiErrorMessage")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_error_message");
+
+                    b.Property<int?>("GeminiProcessingTimeMs")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("gemini_processing_time_ms");
+
+                    b.Property<string>("GeminiPrompt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_prompt");
+
+                    b.Property<DateTime?>("GeminiStartedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_started_at");
+
+                    b.Property<string>("GeminiStatus")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("gemini_status");
+
+                    b.Property<string>("GeneratedDescription")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("generated_description");
+
+                    b.Property<Guid?>("GeneratedImageId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("generated_image_id");
+
+                    b.Property<string>("OriginalRequest")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("original_request");
+
+                    b.Property<string>("OverallStatus")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("overall_status");
+
+                    b.Property<DateTime?>("ReplicateCompletedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_completed_at");
+
+                    b.Property<decimal?>("ReplicateCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_cost");
+
+                    b.Property<string>("ReplicateErrorMessage")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_error_message");
+
+                    b.Property<int?>("ReplicateProcessingTimeMs")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("replicate_processing_time_ms");
+
+                    b.Property<DateTime?>("ReplicateStartedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_started_at");
+
+                    b.Property<string>("ReplicateStatus")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("replicate_status");
+
+                    b.Property<decimal?>("TotalCost")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("total_cost");
+
+                    b.Property<int?>("TotalProcessingTimeMs")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("total_processing_time_ms");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("FlashcardId");
+
+                    b.HasIndex("GeneratedImageId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("image_generation_requests", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.OptionsVocabulary", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<string>("CEFRLevel")
+                        .IsRequired()
+                        .HasMaxLength(2)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("cefr_level");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at")
+                        .HasDefaultValueSql("CURRENT_TIMESTAMP");
+
+                    b.Property<bool>("IsActive")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER")
+                        .HasDefaultValue(true)
+                        .HasColumnName("is_active");
+
+                    b.Property<string>("PartOfSpeech")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("part_of_speech");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at")
+                        .HasDefaultValueSql("CURRENT_TIMESTAMP");
+
+                    b.Property<string>("Word")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("word");
+
+                    b.Property<int>("WordLength")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("word_length");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex(new[] { "IsActive" }, "IX_OptionsVocabulary_Active");
+
+                    b.HasIndex(new[] { "CEFRLevel" }, "IX_OptionsVocabulary_CEFR");
+
+                    b.HasIndex(new[] { "CEFRLevel", "PartOfSpeech", "WordLength" }, "IX_OptionsVocabulary_Core_Matching");
+
+                    b.HasIndex(new[] { "PartOfSpeech" }, "IX_OptionsVocabulary_PartOfSpeech");
+
+                    b.HasIndex(new[] { "Word" }, "IX_OptionsVocabulary_Word")
+                        .IsUnique();
+
+                    b.HasIndex(new[] { "WordLength" }, "IX_OptionsVocabulary_WordLength");
+
+                    b.ToTable("options_vocabularies", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.PronunciationAssessment", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<decimal>("AccuracyScore")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("accuracy_score");
+
+                    b.Property<string>("AudioUrl")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("audio_url");
+
+                    b.Property<decimal>("CompletenessScore")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("completeness_score");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<Guid?>("FlashcardId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("flashcard_id");
+
+                    b.Property<decimal>("FluencyScore")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("fluency_score");
+
+                    b.Property<int>("OverallScore")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("overall_score");
+
+                    b.Property<string>("PhonemeScores")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("phoneme_scores");
+
+                    b.Property<string>("PracticeMode")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("practice_mode");
+
+                    b.Property<decimal>("ProsodyScore")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("prosody_score");
+
+                    b.Property<string>("Suggestions")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("suggestions");
+
+                    b.Property<string>("TargetText")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("target_text");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("FlashcardId");
+
+                    b.HasIndex("UserId", "FlashcardId")
+                        .HasDatabaseName("IX_PronunciationAssessment_UserFlashcard");
+
+                    b.ToTable("pronunciation_assessments", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.SentenceAnalysisCache", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<int>("AccessCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("access_count");
+
+                    b.Property<string>("AnalysisResult")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("analysis_result");
+
+                    b.Property<string>("CorrectedText")
+                        .HasMaxLength(1000)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("corrected_text");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<DateTime>("ExpiresAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("expires_at");
+
+                    b.Property<string>("GrammarCorrections")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("grammar_corrections");
+
+                    b.Property<bool>("HasGrammarErrors")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("has_grammar_errors");
+
+                    b.Property<string>("HighValueWords")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("high_value_words");
+
+                    b.Property<string>("IdiomsDetected")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("idioms_detected");
+
+                    b.Property<string>("InputText")
+                        .IsRequired()
+                        .HasMaxLength(1000)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("input_text");
+
+                    b.Property<string>("InputTextHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("input_text_hash");
+
+                    b.Property<DateTime?>("LastAccessedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("last_accessed_at");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ExpiresAt")
+                        .HasDatabaseName("IX_SentenceAnalysisCache_Expires");
+
+                    b.HasIndex("InputTextHash")
+                        .HasDatabaseName("IX_SentenceAnalysisCache_Hash");
+
+                    b.HasIndex("InputTextHash", "ExpiresAt")
+                        .HasDatabaseName("IX_SentenceAnalysisCache_Hash_Expires");
+
+                    b.ToTable("sentence_analysis_cache", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Tag", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Color")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("color");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("name");
+
+                    b.Property<int>("UsageCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("usage_count");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("tags", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<string>("AvatarUrl")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("avatar_url");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<string>("DisplayName")
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("display_name");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(255)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("email");
+
+                    b.Property<string>("EnglishLevel")
+                        .IsRequired()
+                        .HasMaxLength(10)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("english_level");
+
+                    b.Property<int>("EnglishLevelNumeric")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("INTEGER")
+                        .HasDefaultValue(2)
+                        .HasColumnName("english_level_numeric");
+
+                    b.Property<bool>("IsLevelVerified")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("is_level_verified");
+
+                    b.Property<string>("LevelNotes")
+                        .HasMaxLength(500)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("level_notes");
+
+                    b.Property<DateTime>("LevelUpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("level_updated_at");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasMaxLength(255)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("password_hash");
+
+                    b.Property<string>("Preferences")
+                        .IsRequired()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("preferences");
+
+                    b.Property<string>("SubscriptionType")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("subscription_type");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("username");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email")
+                        .IsUnique();
+
+                    b.HasIndex("Username")
+                        .IsUnique();
+
+                    b.ToTable("user_profiles", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.UserAudioPreferences", b =>
+                {
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.Property<bool>("AutoPlayEnabled")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("auto_play_enabled");
+
+                    b.Property<decimal>("DefaultSpeed")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("default_speed");
+
+                    b.Property<bool>("EnableDetailedFeedback")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("enable_detailed_feedback");
+
+                    b.Property<string>("PreferredAccent")
+                        .IsRequired()
+                        .HasMaxLength(2)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("preferred_accent");
+
+                    b.Property<string>("PreferredVoiceFemale")
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("preferred_voice_female");
+
+                    b.Property<string>("PreferredVoiceMale")
+                        .HasMaxLength(50)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("preferred_voice_male");
+
+                    b.Property<string>("PronunciationDifficulty")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("pronunciation_difficulty");
+
+                    b.Property<int>("TargetScoreThreshold")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("target_score_threshold");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.HasKey("UserId");
+
+                    b.ToTable("user_audio_preferences", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.UserSettings", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<bool>("AutoPlayAudio")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("auto_play_audio");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<int>("DailyGoal")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("daily_goal");
+
+                    b.Property<string>("DifficultyPreference")
+                        .IsRequired()
+                        .HasMaxLength(20)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("difficulty_preference");
+
+                    b.Property<bool>("ReminderEnabled")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("reminder_enabled");
+
+                    b.Property<TimeOnly>("ReminderTime")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("reminder_time");
+
+                    b.Property<bool>("ShowPronunciation")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("show_pronunciation");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId")
+                        .IsUnique();
+
+                    b.ToTable("user_settings", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.WordQueryUsageStats", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("TEXT")
+                        .HasColumnName("id");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("created_at");
+
+                    b.Property<DateOnly>("Date")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("date");
+
+                    b.Property<int>("HighValueWordClicks")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("high_value_word_clicks");
+
+                    b.Property<int>("LowValueWordClicks")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("low_value_word_clicks");
+
+                    b.Property<int>("SentenceAnalysisCount")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("sentence_analysis_count");
+
+                    b.Property<int>("TotalApiCalls")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("total_api_calls");
+
+                    b.Property<int>("UniqueWordsQueried")
+                        .HasColumnType("INTEGER")
+                        .HasColumnName("unique_words_queried");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("updated_at");
+
+                    b.Property<Guid>("UserId")
+                        .HasColumnType("TEXT")
+                        .HasColumnName("user_id");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("CreatedAt")
+                        .HasDatabaseName("IX_WordQueryUsageStats_CreatedAt");
+
+                    b.HasIndex("UserId", "Date")
+                        .IsUnique()
+                        .HasDatabaseName("IX_WordQueryUsageStats_UserDate");
+
+                    b.ToTable("word_query_usage_stats", (string)null);
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.DailyStats", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany("DailyStats")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ErrorReport", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany("ErrorReports")
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "ResolvedByUser")
+                        .WithMany()
+                        .HasForeignKey("ResolvedBy")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany("ErrorReports")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Flashcard");
+
+                    b.Navigation("ResolvedByUser");
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Flashcard", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany("Flashcards")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardExampleImage", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.ExampleImage", "ExampleImage")
+                        .WithMany("FlashcardExampleImages")
+                        .HasForeignKey("ExampleImageId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany("FlashcardExampleImages")
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("ExampleImage");
+
+                    b.Navigation("Flashcard");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardReview", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany()
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Flashcard");
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.FlashcardTag", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany("FlashcardTags")
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DramaLing.Api.Models.Entities.Tag", "Tag")
+                        .WithMany("FlashcardTags")
+                        .HasForeignKey("TagId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Flashcard");
+
+                    b.Navigation("Tag");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ImageGenerationRequest", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany()
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("DramaLing.Api.Models.Entities.ExampleImage", "GeneratedImage")
+                        .WithMany()
+                        .HasForeignKey("GeneratedImageId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Flashcard");
+
+                    b.Navigation("GeneratedImage");
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.PronunciationAssessment", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.Flashcard", "Flashcard")
+                        .WithMany()
+                        .HasForeignKey("FlashcardId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Flashcard");
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Tag", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.UserAudioPreferences", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithOne()
+                        .HasForeignKey("DramaLing.Api.Models.Entities.UserAudioPreferences", "UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.UserSettings", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithOne("Settings")
+                        .HasForeignKey("DramaLing.Api.Models.Entities.UserSettings", "UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.WordQueryUsageStats", b =>
+                {
+                    b.HasOne("DramaLing.Api.Models.Entities.User", "User")
+                        .WithMany()
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("User");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.ExampleImage", b =>
+                {
+                    b.Navigation("FlashcardExampleImages");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Flashcard", b =>
+                {
+                    b.Navigation("ErrorReports");
+
+                    b.Navigation("FlashcardExampleImages");
+
+                    b.Navigation("FlashcardTags");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.Tag", b =>
+                {
+                    b.Navigation("FlashcardTags");
+                });
+
+            modelBuilder.Entity("DramaLing.Api.Models.Entities.User", b =>
+                {
+                    b.Navigation("DailyStats");
+
+                    b.Navigation("ErrorReports");
+
+                    b.Navigation("Flashcards");
+
+                    b.Navigation("Settings");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.cs b/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.cs
new file mode 100644
index 0000000..9139a94
--- /dev/null
+++ b/backend/DramaLing.Api/Migrations/20251007093605_FixSynonymsColumn.cs
@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace DramaLing.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class FixSynonymsColumn : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "synonyms",
+                table: "flashcards",
+                type: "TEXT",
+                maxLength: 2000,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "synonyms",
+                table: "flashcards");
+        }
+    }
+}
diff --git a/backend/DramaLing.Api/Migrations/DramaLingDbContextModelSnapshot.cs b/backend/DramaLing.Api/Migrations/DramaLingDbContextModelSnapshot.cs
index 34e212f..717fbad 100644
--- a/backend/DramaLing.Api/Migrations/DramaLingDbContextModelSnapshot.cs
+++ b/backend/DramaLing.Api/Migrations/DramaLingDbContextModelSnapshot.cs
@@ -348,6 +348,11 @@ namespace DramaLing.Api.Migrations
                         .HasColumnType("TEXT")
                         .HasColumnName("pronunciation");
 
+                    b.Property<string>("Synonyms")
+                        .HasMaxLength(2000)
+                        .HasColumnType("TEXT")
+                        .HasColumnName("synonyms");
+
                     b.Property<string>("Translation")
                         .IsRequired()
                         .HasColumnType("TEXT")
diff --git a/backend/DramaLing.Api/Models/Entities/Flashcard.cs b/backend/DramaLing.Api/Models/Entities/Flashcard.cs
index 12c8b74..d93918c 100644
--- a/backend/DramaLing.Api/Models/Entities/Flashcard.cs
+++ b/backend/DramaLing.Api/Models/Entities/Flashcard.cs
@@ -34,6 +34,9 @@ public class Flashcard
 
     public string? ExampleTranslation { get; set; }
 
+    [MaxLength(2000)]
+    public string? Synonyms { get; set; }
+
     // 基本狀態
     public bool IsFavorite { get; set; } = false;
 
diff --git a/frontend/app/generate/page.tsx b/frontend/app/generate/page.tsx
index 52e2e57..613da61 100644
--- a/frontend/app/generate/page.tsx
+++ b/frontend/app/generate/page.tsx
@@ -202,6 +202,7 @@ function GenerateContent() {
         partOfSpeech: analysis.partOfSpeech || analysis.PartOfSpeech || 'noun',
         example: analysis.example || `Example sentence with ${word}.`, // 使用分析結果的例句
         exampleTranslation: analysis.exampleTranslation,
+        synonyms: analysis.synonyms ? JSON.stringify(analysis.synonyms) : undefined, // 轉換為 JSON 字串
         cefr: cefrValue
       }
 
diff --git a/frontend/components/flashcards/FlashcardContentBlocks.tsx b/frontend/components/flashcards/FlashcardContentBlocks.tsx
index 97cc2db..71b8c25 100644
--- a/frontend/components/flashcards/FlashcardContentBlocks.tsx
+++ b/frontend/components/flashcards/FlashcardContentBlocks.tsx
@@ -22,6 +22,23 @@ export const FlashcardContentBlocks: React.FC<FlashcardContentBlocksProps> = ({
   generationProgress,
   onGenerateImage
 }) => {
+  // 安全解析同義詞 JSON 字串
+  const parseSynonyms = (synonymsData: any): string[] => {
+    if (!synonymsData) return []
+    if (Array.isArray(synonymsData)) return synonymsData
+    if (typeof synonymsData === 'string') {
+      try {
+        const parsed = JSON.parse(synonymsData)
+        return Array.isArray(parsed) ? parsed : []
+      } catch {
+        return []
+      }
+    }
+    return []
+  }
+
+  const synonymsList = parseSynonyms((flashcard as any).synonyms)
+
   return (
     <div className="p-6 space-y-6">
       {/* 翻譯區塊 */}
@@ -173,11 +190,11 @@ export const FlashcardContentBlocks: React.FC<FlashcardContentBlocksProps> = ({
       </div>
 
       {/* 同義詞區塊 */}
-      {(flashcard as any).synonyms && (flashcard as any).synonyms.length > 0 && (
+      {synonymsList.length > 0 && (
         <div className="bg-purple-50 rounded-lg p-4 border border-purple-200">
           <h3 className="font-semibold text-purple-900 mb-3 text-left">同義詞</h3>
           <div className="flex flex-wrap gap-2">
-            {(flashcard as any).synonyms.map((synonym: string, index: number) => (
+            {synonymsList.map((synonym: string, index: number) => (
               <span
                 key={index}
                 className="bg-white text-purple-700 px-3 py-1 rounded-full text-sm border border-purple-200 font-medium"
diff --git a/frontend/components/flashcards/SearchControls.tsx b/frontend/components/flashcards/SearchControls.tsx
index 1017164..e1f9b65 100644
--- a/frontend/components/flashcards/SearchControls.tsx
+++ b/frontend/components/flashcards/SearchControls.tsx
@@ -29,7 +29,6 @@ export const SearchControls: React.FC<SearchControlsProps> = ({
               className="text-sm border border-gray-300 rounded-md px-3 py-1 focus:ring-2 focus:ring-primary focus:border-primary"
             >
               <option value="createdAt">創建時間</option>
-              <option value="masteryLevel">掌握程度</option>
               <option value="word">字母順序</option>
               <option value="cefr">CEFR等級</option>
               <option value="timesReviewed">複習次數</option>
diff --git a/frontend/lib/services/flashcards.ts b/frontend/lib/services/flashcards.ts
index d06bce9..34189fd 100644
--- a/frontend/lib/services/flashcards.ts
+++ b/frontend/lib/services/flashcards.ts
@@ -43,6 +43,7 @@ export interface CreateFlashcardRequest {
   partOfSpeech: string;
   example: string;
   exampleTranslation?: string;
+  synonyms?: string; // AI 生成的同義詞 (JSON 字串格式)
   cefr?: string; // A1, A2, B1, B2, C1, C2
 }