diff --git a/README.md b/README.md
index 292af81..e508bbb 100644
--- a/README.md
+++ b/README.md
@@ -212,6 +212,20 @@ ignore(logger.flush())
 
 </details>
 
+<details><summary>JSON style_tags 示例</summary>
+
+```moonbit
+let config = parse_logger_config_text(
+  "{\"sink\":{\"kind\":\"text_console\",\"text_formatter\":{\"show_timestamp\":false,\"color_mode\":\"always\",\"style_tags\":{\"accent\":{\"fg\":\"#4cc9f0\",\"bold\":true}}}}}",
+)
+
+let logger = build_logger(config)
+
+logger.info("<accent>styled from json</>")
+```
+
+</details>
+
 <details><summary>native 文件 sink 示例</summary>
 
 ```moonbit
@@ -266,7 +280,8 @@ match logger.file_runtime_state() {
 - `message` 支持轻量 inline style tag: `<red>...</>`, `<b>...</>`, `<#ff0000>...</>`, `<bg:#202020>...</>`
 - 运行期样式标签 API: `TextStyle`, `StyleTagRegistry`, `style_tag_registry()`, `default_style_tag_registry()`, `set_tag(...)`, `define_alias(...)`
 - 样式标签优先级: formatter 局部 `style_tags` > 全局 style tag registry > 内置标签
-- 自定义 style tag 当前仅支持运行期 API, 还不支持通过 JSON config 声明
+- `sink.text_formatter.style_tags` 现支持最小对象映射配置, 可声明 `fg`, `bg`, `bold`, `dim`, `italic`, `underline`
+- `define_alias(...)` 仍为运行期 API, 当前不在 JSON schema 中
 - `sink.rotation` 支持 `max_bytes` 与 `max_backups`, 用于基础 size-based rotation 和 backup retention
 - `file_sink(...)` 提供 `reopen()`, `reopen_with_current_policy()`, `reopen_append()`, `reopen_truncate()`, `open_failures()`, `write_failures()`, `flush_failures()`, `rotation_failures()`, 用于基础可观测性
 - `file_sink(...)` 提供 `append_mode()`. 显式传入 `reopen(append=...)` 时, 会更新后续 reopen 使用的 append 策略. `reopen_with_current_policy()` 使用当前保存的策略重开文件, `reopen_append()` / `reopen_truncate()` 提供常见的 append 和 truncate 模式
@@ -291,6 +306,7 @@ match logger.file_runtime_state() {
 - `file_sink_state_to_json(...)`, `stringify_file_sink_state(...)`, `runtime_file_state_to_json(...)`, `stringify_runtime_file_state(...)` 可直接把 file / queued-file 快照导出为 JSON, 便于排障或上报
 - `sink.text_formatter.template` 支持固定 token: `{timestamp}`, `{timestamp_ms}`, `{level}`, `{target}`, `{message}`, `{fields}`
 - `sink.text_formatter.color_mode` 支持 `never`, `auto`, `always`
+- `sink.text_formatter.style_tags.<name>` 支持 `fg`, `bg`, `bold`, `dim`, `italic`, `underline`
 - 可由配置直接组装的 sink 类型: `console`, `json_console`, `text_console`, `file`
 - `queue` 作为显式包装层附着在最终 sink 外侧. 这仍然是同步 drain 模型, 不是 async runtime
 
diff --git a/bitlogger/BitLogger_test.mbt b/bitlogger/BitLogger_test.mbt
index ed53e61..c5ce637 100644
--- a/bitlogger/BitLogger_test.mbt
+++ b/bitlogger/BitLogger_test.mbt
@@ -72,6 +72,28 @@ test "logger config parser reads formatter and queue options" {
   }
 }
 
+test "logger config parser reads formatter style tags" {
+  let config = parse_logger_config_text(
+    "{\"sink\":{\"kind\":\"text_console\",\"text_formatter\":{\"color_mode\":\"always\",\"style_tags\":{\"accent\":{\"fg\":\"#4cc9f0\",\"bold\":true},\"panel\":{\"bg\":\"#202020\",\"underline\":true}}}}}",
+  )
+  inspect(config.sink.text_formatter.style_tags.length(), content="2")
+  match config.sink.text_formatter.style_tags.get("accent") {
+    Some(style) => {
+      inspect(style.fg.unwrap(), content="#4cc9f0")
+      inspect(style.bold, content="true")
+      inspect(style.bg is None, content="true")
+    }
+    None => inspect(false, content="true")
+  }
+  match config.sink.text_formatter.style_tags.get("panel") {
+    Some(style) => {
+      inspect(style.bg.unwrap(), content="#202020")
+      inspect(style.underline, content="true")
+    }
+    None => inspect(false, content="true")
+  }
+}
+
 test "logger config parser reads file rotation options" {
   let config = parse_logger_config_text(
     "{\"sink\":{\"kind\":\"file\",\"path\":\"bitlogger.log\",\"rotation\":{\"max_bytes\":128,\"max_backups\":3}}}",
@@ -119,6 +141,30 @@ test "logger config stringify roundtrips stable fields" {
   inspect(config.sink.text_formatter.template, content="[{level}] {target} {message}")
 }
 
+test "logger config stringify roundtrips formatter style tags" {
+  let text = stringify_logger_config(
+    LoggerConfig::new(
+      sink=SinkConfig::new(
+        kind=SinkKind::TextConsole,
+        text_formatter=TextFormatterConfig::new(
+          color_mode=ColorMode::Always,
+          style_tags={
+            "accent": text_style(fg=Some("#4cc9f0"), bold=true),
+            "panel": text_style(bg=Some("#202020"), dim=true),
+          },
+        ),
+      ),
+    ),
+  )
+  let config = parse_logger_config_text(text)
+  inspect(color_mode_label(config.sink.text_formatter.color_mode), content="always")
+  inspect(config.sink.text_formatter.style_tags.length(), content="2")
+  inspect(config.sink.text_formatter.style_tags.get("accent").unwrap().fg.unwrap(), content="#4cc9f0")
+  inspect(config.sink.text_formatter.style_tags.get("accent").unwrap().bold, content="true")
+  inspect(config.sink.text_formatter.style_tags.get("panel").unwrap().bg.unwrap(), content="#202020")
+  inspect(config.sink.text_formatter.style_tags.get("panel").unwrap().dim, content="true")
+}
+
 test "logger config stringify roundtrips file rotation fields" {
   let text = stringify_logger_config(
     LoggerConfig::new(
@@ -158,9 +204,12 @@ test "config subtype json helpers stringify stable shapes" {
         field_separator=",",
         template="[{level}] {message} :: {fields}",
         color_mode=ColorMode::Always,
+        style_tags={
+          "accent": text_style(fg=Some("#4cc9f0"), bold=true),
+        },
       ),
     ),
-    content="{\"show_timestamp\":false,\"show_level\":true,\"show_target\":false,\"show_fields\":true,\"separator\":\" | \",\"field_separator\":\",\",\"template\":\"[{level}] {message} :: {fields}\",\"color_mode\":\"always\"}",
+    content="{\"show_timestamp\":false,\"show_level\":true,\"show_target\":false,\"show_fields\":true,\"separator\":\" | \",\"field_separator\":\",\",\"template\":\"[{level}] {message} :: {fields}\",\"color_mode\":\"always\",\"style_tags\":{\"accent\":{\"bold\":true,\"dim\":false,\"italic\":false,\"underline\":false,\"fg\":\"#4cc9f0\"}}}",
   )
   inspect(
     stringify_sink_config(
@@ -177,6 +226,22 @@ test "config subtype json helpers stringify stable shapes" {
   )
 }
 
+test "config formatter style tags render in built logger" {
+  let formatter = TextFormatterConfig::new(
+    show_timestamp=false,
+    show_target=false,
+    color_mode=ColorMode::Always,
+    style_tags={
+      "accent": text_style(fg=Some("#4cc9f0"), bold=true),
+    },
+  )
+  let rendered = format_text(
+    Record::new(Level::Info, "<accent>tag</>"),
+    formatter=formatter.to_formatter(),
+  )
+  inspect(rendered, content="[\u{001b}[32mINFO\u{001b}[0m] \u{001b}[38;2;76;201;240;1mtag\u{001b}[0m")
+}
+
 test "build logger from config supports queued text console" {
   let logger = build_logger(
     LoggerConfig::new(
diff --git a/bitlogger/README.mbt.md b/bitlogger/README.mbt.md
index 26e364e..0fc3472 100644
--- a/bitlogger/README.mbt.md
+++ b/bitlogger/README.mbt.md
@@ -217,6 +217,16 @@ test {
 }
 ```
 
+```mbt check
+test {
+  let config = parse_logger_config_text(
+    "{\"sink\":{\"kind\":\"text_console\",\"text_formatter\":{\"show_timestamp\":false,\"color_mode\":\"always\",\"style_tags\":{\"accent\":{\"fg\":\"#4cc9f0\",\"bold\":true}}}}}",
+  )
+  let logger = build_logger(config)
+  logger.info("<accent>styled from json</>")
+}
+```
+
 ## Formatter Template / 模板格式
 
 - supported tokens / 支持的 token: `{timestamp}`, `{timestamp_ms}`, `{level}`, `{target}`, `{message}`, `{fields}`
@@ -224,7 +234,8 @@ test {
 - inline style tags / inline 样式标签: `<red>...</>`, `<b>...</>`, `<#ff0000>...</>`, `<bg:#202020>...</>`
 - runtime style tags / 运行期样式标签: `TextStyle`, `StyleTagRegistry`, `style_tag_registry()`, `default_style_tag_registry()`, `set_tag(...)`, `define_alias(...)`
 - style tag priority / 标签优先级: formatter local `style_tags` > global style tag registry > builtin tags
-- custom style tags are runtime-only for now / 自定义样式标签当前仅支持运行期 API
+- `sink.text_formatter.style_tags` / `sink.text_formatter.style_tags` 现支持最小对象映射: `fg`, `bg`, `bold`, `dim`, `italic`, `underline`
+- `define_alias(...)` is still runtime-only / `define_alias(...)` 目前仍为运行期 API
 - disabled or missing parts render as empty text / 被关闭或缺失的部分会渲染为空字符串
 - `template` is intentionally a simple token replacement layer, not a full DSL / `template` 使用轻量 token 替换方式, 不是完整 DSL
 
diff --git a/bitlogger/config.mbt b/bitlogger/config.mbt
index caeaec4..6999be0 100644
--- a/bitlogger/config.mbt
+++ b/bitlogger/config.mbt
@@ -18,6 +18,7 @@ pub struct TextFormatterConfig {
   field_separator : String
   template : String
   color_mode : ColorMode
+  style_tags : Map[String, TextStyle]
 }
 
 pub fn TextFormatterConfig::new(
@@ -29,6 +30,7 @@ pub fn TextFormatterConfig::new(
   field_separator~ : String = " ",
   template~ : String = "",
   color_mode~ : ColorMode = ColorMode::Never,
+  style_tags~ : Map[String, TextStyle] = {},
 ) -> TextFormatterConfig {
   {
     show_timestamp,
@@ -39,9 +41,18 @@ pub fn TextFormatterConfig::new(
     field_separator,
     template,
     color_mode,
+    style_tags,
   }
 }
 
+fn style_tag_registry_from_config(style_tags : Map[String, TextStyle]) -> StyleTagRegistry {
+  let registry = style_tag_registry()
+  for name, style in style_tags {
+    ignore(registry.set_tag(name, style=style))
+  }
+  registry
+}
+
 pub fn TextFormatterConfig::to_formatter(self : TextFormatterConfig) -> TextFormatter {
   text_formatter(
     show_timestamp=self.show_timestamp,
@@ -52,6 +63,11 @@ pub fn TextFormatterConfig::to_formatter(self : TextFormatterConfig) -> TextForm
     field_separator=self.field_separator,
     template=self.template,
     color_mode=self.color_mode,
+    style_tags=if self.style_tags.length() == 0 {
+      None
+    } else {
+      Some(style_tag_registry_from_config(self.style_tags))
+    },
   )
 }
 
@@ -759,6 +775,19 @@ fn get_string(
   }
 }
 
+fn get_optional_string(
+  obj : Map[String, @json_parser.JsonValue],
+  key : String,
+) -> String? raise ConfigError {
+  match obj.get(key) {
+    None => None
+    Some(value) => match value.as_string() {
+      Some(text) => Some(text)
+      None => raise ConfigError::InvalidConfig("Expected string at key " + key)
+    }
+  }
+}
+
 fn get_bool(
   obj : Map[String, @json_parser.JsonValue],
   key : String,
@@ -848,9 +877,37 @@ fn parse_text_formatter_config(value : @json_parser.JsonValue) -> TextFormatterC
     field_separator=get_string(obj, "field_separator", default=" "),
     template=get_string(obj, "template", default=""),
     color_mode=parse_color_mode(get_string(obj, "color_mode", default="never")),
+    style_tags=match obj.get("style_tags") {
+      None => {}
+      Some(inner) => parse_style_tags_config(inner)
+    },
   )
 }
 
+fn parse_text_style_config(
+  value : @json_parser.JsonValue,
+  context : String,
+) -> TextStyle raise ConfigError {
+  let obj = expect_object(value, context)
+  text_style(
+    fg=get_optional_string(obj, "fg"),
+    bg=get_optional_string(obj, "bg"),
+    bold=get_bool(obj, "bold", default=false),
+    dim=get_bool(obj, "dim", default=false),
+    italic=get_bool(obj, "italic", default=false),
+    underline=get_bool(obj, "underline", default=false),
+  )
+}
+
+fn parse_style_tags_config(value : @json_parser.JsonValue) -> Map[String, TextStyle] raise ConfigError {
+  let obj = expect_object(value, "text_formatter.style_tags")
+  let style_tags : Map[String, TextStyle] = {}
+  for name, item in obj {
+    style_tags[name] = parse_text_style_config(item, "text_formatter.style_tags." + name)
+  }
+  style_tags
+}
+
 fn parse_queue_config(value : @json_parser.JsonValue) -> QueueConfig raise ConfigError {
   let obj = expect_object(value, "queue")
   QueueConfig::new(
@@ -934,7 +991,7 @@ pub fn stringify_queue_config(queue : QueueConfig, pretty~ : Bool = false) -> St
 }
 
 pub fn text_formatter_config_to_json(config : TextFormatterConfig) -> @json_parser.JsonValue {
-  @json_parser.JsonValue::Object({
+  let obj : Map[String, @json_parser.JsonValue] = {
     "show_timestamp": @json_parser.JsonValue::Bool(config.show_timestamp),
     "show_level": @json_parser.JsonValue::Bool(config.show_level),
     "show_target": @json_parser.JsonValue::Bool(config.show_target),
@@ -943,7 +1000,37 @@ pub fn text_formatter_config_to_json(config : TextFormatterConfig) -> @json_pars
     "field_separator": @json_parser.JsonValue::String(config.field_separator),
     "template": @json_parser.JsonValue::String(config.template),
     "color_mode": @json_parser.JsonValue::String(color_mode_label(config.color_mode)),
-  })
+  }
+  if config.style_tags.length() != 0 {
+    obj["style_tags"] = style_tags_config_to_json(config.style_tags)
+  }
+  @json_parser.JsonValue::Object(obj)
+}
+
+fn text_style_config_to_json(style : TextStyle) -> @json_parser.JsonValue {
+  let obj : Map[String, @json_parser.JsonValue] = {
+    "bold": @json_parser.JsonValue::Bool(style.bold),
+    "dim": @json_parser.JsonValue::Bool(style.dim),
+    "italic": @json_parser.JsonValue::Bool(style.italic),
+    "underline": @json_parser.JsonValue::Bool(style.underline),
+  }
+  match style.fg {
+    Some(value) => obj["fg"] = @json_parser.JsonValue::String(value)
+    None => ()
+  }
+  match style.bg {
+    Some(value) => obj["bg"] = @json_parser.JsonValue::String(value)
+    None => ()
+  }
+  @json_parser.JsonValue::Object(obj)
+}
+
+fn style_tags_config_to_json(style_tags : Map[String, TextStyle]) -> @json_parser.JsonValue {
+  let obj : Map[String, @json_parser.JsonValue] = {}
+  for name, style in style_tags {
+    obj[name] = text_style_config_to_json(style)
+  }
+  @json_parser.JsonValue::Object(obj)
 }
 
 pub fn stringify_text_formatter_config(
diff --git a/docs/README-en.md b/docs/README-en.md
index 9787503..8c35bcb 100644
--- a/docs/README-en.md
+++ b/docs/README-en.md
@@ -196,6 +196,18 @@ logger.info("configured from json")
 ignore(logger.flush())
 ```
 
+JSON `style_tags`:
+
+```moonbit
+let config = parse_logger_config_text(
+  "{\"sink\":{\"kind\":\"text_console\",\"text_formatter\":{\"show_timestamp\":false,\"color_mode\":\"always\",\"style_tags\":{\"accent\":{\"fg\":\"#4cc9f0\",\"bold\":true}}}}}",
+)
+
+let logger = build_logger(config)
+
+logger.info("<accent>styled from json</>")
+```
+
 Native file sink:
 
 ```moonbit
@@ -248,7 +260,8 @@ match logger.file_runtime_state() {
 - `message` also supports lightweight inline style tags such as `<red>...</>`, `<b>...</>`, `<#ff0000>...</>`, and `<bg:#202020>...</>`.
 - Runtime style-tag APIs now include `TextStyle`, `StyleTagRegistry`, `style_tag_registry()`, `default_style_tag_registry()`, `set_tag(...)`, and `define_alias(...)`.
 - Style-tag lookup priority is formatter-local `style_tags` > global style tag registry > builtin tags.
-- Custom style tags are runtime-only for now and are not yet part of the JSON config schema.
+- `sink.text_formatter.style_tags` now supports a minimal object mapping with `fg`, `bg`, `bold`, `dim`, `italic`, and `underline`.
+- `define_alias(...)` remains a runtime-only API and is not yet part of the JSON config schema.
 - `sink.rotation` currently supports `max_bytes` and `max_backups` for basic size-based rotation and backup retention.
 - `file_sink(...)` also exposes `reopen()`, `reopen_with_current_policy()`, `reopen_append()`, `reopen_truncate()`, `open_failures()`, `write_failures()`, `flush_failures()`, and `rotation_failures()` for basic observability.
 - `file_sink(...)` also exposes `append_mode()`. Passing `append=...` to `reopen(...)` updates the current append policy used by later reopen calls, `reopen_with_current_policy()` makes that stored-policy reopen path explicit, and `reopen_append()` / `reopen_truncate()` cover the two common policy switches directly.
@@ -273,6 +286,7 @@ match logger.file_runtime_state() {
 - `file_sink_state_to_json(...)`, `stringify_file_sink_state(...)`, `runtime_file_state_to_json(...)`, and `stringify_runtime_file_state(...)` can export file and queued-file snapshots directly as JSON for diagnostics or reporting.
 - `sink.text_formatter.template` currently supports fixed tokens: `{timestamp}`, `{timestamp_ms}`, `{level}`, `{target}`, `{message}`, and `{fields}`.
 - `sink.text_formatter.color_mode` currently supports `never`, `auto`, and `always`.
+- `sink.text_formatter.style_tags.<name>` currently supports `fg`, `bg`, `bold`, `dim`, `italic`, and `underline`.
 - Config-driven sink assembly currently supports `console`, `json_console`, `text_console`, and `file`.
 - `queue` remains a synchronous bounded wrapper around the final sink, not an async runtime.
 
diff --git a/docs/changes/0.4.0.md b/docs/changes/0.4.0.md
index 0cd62e1..386919f 100644
--- a/docs/changes/0.4.0.md
+++ b/docs/changes/0.4.0.md
@@ -13,6 +13,7 @@ version 0.4.0
 - feat: keep JSON formatter output unchanged and limit inline style parsing to text message rendering only
 - feat: add `TextStyle`, `StyleTagRegistry`, `style_tag_registry()`, and `default_style_tag_registry()` for reusable inline style tags
 - feat: add formatter-local `style_tags`, global style tag registry helpers, builtin-tag override support, and alias reuse via `define_alias(...)`
+- feat: support minimal `sink.text_formatter.style_tags` JSON config parsing and serialization for custom formatter tag styles
 
 ### Test
 
@@ -22,10 +23,12 @@ version 0.4.0
 - test: cover named inline color tags in ANSI mode
 - test: cover plain mode tag stripping, nested tags, hex tags, and unknown-tag fallback behavior
 - test: cover custom tags, builtin-tag override, formatter-vs-global priority, global registry fallback, and alias reuse
+- test: cover formatter `style_tags` JSON parsing, config roundtrip, JSON helper export, and config-driven styled formatter rendering
 
 ### Example
 
 - docs: add `color_mode` usage examples to formatter documentation
+- docs: add runtime and JSON `style_tags` examples, and document current JSON schema scope
 
 ### Notes
 
@@ -33,3 +36,4 @@ version 0.4.0
 - inline style markup currently supports short close `</>` only
 - unknown or invalid inline tags currently fall back to plain text and do not raise formatter errors
 - formatter-local tag lookup currently takes precedence over global tag lookup, and global lookup takes precedence over builtin tags
+- JSON config currently supports concrete style objects only; alias-style declarations remain runtime-only