diff --git a/README.md b/README.md
index c622bd6..4153fcb 100644
--- a/README.md
+++ b/README.md
@@ -4,13 +4,13 @@
 
 ## 功能
 
-- 📥 拖入即用：拖拽或选择 `.ics` 文件，浏览器内直接解析
-- 🔁 智能去重：自动检测重复模式，将扁平事件合并为 RRULE 重复事件 + EXDATE
-- ✏️ 可视化编辑：编辑标题/地点/时间/重复规则，点击网格切换排除日期
-- ✂️ 拆分事件：把一个重复事件按日期拆成前后两段
-- ➕ 增删事件：新增单次/重复事件，删除任意事件
-- ↶ 撤销重做：快照式 undo/redo，最多 50 步
-- ⬇️ 导出 ICS：下载整理后的 `.ics`，可直接导入日历应用
+- 拖入即用：拖拽或选择 `.ics` 文件，浏览器内直接解析
+- 智能去重：自动检测重复模式，将扁平事件合并为 RRULE 重复事件 + EXDATE
+- 可视化编辑：编辑标题/地点/时间/重复规则，点击网格切换排除日期
+- 拆分事件：把一个重复事件按日期拆成前后两段
+- 增删事件：新增单次/重复事件，删除任意事件
+- 撤销重做：快照式 undo/redo，最多 50 步
+- 导出 ICS：下载整理后的 `.ics`，可直接导入日历应用
 
 ## 项目结构
 
diff --git a/src/App.vue b/src/App.vue
index 277cf5d..9944afa 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -11,7 +11,7 @@ const { isLoaded } = useCalendar()
 <template>
   <div class="app">
     <header class="app-header">
-      <h1>📅 ICS 日程整理器</h1>
+      <h1>ICS 日程整理器</h1>
       <HeaderBar />
     </header>
     <main class="app-main">
diff --git a/src/components/DropZone.vue b/src/components/DropZone.vue
index 6767571..323e753 100644
--- a/src/components/DropZone.vue
+++ b/src/components/DropZone.vue
@@ -39,7 +39,7 @@ function onPick(e) {
     @drop.prevent="onDrop"
   >
     <div class="dropzone-content">
-      <div class="icon">📅</div>
+      <div class="icon">日历</div>
       <p class="hint">拖入 .ics 文件，或</p>
       <label class="pick-btn">
         点击选择文件
diff --git a/src/components/EventDetail.vue b/src/components/EventDetail.vue
index 4a7254e..91bb8f1 100644
--- a/src/components/EventDetail.vue
+++ b/src/components/EventDetail.vue
@@ -7,7 +7,7 @@ import OccurrenceGrid from './OccurrenceGrid.vue'
 
 const { selectedEvent, updateEvent, deleteEvent, splitEvent, toggleOccurrence } = useCalendar()
 
-// Local form state, synced when selection changes
+// 本地表单状态, 选择切换时同步
 const form = ref({})
 const showSplit = ref(false)
 const splitDate = ref('')
@@ -94,7 +94,7 @@ function onToggleOcc(date) {
 <template>
   <div v-if="!selectedEvent" class="empty">从左侧选择一个日程进行编辑</div>
   <div v-else class="detail">
-    <!-- Basic info -->
+    <!-- 基本信息 -->
     <div class="section-title">基本信息</div>
     <div class="form-group">
       <label>标题 (SUMMARY)</label>
@@ -119,7 +119,7 @@ function onToggleOcc(date) {
       <textarea v-model="form.description"></textarea>
     </div>
 
-    <!-- RRULE -->
+    <!-- 重复规则 (RRULE) -->
     <div class="section-title">重复规则 (RRULE)</div>
     <div class="form-group">
       <label>
@@ -156,7 +156,7 @@ function onToggleOcc(date) {
       </div>
     </div>
 
-    <!-- Occurrence grid -->
+    <!-- occurrence / 排除日期网格 -->
     <div v-if="form.is_recurring" class="section-title">occurrence / 排除日期</div>
     <OccurrenceGrid
       v-if="form.is_recurring && selectedEvent.rrule"
@@ -164,7 +164,7 @@ function onToggleOcc(date) {
       @toggle="onToggleOcc"
     />
 
-    <!-- Toolbar -->
+    <!-- 工具栏 -->
     <div class="toolbar">
       <button class="btn btn-primary" @click="applyChanges">应用更改</button>
       <button
@@ -172,12 +172,12 @@ function onToggleOcc(date) {
         class="btn btn-secondary"
         @click="showSplit = !showSplit"
       >
-        ✂ 拆分此日程
+        拆分此日程
       </button>
       <button class="btn btn-danger" @click="onDelete">删除此日程</button>
     </div>
 
-    <!-- Split panel -->
+    <!-- 拆分面板 -->
     <div v-if="showSplit && selectedEvent.rrule" class="split-panel">
       <p>从指定日期起，把此重复事件拆成前后两段。</p>
       <input type="date" v-model="splitDate" />
diff --git a/src/components/EventList.vue b/src/components/EventList.vue
index a544252..c334b27 100644
--- a/src/components/EventList.vue
+++ b/src/components/EventList.vue
@@ -15,7 +15,7 @@ function dowFor(ev) {
     <div class="stat">
       共 {{ stats.total }} 个日程（{{ stats.recurring }} 重复 / {{ stats.single }} 单次）
     </div>
-    <button class="add-btn" @click="addEvent">➕ 新增日程</button>
+    <button class="add-btn" @click="addEvent">新增日程</button>
     <div class="list">
       <div
         v-for="ev in state.events"
diff --git a/src/components/HeaderBar.vue b/src/components/HeaderBar.vue
index 46e844a..90578fa 100644
--- a/src/components/HeaderBar.vue
+++ b/src/components/HeaderBar.vue
@@ -41,13 +41,13 @@ function onDownload() {
 <template>
   <div class="header-actions">
     <button class="btn btn-primary" @click="onOrganize" :disabled="state.events.length === 0">
-      🔁 整理去重
+      整理去重
     </button>
-    <button class="btn btn-secondary" @click="undo" :disabled="!canUndo">↶ 撤销</button>
-    <button class="btn btn-secondary" @click="redo" :disabled="!canRedo">↷ 重做</button>
-    <button class="btn btn-secondary" @click="onImport">📥 导入文件</button>
+    <button class="btn btn-secondary" @click="undo" :disabled="!canUndo">撤销</button>
+    <button class="btn btn-secondary" @click="redo" :disabled="!canRedo">重做</button>
+    <button class="btn btn-secondary" @click="onImport">导入文件</button>
     <button class="btn btn-success" @click="onDownload" :disabled="state.events.length === 0">
-      ⬇ 下载 ICS
+      下载 ICS
     </button>
     <span v-if="state.dirty" class="dirty-dot" title="有未保存更改">●</span>
     <input ref="fileInput" type="file" accept=".ics" @change="onFilePicked" hidden />
diff --git a/src/composables/useCalendar.js b/src/composables/useCalendar.js
index 14cf58c..ee29575 100644
--- a/src/composables/useCalendar.js
+++ b/src/composables/useCalendar.js
@@ -6,7 +6,7 @@ import { splitRecurringEvent } from '../lib/split.js'
 
 const MAX_HISTORY = 50
 
-// Singleton reactive state
+// 单例响应式状态
 const state = reactive({
   meta: null,
   events: [],
@@ -18,7 +18,7 @@ const state = reactive({
 })
 
 // ------------------------------------------------------------------ //
-// Snapshot / undo
+// 快照 / 撤销
 // ------------------------------------------------------------------ //
 function snapshot() {
   return {
@@ -41,7 +41,7 @@ function restore(snap) {
 }
 
 // ------------------------------------------------------------------ //
-// Actions
+// 操作
 // ------------------------------------------------------------------ //
 function loadFile(file) {
   return file.text().then((text) => {
@@ -143,7 +143,7 @@ function markSaved() {
 }
 
 // ------------------------------------------------------------------ //
-// Computed
+// 计算属性
 // ------------------------------------------------------------------ //
 const selectedEvent = computed(() =>
   state.events.find((e) => e.uid === state.selectedUid) || null,
diff --git a/src/lib/date.js b/src/lib/date.js
index 3f47198..47c4057 100644
--- a/src/lib/date.js
+++ b/src/lib/date.js
@@ -1,59 +1,58 @@
 /**
- * Centralized date-string utilities.
+ * 集中式的日期字符串工具集。
  *
- * All date values in the app use the 'YYYY-MM-DD' (wall-clock) format.
- * These helpers are the single source of truth for formatting and
- * arithmetic on that format, replacing ad-hoc inline code that was
- * duplicated across organize.js, recur.js, useCalendar.js, and ical-io.js.
+ * 应用内所有日期值统一使用 'YYYY-MM-DD' (本地墙钟时间) 格式。
+ * 本模块是格式化与日期运算的唯一来源, 替代此前散落在 organize.js、
+ * recur.js、useCalendar.js、ical-io.js 中的重复实现。
  */
 
-/** Pad a number to 2 digits with leading zero. */
+/** 将数字补零为 2 位字符串。 */
 export function pad2(n) {
   return String(n).padStart(2, '0')
 }
 
-/** Convert a JS Date to 'YYYY-MM-DD' (local wall-clock). */
+/** 将 JS Date 转换为 'YYYY-MM-DD' (本地墙钟时间)。 */
 export function toISODate(date) {
   return `${date.getFullYear()}-${pad2(date.getMonth() + 1)}-${pad2(date.getDate())}`
 }
 
-/** Parse 'YYYY-MM-DD' into { year, month, day } (month is 1-based). */
+/** 将 'YYYY-MM-DD' 解析为 { year, month, day } (month 为 1 基)。 */
 export function parseISODate(s) {
   const [y, m, d] = s.split('-').map(Number)
   return { year: y, month: m, day: d }
 }
 
-/** Build a local JS Date at midnight from 'YYYY-MM-DD'. */
+/** 由 'YYYY-MM-DD' 构造本地午夜 JS Date。 */
 export function toDate(isoDate) {
   return new Date(isoDate + 'T00:00:00')
 }
 
-/** Add `days` days to an ISO date string, return new ISO string. */
+/** 在 ISO 日期字符串上增加 `days` 天, 返回新的 ISO 字符串。 */
 export function addDays(isoDate, days) {
   const d = toDate(isoDate)
   d.setDate(d.getDate() + days)
   return toISODate(d)
 }
 
-/** Whole-day difference between two ISO date strings (b - a). */
+/** 两个 ISO 日期字符串之间的整天差 (b - a)。 */
 export function daysBetween(isoA, isoB) {
   return Math.round((toDate(isoB) - toDate(isoA)) / (24 * 3600 * 1000))
 }
 
-/** Today's date as 'YYYY-MM-DD' (local). */
+/** 今天的日期, 格式为 'YYYY-MM-DD' (本地)。 */
 export function todayISO() {
   return toISODate(new Date())
 }
 
 /**
- * Current UTC timestamp in compact RFC 5545 form (e.g. '20260711T085008Z').
- * Used for DTSTAMP on new events.
+ * 当前 UTC 时间戳, 紧凑 RFC 5545 格式 (如 '20260711T085008Z')。
+ * 用于新事件的 DTSTAMP。
  */
 export function nowCompactTimestamp() {
   return new Date().toISOString().replace(/[-:]/g, '').split('.')[0] + 'Z'
 }
 
-/** Format a JS Date's time as 'HH:MM'. */
+/** 将 JS Date 的时间格式化为 'HH:MM'。 */
 export function toHHMM(date) {
   return `${pad2(date.getHours())}:${pad2(date.getMinutes())}`
 }
diff --git a/src/lib/event-factory.js b/src/lib/event-factory.js
index 9df22fb..bc424b0 100644
--- a/src/lib/event-factory.js
+++ b/src/lib/event-factory.js
@@ -1,17 +1,16 @@
 /**
- * Event model factory and helpers.
+ * 事件模型工厂与辅助函数。
  *
- * The EventModel is the plain-JS shape used throughout the app (see
- * docs/superpowers/specs/... §4.2). This module centralizes creation
- * and cloning so that useCalendar.js stays focused on state management.
+ * EventModel 是应用内通用的纯 JS 数据结构 (见 docs/superpowers/specs/...
+ * §4.2)。本模块集中管理事件的创建与克隆, 使 useCalendar.js 专注于状态管理。
  */
 import { todayISO, nowCompactTimestamp } from './date.js'
 import { genUUID } from './uuid.js'
 
 /**
- * Create a new single-occurrence event with sensible defaults.
- * @param {object} [overrides] - partial fields to override
- * @returns {object} a fresh EventModel
+ * 创建一个具有合理默认值的单次事件。
+ * @param {object} [overrides] - 需覆盖的部分字段
+ * @returns {object} 一个全新的 EventModel
  */
 export function createEvent(overrides = {}) {
   return {
@@ -31,12 +30,11 @@ export function createEvent(overrides = {}) {
 }
 
 /**
- * Deep-clone an event (or any plain-data object).
+ * 深拷贝一个事件 (或任意纯数据对象)。
  *
- * Uses JSON round-trip rather than structuredClone because events may be
- * wrapped in Vue reactive proxies, which structuredClone cannot handle.
- * EventModel contains only plain data (strings, arrays, nested objects),
- * so JSON cloning is safe and lossless here.
+ * 使用 JSON 往返而非 structuredClone, 因为事件可能被 Vue 响应式代理包裹,
+ * structuredClone 无法处理。EventModel 仅含纯数据 (字符串、数组、嵌套对象),
+ * 因此 JSON 拷贝在此是安全且无损的。
  */
 export function cloneEvent(ev) {
   return JSON.parse(JSON.stringify(ev))
diff --git a/src/lib/ical-io.js b/src/lib/ical-io.js
index 70d1e21..498c62d 100644
--- a/src/lib/ical-io.js
+++ b/src/lib/ical-io.js
@@ -2,7 +2,7 @@ import ICAL from 'ical.js'
 import { pad2, parseISODate } from './date.js'
 
 // ------------------------------------------------------------------ //
-// Timezone registration (ical.js does not bundle IANA zones)
+// 时区注册 (ical.js 不内置 IANA 时区)
 // ------------------------------------------------------------------ //
 function registerTimezones(vcalendar) {
   for (const vtz of vcalendar.getAllSubcomponents('vtimezone')) {
@@ -14,8 +14,8 @@ function registerTimezones(vcalendar) {
 }
 
 // ------------------------------------------------------------------ //
-// ICAL.Time <-> plain string helpers
-// (ICAL.Time exposes .year/.month/.day/.hour/.minute directly)
+// ICAL.Time <-> 普通字符串辅助函数
+// (ICAL.Time 直接暴露 .year/.month/.day/.hour/.minute)
 // ------------------------------------------------------------------ //
 function icalTimeToISODate(t) {
   return `${t.year}-${pad2(t.month)}-${pad2(t.day)}`
@@ -33,14 +33,14 @@ function getTzid(component, propName) {
 }
 
 // ------------------------------------------------------------------ //
-// Parse a single VEVENT component -> plain EventModel
+// 解析单个 VEVENT 组件 -> 普通 EventModel
 // ------------------------------------------------------------------ //
 function parseEvent(veventComp) {
   const event = new ICAL.Event(veventComp)
   const start = event.startDate
   const end = event.endDate
 
-  // Determine tzid
+  // 确定 tzid
   const tzid = getTzid(veventComp, 'dtstart')
 
   // RRULE
@@ -61,7 +61,7 @@ function parseEvent(veventComp) {
     }
   }
 
-  // EXDATEs
+  // EXDATE
   const exdates = []
   for (const prop of veventComp.getAllProperties('exdate')) {
     for (const t of prop.getValues()) {
@@ -69,9 +69,9 @@ function parseEvent(veventComp) {
     }
   }
 
-  // _raw: capture DTSTAMP and any other unmapped properties
-  // Use toICALString() to preserve the compact RFC5545 form ("20260711T085008Z")
-  // rather than toString()'s ISO 8601 form ("2026-07-11T08:50:08Z").
+  // _raw: 保存 DTSTAMP 及其他未映射的属性
+  // 使用 toICALString() 保留紧凑 RFC5545 形式 ("20260711T085008Z"),
+  // 而非 toString() 的 ISO 8601 形式 ("2026-07-11T08:50:08Z")。
   const _raw = {}
   const dtstamp = veventComp.getFirstPropertyValue('dtstamp')
   if (dtstamp) _raw.dtstamp = dtstamp.toICALString()
@@ -92,16 +92,16 @@ function parseEvent(veventComp) {
 }
 
 // ------------------------------------------------------------------ //
-// Parse full ICS text -> { meta, events }
+// 解析完整 ICS 文本 -> { meta, events }
 // ------------------------------------------------------------------ //
 export function parseICS(text) {
   const jcal = ICAL.parse(text)
   const vcalendar = new ICAL.Component(jcal)
 
-  // Register timezones from VTIMEZONEs before constructing zoned Times
+  // 在构造带时区的 Time 之前, 先从 VTIMEZONE 注册时区
   registerTimezones(vcalendar)
 
-  // Meta
+  // 日历元信息
   const meta = {
     prodid: vcalendar.getFirstPropertyValue('prodid') || '',
     version: vcalendar.getFirstPropertyValue('version') || '2.0',
@@ -109,19 +109,19 @@ export function parseICS(text) {
     method: vcalendar.getFirstPropertyValue('method') || null,
     xWrCalname: vcalendar.getFirstPropertyValue('x-wr-calname') || null,
     xWrTimezone: vcalendar.getFirstPropertyValue('x-wr-timezone') || null,
-    // Store raw jCal arrays (not ICAL.Component instances) so the meta stays
-    // plain-serializable for Vue reactivity and JSON snapshot cloning.
+    // 存储原始 jCal 数组 (而非 ICAL.Component 实例), 使 meta 保持纯可序列化,
+    // 便于 Vue 响应式与 JSON 快照克隆。
     vtimezones: vcalendar.getAllSubcomponents('vtimezone').map((vtz) => vtz.jCal),
   }
 
-  // Events
+  // 事件
   const events = vcalendar.getAllSubcomponents('vevent').map(parseEvent)
 
   return { meta, events }
 }
 
 // ------------------------------------------------------------------ //
-// Helpers for serialization
+// 序列化辅助函数
 // ------------------------------------------------------------------ //
 function parseHHMM(s) {
   const [h, m] = s.split(':').map(Number)
@@ -143,10 +143,10 @@ function makeTime(dateStr, timeStr, tzid) {
   )
 }
 
-// Parse a compact RFC5545 date-time string (e.g. "20260711T085008Z" or
-// "20260711T085008") back into an ICAL.Time. ical.js's public Time.fromString
-// rejects the compact form, so we parse it manually and hand the Time object
-// to updatePropertyWithValue (which writes it back in compact form).
+// 解析紧凑 RFC5545 日期时间字符串 (如 "20260711T085008Z" 或
+// "20260711T085008") 为 ICAL.Time。ical.js 的 Time.fromString 不接受紧凑
+// 格式, 因此手动解析后构造 Time 对象传给 updatePropertyWithValue
+// (该方法会以紧凑格式写回)。
 function parseCompactDateTime(s) {
   const isUtc = s.endsWith('Z')
   const core = isUtc ? s.slice(0, -1) : s
@@ -168,7 +168,7 @@ function parseCompactDateTime(s) {
 }
 
 // ------------------------------------------------------------------ //
-// Serialize { meta, events } -> ICS text
+// 序列化 { meta, events } -> ICS 文本
 // ------------------------------------------------------------------ //
 export function serializeICS({ meta, events }) {
   const vcalendar = new ICAL.Component('vcalendar')
@@ -180,8 +180,8 @@ export function serializeICS({ meta, events }) {
   if (meta.xWrCalname) vcalendar.updatePropertyWithValue('x-wr-calname', meta.xWrCalname)
   if (meta.xWrTimezone) vcalendar.updatePropertyWithValue('x-wr-timezone', meta.xWrTimezone)
 
-  // Re-add VTIMEZONEs. meta.vtimezones stores raw jCal arrays (see parseICS),
-  // so wrap each directly in a new Component (avoids moving the original).
+  // 重新添加 VTIMEZONE。meta.vtimezones 存储的是原始 jCal 数组 (见 parseICS),
+  // 因此直接用新 Component 包裹 (避免移动原始组件)。
   for (const vtzJCal of meta.vtimezones || []) {
     vcalendar.addSubcomponent(new ICAL.Component(vtzJCal))
   }
@@ -204,10 +204,9 @@ export function serializeICS({ meta, events }) {
     const deProp = vevent.addPropertyWithValue('dtend', dtend)
     if (ev.tzid && ev.tzid !== 'UTC') deProp.setParameter('tzid', ev.tzid)
 
-    // DTSTAMP - _raw.dtstamp is stored in compact RFC5545 form
-    // ("20260711T085008Z"); pass an ICAL.Time object so ical.js decorates it
-    // correctly and writes it back in the same compact form. Passing the raw
-    // string fails (ical.js 2.x rejects compact form in fromDateTimeString).
+    // DTSTAMP - _raw.dtstamp 以紧凑 RFC5545 格式存储 ("20260711T085008Z");
+    // 传入 ICAL.Time 对象使 ical.js 正确装饰并以相同紧凑格式写回。
+    // 直接传原始字符串会失败 (ical.js 2.x 的 fromDateTimeString 不接受紧凑格式)。
     const dtstampRaw = ev._raw?.dtstamp
     const dtstampTime = dtstampRaw
       ? parseCompactDateTime(dtstampRaw)
@@ -220,7 +219,7 @@ export function serializeICS({ meta, events }) {
       const recurData = { freq: r.freq, interval: r.interval || 1 }
       if (r.freq === 'WEEKLY' && r.byday) recurData.byday = r.byday
       if (r.untilDate) {
-        // UNTIL as UTC (RFC 5545): build zoned time at 23:59 then convert
+        // UNTIL 使用 UTC (RFC 5545): 先构造 23:59 的带时区时间再转换
         const untilLocal = makeTime(r.untilDate, '23:59', ev.tzid)
         recurData.until = untilLocal.convertToZone(ICAL.Timezone.utcTimezone)
       }
@@ -228,7 +227,7 @@ export function serializeICS({ meta, events }) {
       vevent.addPropertyWithValue('rrule', recur)
     }
 
-    // EXDATEs (in DTSTART's timezone)
+    // EXDATE (使用 DTSTART 的时区)
     for (const exDate of ev.exdates || []) {
       const exTime = makeTime(exDate, ev.dtstartTime, ev.tzid)
       const exProp = vevent.addPropertyWithValue('exdate', exTime)
diff --git a/src/lib/organize.js b/src/lib/organize.js
index 3cd4d76..f500229 100644
--- a/src/lib/organize.js
+++ b/src/lib/organize.js
@@ -1,17 +1,17 @@
 /**
- * GCD-based recurrence detection - port of ical_organizer.py.
- * Collapses a flat list of per-occurrence events into RRULE + EXDATE.
+ * 基于 GCD 的重复检测 - 移植自 ical_organizer.py。
+ * 将扁平的单次事件列表合并为 RRULE + EXDATE。
  */
 import { bydayFromDate } from './weekday.js'
 import { toDate, toISODate, addDays, daysBetween } from './date.js'
 
 // ------------------------------------------------------------------ //
-// Grouping
+// 分组
 // ------------------------------------------------------------------ //
 /**
- * Identity of a recurring series.
- * Two events belong together iff they share summary, location, start
- * wall-clock time, duration (minutes), and weekday.
+ * 重复系列的标识。
+ * 两个事件属于同一系列当且仅当: 标题、地点、开始墙钟时间、
+ * 时长 (分钟)、星期均相同。
  */
 export function seriesKey(ev) {
   const [sh, sm] = ev.dtstartTime.split(':').map(Number)
@@ -22,7 +22,7 @@ export function seriesKey(ev) {
 }
 
 // ------------------------------------------------------------------ //
-// Interval detection
+// 间隔检测
 // ------------------------------------------------------------------ //
 function gcd(a, b) {
   while (b) { [a, b] = [b, a % b] }
@@ -30,8 +30,8 @@ function gcd(a, b) {
 }
 
 /**
- * Return the recurrence interval in days, or null if irregular.
- * Computes GCD of all consecutive date gaps.
+ * 返回重复间隔 (天数), 不规则时返回 null。
+ * 计算所有相邻日期间隔的 GCD。
  */
 export function detectInterval(dateStrings) {
   if (dateStrings.length < 2) return null
@@ -48,13 +48,13 @@ export function detectInterval(dateStrings) {
 }
 
 // ------------------------------------------------------------------ //
-// Series fitting
+// 系列拟合
 // ------------------------------------------------------------------ //
 const byDate = (a, b) => (a.dtstartDate < b.dtstartDate ? -1 : a.dtstartDate > b.dtstartDate ? 1 : 0)
 
 /**
- * Build the expected occurrence grid from first to last at the given interval.
- * Returns { expected: string[], missing: string[] } relative to present dates.
+ * 从首日期到末日期按给定间隔构建期望的 occurrence 网格。
+ * 返回 { expected, missing, offGrid } (相对于实际存在的日期)。
  */
 function buildGrid(firstDate, lastDate, interval, present) {
   const expected = []
@@ -70,8 +70,8 @@ function buildGrid(firstDate, lastDate, interval, present) {
 }
 
 /**
- * Try to collapse events into one recurring event.
- * Returns { base, rrule, exdates } or null to decline.
+ * 尝试将事件合并为一个重复事件。
+ * 返回 { base, rrule, exdates }, 无法合并时返回 null。
  */
 export function fitSeries(evs) {
   if (evs.length < 2) return null
@@ -88,10 +88,10 @@ export function fitSeries(evs) {
   const { missing, offGrid } = buildGrid(first.dtstartDate, last.dtstartDate, interval, present)
   if (offGrid.length > 0) return null
 
-  // "Mostly regular": at least 2 occurrences and occurrences >= skips
+  // "基本规律": 至少 2 个 occurrence, 且 occurrence 数 >= 跳过数
   if (evs.length < 2 || missing.length >= evs.length) return null
 
-  // Build rrule
+  // 构建 rrule
   const firstDate = toDate(first.dtstartDate)
   let freq, step, byday
   if (interval % 7 === 0) {
@@ -109,14 +109,14 @@ export function fitSeries(evs) {
 }
 
 // ------------------------------------------------------------------ //
-// Organize
+// 整理
 // ------------------------------------------------------------------ //
 /**
- * Collapse flat events into recurring series.
- * Returns { events, stats: { series, flat } }.
+ * 将扁平事件合并为重复系列。
+ * 返回 { events, stats: { series, flat } }。
  */
 export function organize(events) {
-  // Group by series key
+  // 按系列标识分组
   const groups = new Map()
   for (const ev of events) {
     const key = seriesKey(ev)
@@ -133,7 +133,7 @@ export function organize(events) {
 
     const fit = fitSeries(evs)
     if (fit) {
-      // Collapsed event: preserve base's UID (not reassign)
+      // 合并后的事件: 保留 base 的 UID (不重新分配)
       result.push({
         ...fit.base,
         rrule: fit.rrule,
@@ -141,7 +141,7 @@ export function organize(events) {
       })
       nSeries++
     } else {
-      // Keep flat
+      // 保留为独立事件
       for (const ev of evs) {
         result.push(ev)
         nFlat++
diff --git a/src/lib/recur.js b/src/lib/recur.js
index b29b209..c773ab9 100644
--- a/src/lib/recur.js
+++ b/src/lib/recur.js
@@ -1,10 +1,10 @@
 /**
- * Recurrence grid expansion - port of ical_editor.py's occurrence generation.
- * occurrences are computed on-demand from exdates, never stored on the model.
+ * 重复网格展开 - 移植自 ical_editor.py 的 occurrence 生成逻辑。
+ * occurrence 按需从 exdates 计算, 不存储在模型上。
  */
 import { toISODate, toDate, addDays } from './date.js'
 
-/** Interval in days for a recurring event. */
+/** 重复事件的间隔天数。 */
 export function intervalDays(ev) {
   if (!ev.rrule) return 0
   const { freq, interval } = ev.rrule
@@ -15,11 +15,11 @@ export function intervalDays(ev) {
 const MAX_OCCURRENCES = 500
 
 /**
- * Expand a recurring event into an occurrence grid.
- * Returns [{ date: 'YYYY-MM-DD', skipped: boolean }].
+ * 将重复事件展开为 occurrence 网格。
+ * 返回 [{ date: 'YYYY-MM-DD', skipped: boolean }]。
  */
 export function expandOccurrences(ev) {
-  // Non-recurring: single occurrence
+  // 非重复事件: 单个 occurrence
   if (!ev.rrule) {
     return [{ date: ev.dtstartDate, skipped: false }]
   }
diff --git a/src/lib/split.js b/src/lib/split.js
index 886d5f9..078ace8 100644
--- a/src/lib/split.js
+++ b/src/lib/split.js
@@ -1,21 +1,20 @@
 /**
- * Split a recurring event into two at a given date.
+ * 将一个重复事件在指定日期拆分为两段。
  *
- * Extracted from useCalendar.js as a pure function so the store stays
- * focused on state management. The grid-snapping logic reuses
- * intervalDays from recur.js (single source of truth for step size).
+ * 从 useCalendar.js 提取为纯函数, 使 store 专注于状态管理。
+ * 网格对齐逻辑复用 recur.js 的 intervalDays (步长的唯一来源)。
  *
- * @param {object} ev - the event to split (must have a non-null rrule)
- * @param {string} splitDate - 'YYYY-MM-DD', must be within the event's range
- * @returns {[object, object]|null} [partA, partB] or null if the date is
- *   out of range or the event is not recurring.
+ * @param {object} ev - 待拆分的事件 (必须有非空 rrule)
+ * @param {string} splitDate - 'YYYY-MM-DD', 必须在事件范围内
+ * @returns {[object, object]|null} [partA, partB], 日期超出范围或
+ *   事件非重复时返回 null。
  */
 import { intervalDays } from './recur.js'
 import { cloneEvent } from './event-factory.js'
 import { genUUID } from './uuid.js'
 import { toDate, toISODate, addDays, daysBetween } from './date.js'
 
-/** Snap a date forward to the next grid point on or after it. */
+/** 将日期向前对齐到不早于它的网格点。 */
 function snapToGrid(startDate, targetDate, stepDays, untilDate) {
   const start = toDate(startDate)
   let snap = toDate(targetDate)
diff --git a/src/lib/weekday.js b/src/lib/weekday.js
index f05d002..2a33d68 100644
--- a/src/lib/weekday.js
+++ b/src/lib/weekday.js
@@ -1,17 +1,17 @@
-// JS getDay() index: 0=Sunday .. 6=Saturday
+// JS getDay() 索引: 0=周日 .. 6=周六
 export const DOW = ['周日', '周一', '周二', '周三', '周四', '周五', '周六']
 
-// BYDAY codes indexed by JS getDay(): DOW_EN[getDay()] => 'SU'..'SA'
+// BYDAY 编码, 按 JS getDay() 索引: DOW_EN[getDay()] => 'SU'..'SA'
 export const DOW_EN = ['SU', 'MO', 'TU', 'WE', 'TH', 'FR', 'SA']
 
 export const BYDAY_TO_INDEX = { SU: 0, MO: 1, TU: 2, WE: 3, TH: 4, FR: 5, SA: 6 }
 
-/** Return the BYDAY code ('SU'..'SA') for a JS Date. */
+/** 返回 JS Date 对应的 BYDAY 编码 ('SU'..'SA')。 */
 export function bydayFromDate(date) {
   return DOW_EN[date.getDay()]
 }
 
-/** Return the Chinese weekday label for a JS Date. */
+/** 返回 JS Date 对应的中文星期标签。 */
 export function dowLabel(date) {
   return DOW[date.getDay()]
 }