diff --git a/apps/api/src/routes/ai.ts b/apps/api/src/routes/ai.ts
index a7c3a07..6db7e08 100644
--- a/apps/api/src/routes/ai.ts
+++ b/apps/api/src/routes/ai.ts
@@ -102,6 +102,7 @@ async function buildDetail(user: AuthUser, start: string, end: string) {
   const problemIds = firstAc.map((item) => item.problemId)
   if (!problemIds.length) return aiDetailSchema.parse({
     user: user.username, className: user.className, start, end, solved: [], flowcharts: [], grade: "", tags: {}, difficulty: {}, contestCount: 0,
+    rankScope: "global",
   })
   const classUsers = user.className ? await db.select({ id: schema.user.id }).from(schema.user).where(eq(schema.user.className, user.className)) : []
   const scopeIds = classUsers.length > 1 ? classUsers.map((item) => item.id) : null
@@ -166,6 +167,7 @@ async function buildDetail(user: AuthUser, start: string, end: string) {
     user: user.username, className: user.className, start, end, solved, flowcharts,
     grade: averageGrade(solved.map((item) => item.grade)), tags: topTags, difficulty,
     contestCount: new Set(solved.flatMap((item) => item.problem.contestId ?? [])).size,
+    rankScope: scopeIds ? "class" : "global",
   })
 }
 
@@ -258,7 +260,8 @@ async function buildDuration(user: AuthUser, endText: string, duration: string)
     const from = bucket.start.getTime()
     const to = bucket.end.getTime()
     const inRange = rows.filter((row) => row.time >= from && row.time <= to)
-    const solved = [...new Set(inRange.filter((row) => accepted.includes(row.result)).map((row) => row.problemId))]
+    const acceptedRows = inRange.filter((row) => accepted.includes(row.result))
+    const solved = [...new Set(acceptedRows.map((row) => row.problemId))]
     return durationDataSchema.parse({
       unit: config.unit,
       index: config.count - 1 - index,
@@ -266,6 +269,7 @@ async function buildDuration(user: AuthUser, endText: string, duration: string)
       end: bucket.end.toISOString(),
       grade: solved.length ? bucketGrade(solved, from, to) : "",
       problemCount: solved.length,
+      acceptedCount: acceptedRows.length,
       submissionCount: inRange.length,
     })
   })
diff --git a/apps/web/src/oj/ai/components/DifficultyGradeChart.vue b/apps/web/src/oj/ai/components/DifficultyGradeChart.vue
index b21aa4b..5ebda95 100644
--- a/apps/web/src/oj/ai/components/DifficultyGradeChart.vue
+++ b/apps/web/src/oj/ai/components/DifficultyGradeChart.vue
@@ -6,7 +6,7 @@
       </n-text>
     </template>
     <div style="height: 300px">
-      <Bar :data="data" :options="options" />
+      <Bar :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -23,11 +23,13 @@ import {
   Legend,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 import type { Grade } from "utils/types"
 
 ChartJS.register(CategoryScale, LinearScale, BarElement, Title, Tooltip, Legend)
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 // 难度和等级的顺序（后端返回的是中文）
 const difficultyOrder = ["简单", "中等", "困难"]
diff --git a/apps/web/src/oj/ai/components/DurationChart.vue b/apps/web/src/oj/ai/components/DurationChart.vue
index 2039f12..f0fec77 100644
--- a/apps/web/src/oj/ai/components/DurationChart.vue
+++ b/apps/web/src/oj/ai/components/DurationChart.vue
@@ -4,7 +4,7 @@
       <n-text depth="3" style="font-size: 12px"> 全面评估学习情况 </n-text>
     </template>
     <div class="chart">
-      <Chart type="bar" :data="data" :options="options" />
+      <Chart type="bar" :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -25,6 +25,7 @@ import {
   LineController,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 import { parseTime } from "utils/functions"
 
 // 注册混合图表（Bar + Line）所需的 Chart.js 组件
@@ -42,6 +43,7 @@ ChartJS.register(
 )
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 const gradeOrder = ["C", "B", "A", "S"] as const
 
@@ -89,7 +91,6 @@ const data = computed<ChartData<"bar" | "line">>(() => {
         spanGaps: false,
         tension: 0.4,
         yAxisID: "y1",
-        barThickness: 10,
         order: 1,
         borderWidth: 2,
         pointRadius: 4,
@@ -128,8 +129,11 @@ const options = computed<ChartOptions<"bar" | "line">>(() => {
         max: gradeOrder.length - 0.5,
         ticks: {
           stepSize: 1,
+          // 轴是 -0.5 ~ 3.5，chart.js 生成的刻度值就是 -0.5/0.5/1.5/2.5/3.5，
+          // 直接拿去索引 gradeOrder 全是 undefined —— 右轴的 S/A/B/C 一个都不会显示。
+          // 四舍五入到整数档再取，和 ProgressChart 的写法一致
           callback: (v) => {
-            const idx = Number(v)
+            const idx = Math.round(Number(v))
             return gradeOrder[idx] || ""
           },
         },
@@ -167,24 +171,15 @@ const options = computed<ChartOptions<"bar" | "line">>(() => {
             }
             return `${dsLabel}: ${ctx.formattedValue}`
           },
+          // AC 率直接读该周期的 acceptedCount / submissionCount。原来拿柱子上的
+          // 「完成题目数 / 总提交次数」当 AC 率，分子是去重后的题数，不是一回事
           footer: (items: TooltipItem<"bar" | "line">[]) => {
-            const barItems = items.filter(
-              (item) => (item.dataset as any).yAxisID === "y",
-            )
-            if (barItems.length >= 2) {
-              const problemCount =
-                barItems.find((item) => item.dataset.label === "完成题目数")
-                  ?.parsed.y || 0
-              const submissionCount =
-                barItems.find((item) => item.dataset.label === "总提交次数")
-                  ?.parsed.y || 0
-              const efficiency =
-                submissionCount > 0
-                  ? ((problemCount / submissionCount) * 100).toFixed(1)
-                  : "0"
-              return `AC率: ${efficiency}%`
-            }
-            return ""
+            const index = items[0]?.dataIndex
+            const bucket =
+              index === undefined ? undefined : aiStore.durationData[index]
+            if (!bucket || bucket.submissionCount === 0) return ""
+            const rate = (bucket.acceptedCount / bucket.submissionCount) * 100
+            return `AC率: ${rate.toFixed(1)}%（通过 ${bucket.acceptedCount} / 共 ${bucket.submissionCount} 次）`
           },
         },
       },
diff --git a/apps/web/src/oj/ai/components/EfficiencyChart.vue b/apps/web/src/oj/ai/components/EfficiencyChart.vue
index 0e724e6..02f4c8b 100644
--- a/apps/web/src/oj/ai/components/EfficiencyChart.vue
+++ b/apps/web/src/oj/ai/components/EfficiencyChart.vue
@@ -4,7 +4,7 @@
       <n-text depth="3" style="font-size: 12px">反映刷题质量提升</n-text>
     </template>
     <div class="chart">
-      <Chart type="line" :data="data" :options="options" />
+      <Chart type="line" :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -23,6 +23,7 @@ import {
   Filler,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 import { parseTime } from "utils/functions"
 
 // 注册折线图所需的 Chart.js 组件
@@ -38,6 +39,7 @@ ChartJS.register(
 )
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 const title = computed(() => {
   if (aiStore.duration === "months:2") {
@@ -60,15 +62,17 @@ const show = computed(() => {
 const efficiencyData = computed(() => {
   return aiStore.durationData.map((duration) => {
     const problemCount = duration.problemCount || 0
+    const acceptedCount = duration.acceptedCount || 0
     const submissionCount = duration.submissionCount || 0
 
     // 计算效率：提交次数/完成题目数
     // 值越接近1，说明一次AC率越高
     const efficiency = problemCount > 0 ? submissionCount / problemCount : 0
 
-    // AC率：AC题目数 / 总提交次数（越高说明提交质量越好）
-    const onePassRate =
-      submissionCount > 0 ? (problemCount / submissionCount) * 100 : 0
+    // AC 率 = 判为通过的提交数 / 总提交数。原来分子用的是去重后的题目数，
+    // 那既不是 AC 率，算出来还正好是上面 efficiency 的倒数 —— 双轴画的是同一个数
+    const acRate =
+      submissionCount > 0 ? (acceptedCount / submissionCount) * 100 : 0
 
     return {
       label: [
@@ -76,8 +80,9 @@ const efficiencyData = computed(() => {
         parseTime(duration.end, "M月D日"),
       ].join("～"),
       efficiency: efficiency,
-      onePassRate: onePassRate,
+      acRate: acRate,
       problemCount: problemCount,
+      acceptedCount: acceptedCount,
       submissionCount: submissionCount,
     }
   })
@@ -107,7 +112,7 @@ const data = computed<ChartData<"line">>(() => {
       },
       {
         label: "提交AC率",
-        data: efficiency.map((e) => e.onePassRate),
+        data: efficiency.map((e) => e.acRate),
         borderColor: "rgb(34, 197, 94)",
         backgroundColor: "rgba(34, 197, 94, 0.1)",
         tension: 0.4,
@@ -203,8 +208,8 @@ const options = computed(() => {
             } else {
               // 提交AC率
               return [
-                `${dsLabel}: ${item.onePassRate.toFixed(1)}%`,
-                `提示: AC题目数 / 总提交次数，越高表示提交质量越好`,
+                `${dsLabel}: ${item.acRate.toFixed(1)}%`,
+                `通过 ${item.acceptedCount} 次 / 共提交 ${item.submissionCount} 次`,
               ]
             }
           },
diff --git a/apps/web/src/oj/ai/components/Heatmap.vue b/apps/web/src/oj/ai/components/Heatmap.vue
index 2c4f4a8..5aa8f19 100644
--- a/apps/web/src/oj/ai/components/Heatmap.vue
+++ b/apps/web/src/oj/ai/components/Heatmap.vue
@@ -4,7 +4,11 @@
       <n-text depth="3" style="font-size: 12px">激励持续学习</n-text>
     </template>
     <n-spin :show="aiStore.loading.heatmap" :delay="50">
-      <div class="heatmap-container" ref="containerRef">
+      <div
+        class="heatmap-container"
+        ref="containerRef"
+        :style="{ '--cell-stroke': cellStroke, '--cell-stroke-hover': cellStrokeHover }"
+      >
         <svg
           :viewBox="`0 0 ${svgWidth} ${svgHeight}`"
           preserveAspectRatio="xMinYMin meet"
@@ -58,8 +62,10 @@
 <script setup lang="ts">
 import { useAIStore } from "oj/store/ai"
 import { parseTime } from "utils/functions"
+import { useChartTheme } from "shared/composables/chartTheme"
 
 const aiStore = useAIStore()
+const { isDark } = useChartTheme()
 const containerRef = useTemplateRef<HTMLElement>("containerRef")
 
 const CELL_SIZE = 12
@@ -68,30 +74,49 @@ const CELL_TOTAL = CELL_SIZE + CELL_GAP
 const DAY_WIDTH = 20
 const MONTH_HEIGHT = 20
 const RIGHT_PADDING = 5
-const COLORS = ["#ebedf0", "#c6e48b", "#7bc96f", "#239a3b", "#196127"]
+// 深色下空格子不能再用接近白的 #ebedf0，整张图会变成一片发亮的方块
+const LIGHT_COLORS = ["#ebedf0", "#c6e48b", "#7bc96f", "#239a3b", "#196127"]
+const DARK_COLORS = ["#22272e", "#0e4429", "#006d32", "#26a641", "#39d353"]
 const WEEK_DAYS = ["", "一", "", "三", "", "五", ""]
 
-const getColor = (count: number) =>
-  count === 0
-    ? COLORS[0]
-    : count <= 2
-      ? COLORS[1]
-      : count <= 4
-        ? COLORS[2]
-        : count <= 7
-          ? COLORS[3]
-          : COLORS[4]
+const COLORS = computed(() => (isDark.value ? DARK_COLORS : LIGHT_COLORS))
+const cellStroke = computed(() =>
+  isDark.value ? "rgba(255, 255, 255, 0.08)" : "rgba(0, 0, 0, 0.05)",
+)
+const cellStrokeHover = computed(() =>
+  isDark.value ? "rgba(255, 255, 255, 0.45)" : "rgba(0, 0, 0, 0.3)",
+)
+
+const getColor = (count: number) => {
+  const palette = COLORS.value
+  if (count === 0) return palette[0]
+  if (count <= 2) return palette[1]
+  if (count <= 4) return palette[2]
+  if (count <= 7) return palette[3]
+  return palette[4]
+}
+
+// 第一格未必是周日 —— 后端给的是「今天往前推 364 天」那天开始的 365 天。
+// 原来直接拿 i % 7 当行号，等于假设首日是周日，左边 一/三/五 的标签和月份标签
+// 会整体错位（今天是周四就错四行）。这里按首日真实的星期做偏移。
+const weekdayOffset = computed(() => {
+  const first = aiStore.heatmapData[0]
+  return first ? new Date(first.timestamp).getDay() : 0
+})
 
 const cells = computed(() =>
-  aiStore.heatmapData.map((item, i) => ({
-    date: new Date(item.timestamp),
-    count: item.value,
-    color: getColor(item.value),
-    week: Math.floor(i / 7),
-    day: i % 7,
-    x: Math.floor(i / 7) * CELL_TOTAL,
-    y: (i % 7) * CELL_TOTAL,
-  })),
+  aiStore.heatmapData.map((item, i) => {
+    const slot = weekdayOffset.value + i
+    return {
+      date: new Date(item.timestamp),
+      count: item.value,
+      color: getColor(item.value),
+      week: Math.floor(slot / 7),
+      day: slot % 7,
+      x: Math.floor(slot / 7) * CELL_TOTAL,
+      y: (slot % 7) * CELL_TOTAL,
+    }
+  }),
 )
 
 const monthLabels = computed(() => {
@@ -100,9 +125,9 @@ const monthLabels = computed(() => {
 
   cells.value.forEach((cell, i) => {
     const month = cell.date.getMonth()
-    const isWeekStart = cell.date.getDay() === 0 || i === 0
+    const isWeekStart = cell.day === 0 || i === 0
 
-    if (month !== lastMonth && (isWeekStart || cell.date.getDay() <= 3)) {
+    if (month !== lastMonth && (isWeekStart || cell.day <= 3)) {
       labels.push({
         text: `${month + 1}月`,
         x: DAY_WIDTH + cell.week * CELL_TOTAL,
@@ -114,10 +139,11 @@ const monthLabels = computed(() => {
   return labels
 })
 
-const svgWidth = computed(
-  () =>
-    DAY_WIDTH + Math.ceil(cells.value.length / 7) * CELL_TOTAL + RIGHT_PADDING,
-)
+const svgWidth = computed(() => {
+  const last = cells.value[cells.value.length - 1]
+  const weeks = last ? last.week + 1 : 0
+  return DAY_WIDTH + weeks * CELL_TOTAL + RIGHT_PADDING
+})
 
 const svgHeight = computed(() => MONTH_HEIGHT + 7 * CELL_TOTAL)
 
@@ -188,12 +214,12 @@ const hideTooltip = () => {
 .cell {
   cursor: pointer;
   transition: all 0.2s ease;
-  stroke: rgba(0, 0, 0, 0.05);
+  stroke: var(--cell-stroke);
   stroke-width: 0.5;
 }
 
 .cell:hover {
-  stroke: rgba(0, 0, 0, 0.3);
+  stroke: var(--cell-stroke-hover);
   stroke-width: 1.5;
   filter: brightness(0.9);
 }
diff --git a/apps/web/src/oj/ai/components/ProgressChart.vue b/apps/web/src/oj/ai/components/ProgressChart.vue
index e3a92f8..83d13de 100644
--- a/apps/web/src/oj/ai/components/ProgressChart.vue
+++ b/apps/web/src/oj/ai/components/ProgressChart.vue
@@ -4,7 +4,7 @@
       <n-text depth="3" style="font-size: 12px">追踪学习成长轨迹</n-text>
     </template>
     <div class="chart">
-      <Chart type="line" :data="data" :options="options" />
+      <Chart type="line" :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -24,6 +24,7 @@ import {
   Filler,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 import { parseTime } from "utils/functions"
 import type { Grade } from "utils/types"
 
@@ -41,6 +42,7 @@ ChartJS.register(
 )
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 const gradeOrder = ["C", "B", "A", "S"] as const
 const gradeColors: Record<Grade, string> = {
@@ -78,8 +80,11 @@ const progressData = computed(() => {
     const problemCount = duration.problemCount || 0
     cumulativeCount += problemCount
 
-    // 计算本期等级的权重值
-    const currentGradeValue = gradeOrder.indexOf(duration.grade || "C")
+    // 契约里空串是「无评级」（该周期没有活动），不能当成 C —— 那会在 tooltip 上
+    // 把一个没做题的周期写成「本期等级: C」。这里权重取 0，反正 problemCount 也是 0
+    const currentGradeValue = duration.grade
+      ? gradeOrder.indexOf(duration.grade)
+      : 0
 
     // 累加加权等级
     totalWeightedGrade += currentGradeValue * problemCount
@@ -97,7 +102,7 @@ const progressData = computed(() => {
       start: parseTime(duration.start, "YYYY-MM-DD"),
       end: parseTime(duration.end, "YYYY-MM-DD"),
       count: cumulativeCount,
-      grade: duration.grade || "C",
+      grade: duration.grade,
       gradeValue: currentGradeValue,
       avgGradeValue: avgGradeValue, // 累计平均等级
       problemCount: problemCount,
@@ -235,7 +240,7 @@ const options = computed<ChartOptions<"line">>(() => {
               const avgIdx = Math.round(Number(ctx.parsed.y))
               return [
                 `${dsLabel}: ${gradeOrder[avgIdx] || ""}`,
-                `本期等级: ${progress.grade}`,
+                `本期等级: ${progress.grade || "无"}`,
                 `本期完成: ${progress.problemCount} 题`,
               ]
             } else {
diff --git a/apps/web/src/oj/ai/components/RankDistributionChart.vue b/apps/web/src/oj/ai/components/RankDistributionChart.vue
index 38d25a8..017e339 100644
--- a/apps/web/src/oj/ai/components/RankDistributionChart.vue
+++ b/apps/web/src/oj/ai/components/RankDistributionChart.vue
@@ -6,7 +6,7 @@
       </n-text>
     </template>
     <div style="height: 300px">
-      <Pie :data="data" :options="options" />
+      <Pie :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -15,10 +15,12 @@
 import { Pie } from "vue-chartjs"
 import { Chart as ChartJS, ArcElement, Title, Tooltip, Legend } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 
 ChartJS.register(ArcElement, Title, Tooltip, Legend)
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 // 排名区间定义
 const RANK_RANGES = [
@@ -42,19 +44,21 @@ const rankDistribution = computed(() => {
     const acCount = item.periodAcCount
 
     if (rank && acCount && acCount > 0) {
-      const percentile = (rank / acCount) * 100
+      // 口径和后端 grade() 一致：(rank - 1) / count。少减这个 1 会让每道题整体降一档，
+      // 而且 rank === acCount 时正好算出 100，落在 [70, 100) 之外被 findIndex 丢掉 ——
+      // 班里只有他一个人做出来的题（1 / 1）既被当成垫底又整个消失
+      const percentile = ((rank - 1) / acCount) * 100
 
-      // 找到对应的区间
+      // 找到对应的区间；万一越界也归到最后一档，别让这道题凭空不见
       const rangeIndex = RANK_RANGES.findIndex(
         (r) => percentile >= r.min && percentile < r.max,
       )
+      const index = rangeIndex === -1 ? RANK_RANGES.length - 1 : rangeIndex
 
-      if (rangeIndex !== -1) {
-        distribution[rangeIndex].count++
-        distribution[rangeIndex].problems.push(
-          `${item.problem.displayId}: ${item.problem.title}`,
-        )
-      }
+      distribution[index].count++
+      distribution[index].problems.push(
+        `${item.problem.displayId}: ${item.problem.title}`,
+      )
     }
   })
 
diff --git a/apps/web/src/oj/ai/components/SolvedTable.vue b/apps/web/src/oj/ai/components/SolvedTable.vue
index 8842be6..44ad4df 100644
--- a/apps/web/src/oj/ai/components/SolvedTable.vue
+++ b/apps/web/src/oj/ai/components/SolvedTable.vue
@@ -80,7 +80,10 @@ const columns: DataTableColumn<SolvedProblem>[] = [
       ),
   },
   {
-    title: () => (aiStore.detailsData.className ? "班级排名" : "全服排名"),
+    // 用后端下发的 rankScope，不要看 className 有没有值：班里只有一个人时
+    // 后端会回退到全服排名，那种学生原来看到的是「班级排名」配全服数据
+    title: () =>
+      aiStore.detailsData.rankScope === "class" ? "班级排名" : "全服排名",
     key: "rank",
     width: 100,
     align: "center",
diff --git a/apps/web/src/oj/ai/components/TagsRadarChart.vue b/apps/web/src/oj/ai/components/TagsRadarChart.vue
index 42b6e37..53998d9 100644
--- a/apps/web/src/oj/ai/components/TagsRadarChart.vue
+++ b/apps/web/src/oj/ai/components/TagsRadarChart.vue
@@ -4,7 +4,7 @@
       <n-text depth="3" style="font-size: 12px">可视化知识点覆盖面</n-text>
     </template>
     <div class="chart">
-      <Radar :data="data" :options="options" />
+      <Radar :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -20,6 +20,7 @@ import {
   Legend,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 
 // 注册雷达图所需的 Chart.js 组件
 ChartJS.register(
@@ -32,13 +33,15 @@ ChartJS.register(
 )
 
 const aiStore = useAIStore()
+const { chartKey, gridColor } = useChartTheme()
 
 const show = computed(() => {
   return Object.keys(aiStore.detailsData.tags).length > 0
 })
 
-// 最多显示前10个标签，避免雷达图过于拥挤
-const MAX_TAGS = 10
+// 后端 /ai/detail 已经把 tags 截到前 5（routes/ai.ts 的 topTags），这里取同一个上限。
+// 原来写 10 是取不满的死数
+const MAX_TAGS = 5
 
 const title = computed(() => {
   const totalTags = Object.keys(aiStore.detailsData.tags).length
@@ -112,11 +115,11 @@ const options = computed(() => {
           },
         },
         grid: {
-          color: "rgba(0, 0, 0, 0.1)",
+          color: gridColor.value,
           circular: true,
         },
         angleLines: {
-          color: "rgba(0, 0, 0, 0.1)",
+          color: gridColor.value,
         },
         pointLabels: {
           font: {
@@ -138,7 +141,8 @@ const options = computed(() => {
             const index = context.dataIndex
             const actualValue = tagData[index].value
             const percentage = Math.round(Number(context.parsed.r))
-            return `完成 ${actualValue} 道题 (掌握度 ${percentage}%)`
+            // 这个百分比是「占最多的那个标签的比例」，不是掌握度 —— 第一名恒为 100%
+            return `完成 ${actualValue} 道题 (占最多标签的 ${percentage}%)`
           },
         },
       },
diff --git a/apps/web/src/oj/ai/components/TimeActivityHeatmap.vue b/apps/web/src/oj/ai/components/TimeActivityHeatmap.vue
index daa85ad..60a205c 100644
--- a/apps/web/src/oj/ai/components/TimeActivityHeatmap.vue
+++ b/apps/web/src/oj/ai/components/TimeActivityHeatmap.vue
@@ -6,7 +6,7 @@
       </n-text>
     </template>
     <div style="height: 300px">
-      <Bar :data="data" :options="options" />
+      <Bar :key="chartKey" :data="data" :options="options" />
     </div>
   </n-card>
 </template>
@@ -23,10 +23,12 @@ import {
   Legend,
 } from "chart.js"
 import { useAIStore } from "oj/store/ai"
+import { useChartTheme } from "shared/composables/chartTheme"
 
 ChartJS.register(CategoryScale, LinearScale, BarElement, Title, Tooltip, Legend)
 
 const aiStore = useAIStore()
+const { chartKey } = useChartTheme()
 
 const WEEKDAYS = ["周日", "周一", "周二", "周三", "周四", "周五", "周六"]
 const TIME_PERIODS = [
diff --git a/apps/web/src/oj/store/ai.ts b/apps/web/src/oj/store/ai.ts
index daedef5..7d6ceb2 100644
--- a/apps/web/src/oj/store/ai.ts
+++ b/apps/web/src/oj/store/ai.ts
@@ -25,6 +25,7 @@ export const useAIStore = defineStore("ai", () => {
     contestCount: 0,
     solved: [],
     flowcharts: [],
+    rankScope: "global",
   })
   const heatmapData = ref<{ timestamp: number; value: number }[]>([])
 
@@ -51,6 +52,7 @@ export const useAIStore = defineStore("ai", () => {
     detailsData.tags = res.tags
     detailsData.difficulty = res.difficulty
     detailsData.contestCount = res.contestCount
+    detailsData.rankScope = res.rankScope
     detailsData.flowcharts = res.flowcharts
   }
 
diff --git a/apps/web/src/shared/composables/chartTheme.ts b/apps/web/src/shared/composables/chartTheme.ts
new file mode 100644
index 0000000..15a2ea7
--- /dev/null
+++ b/apps/web/src/shared/composables/chartTheme.ts
@@ -0,0 +1,40 @@
+import { useDark } from "@vueuse/core"
+import { Chart as ChartJS } from "chart.js"
+
+/**
+ * chart.js 的默认配色是写死的浅色（文字 #666、网格线 rgba(0,0,0,0.1)），深色主题下
+ * 坐标轴刻度和图例几乎看不见。这里挂一次全局默认值，跟着 isDark 走。
+ *
+ * 只改默认值还不够：options 不是 computed 的图表在主题切换后不会重绘，
+ * 所以另外给出 chartKey —— 图表绑到 :key 上，切换时整个重新挂载。
+ */
+export function useChartTheme() {
+  const isDark = useDark()
+
+  const textColor = computed(() =>
+    isDark.value ? "rgba(255, 255, 255, 0.75)" : "#606266",
+  )
+  const gridColor = computed(() =>
+    isDark.value ? "rgba(255, 255, 255, 0.12)" : "rgba(0, 0, 0, 0.1)",
+  )
+  const chartKey = computed(() => (isDark.value ? "dark" : "light"))
+
+  watchEffect(() => {
+    ChartJS.defaults.color = textColor.value
+    // 网格线只能从 scale 这边改，**不要**去动 ChartJS.defaults.borderColor：
+    // Colors 插件的 containsDefaultColorsDefenitions() 一看到根上的 borderColor
+    // 不等于出厂值就整个罢工，靠它自动配色的图（DurationChart）会退成近黑的柱子和图例
+    // 网格线走 defaults.set("scale", ...)，所有轴类型都继承这一层。
+    // **不要**去动 ChartJS.defaults.borderColor：Colors 插件的
+    // containsDefaultColorsDefenitions() 一看到根上的 borderColor 不等于出厂值
+    // 就整个罢工，靠它自动配色的图（DurationChart）会退成近黑的柱子和图例。
+    // 也不要直接写 defaults.scales.linear.border —— 那要求对应的 scale 已经注册，
+    // 只注册了 radialLinear 的雷达图会在 setup 里抛错。
+    ChartJS.defaults.set("scale", {
+      grid: { color: gridColor.value },
+      border: { color: gridColor.value },
+    })
+  })
+
+  return { isDark, textColor, gridColor, chartKey }
+}
diff --git a/packages/contract/src/ai.ts b/packages/contract/src/ai.ts
index 3c8b6cc..02662f2 100644
--- a/packages/contract/src/ai.ts
+++ b/packages/contract/src/ai.ts
@@ -13,6 +13,8 @@ export const durationDataSchema = z.object({
   end: z.string(),
   grade: gradeSchema,
   problemCount: z.number().int(),
+  /** 该周期内判为通过的提交数。problemCount 是去重后的题数，两者不能互相代替 */
+  acceptedCount: z.number().int(),
   submissionCount: z.number().int(),
 })
 
@@ -53,6 +55,11 @@ export const aiDetailSchema = z.object({
   tags: z.record(z.string(), z.number().int()),
   difficulty: z.record(z.string(), z.number().int()),
   contestCount: z.number().int(),
+  /**
+   * solved 里的 rank/acCount 是在哪个范围里排的。班里只有一个人时后端会回退到全服，
+   * 前端不能只看 className 有没有值就写「班级排名」。
+   */
+  rankScope: z.enum(["class", "global"]),
 })
 
 /**