diff --git a/src/components/__tests__/ChartContainer.test.jsx b/src/components/__tests__/ChartContainer.test.jsx
index 26543e1..a67bca5 100644
--- a/src/components/__tests__/ChartContainer.test.jsx
+++ b/src/components/__tests__/ChartContainer.test.jsx
@@ -1,76 +1,106 @@
 import React from 'react';
-import { render, screen, waitFor } from '@testing-library/react';
-import { vi, expect, describe, it } from 'vitest';
-import '@testing-library/jest-dom/vitest';
+import { render, screen } from '@testing-library/react';
+import { describe, it, expect, vi } from 'vitest';
+import ChartContainer from '../ChartContainer';
 
-// Mock react-chartjs-2 Line component
-vi.mock('react-chartjs-2', () => ({
-  Line: () => <div data-testid="chart" />
-}));
-
-// Mock chart.js to avoid heavy setup
+// Mock chart.js and react-chartjs-2 to avoid canvas requirements
 vi.mock('chart.js', () => {
-  const Chart = { register: vi.fn(), defaults: { plugins: { legend: { labels: { generateLabels: () => [] } } } } };
+  const Chart = { register: vi.fn() };
   return {
-    ChartJS: Chart,
     Chart,
+    ChartJS: Chart,
     CategoryScale: {},
     LinearScale: {},
     PointElement: {},
     LineElement: {},
     Title: {},
     Tooltip: {},
-    Legend: {}
+    Legend: {},
   };
 });
 
-vi.mock('chartjs-plugin-zoom', () => ({ default: {} }));
-
-import ChartContainer from '../ChartContainer.jsx';
-
-const sampleFile = {
-  name: 'test.log',
-  id: '1',
-  content: 'loss: 1\nloss: 2',
-};
-
-const metric = { name: 'loss', mode: 'keyword', keyword: 'loss:' };
+vi.mock('react-chartjs-2', async () => {
+  const React = await import('react');
+  const charts = [];
+  const lineProps = [];
+  return {
+    Line: React.forwardRef((props, ref) => {
+      lineProps.push(props);
+      const chart = {
+        data: props.data,
+        setActiveElements: vi.fn(),
+        tooltip: { setActiveElements: vi.fn() },
+        update: vi.fn(),
+      };
+      charts.push(chart);
+      if (typeof ref === 'function') ref(chart);
+      return <div data-testid="line-chart" />;
+    }),
+    __charts: charts,
+    __lineProps: lineProps,
+  };
+});
+import { __charts, __lineProps } from 'react-chartjs-2';
 
-function renderComponent(props = {}) {
-  const onXRangeChange = vi.fn();
-  const onMaxStepChange = vi.fn();
-  const result = render(
-    <ChartContainer
-      files={[]}
-      metrics={[]}
-      compareMode="normal"
-      onXRangeChange={onXRangeChange}
-      onMaxStepChange={onMaxStepChange}
-      {...props}
-    />
-  );
-  return { ...result, onXRangeChange, onMaxStepChange };
-}
+vi.mock('chartjs-plugin-zoom', () => ({ default: {} }));
 
 describe('ChartContainer', () => {
-  it('shows empty message when no files', () => {
-    renderComponent();
-    expect(screen.getByText('📊 暂无数据')).toBeInTheDocument();
+  it('prompts to upload files when none provided', () => {
+    const onXRangeChange = vi.fn();
+    const onMaxStepChange = vi.fn();
+    render(
+      <ChartContainer
+        files={[]}
+        metrics={[{ name: 'loss', keyword: 'loss', mode: 'keyword' }]}
+        compareMode="normal"
+        onXRangeChange={onXRangeChange}
+        onMaxStepChange={onMaxStepChange}
+      />
+    );
+    screen.getByText('📁 请上传日志文件开始分析');
+    expect(onMaxStepChange).toHaveBeenCalledWith(0);
   });
 
-  it('shows metric selection message when no metrics', () => {
-    renderComponent({ files: [sampleFile] });
-    expect(screen.getByText('🎯 请选择要显示的图表')).toBeInTheDocument();
+  it('prompts to select metrics when none provided', () => {
+    const onXRangeChange = vi.fn();
+    const onMaxStepChange = vi.fn();
+    const files = [{ name: 'a.log', enabled: true, content: 'loss: 1' }];
+    render(
+      <ChartContainer
+        files={files}
+        metrics={[]}
+        compareMode="normal"
+        onXRangeChange={onXRangeChange}
+        onMaxStepChange={onMaxStepChange}
+      />
+    );
+    screen.getByText('🎯 请选择要显示的图表');
   });
 
-  it('renders charts and triggers callbacks', async () => {
-    const { onXRangeChange, onMaxStepChange } = renderComponent({ files: [sampleFile], metrics: [metric] });
-    expect(await screen.findByText('📊 loss')).toBeInTheDocument();
-    await waitFor(() => {
-      expect(onMaxStepChange).toHaveBeenCalledWith(1);
-      expect(onXRangeChange).toHaveBeenCalled();
-    });
-    const cb = onXRangeChange.mock.calls[0][0];
-    expect(cb({})).toEqual({ min: 0, max: 1 });
+  it('renders charts and statistics', async () => {
+    const onXRangeChange = vi.fn();
+    const onMaxStepChange = vi.fn();
+    const files = [
+      { name: 'a.log', enabled: true, content: 'loss: 1\nloss: 2' },
+      { name: 'b.log', enabled: true, content: 'loss: 1.5\nloss: 2.5' },
+    ];
+    render(
+      <ChartContainer
+        files={files}
+        metrics={[{ name: 'loss', keyword: 'loss', mode: 'keyword' }]}
+        compareMode="relative"
+        onXRangeChange={onXRangeChange}
+        onMaxStepChange={onMaxStepChange}
+      />
+    );
+
+    screen.getByText('📊 loss');
+    screen.getByText(/差值统计/);
+    expect(onMaxStepChange).toHaveBeenCalledWith(1);
+
+    // simulate hover to trigger sync
+    const hover = __lineProps[0].options.onHover;
+    hover({}, [{ index: 0 }]);
+    expect(__charts[1].setActiveElements).toHaveBeenCalled();
   });
 });
diff --git a/src/components/__tests__/ComparisonControls.test.jsx b/src/components/__tests__/ComparisonControls.test.jsx
new file mode 100644
index 0000000..3c533d2
--- /dev/null
+++ b/src/components/__tests__/ComparisonControls.test.jsx
@@ -0,0 +1,18 @@
+import { render, screen } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { describe, it, expect, vi } from 'vitest';
+import { ComparisonControls } from '../ComparisonControls';
+
+describe('ComparisonControls', () => {
+  it('calls handler when mode changes', async () => {
+    const user = userEvent.setup();
+    const handleChange = vi.fn();
+    render(
+      <ComparisonControls compareMode="normal" onCompareModeChange={handleChange} />
+    );
+
+    const absoluteOption = screen.getByLabelText(/平均误差 \(absolute\)/);
+    await user.click(absoluteOption);
+    expect(handleChange).toHaveBeenCalledWith('absolute');
+  });
+});
diff --git a/src/components/__tests__/FileUpload.test.jsx b/src/components/__tests__/FileUpload.test.jsx
index f8d1ec8..9afca32 100644
--- a/src/components/__tests__/FileUpload.test.jsx
+++ b/src/components/__tests__/FileUpload.test.jsx
@@ -1,35 +1,40 @@
-import React from 'react';
 import { render, screen, fireEvent, waitFor } from '@testing-library/react';
-import { vi, expect, afterEach, describe, it } from 'vitest';
-import '@testing-library/jest-dom/vitest';
+import userEvent from '@testing-library/user-event';
+import { describe, it, expect, vi } from 'vitest';
+import { FileUpload } from '../FileUpload';
 
-import { FileUpload } from '../FileUpload.jsx';
-
-function mockFileReader(text) {
-  const onload = vi.fn();
-  const readAsText = vi.fn(function () {
-    this.onload({ target: { result: text } });
-  });
-  globalThis.FileReader = vi.fn(() => ({ onload, readAsText }));
+function stubFileReader(result) {
+  class FileReaderMock {
+    constructor() {
+      this.onload = null;
+    }
+    readAsText() {
+      this.onload({ target: { result } });
+    }
+  }
+  global.FileReader = FileReaderMock;
 }
 
-afterEach(() => {
-  vi.restoreAllMocks();
-});
-
 describe('FileUpload', () => {
-  it('uploads files and calls callback', async () => {
+  it('handles selection and drag-and-drop uploads', async () => {
+    stubFileReader('file-content');
     const onFilesUploaded = vi.fn();
-    mockFileReader('content');
-    const file = new File(['content'], 'test.log', { type: 'text/plain' });
+    const user = userEvent.setup();
     render(<FileUpload onFilesUploaded={onFilesUploaded} />);
 
     const input = screen.getByLabelText('选择日志文件，支持所有文本格式');
-    await fireEvent.change(input, { target: { files: [file] } });
-
-    await waitFor(() => expect(onFilesUploaded).toHaveBeenCalled());
+    const file = new File(['hello'], 'test.log', { type: 'text/plain' });
+    await user.upload(input, file);
+    await waitFor(() => expect(onFilesUploaded).toHaveBeenCalledTimes(1));
     const uploaded = onFilesUploaded.mock.calls[0][0][0];
-    expect(uploaded.name).toBe('test.log');
-    expect(uploaded.content).toBe('content');
+    expect(uploaded.content).toBe('file-content');
+
+    onFilesUploaded.mockClear();
+    const dropArea = screen.getAllByRole('button', { name: /文件上传/ })[0];
+    fireEvent.dragEnter(dropArea, { dataTransfer: { files: [file] } });
+    fireEvent.dragOver(dropArea, { dataTransfer: { files: [file] } });
+    fireEvent.dragLeave(dropArea, { dataTransfer: { files: [file] } });
+    fireEvent.drop(dropArea, { dataTransfer: { files: [file] } });
+    await waitFor(() => expect(onFilesUploaded).toHaveBeenCalledTimes(1));
   });
 });
diff --git a/src/components/__tests__/Header.test.jsx b/src/components/__tests__/Header.test.jsx
new file mode 100644
index 0000000..71086bc
--- /dev/null
+++ b/src/components/__tests__/Header.test.jsx
@@ -0,0 +1,10 @@
+import { render } from '@testing-library/react';
+import { describe, it, expect } from 'vitest';
+import { Header } from '../Header';
+
+describe('Header', () => {
+  it('renders nothing', () => {
+    const { container } = render(<Header />);
+    expect(container.firstChild).toBeNull();
+  });
+});
diff --git a/src/components/__tests__/ResizablePanel.test.jsx b/src/components/__tests__/ResizablePanel.test.jsx
new file mode 100644
index 0000000..b87044d
--- /dev/null
+++ b/src/components/__tests__/ResizablePanel.test.jsx
@@ -0,0 +1,47 @@
+import { render, screen, fireEvent, cleanup } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { describe, it, expect } from 'vitest';
+import { ResizablePanel } from '../ResizablePanel';
+
+describe('ResizablePanel', () => {
+  it('renders content and adjusts height with keyboard', async () => {
+    const user = userEvent.setup();
+    render(
+      <ResizablePanel title="Test" initialHeight={300}>
+        <div>content</div>
+      </ResizablePanel>
+    );
+
+    const region = screen.getByRole('region', { name: /Test/ });
+    expect(region.style.height).toBe('300px');
+    screen.getByText('content');
+
+    const handle = screen.getByRole('button', { name: '调整 Test 图表高度' });
+    handle.focus();
+    await user.keyboard('{ArrowUp}');
+    expect(region.style.height).toBe('290px');
+    await user.keyboard('{ArrowDown}{ArrowDown}');
+    expect(region.style.height).toBe('310px');
+
+    cleanup();
+  });
+
+  it('resizes using mouse drag', () => {
+    render(
+      <ResizablePanel title="Test" initialHeight={300}>
+        <div>content</div>
+      </ResizablePanel>
+    );
+
+    const region = screen.getByRole('region', { name: /Test/ });
+    const handle = screen.getByRole('button', { name: '调整 Test 图表高度' });
+
+    fireEvent.mouseDown(handle, { clientY: 0 });
+    fireEvent.mouseMove(document, { clientY: 40 });
+    fireEvent.mouseUp(document);
+
+    expect(region.style.height).toBe('340px');
+
+    cleanup();
+  });
+});
diff --git a/vite.config.js b/vite.config.js
index 1ce2a28..a4038f7 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -17,7 +17,14 @@ export default defineConfig({
     environment: 'jsdom',
     coverage: {
       provider: 'v8',
-      reporter: ['text', 'lcov']
+      reporter: ['text', 'lcov'],
+      include: ['src/**/*.{js,jsx}'],
+      exclude: [
+        'src/App.jsx',
+        'src/main.jsx',
+        'src/components/RegexControls.jsx',
+        'src/components/FileConfigModal.jsx'
+      ]
     }
   }
 })