diff --git a/src/App.js b/src/App.js
index 9ea0cc5..3af81d2 100644
--- a/src/App.js
+++ b/src/App.js
@@ -1,5 +1,5 @@
 import React from 'react';
-import AnnotationMain from './components/AnnotationMain';
+import AnnotationMain from './components/AnnotationMain/AnnotationMain';
 
 function App() {
 
diff --git a/src/components/AnnotationControls.js b/src/components/AnnotationControls.js
deleted file mode 100644
index 65abab8..0000000
--- a/src/components/AnnotationControls.js
+++ /dev/null
@@ -1,91 +0,0 @@
-import React from 'react';
-
-function AnnotationControls({ onFrameBackward, onPlayPause, isPlaying, onFrameForward, onSaveAnnotation, onDelete }) {
-    return (
-        <div style={{
-            display: 'flex',
-            justifyContent: 'center',
-            position: 'relative',
-            zIndex: 1,
-            padding: '10px',
-            background: '#f5f5f5',
-            borderRadius: '4px',
-            marginTop: '10px'
-        }}>
-            <button
-                style={{
-                    padding: '10px 20px',
-                    fontSize: '16px',
-                    margin: '0 5px',
-                    background: '#e0e0e0',
-                    border: '1px solid #ccc',
-                    borderRadius: '4px',
-                    cursor: 'pointer'
-                }}
-                onClick={onFrameBackward}
-                title="Previous Frame"
-            >
-                ⏮️
-            </button>
-            <button
-                style={{
-                    padding: '10px 20px',
-                    fontSize: '16px',
-                    margin: '0 5px',
-                    background: isPlaying ? '#ff8a8a' : '#8aff8a',
-                    border: '1px solid #ccc',
-                    borderRadius: '4px',
-                    cursor: 'pointer'
-                }}
-                onClick={onPlayPause}
-            >
-                {isPlaying ? '⏸️ Pause' : '▶️ Play'}
-            </button>
-            <button
-                style={{
-                    padding: '10px 20px',
-                    fontSize: '16px',
-                    margin: '0 5px',
-                    background: '#e0e0e0',
-                    border: '1px solid #ccc',
-                    borderRadius: '4px',
-                    cursor: 'pointer'
-                }}
-                onClick={onFrameForward}
-                title="Next Frame"
-            >
-                ⏭️
-            </button>
-            <button
-                style={{
-                    padding: '10px 20px',
-                    fontSize: '16px',
-                    margin: '0 5px',
-                    background: '#8ad4ff',
-                    border: '1px solid #ccc',
-                    borderRadius: '4px',
-                    cursor: 'pointer'
-                }}
-                onClick={onSaveAnnotation}
-            >
-                💾 Save
-            </button>
-            <button
-                style={{
-                    padding: '10px 20px',
-                    fontSize: '16px',
-                    margin: '0 5px',
-                    background: '#ffb38a',
-                    border: '1px solid #ccc',
-                    borderRadius: '4px',
-                    cursor: 'pointer'
-                }}
-                onClick={onDelete}
-            >
-                🗑️ Delete
-            </button>
-        </div>
-    );
-}
-
-export default AnnotationControls;
\ No newline at end of file
diff --git a/src/components/AnnotationControls/AnnotationControls.css b/src/components/AnnotationControls/AnnotationControls.css
new file mode 100644
index 0000000..98e4a8c
--- /dev/null
+++ b/src/components/AnnotationControls/AnnotationControls.css
@@ -0,0 +1,39 @@
+.buttons-group {
+    display: flex;
+    justify-content: center;
+    position: relative;
+    z-index: 1;
+    padding: 10px;
+    background: #f5f5f5;
+    border-radius: 4px;
+    margin-top: 10px;
+}
+
+.control-btn {
+    padding: 10px 20px;
+    font-size: 16px;
+    margin: 0 5px;
+    border: 1px solid #ccc;
+    border-radius: 4px;
+    cursor: pointer;
+}
+
+.play-btn{
+    background: #8aff8a;
+}
+
+.pause-btn{
+    background: #ff8a8a;
+}
+
+.arrow-btn{
+    background: #e0e0e0;
+}
+
+.save-btn{
+    background: #8ad4ff;
+}
+
+.delete-btn{
+    background: #ffb38a;
+}
\ No newline at end of file
diff --git a/src/components/AnnotationControls/AnnotationControls.js b/src/components/AnnotationControls/AnnotationControls.js
new file mode 100644
index 0000000..f11474b
--- /dev/null
+++ b/src/components/AnnotationControls/AnnotationControls.js
@@ -0,0 +1,43 @@
+import React from 'react';
+import './AnnotationControls.css';
+
+function AnnotationControls({ onFrameBackward, onPlayPause, isPlaying, onFrameForward, onSaveAnnotation, onDelete }) {
+    return (
+        <div className='buttons-group' >
+            <button 
+                className='control-btn arrow-btn'
+                onClick={onFrameBackward}
+                title="Previous Frame"
+            >
+                ⏮️
+            </button>
+            <button
+                className={isPlaying ? 'control-btn pause-btn': 'control-btn play-btn'}
+                onClick={onPlayPause}
+            >
+                {isPlaying ? '⏸️ Pause' : '▶️ Play'}
+            </button>
+            <button
+                className='control-btn arrow-btn'
+                onClick={onFrameForward}
+                title="Next Frame"
+            >
+                ⏭️
+            </button>
+            <button
+                className='control-btn save-btn'
+                onClick={onSaveAnnotation}
+            >
+                💾 Save
+            </button>
+            <button
+                className='control-btn delete-btn'
+                onClick={onDelete}
+            >
+                🗑️ Delete
+            </button>
+        </div>
+    );
+}
+
+export default AnnotationControls;
\ No newline at end of file
diff --git a/src/components/AnnotationList.js b/src/components/AnnotationList.js
index bcfd959..241964f 100644
--- a/src/components/AnnotationList.js
+++ b/src/components/AnnotationList.js
@@ -5,7 +5,7 @@ import React from 'react';
 function AnnotationList({ annotations, onAnnotationClick }) {
     return (
         <div>
-            <h3>Annotations</h3>
+            <h3 className='menu-title'>Annotations</h3>
             <ul>
                 {annotations.map((annotation, index) => (
                     <li key={index} onClick={() => onAnnotationClick(annotation.time)}>
diff --git a/src/components/AnnotationMain/AnnotationMain.css b/src/components/AnnotationMain/AnnotationMain.css
new file mode 100644
index 0000000..8c28be9
--- /dev/null
+++ b/src/components/AnnotationMain/AnnotationMain.css
@@ -0,0 +1,54 @@
+.content-wrapper {
+    display: flex;
+    height: 100vh;
+    overflow: hidden;
+}
+
+.side-menu {
+    display: flex;
+    flex-direction: column;
+    width: 15%;
+    height: 100%;
+}
+
+.left-menu{
+    border-right: 1px solid #ccc;
+}
+
+.right-menu{
+    overflow-y: auto;
+    border-left: 1px solid #ccc;
+}
+
+.player-wrapper {
+    width: 70%;
+    height: 100%;
+    display: flex;
+    flex-direction: column;
+}
+
+.error-message {
+    background: #ffdddd;
+    color: #d8000c;
+    padding: 6px;
+    margin: 6px;
+    border-radius: 4px;
+}
+
+.player-container {
+    display: flex;
+    flex: 1;
+    flex-direction: column;
+    position: relative;
+    min-height: 0;
+}
+
+.player-block {
+    display: flex;
+    flex: 1;
+    position: relative;
+    background: #000;
+    justify-content: center;
+    align-items: center;
+    overflow: hidden;
+}
\ No newline at end of file
diff --git a/src/components/AnnotationMain.js b/src/components/AnnotationMain/AnnotationMain.js
similarity index 75%
rename from src/components/AnnotationMain.js
rename to src/components/AnnotationMain/AnnotationMain.js
index 38d1d40..903dd11 100644
--- a/src/components/AnnotationMain.js
+++ b/src/components/AnnotationMain/AnnotationMain.js
@@ -1,12 +1,13 @@
 import React, { useState, useEffect, useRef } from 'react';
-import VideoPlayer from './VideoPlayer';
-import AnnotationList from './AnnotationList';
-import MediaList from './MediaList';
-import DetectionClassList from './DetectionClassList';
-import CanvasEditor from './CanvasEditor';
-import * as AnnotationService from '../services/AnnotationService';
-import AnnotationControls from './AnnotationControls';
-import saveAnnotation from '../services/DataHandler';
+import VideoPlayer from '../VideoPlayer/VideoPlayer';
+import AnnotationList from '../AnnotationList';
+import MediaList from '../MediaList/MediaList';
+import DetectionClassList from '../DetectionClassList/DetectionClassList';
+import CanvasEditor from '../CanvasEditor/CanvasEditor';
+import * as AnnotationService from '../../services/AnnotationService';
+import AnnotationControls from '../AnnotationControls/AnnotationControls';
+import saveAnnotation from '../../services/DataHandler';
+import './AnnotationMain.css';
 
 function AnnotationMain() {
     const [files, setFiles] = useState([]);
@@ -169,60 +170,27 @@ function AnnotationMain() {
     }, []);
 
     return (
-        <div style={{ display: 'flex', height: '100vh', overflow: 'hidden' }}>
-            <div style={{
-                width: '15%',
-                height: '100%',
-                overflowY: 'auto',
-                borderRight: '1px solid #ccc',
-                display: 'flex',
-                flexDirection: 'column'
-            }}>
+        <div className='content-wrapper' >
+            <div className='side-menu left-menu' >
                 <MediaList
                     files={files}
                     selectedFile={selectedFile}
                     onFileSelect={handleFileSelect}
                     onDropNewFiles={handleDropNewFiles}
                 />
-                <div style={{ flexGrow: 1 }}>
-                    <DetectionClassList onClassSelect={handleClassSelect} />
-                </div>
+
+                <DetectionClassList onClassSelect={handleClassSelect} />
             </div>
 
-            <div style={{
-                width: '70%',
-                height: '100%',
-                display: 'flex',
-                flexDirection: 'column'
-            }}>
+            <div className='player-wrapper' >
                 {errorMessage && (
-                    <div style={{
-                        backgroundColor: '#ffdddd',
-                        color: '#d8000c',
-                        padding: '6px',
-                        margin: '6px',
-                        borderRadius: '4px'
-                    }}>
+                    <div className='error-message' >
                         {errorMessage}
                     </div>
                 )}
 
-                <div style={{
-                    flex: 1,
-                    display: 'flex',
-                    flexDirection: 'column',
-                    position: 'relative',
-                    minHeight: 0
-                }} ref={containerRef}>
-                    <div style={{
-                        flex: 1,
-                        position: 'relative',
-                        backgroundColor: '#000',
-                        display: 'flex',
-                        justifyContent: 'center',
-                        alignItems: 'center',
-                        overflow: 'hidden'
-                    }}>
+                <div className='player-container' ref={containerRef}>
+                    <div className='player-block' >
                         <VideoPlayer
                             videoFile={selectedFile}
                             currentTime={currentTime}
@@ -254,12 +222,7 @@ function AnnotationMain() {
                 </div>
             </div>
 
-            <div style={{
-                width: '15%',
-                height: '100%',
-                overflowY: 'auto',
-                borderLeft: '1px solid #ccc'
-            }}>
+            <div className='side-menu right-menu'>
                 <AnnotationList
                     annotations={Object.values(annotations)}
                     onAnnotationClick={handleAnnotationClick}
diff --git a/src/components/CanvasEditor/CanvasEditor.css b/src/components/CanvasEditor/CanvasEditor.css
new file mode 100644
index 0000000..57a20cc
--- /dev/null
+++ b/src/components/CanvasEditor/CanvasEditor.css
@@ -0,0 +1,15 @@
+.editor-container {
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    top: 0;
+    left: 0;
+    pointer-events: auto;
+}
+
+.canvas-editor {
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    pointer-events: auto;
+}
\ No newline at end of file
diff --git a/src/components/CanvasEditor.js b/src/components/CanvasEditor/CanvasEditor.js
similarity index 88%
rename from src/components/CanvasEditor.js
rename to src/components/CanvasEditor/CanvasEditor.js
index e1dc603..539b155 100644
--- a/src/components/CanvasEditor.js
+++ b/src/components/CanvasEditor/CanvasEditor.js
@@ -1,18 +1,19 @@
 import React, { useRef, useState, useEffect } from 'react';
-import * as AnnotationService from '../services/AnnotationService';
-import DetectionContainer from './DetectionContainer';
+import * as AnnotationService from '../../services/AnnotationService';
+import DetectionContainer from '../DetectionContainer';
+import './CanvasEditor.css';
 
 function CanvasEditor({
-                          width,
-                          height,
-                          detections,
-                          initialCurrentDetection = null,
-                          selectedDetectionIndices,
-                          onDetectionsChange,
-                          onSelectionChange,
-                          children,
-                          detectionClass
-                      }) {
+    width,
+    height,
+    detections,
+    initialCurrentDetection = null,
+    selectedDetectionIndices,
+    onDetectionsChange,
+    onSelectionChange,
+    children,
+    detectionClass
+}) {
     const containerRef = useRef(null);
     const [currentDetection, setCurrentDetection] = useState(initialCurrentDetection);
     const [mouseDownPos, setMouseDownPos] = useState(null);
@@ -197,7 +198,7 @@ function CanvasEditor({
             x: mouseX - localDetections[index].x1,
             y: mouseY - localDetections[index].y1,
         });
-        setMouseDownPos({x: mouseX, y: mouseY});
+        setMouseDownPos({ x: mouseX, y: mouseY });
         setIsDragging(true);
     };
 
@@ -209,7 +210,7 @@ function CanvasEditor({
                 setLocalSelectedIndices([index]);
                 onSelectionChange && onSelectionChange([index]);
             }
-            else{
+            else {
                 const newSelectedIndices = [...localSelectedIndices, index];
                 setLocalSelectedIndices(newSelectedIndices);
                 onSelectionChange && onSelectionChange(newSelectedIndices);
@@ -240,27 +241,13 @@ function CanvasEditor({
     }, [isDragging, resizeData, mouseDownPos]);
 
     return (
-        <div
-            style={{
-                position: 'absolute',
-                width: '100%',
-                height: '100%',
-                top: 0,
-                left: 0,
-                pointerEvents: 'auto',
-            }}
-        >
-            <div ref={containerRef}
-                 style={{
-                     position: 'absolute',
-                     width: '100%',
-                     height: '100%',
-                     pointerEvents: 'auto',
-                 }}
-                 onMouseDown={handleMouseDown}
-                 onMouseMove={handleMouseMove}
-                 onMouseUp={handleMouseUp}
-                 onMouseLeave={handleMouseUp}
+        <div className='editor-container' >
+            <div className='canvas-editor'
+                ref={containerRef}
+                onMouseDown={handleMouseDown}
+                onMouseMove={handleMouseMove}
+                onMouseUp={handleMouseUp}
+                onMouseLeave={handleMouseUp}
             >
                 {children}
                 <DetectionContainer
diff --git a/src/components/DetectionClassList/DetectionClassList.css b/src/components/DetectionClassList/DetectionClassList.css
new file mode 100644
index 0000000..b9355c9
--- /dev/null
+++ b/src/components/DetectionClassList/DetectionClassList.css
@@ -0,0 +1,19 @@
+.class-list {
+    flex-grow: 1;
+}
+
+.class-list-group {
+    list-style-type: none;
+    padding: 0;
+    margin: 0;
+}
+
+.class-list-item {
+    display: flex;
+    align-items: center;
+    cursor: pointer;
+    padding: 8px;
+    font-size: 14px;
+    margin-bottom: 2px;
+    border-radius: 4px;
+}
\ No newline at end of file
diff --git a/src/components/DetectionClassList.js b/src/components/DetectionClassList/DetectionClassList.js
similarity index 88%
rename from src/components/DetectionClassList.js
rename to src/components/DetectionClassList/DetectionClassList.js
index 0b3c628..a56dd54 100644
--- a/src/components/DetectionClassList.js
+++ b/src/components/DetectionClassList/DetectionClassList.js
@@ -1,5 +1,6 @@
 import React, { useEffect, useState } from 'react';
-import DetectionClass from '../models/DetectionClass';
+import DetectionClass from '../../models/DetectionClass';
+import './DetectionClassList.css';
 
 function DetectionClassList({ onClassSelect }) {
     const [detectionClasses, setDetectionClasses] = useState([]);
@@ -83,9 +84,9 @@ function DetectionClassList({ onClassSelect }) {
     };
 
     return (
-        <div>
-            <h3 style={{ marginTop: '15px', fontSize: '14px' }}>Classes</h3>
-            <ul style={{ listStyleType: 'none', padding: 0, margin: 0 }}>
+        <div className='class-list'>
+            <h3 className='menu-title'>Classes</h3>
+            <ul className='class-list-group' >
                 {detectionClasses.map((cls) => {
                     const backgroundColor = calculateColor(cls.Id);
                     const darkBg = calculateColor(cls.Id, '0.8');
@@ -94,16 +95,10 @@ function DetectionClassList({ onClassSelect }) {
                     return (
                         <li
                             key={cls.Id}
+                            className='class-list-item'
                             style={{
-                                cursor: 'pointer',
-                                padding: '8px',
                                 border: `1px solid ${isSelected ? '#000' : '#eee'}`,
                                 backgroundColor: isSelected ? darkBg : backgroundColor,
-                                fontSize: '14px',
-                                marginBottom: '2px',
-                                display: 'flex',
-                                alignItems: 'center',
-                                borderRadius: '4px',
                             }}
                             onClick={() => handleClassClick(cls)}
                         >
diff --git a/src/components/MediaList/MediaList.css b/src/components/MediaList/MediaList.css
new file mode 100644
index 0000000..9ab905e
--- /dev/null
+++ b/src/components/MediaList/MediaList.css
@@ -0,0 +1,28 @@
+.menu-title {
+    font-size: 14px;
+    margin: 15px 0;
+}
+
+.file-list-group {
+    padding: 0;
+    list-style-type: none;
+}
+
+.file-list-item {
+    cursor: pointer;
+    padding: 6px;
+    border-bottom: 1px solid #eee;
+    font-size: 12px;
+}
+
+.label {
+    font-size: 12px;
+}
+
+.file-input-block {
+    border: 2px dashed #ccc;
+    padding: 8px;
+    text-align: center;
+    margin-top: 10px;
+    cursor: pointer;
+}
\ No newline at end of file
diff --git a/src/components/MediaList.js b/src/components/MediaList/MediaList.js
similarity index 57%
rename from src/components/MediaList.js
rename to src/components/MediaList/MediaList.js
index c8cefaf..506e777 100644
--- a/src/components/MediaList.js
+++ b/src/components/MediaList/MediaList.js
@@ -1,5 +1,6 @@
 import React from 'react';
 import { useDropzone } from 'react-dropzone';
+import './MediaList.css'
 
 function MediaList({ files, selectedFile, onFileSelect, onDropNewFiles }) {
     const { getRootProps, getInputProps, isDragActive } = useDropzone({
@@ -7,18 +8,15 @@ function MediaList({ files, selectedFile, onFileSelect, onDropNewFiles }) {
     });
 
     return (
-        <div>
-            <h3 style={{ fontSize: '14px' }}>Files</h3>
-            <ul style={{ listStyleType: 'none', padding: 0 }}>
+        <div className='explorer'>
+            <h3 className='menu-title' >Files</h3>
+            <ul className='file-list-group' >
                 {files.map((file) => (
                     <li
+                        className='file-list-item'
                         key={file.name}
                         style={{
-                            cursor: 'pointer',
-                            padding: '6px',
-                            borderBottom: '1px solid #eee',
-                            backgroundColor: selectedFile === file ? '#f0f0f0' : 'transparent',
-                            fontSize: '12px',
+                            backgroundColor: selectedFile === file ? '#f0f0f0' : 'transparent'
                         }}
                         onClick={() => onFileSelect(file)}
                     >
@@ -26,12 +24,12 @@ function MediaList({ files, selectedFile, onFileSelect, onDropNewFiles }) {
                     </li>
                 ))}
             </ul>
-            <div {...getRootProps()} style={{ border: '2px dashed #ccc', padding: '8px', textAlign: 'center', marginTop: '10px', cursor: 'pointer' }}>
+            <div className='file-input-block' {...getRootProps()} >
                 <input {...getInputProps()} />
                 {isDragActive ? (
-                    <p style={{ fontSize: '12px' }}>Drop here</p>
+                    <p className='label' >Drop here</p>
                 ) : (
-                    <p style={{ fontSize: '12px' }}>Drag new files</p>
+                    <p className='label' >Drag new files</p>
                 )}
             </div>
         </div>
diff --git a/src/components/VideoPlayer/VideoPlayer.css b/src/components/VideoPlayer/VideoPlayer.css
new file mode 100644
index 0000000..4d1c8c0
--- /dev/null
+++ b/src/components/VideoPlayer/VideoPlayer.css
@@ -0,0 +1,40 @@
+.player {
+    position: relative;
+    width: 100%;
+    height: 100%;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: #000;
+    overflow: hidden;
+}
+
+.video {
+    width: 100%;
+    height: auto;
+    max-height: 100%;
+    display: block;
+    object-fit: contain;
+    pointer-events: none;
+}
+
+.player-error {
+    position: absolute;
+    top: 10px;
+    left: 10px;
+    background: rgba(255, 0, 0, 0.7);
+    color: white;
+    padding: 5px;
+    border-radius: 3px;
+    font-size: 12px;
+    z-index: 10;
+}
+
+.player-item{
+    position: absolute;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 100%;
+    pointer-events: auto;
+}
\ No newline at end of file
diff --git a/src/components/VideoPlayer.js b/src/components/VideoPlayer/VideoPlayer.js
similarity index 75%
rename from src/components/VideoPlayer.js
rename to src/components/VideoPlayer/VideoPlayer.js
index 85edf47..4ec95bf 100644
--- a/src/components/VideoPlayer.js
+++ b/src/components/VideoPlayer/VideoPlayer.js
@@ -1,4 +1,5 @@
 import React, { useEffect, useRef, useState } from 'react';
+import './VideoPlayer.css';
 
 function VideoPlayer({ children, videoFile, currentTime, videoRef, isPlaying, onSizeChanged, onSetCurrentTime }) {
     const containerRef = useRef(null);
@@ -131,58 +132,15 @@ function VideoPlayer({ children, videoFile, currentTime, videoRef, isPlaying, on
     }, [onSetCurrentTime, isPlaying]);
 
     return (
-        <div
-            ref={containerRef}
-            style={{
-                position: 'relative',
-                width: '100%',
-                height: '100%',
-                display: 'flex',
-                alignItems: 'center',
-                justifyContent: 'center',
-                backgroundColor: '#000',
-                overflow: 'hidden'
-            }}
-        >
-            <video
-                ref={videoRef}
-                style={{
-                    width: '100%',
-                    height: 'auto',
-                    maxHeight: '100%',
-                    display: 'block',
-                    objectFit: 'contain',
-                    pointerEvents: 'none'
-                }}
-                preload="auto"
-                playsInline
-                muted
-            />
+        <div className='player' ref={containerRef} >
+            <video className='video' ref={videoRef} preload="auto" playsInline muted />
+            
             {playbackError && (
-                <div style={{
-                    position: 'absolute',
-                    top: '10px',
-                    left: '10px',
-                    background: 'rgba(255,0,0,0.7)',
-                    color: 'white',
-                    padding: '5px',
-                    borderRadius: '3px',
-                    fontSize: '12px',
-                    zIndex: 10
-                }}>
+                <div className='player-error' >
                     {playbackError}
                 </div>
             )}
-            <div
-                style={{
-                    position: 'absolute',
-                    top: 0,
-                    left: 0,
-                    width: '100%',
-                    height: '100%',
-                    pointerEvents: 'auto'
-                }}
-            >
+            <div className='player-item'>
                 {children}
             </div>
         </div>