* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Roboto', sans-serif;
    background-color: #f0f0f0;
    height: 100vh;
    display: flex;
}

.app {
    display: flex;
    width: 100%;
}

.sidebar {
    width: 270px;
    background-color: #ffffff;
    box-shadow: 2px 0 5px rgba(0, 0, 0, 0.1);
    padding: 20px;
    display: flex;
    flex-direction: column;
}

.sidebar header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.sidebar header h2 {
    font-size: 24px;
    margin: 0;
}

.sidebar .new-chat {
    background-color: #25D366;
    color: white;
    padding: 10px;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    text-align: center;
}

.sidebar .chat-list {
    list-style-type: none;
    padding: 0;
    margin-top: 20px;
    overflow-y: auto;
}

.sidebar .chat-list li {
    display: flex;
    align-items: center;
    margin-bottom: 15px;
    cursor: pointer;
}

.sidebar .chat-list li:hover {
    background-color: #f1f1f1;
    border-radius: 8px;
}

.sidebar .chat-list li img {
    border-radius: 50%;
    width: 50px;
    height: 50px;
    margin-right: 10px;
}

.sidebar .chat-list li .name {
    font-weight: 500;
    font-size: 16px;
}

.sidebar .chat-list li .last-message {
    color: #888;
    font-size: 14px;
}

.chat-area {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    padding: 20px;
    background-color: #ffffff;
}

.chat-header {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
}

.chat-header img {
    border-radius: 50%;
    width: 50px;
    height: 50px;
    margin-right: 10px;
}

.chat-header h3 {
    font-size: 24px;
    font-weight: 500;
}

.messages {
    flex-grow: 1;
    overflow-y: auto;
    margin-bottom: 20px;
}

.messages .message {
    display: flex;
    margin-bottom: 10px;
}

.messages .message .message-bubble {
    background-color: #f1f1f1;
    padding: 10px;
    border-radius: 10px;
    max-width: 70%;
}

.messages .message .sent .message-bubble {
    background-color: #dcf8c6;
    align-self: flex-end;
}

.messages .message .received .message-bubble {
    background-color: #ffffff;
    align-self: flex-start;
}

.input-area {
    display: flex;
    align-items: center;
    border-top: 1px solid #ddd;
    padding-top: 10px;
    padding-bottom: 10px;
}

.input-area input {
    flex-grow: 1;
    padding: 10px;
    border-radius: 20px;
    border: 1px solid #ddd;
    margin-right: 10px;
}

.input-area button {
    background-color: #25D366;
    border: none;
    padding: 10px 15px;
    border-radius: 20px;
    color: white;
    cursor: pointer;
}