body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

.container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

header {
    background-color: #0078d4;
    color: white;
    padding: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

button {
    background-color: #0078d4;
    color: white;
    border: none;
    padding: 10px;
    cursor: pointer;
    margin: 5px;
}

.chat-container {
    display: flex;
    flex-direction: column;
    flex: 1;
    padding: 10px;
    background-color: #f1f1f1;
    overflow: hidden;
}

.messages {
    flex: 1;
    overflow-y: auto;
}

.message {
    margin-bottom: 10px;
    padding: 10px;
    border-radius: 5px;
}

.message.sent {
    background-color: #0078d4;
    color: white;
    align-self: flex-end;
}

.message.received {
    background-color: #e0e0e0;
    color: black;
    align-self: flex-start;
}

.username {
    font-weight: bold;
}

.timestamp {
    font-size: 0.8em;
    color: gray;
}

.message-input {
    display: flex;
    border-top: 1px solid #ccc;
    padding-top: 10px;
}

#messageInput {
    flex: 1;
    padding: 10px;
}

.contacts {
    background-color: #f9f9f9;
    padding: 10px;
}

.contacts h2 {
    margin: 0;
    padding: 0;
}

.contacts ul {
    list-style: none;
    padding: 0;
}

.contacts li {
    margin: 5px 0;
}

.contacts a {
    text-decoration: none;
    color: #0078d4;
}