body {
    background-color: #008080; /* Classic Windows Teal */
    font-family: "Tahoma", sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.messenger-container {
    width: 800px;
    height: 500px;
    background: #d4d0c8; /* Classic Windows Grey */
    border: 2px solid #fff;
    box-shadow: 2px 2px 10px rgba(0,0,0,0.5);
    display: flex;
    flex-direction: column;
}

.title-bar {
    background: linear-gradient(90deg, #000080, #1084d0);
    color: white;
    padding: 5px 10px;
    display: flex;
    justify-content: space-between;
    font-weight: bold;
    font-size: 14px;
}

.main-layout {
    display: flex;
    flex: 1;
    overflow: hidden;
    padding: 5px;
}

.sidebar {
    width: 200px;
    background: white;
    border: 1px solid #808080;
    margin-right: 5px;
    padding: 10px;
    overflow-y: auto;
}

.room-group h4 {
    margin: 10px 0 5px 0;
    font-size: 13px;
    color: #000080;
}

.sidebar button {
    display: block;
    width: 100%;
    text-align: left;
    background: none;
    border: none;
    cursor: pointer;
    padding: 3px;
    font-size: 12px;
}

.sidebar button:hover {
    background: #000080;
    color: white;
}

.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.chat-box {
    flex: 1;
    background: white;
    border: 1px solid #808080;
    padding: 10px;
    overflow-y: scroll;
    font-size: 13px;
}

.system-msg { color: #008000; font-weight: bold; }

.input-area {
    display: flex;
    margin-top: 5px;
}

input {
    flex: 1;
    padding: 5px;
    border: 1px solid #808080;
}

button {
    padding: 5px 15px;
    background: #d4d0c8;
    border: 2px solid #fff;
    border-right: 2px solid #808080;
    border-bottom: 2px solid #808080;
    cursor: pointer;
}