/* Reset y base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    height: 100vh;
    display: flex;
}

/* Barra lateral */
#sidebar {
    width: 220px;
    background-color: #2c3e50;
    color: white;
    padding: 20px;
    display: flex;
    flex-direction: column;
}

#sidebar h2 {
    margin-bottom: 20px;
    font-weight: 600;
    font-size: 1.5em;
    text-align: center;
}

#topics {
    list-style: none;
}

#topics li {
    padding: 12px 15px;
    margin-bottom: 10px;
    cursor: pointer;
    border-radius: 8px;
    transition: background-color 0.3s ease;
}

#topics li:hover {
    background-color: #34495e;
}

#topics li.active {
    background-color: #1abc9c;
    font-weight: bold;
}

/* Área de chat */
#chat {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    background-color: #ecf0f1;
    border-left: 1px solid #bdc3c7;
}

/* Mensajes */
#messages {
    flex-grow: 1;
    overflow-y: auto;
    padding: 15px;
}

.message {
    background-color: white;
    padding: 8px 12px;
    margin-bottom: 10px;
    border-radius: 10px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.1);
    max-width: 70%;
}

.message .user {
    font-weight: 700;
    margin-bottom: 4px;
    color: #2c3e50;
}

.message .time {
    font-size: 0.75em;
    color: #7f8c8d;
    margin-left: 8px;
}

/* Formulario de entrada */
#inputForm {
    display: flex;
    padding: 15px;
    background-color: #bdc3c7;
    gap: 10px;
}

#messageInput {
    flex-grow: 1;
    padding: 10px 15px;
    font-size: 1em;
    border: none;
    border-radius: 25px;
}

#inputForm button {
    background-color: #1abc9c;
    border: none;
    padding: 10px 20px;
    color: white;
    font-weight: 600;
    border-radius: 25px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

#inputForm button:hover {
    background-color: #16a085;
}