body {
    margin: 0;
    font-family: Arial, sans-serif;
    color: #eee;
    background: url('bg.jpg') no-repeat center center fixed;
    background-size: cover;
}

.overlay {
    position: fixed;
    width: 100%;
    height: 100%;
    background: rgba(10,10,10,0.85);
    z-index: 0;
}

.app {
    position: relative;
    z-index: 1;
    display: flex;
    flex-direction: column;
    height: 100vh;
}

header {
    padding: 15px;
    background: #111;
    text-align: center;
    border-bottom: 1px solid #333;
}

main {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
}

.message {
    margin-bottom: 15px;
    padding: 10px;
    border-radius: 10px;
    max-width: 70%;
}

.user {
    background: #1f8aff;  /* 2a2a2a  */
    align-self: flex-end;
}

.bot {
    background: #1a1a1a;
    align-self: flex-start;
}

footer {
    display: flex;
    padding: 10px;
    background: #111;
    border-top: 1px solid #333;
}

input {
    flex: 1;
    padding: 10px;
    border: none;
    border-radius: 5px;
    background: #222;
    color: #fff;
}

button {
    margin-left: 10px;
    padding: 10px 15px;
    background: #4CAF50;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    color: white;
}

button:hover {
    background: #45a049;
}

button:disabled {
opacity: 0.5;
cursor: not-allowed;
}