:root {
    --primary-color: #1a1a1a; /* Darker shade for header */
    --background-color: #121212; /* Dark background for the body */
    --user-message-bg: #0d47a1; /* Darker blue for user messages */
    --bot-message-bg: #424242; /* Dark gray for bot messages */
    --text-color: #ffffff; /* White text for better contrast */
    --input-bg: #1e1e1e; /* Dark background for input area */
    --input-border: #333333; /* Dark border for input */
    --button-bg: #1976d2; /* Slightly lighter blue for the button */
    --button-hover-bg: #1565c0; /* Darker blue for button hover state */
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 15px;
}

#chat-container {
    width: 100%;
    max-width: 450px;
    height: 90vh;
    max-height: 700px;
    background-color: var(--primary-color);
    border-radius: 15px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

header {
    background-color: var(--primary-color);
    color: var(--text-color);
    text-align: center;
    padding: 15px;
    font-weight: 300;
}

#chat-box {
    flex-grow: 1;
    overflow-y: auto;
    padding: 15px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.message {
    max-width: 75%;
    padding: 10px 15px;
    border-radius: 15px;
    line-height: 1.4;
    word-wrap: break-word;
    color: var(--text-color);
}

.user-message {
    background-color: var(--user-message-bg);
    align-self: flex-end;
    margin-left: auto;
}

.bot-message {
    background-color: var(--bot-message-bg);
    align-self: flex-start;
    margin-right: auto;
}

#input-area {
    display: flex;
    padding: 15px;
    background-color: var(--input-bg);
    border-top: 1px solid var(--input-border);
}

#user-input {
    flex-grow: 1;
    padding: 10px;
    border: 1px solid var(--input-border);
    border-radius: 20px;
    margin-right: 10px;
    width: 100%;
    background-color: var(--input-bg);
    color: var(--text-color);
}

#send-btn {
    background-color: var(--button-bg);
    color: var(--text-color);
    border: none;
    padding: 10px 20px;
    border-radius: 20px;
    cursor: pointer;
    white-space: nowrap;
}

#send-btn:hover {
    background-color: var(--button-hover-bg);
}

/* Mobile Responsiveness */
@media screen and (max-width: 480px) {
    #chat-container {
        width: 100%;
        height: 100vh;
        max-height: none;
        border-radius: 0;
    }

    .message {
        max-width: 85%;
    }

    #input-area {
        padding: 10px;
    }

    #user-input, #send-btn {
        padding: 8px 15px;
    }
}

/* Ensure scrolling on smaller screens */
#chat-box {
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

/* typing animation */
#typing-indicator {
    font-style: italic;
    color: gray;
    margin-left: 10px;
}