/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --user-message-bg: #6366f1;
    --bot-message-bg: #1e293b;
    --error-color: #ef4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 800px;
    height: 90vh;
    display: flex;
    flex-direction: column;
    background-color: var(--surface-color);
    border-radius: 16px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    overflow: hidden;
}

/* Header */
.header {
    padding: 24px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    background: linear-gradient(135deg, var(--surface-color) 0%, var(--surface-light) 100%);
}

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Chat container */
.chat-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Messages */
.message {
    display: flex;
    max-width: 85%;
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.user-message {
    align-self: flex-end;
}

.bot-message {
    align-self: flex-start;
}

.message-content {
    padding: 12px 18px;
    border-radius: 16px;
    line-height: 1.5;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.user-message .message-content {
    background-color: var(--user-message-bg);
    border-bottom-right-radius: 4px;
}

.bot-message .message-content {
    background-color: var(--bot-message-bg);
    border: 1px solid var(--border-color);
    border-bottom-left-radius: 4px;
}

.error-message .message-content {
    background-color: var(--error-color);
    opacity: 0.9;
}

/* Chat form */
.chat-form {
    display: flex;
    gap: 12px;
    padding: 20px 24px;
    border-top: 1px solid var(--border-color);
    background-color: var(--surface-color);
}

#message-input {
    flex: 1;
    padding: 14px 18px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

#message-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

#message-input::placeholder {
    color: var(--text-secondary);
}

#send-button {
    padding: 14px 24px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 120px;
}

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

#send-button:active {
    transform: scale(0.98);
}

#send-button:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.hidden {
    display: none !important;
}

/* Footer */
.footer {
    padding: 16px 24px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background-color: var(--surface-color);
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.version {
    margin-top: 4px;
    opacity: 0.7;
}

/* Scrollbar */
.chat-messages::-webkit-scrollbar {
    width: 8px;
}

.chat-messages::-webkit-scrollbar-track {
    background: var(--surface-color);
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--surface-light);
    border-radius: 4px;
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: var(--border-color);
}

/* Responsive */
@media (max-width: 600px) {
    body {
        padding: 0;
    }

    .container {
        height: 100vh;
        border-radius: 0;
    }

    .header {
        padding: 16px;
    }

    .header h1 {
        font-size: 1.5rem;
    }

    .chat-messages {
        padding: 16px;
    }

    .chat-form {
        padding: 16px;
    }

    #send-button {
        min-width: auto;
        padding: 14px 18px;
    }

    .button-text {
        display: none;
    }

    #send-button::after {
        content: '→';
        font-size: 1.2rem;
    }
}

/* Loading dots animation */
.loading-dots::after {
    content: '';
    animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
    0%, 20% { content: ''; }
    40% { content: '.'; }
    60% { content: '..'; }
    80%, 100% { content: '...'; }
}