:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --background: #f9fafb;
    --surface: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --error: #dc2626;
    --border: #e5e7eb;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    padding: 20px 0;
    border-bottom: 2px solid var(--border);
    margin-bottom: 20px;
}

h1 {
    font-size: 24px;
    font-weight: 600;
}

#auth-status {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 8px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.logout-btn {
    padding: 4px 12px;
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 13px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: background 0.2s;
}

.logout-btn:hover {
    background: var(--background);
    color: var(--text-primary);
}

.screen {
    display: none;
    flex-direction: column;
    flex: 1;
}

.screen.active {
    display: flex;
}

/* Auth Screen */
#auth-screen {
    justify-content: center;
    align-items: center;
}

#auth-form {
    background: var(--surface);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
}

#auth-form h2 {
    margin-bottom: 24px;
    text-align: center;
    color: var(--text-primary);
}

#auth-form input {
    width: 100%;
    padding: 12px;
    margin-bottom: 16px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 16px;
}

#auth-form button {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

#auth-form button:hover {
    background: var(--secondary-color);
}

.error {
    color: var(--error);
    font-size: 14px;
    margin-top: 12px;
    text-align: center;
}

/* Chat Screen */
#chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    background: var(--surface);
    border-radius: 12px;
    margin-bottom: 20px;
}

.message {
    margin-bottom: 16px;
    padding: 12px 16px;
    border-radius: 8px;
    max-width: 80%;
}

.message.user {
    background: var(--primary-color);
    color: white;
    margin-left: auto;
}

.message.assistant {
    background: var(--border);
    color: var(--text-primary);
}

.message.error {
    background: #fee2e2;
    color: var(--error);
    max-width: 100%;
}

/* Markdown formatting within assistant messages */
.message.assistant h1,
.message.assistant h2,
.message.assistant h3 {
    margin-top: 12px;
    margin-bottom: 8px;
    font-weight: 600;
    line-height: 1.3;
}

.message.assistant h1 { font-size: 1.4em; }
.message.assistant h2 { font-size: 1.2em; }
.message.assistant h3 { font-size: 1.1em; }

.message.assistant h1:first-child,
.message.assistant h2:first-child,
.message.assistant h3:first-child {
    margin-top: 0;
}

.message.assistant p {
    margin-bottom: 12px;
    line-height: 1.6;
}

.message.assistant p:last-child {
    margin-bottom: 0;
}

.message.assistant strong {
    font-weight: 600;
    color: var(--text-primary);
}

.message.assistant ul,
.message.assistant ol {
    margin: 12px 0;
    padding-left: 24px;
}

.message.assistant li {
    margin-bottom: 6px;
    line-height: 1.5;
}

.message.assistant li:last-child {
    margin-bottom: 0;
}

.message.assistant code {
    background: rgba(0, 0, 0, 0.05);
    padding: 2px 6px;
    border-radius: 3px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

.message.assistant pre {
    background: rgba(0, 0, 0, 0.05);
    padding: 12px;
    border-radius: 6px;
    overflow-x: auto;
    margin: 12px 0;
}

.message.assistant pre code {
    background: none;
    padding: 0;
}

.message.assistant blockquote {
    border-left: 3px solid var(--primary-color);
    padding-left: 12px;
    margin: 12px 0;
    font-style: italic;
    color: var(--text-secondary);
}

#chat-form {
    display: flex;
    gap: 12px;
}

#message-input {
    flex: 1;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 16px;
    font-family: inherit;
    resize: vertical;
}

#chat-form button {
    padding: 12px 24px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}

#chat-form button:hover {
    background: var(--secondary-color);
}

#chat-form button:disabled {
    background: var(--text-secondary);
    cursor: not-allowed;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    #auth-form {
        padding: 20px;
    }

    .message {
        max-width: 90%;
    }
}