/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #0ea5e9;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --dark-bg: #1a1a1a;
    --sidebar-bg: #0f172a;
    --chat-bg: #f8fafc;
    --message-user: #2563eb;
    --message-bot: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--dark-bg);
    color: var(--text-primary);
    overflow: hidden;
}

.hidden {
    display: none !important;
}

/* Authentication Screens */
.auth-screen {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
}

.auth-container {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.auth-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn-primary {
    width: 100%;
    padding: 0.75rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-primary:hover {
    background: #1d4ed8;
}

.auth-footer {
    text-align: center;
    margin-top: 1.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.auth-footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

/* Main App Layout */
#app {
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 280px;
    background: var(--sidebar-bg);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border-color);
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.btn-new-chat {
    width: 100%;
    padding: 0.75rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    transition: background 0.2s;
}

.btn-new-chat:hover {
    background: #1d4ed8;
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.conversations-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.conversation-item {
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
    border: none;
    text-align: left;
    color: white;
}

.conversation-item:hover {
    background: rgba(255, 255, 255, 0.1);
}

.conversation-item.active {
    background: rgba(37, 99, 235, 0.3);
}

.conversation-item h4 {
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0.25rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.conversation-item p {
    font-size: 0.75rem;
    color: #94a3b8;
}

.sidebar-footer {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: white;
}

.user-profile i {
    font-size: 1.5rem;
}

.btn-logout {
    background: none;
    border: none;
    color: #94a3b8;
    cursor: pointer;
    font-size: 1.25rem;
    padding: 0.5rem;
    border-radius: 6px;
    transition: color 0.2s;
}

.btn-logout:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

/* Chat Area */
.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--chat-bg);
}

.chat-header {
    padding: 1.5rem 2rem;
    background: white;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.chat-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.welcome-message {
    text-align: center;
    padding: 3rem 1rem;
}

.welcome-message i {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.welcome-message h2 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.welcome-message p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.suggestions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.suggestion-btn {
    padding: 0.75rem 1.5rem;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.suggestion-btn:hover {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: white;
}

.message {
    display: flex;
    gap: 1rem;
    max-width: 800px;
    margin: 0 auto;
    width: 100%;
}

.message.user {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background: var(--message-user);
    color: white;
}

.message.bot .message-avatar {
    background: var(--message-bot);
    border: 2px solid var(--border-color);
}

.message-content {
    padding: 1rem;
    border-radius: 12px;
    max-width: calc(100% - 60px);
}

.message.user .message-content {
    background: var(--message-user);
    color: white;
}

.message.bot .message-content {
    background: var(--message-bot);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
}

.message-content p {
    margin-bottom: 0.75rem;
    line-height: 1.6;
}

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

.message-content code {
    background: rgba(0, 0, 0, 0.05);
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.message-content pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 1rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 0.75rem 0;
}

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

.chat-input-container {
    padding: 1.5rem 2rem;
    background: white;
    border-top: 1px solid var(--border-color);
}

#message-form {
    max-width: 800px;
    margin: 0 auto;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
}

#message-input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    max-height: 120px;
    transition: border-color 0.2s;
}

#message-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn-send {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--primary-color);
    color: white;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s;
    flex-shrink: 0;
}

.btn-send:hover:not(:disabled) {
    background: #1d4ed8;
}

.btn-send:disabled {
    background: var(--text-secondary);
    opacity: 0.5;
    cursor: not-allowed;
}

.disclaimer {
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        height: 100%;
        z-index: 1000;
        transform: translateX(-100%);
        transition: transform 0.3s;
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .chat-area {
        width: 100%;
    }
    
    .chat-header,
    .chat-input-container {
        padding: 1rem;
    }
    
    .chat-messages {
        padding: 1rem;
    }
}