.chat-header { 
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid #e5e7eb;
    background: linear-gradient(135deg, #f8fafc 0%, #ffffff 100%);
    border-radius: 20px 20px 0 0;
    margin-bottom: 0.5rem;
}

.chat-header h3 {
    margin: 0;
    font-size: 1.25rem;
    font-weight: 600;
    color: #111827;
}

.chat-header h2 {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 600;
    color: #111827;
}

.connection-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: #6b7280;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #ef4444;
    animation: pulse 2s infinite;
}

.connection-status.connected .status-dot {
    background: var(--color-success);
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.error-message {
    margin-top: var(--space-2);
    padding: var(--space-3);
    background: var(--color-error-bg);
    color: var(--color-error);
    border-radius: var(--radius-md);
    font-size: var(--font-small);
}

.chat-messages {
    flex: 1 1 auto;
    min-height: 0;
    overflow-y: auto;
    padding: var(--space-6) var(--space-2);
    background: var(--neutral-50);
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
    scroll-behavior: smooth;
}

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

.chat-messages::-webkit-scrollbar-track {
    background: var(--neutral-100);
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--neutral-300);
    border-radius: 4px;
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: var(--neutral-400);
}

/* Hero empty state & welcome share same content */
.empty-state,
.welcome-message {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100%;
    padding: var(--space-8) var(--space-4);
}

.empty-state-inner {
    text-align: center;
    max-width: 360px;
}

.empty-state-icon {
    color: var(--color-primary);
    opacity: 0.85;
    margin-bottom: var(--space-6);
}

.empty-state-icon svg {
    display: inline-block;
    animation: empty-state-float 4s ease-in-out infinite;
}

@keyframes empty-state-float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

@media (prefers-reduced-motion: reduce) {
    .empty-state-icon svg {
        animation: none;
    }
}

.empty-state-title {
    font-size: var(--font-h2);
    line-height: var(--font-h2-line);
    font-weight: 600;
    color: var(--neutral-800);
    margin: 0 0 var(--space-2);
    letter-spacing: -0.02em;
}

.empty-state-subtitle {
    font-size: var(--font-small);
    line-height: var(--font-small-line);
    color: var(--neutral-500);
    margin: 0;
}

.welcome-message .message {
    animation: none;
}

.message {
    display: flex;
    flex-direction: column;
    animation: fadeIn 0.3s ease-in;
    gap: 0.25rem;
    background: transparent;
    margin: 0;
    padding: 0;
}

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

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

.message.assistant {
    align-items: flex-start;
}

.message-content {
    display: flex;
    flex-direction: column;
    gap: 0;
    max-width: 90%;
    align-items: flex-start;
}

.message.user .message-content {
    flex-direction: column;
    align-items: flex-end;
}

.message.message-with-attachments .message-content {
    flex-direction: column;
    gap: 0.25rem;
}

.message.user.message-with-attachments .message-content {
    align-items: flex-end;
}

.message.message-with-attachments .message-attachments {
    margin-top: 0;
    margin-bottom: 0;
}

.message-avatar {
    display: none !important;
}

.user-avatar {
    background: #3b82f6;
}

.assistant-avatar {
    background: #10b981;
}

.message-text {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-lg);
    line-height: 1.5;
    word-wrap: break-word;
    white-space: pre-wrap;
}

.message.user .message-text {
    background: linear-gradient(135deg, #dbeafe 0%, #e0e7ff 100%);
    color: var(--neutral-800);
    border: none;
    border-bottom-right-radius: var(--space-1);
    box-shadow: var(--shadow-card);
}

.message.assistant .message-text {
    background: #ffffff;
    color: var(--neutral-900);
    border: 1px solid var(--neutral-200);
    border-bottom-left-radius: var(--space-1);
    box-shadow: var(--shadow-card);
}

.message.error .message-text {
    background: var(--color-error-bg);
    color: var(--color-error);
    border: 1px solid #fecaca;
}

.message.system .message-text {
    background: #f3f4f6;
    color: #6b7280;
    border: 1px solid #d1d5db;
    font-style: italic;
    text-align: center;
    border-radius: 0.75rem;
}

.message.methodology .message-text {
    background: linear-gradient(135deg, #f0f4ff 0%, #f5f3ff 100%);
    color: #1e293b;
    border: 1.5px solid #c7d2fe;
    border-left: 4px solid #6366f1;
    padding: 1rem;
    border-radius: 0.75rem;
    font-size: 0.95rem;
    line-height: 1.6;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.12);
}

.message.methodology .message-text strong {
    color: #4f46e5;
    font-weight: 600;
}

.message.methodology .message-text em {
    color: #5b21b6;
}

/* Responsive tweaks for messages & empty state */
@media (max-width: 1024px) {
    .chat-messages {
        padding: var(--space-4) var(--space-2);
    }
    .message-content {
        max-width: 95%;
    }
    .empty-state-inner {
        max-width: 100%;
    }
}

@media (max-width: 768px) and (pointer: coarse) {
    .chat-messages {
        padding: var(--space-3) var(--space-2);
    }
    .message-text {
        padding: var(--space-2) var(--space-3);
        font-size: var(--font-small);
    }
    .empty-state,
    .welcome-message {
        padding: var(--space-4) var(--space-2);
    }
    .empty-state-title {
        font-size: var(--font-h3);
    }
    .empty-state-subtitle {
        font-size: 0.8125rem;
    }
}