:root {
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: #dbeafe;
    --border-color: #e2e8f0;
    --user-msg-bg: #2563eb;
    --user-msg-text: #ffffff;
    --bot-msg-bg: #ffffff;
    --bot-msg-text: #0f172a;
    --danger: #ef4444;
    --success: #10b981;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    --sidebar-width: 280px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #60a5fa;
    --accent-light: #1e3a8a;
    --border-color: #334155;
    --bot-msg-bg: #1e293b;
    --bot-msg-text: #f8fafc;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s, color 0.3s;
}

.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 1.25rem;
    transition: var(--transition);
    z-index: 10;
}

.sidebar-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.logo {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--accent-color), #8b5cf6);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    box-shadow: var(--shadow-sm);
}

.sidebar-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    background: linear-gradient(to right, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.new-chat-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.75rem;
    background-color: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 1.5rem;
}

.new-chat-btn:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--text-secondary);
}

.chat-history {
    flex: 1;
    overflow-y: auto;
}

.history-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    letter-spacing: 0.05em;
}

#history-list {
    list-style: none;
}

.history-item {
    padding: 0.75rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 0.875rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: var(--transition);
    margin-bottom: 0.25rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.history-item i {
    font-size: 0.75rem;
}

.history-item:hover, .history-item.active {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.sidebar-footer {
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.theme-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.75rem;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition);
    border-radius: var(--radius-md);
    justify-content: flex-start;
}

.theme-toggle:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

/* Main Chat Area */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
}

.chat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 1px 2px rgba(0,0,0,0.02);
}

.header-info h1 {
    font-size: 1.125rem;
    font-weight: 600;
}

.header-info p {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--bg-tertiary);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 500;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
}

.status-dot.online {
    background-color: var(--success);
    box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.2);
}

.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    position: relative;
    scroll-behavior: smooth;
}

/* Welcome Screen */
.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    animation: fadeIn 0.5s ease-out;
}

.welcome-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--accent-light), #f3e8ff);
    color: var(--accent-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-md);
}

[data-theme="dark"] .welcome-icon {
    background: linear-gradient(135deg, var(--accent-color), #6b21a8);
    color: white;
}

.welcome-screen h2 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.welcome-screen p {
    color: var(--text-secondary);
    margin-bottom: 3rem;
    font-size: 1.125rem;
    max-width: 600px;
}

.suggestion-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    width: 100%;
}

.card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-color);
}

.card i {
    font-size: 1.5rem;
    color: var(--accent-color);
}

.card p {
    font-size: 0.875rem;
    color: var(--text-primary);
    margin: 0;
    font-weight: 500;
}

/* Messages */
.messages-wrapper {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 800px;
    margin: 0 auto;
    padding-bottom: 2rem;
}

.message {
    display: flex;
    gap: 1rem;
    max-width: 85%;
    animation: slideUp 0.3s ease-out;
}

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

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

.avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: 1rem;
    box-shadow: var(--shadow-sm);
}

.user .avatar {
    background-color: var(--text-primary);
    color: var(--bg-primary);
}

.bot .avatar {
    background: linear-gradient(135deg, var(--accent-color), #8b5cf6);
    color: white;
}

.message-content {
    padding: 1rem 1.25rem;
    border-radius: var(--radius-lg);
    font-size: 0.9375rem;
    box-shadow: var(--shadow-sm);
    line-height: 1.6;
}

.user .message-content {
    background-color: var(--user-msg-bg);
    color: var(--user-msg-text);
    border-top-right-radius: 0;
}

.bot .message-content {
    background-color: var(--bot-msg-bg);
    color: var(--bot-msg-text);
    border-top-left-radius: 0;
    border: 1px solid var(--border-color);
}

.message.emergency .message-content {
    background-color: #fef2f2;
    border-color: #fca5a5;
    color: #991b1b;
}

[data-theme="dark"] .message.emergency .message-content {
    background-color: #7f1d1d;
    border-color: #b91c1c;
    color: #fecaca;
}

/* Markdown styling in messages */
.message-content p { margin-bottom: 0.75rem; }
.message-content p:last-child { margin-bottom: 0; }
.message-content ul, .message-content ol { margin-left: 1.5rem; margin-bottom: 0.75rem; }
.message-content strong { font-weight: 600; color: inherit; }
.message-content a { color: var(--accent-color); text-decoration: underline; }
[data-theme="dark"] .bot .message-content a { color: var(--accent-hover); }

/* Source References */
.source-references {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.user .source-references { border-color: rgba(255,255,255,0.2); }

.source-badge {
    font-size: 0.7rem;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    cursor: pointer;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.source-badge:hover {
    background-color: var(--accent-light);
    color: var(--accent-color);
    border-color: var(--accent-light);
}

[data-theme="dark"] .source-badge:hover {
    background-color: var(--accent-color);
    color: white;
}

/* Typing Indicator */
.typing-indicator {
    display: flex;
    gap: 0.3rem;
    padding: 1.25rem;
    background-color: var(--bot-msg-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    border-top-left-radius: 0;
    width: fit-content;
    box-shadow: var(--shadow-sm);
    margin-left: 3.25rem; /* avatar width + gap */
}

.typing-indicator span {
    width: 6px;
    height: 6px;
    background-color: var(--text-secondary);
    border-radius: 50%;
    animation: typing 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) { animation-delay: 0s; }
.typing-indicator span:nth-child(2) { animation-delay: 0.2s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.4s; }

.hidden { display: none !important; }

/* Input Area */
.input-area {
    padding: 1.5rem 2rem;
    background-color: var(--bg-primary);
    position: relative;
}

.input-area::before {
    content: '';
    position: absolute;
    top: -40px;
    left: 0;
    right: 0;
    height: 40px;
    background: linear-gradient(to top, var(--bg-primary), transparent);
    pointer-events: none;
}

.input-form {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 0.5rem;
    box-shadow: var(--shadow-md);
    transition: border-color 0.3s, box-shadow 0.3s;
}

.input-form:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px var(--accent-light);
}

.attachment-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1.25rem;
}

.attachment-btn:hover {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.input-wrapper {
    flex: 1;
    display: flex;
    align-items: center;
}

#message-input {
    width: 100%;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    padding: 0.6rem 0;
    resize: none;
    max-height: 150px;
    outline: none;
    line-height: 1.5;
}

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

.send-btn {
    background-color: var(--accent-color);
    border: none;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
}

.send-btn:hover:not(:disabled) {
    background-color: var(--accent-hover);
    transform: scale(1.05);
}

.send-btn:disabled {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    cursor: not-allowed;
}

.disclaimer {
    text-align: center;
    font-size: 0.7rem;
    color: var(--text-secondary);
    margin-top: 0.75rem;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
    backdrop-filter: blur(4px);
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.modal-content {
    background-color: var(--bg-secondary);
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    transform: scale(0.95);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border: 1px solid var(--border-color);
}

.modal-overlay.active .modal-content {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.125rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.close-modal {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: color 0.2s;
}

.close-modal:hover {
    color: var(--danger);
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
    font-size: 0.9375rem;
    line-height: 1.6;
    color: var(--text-primary);
}

.modal-body p {
    margin-bottom: 1rem;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes typing {
    0%, 100% { transform: translateY(0); opacity: 0.4; }
    50% { transform: translateY(-4px); opacity: 1; }
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        position: absolute;
        transform: translateX(-100%);
    }
    
    .message {
        max-width: 95%;
    }
    
    .chat-container {
        padding: 1rem;
    }
}