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

:root {
    --bg-primary: #1a1a1a;
    --bg-secondary: #262626;
    --bg-tertiary: #2d2d2d;
    --bg-hover: #363636;
    --text-primary: #ececec;
    --text-secondary: #a1a1a1;
    --text-muted: #737373;
    --accent: #d97706;
    --accent-hover: #f59e0b;
    --border-color: #404040;
    --user-bg: #3b3b3b;
    --assistant-bg: transparent;
    --code-bg: #1e1e1e;
    --success: #22c55e;
    --sidebar-width: 260px;
    --safe-area-inset-bottom: env(safe-area-inset-bottom, 0px);
    --safe-area-inset-top: env(safe-area-inset-top, 0px);
}

html {
    height: 100%;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    height: 100%;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.app-container {
    display: flex;
    height: 100%;
    position: relative;
}

/* ============================================
   SIDEBAR
   ============================================ */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 100;
}

.sidebar.hidden {
    transform: translateX(-100%);
}

.sidebar-header {
    padding: 12px;
    padding-top: calc(12px + var(--safe-area-inset-top));
}

.new-chat-btn {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 14px 16px;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    -webkit-tap-highlight-color: transparent;
}

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

.new-chat-btn:active {
    transform: scale(0.98);
}

.chat-history {
    flex: 1;
    overflow-y: auto;
    padding: 8px 12px;
    -webkit-overflow-scrolling: touch;
}

.chat-history-item {
    padding: 12px 14px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 4px;
    transition: background-color 0.15s;
    -webkit-tap-highlight-color: transparent;
}

.chat-history-item:hover {
    background-color: var(--bg-hover);
}

.chat-history-item:active {
    background-color: var(--bg-tertiary);
}

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

.sidebar-footer {
    padding: 16px;
    border-top: 1px solid var(--border-color);
    padding-bottom: calc(16px + var(--safe-area-inset-bottom));
}

.model-info {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
}

.powered-by {
    display: block;
    font-size: 12px;
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.2s;
    padding: 4px 0;
}

.powered-by:hover {
    color: var(--accent);
}

.model-badge {
    font-size: 12px;
    padding: 4px 10px;
    background-color: var(--bg-tertiary);
    border-radius: 6px;
    color: var(--text-secondary);
}

.status-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--text-muted);
}

.status-indicator.online {
    background-color: var(--success);
    box-shadow: 0 0 6px var(--success);
}

/* Sidebar Overlay */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.6);
    z-index: 99;
    opacity: 0;
    transition: opacity 0.3s ease;
    -webkit-tap-highlight-color: transparent;
}

.sidebar-overlay.active {
    display: block;
    opacity: 1;
}

/* ============================================
   MAIN CONTENT
   ============================================ */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-width: 0;
}

/* ============================================
   TOP BAR
   ============================================ */
.top-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 16px;
    padding-top: calc(10px + var(--safe-area-inset-top));
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-primary);
    flex-shrink: 0;
}

.toggle-sidebar-btn {
    width: 44px;
    height: 44px;
    min-width: 44px;
    border-radius: 10px;
    border: none;
    background-color: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    -webkit-tap-highlight-color: transparent;
}

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

.toggle-sidebar-btn:active {
    background-color: var(--bg-hover);
    transform: scale(0.95);
}

.top-bar-title {
    font-size: 17px;
    font-weight: 600;
    color: var(--text-primary);
}

/* ============================================
   WELCOME SCREEN
   ============================================ */
.welcome-screen {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

.welcome-screen.hidden {
    display: none;
}

.welcome-content {
    text-align: center;
    max-width: 600px;
    width: 100%;
    padding: 20px 0;
}

.logo {
    margin-bottom: 16px;
    color: var(--accent);
}

.logo svg {
    width: 48px;
    height: 48px;
}

.welcome-content h1 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 8px;
}

.subtitle {
    color: var(--text-secondary);
    margin-bottom: 32px;
    font-size: 15px;
}

.suggestions {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.suggestion-btn {
    padding: 14px 16px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-secondary);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
    line-height: 1.4;
    -webkit-tap-highlight-color: transparent;
}

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

.suggestion-btn:active {
    transform: scale(0.98);
}

/* ============================================
   CHAT CONTAINER
   ============================================ */
.chat-container {
    flex: 1;
    overflow-y: auto;
    display: none;
    -webkit-overflow-scrolling: touch;
}

.chat-container.active {
    display: block;
}

.messages {
    max-width: 800px;
    margin: 0 auto;
    padding: 16px 20px;
}

/* ============================================
   MESSAGE STYLES
   ============================================ */
.message {
    display: flex;
    gap: 14px;
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
}

.message:last-child {
    border-bottom: none;
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: 13px;
    font-weight: 600;
}

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

.message.assistant .message-avatar {
    background: linear-gradient(135deg, var(--bg-tertiary), var(--bg-hover));
    color: var(--text-primary);
}

.message-content {
    flex: 1;
    line-height: 1.65;
    overflow-wrap: break-word;
    word-break: break-word;
    font-size: 15px;
    min-width: 0;
}

.message-content p {
    margin-bottom: 12px;
}

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

.message-content pre {
    background-color: var(--code-bg);
    border-radius: 10px;
    padding: 14px;
    overflow-x: auto;
    margin: 12px 0;
    -webkit-overflow-scrolling: touch;
}

.message-content code {
    font-family: 'SF Mono', 'Menlo', 'Monaco', 'Courier New', monospace;
    font-size: 13px;
}

.message-content :not(pre) > code {
    background-color: var(--bg-tertiary);
    padding: 3px 7px;
    border-radius: 5px;
    font-size: 0.9em;
}

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

.message-content li {
    margin-bottom: 6px;
}

.message-content h1, .message-content h2, .message-content h3 {
    margin: 20px 0 10px 0;
    font-weight: 600;
}

.message-content h1 { font-size: 1.4em; }
.message-content h2 { font-size: 1.25em; }
.message-content h3 { font-size: 1.1em; }

.message-content blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 16px;
    color: var(--text-secondary);
    margin: 12px 0;
    font-style: italic;
}

.message-content a {
    color: var(--accent);
    text-decoration: none;
}

.message-content a:hover {
    text-decoration: underline;
}

/* ============================================
   STATUS MESSAGE (Escalation Feedback)
   ============================================ */
.status-message {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    background: linear-gradient(135deg, rgba(217, 119, 6, 0.1), rgba(245, 158, 11, 0.05));
    border: 1px solid rgba(217, 119, 6, 0.2);
    border-radius: 10px;
    color: var(--accent);
    font-size: 14px;
    animation: pulse-border 2s ease-in-out infinite;
}

.status-icon {
    font-size: 18px;
    animation: bounce-icon 1s ease-in-out infinite;
}

@keyframes pulse-border {
    0%, 100% { border-color: rgba(217, 119, 6, 0.2); }
    50% { border-color: rgba(217, 119, 6, 0.5); }
}

@keyframes bounce-icon {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-3px); }
}

/* Expert Response Styling */
.message.expert-response .message-avatar {
    background: linear-gradient(135deg, var(--accent), var(--accent-hover));
    color: white;
}

.message.expert-response {
    border-left: 3px solid var(--accent);
    padding-left: 12px;
    margin-left: -15px;
}

@media (max-width: 768px) {
    .message.expert-response {
        margin-left: -12px;
        padding-left: 9px;
    }
}

/* ============================================
   TYPING INDICATOR
   ============================================ */
.typing-indicator {
    display: flex;
    gap: 5px;
    padding: 8px 0;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background-color: var(--text-muted);
    animation: bounce 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) { animation-delay: -0.32s; }
.typing-indicator span:nth-child(2) { animation-delay: -0.16s; }

@keyframes bounce {
    0%, 80%, 100% { transform: scale(0.8); opacity: 0.5; }
    40% { transform: scale(1); opacity: 1; }
}

/* ============================================
   INPUT AREA
   ============================================ */
.input-area {
    padding: 12px 16px;
    padding-bottom: calc(16px + var(--safe-area-inset-bottom));
    background-color: var(--bg-primary);
    flex-shrink: 0;
}

.input-wrapper {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    display: flex;
    align-items: flex-end;
    gap: 8px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 8px 8px 8px 16px;
    transition: border-color 0.2s;
}

.input-wrapper:focus-within {
    border-color: var(--accent);
}

#messageInput {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 16px;
    font-family: inherit;
    resize: none;
    max-height: 150px;
    min-height: 24px;
    padding: 8px 0;
    line-height: 1.5;
    -webkit-appearance: none;
}

#messageInput:focus {
    outline: none;
}

#messageInput::placeholder {
    color: var(--text-muted);
}

.send-btn, .stop-btn {
    width: 44px;
    height: 44px;
    min-width: 44px;
    border-radius: 12px;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    flex-shrink: 0;
    -webkit-tap-highlight-color: transparent;
}

.send-btn {
    background-color: var(--accent);
    color: white;
}

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

.send-btn:active:not(:disabled) {
    transform: scale(0.95);
}

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

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

.stop-btn:hover {
    background-color: var(--bg-hover);
}

.stop-btn:active {
    transform: scale(0.95);
}

.hidden {
    display: none !important;
}

.disclaimer {
    text-align: center;
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 10px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    padding: 0 10px;
}

/* ============================================
   SCROLLBAR
   ============================================ */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background-color: var(--bg-hover);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background-color: var(--text-muted);
}

/* ============================================
   TABLET STYLES (768px - 1024px)
   ============================================ */
@media (max-width: 1024px) {
    .messages {
        padding: 16px;
    }

    .suggestions {
        gap: 8px;
    }

    .suggestion-btn {
        padding: 12px 14px;
        font-size: 13px;
    }
}

/* ============================================
   MOBILE STYLES (< 768px)
   ============================================ */
@media (max-width: 768px) {
    :root {
        --sidebar-width: 280px;
    }

    /* Mobile Sidebar - Slide over */
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        height: 100%;
        width: var(--sidebar-width);
        max-width: 85vw;
        transform: translateX(-100%);
        box-shadow: 4px 0 20px rgba(0, 0, 0, 0.3);
    }

    .sidebar:not(.hidden) {
        transform: translateX(0);
    }

    .sidebar.hidden {
        transform: translateX(-100%);
    }

    /* Welcome screen adjustments */
    .welcome-content h1 {
        font-size: 24px;
    }

    .logo svg {
        width: 40px;
        height: 40px;
    }

    .subtitle {
        font-size: 14px;
        margin-bottom: 24px;
    }

    .suggestions {
        grid-template-columns: 1fr;
        gap: 8px;
    }

    .suggestion-btn {
        padding: 14px 16px;
        font-size: 14px;
    }

    /* Messages */
    .messages {
        padding: 12px 16px;
    }

    .message {
        gap: 10px;
        padding: 16px 0;
    }

    .message-avatar {
        width: 28px;
        height: 28px;
        font-size: 12px;
    }

    .message-content {
        font-size: 15px;
    }

    .message-content pre {
        padding: 12px;
        font-size: 12px;
    }

    /* Input area */
    .input-area {
        padding: 10px 12px;
        padding-bottom: calc(12px + var(--safe-area-inset-bottom));
    }

    .input-wrapper {
        border-radius: 24px;
        padding: 6px 6px 6px 14px;
    }

    #messageInput {
        font-size: 16px; /* Prevents zoom on iOS */
        padding: 10px 0;
    }

    .send-btn, .stop-btn {
        width: 40px;
        height: 40px;
        min-width: 40px;
        border-radius: 20px;
    }

    .disclaimer {
        font-size: 10px;
        margin-top: 8px;
    }

    /* Top bar */
    .top-bar {
        padding: 8px 12px;
        padding-top: calc(8px + var(--safe-area-inset-top));
    }

    .top-bar-title {
        font-size: 16px;
    }

    .toggle-sidebar-btn {
        width: 40px;
        height: 40px;
        min-width: 40px;
    }
}

/* ============================================
   SMALL MOBILE (< 380px)
   ============================================ */
@media (max-width: 380px) {
    .welcome-content {
        padding: 10px 0;
    }

    .welcome-content h1 {
        font-size: 22px;
    }

    .suggestion-btn {
        padding: 12px 14px;
        font-size: 13px;
    }

    .message-content {
        font-size: 14px;
    }

    .messages {
        padding: 10px 12px;
    }
}

/* ============================================
   LANDSCAPE MOBILE
   ============================================ */
@media (max-height: 500px) and (orientation: landscape) {
    .welcome-screen {
        padding: 10px;
    }

    .welcome-content {
        padding: 0;
    }

    .logo {
        margin-bottom: 8px;
    }

    .logo svg {
        width: 32px;
        height: 32px;
    }

    .welcome-content h1 {
        font-size: 20px;
        margin-bottom: 4px;
    }

    .subtitle {
        margin-bottom: 16px;
        font-size: 13px;
    }

    .suggestions {
        grid-template-columns: repeat(2, 1fr);
        gap: 6px;
    }

    .suggestion-btn {
        padding: 10px 12px;
        font-size: 12px;
    }

    .top-bar {
        padding: 6px 12px;
    }

    .input-area {
        padding: 8px 12px;
    }
}

/* ============================================
   DESKTOP STYLES (> 1024px)
   ============================================ */
@media (min-width: 1025px) {
    /* Desktop sidebar animation */
    .sidebar.hidden {
        margin-left: calc(var(--sidebar-width) * -1);
        transform: none;
    }

    .sidebar:not(.hidden) {
        transform: none;
    }

    /* Hide overlay on desktop */
    .sidebar-overlay {
        display: none !important;
    }
}

/* ============================================
   DARK MODE SCROLLBAR FOR FIREFOX
   ============================================ */
* {
    scrollbar-width: thin;
    scrollbar-color: var(--bg-hover) transparent;
}

/* ============================================
   FOCUS VISIBLE FOR ACCESSIBILITY
   ============================================ */
button:focus-visible,
textarea:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* ============================================
   REDUCED MOTION
   ============================================ */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}