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

:root {
    --bg-primary: #212121;
    --bg-secondary: #171717;
    --bg-tertiary: #2f2f2f;
    --bg-hover: #383838;
    --bg-active: #424242;
    --text-primary: #ececec;
    --text-secondary: #b4b4b4;
    --text-muted: #8e8ea0;
    --border-color: #383838;
    --accent-color: #7c6f5b;
    --accent-hover: #968768;
    --user-msg-bg: #2f2f2f;
    --scrollbar-thumb: #565869;
    --scrollbar-track: transparent;
    --danger: #ef4444;
    --success: #22c55e;
    --shadow: 0 2px 6px rgba(0,0,0,0.3);
}

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

::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
}
::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
    background: #6b6b80;
}

#app {
    display: flex;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

#sidebar {
    width: 260px;
    min-width: 260px;
    background: var(--bg-secondary);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border-color);
    transition: margin-left 0.3s ease;
    flex-shrink: 0;
    z-index: 100;
}

#sidebar.collapsed {
    margin-left: -260px;
}

.sidebar-header {
    padding: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px;
    flex: 1;
}

.sidebar-brand img {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    object-fit: cover;
}

.sidebar-brand span {
    font-size: 15px;
    font-weight: 600;
    font-style: italic;
    color: var(--text-primary);
    letter-spacing: 0.5px;
}

#newChatBtn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    cursor: pointer;
    transition: background 0.2s;
    flex-shrink: 0;
}

#newChatBtn:hover {
    background: var(--bg-hover);
}

#newChatBtn svg {
    width: 18px;
    height: 18px;
}

.sidebar-divider {
    height: 1px;
    background: var(--border-color);
    margin: 0 12px;
}

#conversationList {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
}

.conv-group-label {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    padding: 12px 8px 6px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.conv-item {
    display: flex;
    align-items: center;
    padding: 10px 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
    gap: 8px;
    position: relative;
    margin-bottom: 2px;
}

.conv-item:hover {
    background: var(--bg-tertiary);
}

.conv-item.active {
    background: var(--bg-tertiary);
}

.conv-item-title {
    flex: 1;
    font-size: 13px;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.conv-item-delete {
    display: none;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: color 0.2s;
}

.conv-item:hover .conv-item-delete {
    display: flex;
}

.conv-item-delete:hover {
    color: var(--danger);
}

.conv-item-delete svg {
    width: 14px;
    height: 14px;
}

.sidebar-footer {
    padding: 12px;
    border-top: 1px solid var(--border-color);
}

.sidebar-footer-text {
    font-size: 11px;
    color: var(--text-muted);
    text-align: center;
}

#main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    position: relative;
}

#header {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-primary);
    z-index: 10;
    gap: 12px;
    min-height: 56px;
}

#sidebarToggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: 8px;
    transition: background 0.2s, color 0.2s;
}

#sidebarToggle:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

#sidebarToggle svg {
    width: 20px;
    height: 20px;
}

.header-title {
    font-size: 16px;
    font-weight: 600;
    font-style: italic;
    color: var(--text-primary);
    letter-spacing: 0.3px;
}

.header-model {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 400;
    margin-left: 4px;
}

#chatArea {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

#welcome {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    text-align: center;
}

#welcome.hidden {
    display: none;
}

.welcome-logo {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 20px;
    border: 3px solid var(--border-color);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}

.welcome-title {
    font-size: 28px;
    font-weight: 700;
    font-style: italic;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: 1px;
}

.welcome-subtitle {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 36px;
    max-width: 400px;
    line-height: 1.5;
}

.suggestions-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    max-width: 600px;
    width: 100%;
}

.suggestion-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 16px;
    cursor: pointer;
    transition: background 0.2s, border-color 0.2s;
    text-align: left;
}

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

.suggestion-card-title {
    font-size: 13px;
    color: var(--text-primary);
    font-weight: 500;
    line-height: 1.4;
}

.suggestion-card-desc {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

#messages {
    display: none;
    flex-direction: column;
    padding: 0;
    max-width: 768px;
    width: 100%;
    margin: 0 auto;
}

#messages.visible {
    display: flex;
    flex: 1;
}

.message {
    padding: 20px 24px;
    display: flex;
    gap: 16px;
    animation: msgFadeIn 0.3s ease;
}

@keyframes msgFadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
}

.message.user .message-avatar {
    background: #5a4a3a;
    color: #f0d9b5;
}

.message.assistant .message-avatar {
    overflow: hidden;
}

.message.assistant .message-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.message-body {
    flex: 1;
    min-width: 0;
}

.message-role {
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.message-content {
    font-size: 15px;
    line-height: 1.7;
    color: var(--text-primary);
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.message-content p {
    margin-bottom: 10px;
}

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

.message-content ul, .message-content ol {
    margin: 8px 0 8px 20px;
}

.message-content li {
    margin-bottom: 4px;
}

.message-content code {
    background: var(--bg-secondary);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 13px;
    font-family: 'Consolas', 'Monaco', monospace;
}

.message-content pre {
    background: var(--bg-secondary);
    border-radius: 8px;
    padding: 16px;
    overflow-x: auto;
    margin: 12px 0;
    border: 1px solid var(--border-color);
}

.message-content pre code {
    background: none;
    padding: 0;
    font-size: 13px;
}

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

.message-content em {
    font-style: italic;
}

.message-content h1, .message-content h2, .message-content h3 {
    margin: 16px 0 8px;
    font-weight: 600;
}

.message-content h1 { font-size: 20px; }
.message-content h2 { font-size: 18px; }
.message-content h3 { font-size: 16px; }

.message-content blockquote {
    border-left: 3px solid var(--accent-color);
    padding-left: 12px;
    color: var(--text-secondary);
    margin: 8px 0;
}

.message-content table {
    border-collapse: collapse;
    width: 100%;
    margin: 12px 0;
}

.message-content th, .message-content td {
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    text-align: left;
}

.message-content th {
    background: var(--bg-tertiary);
    font-weight: 600;
}

.typing-indicator {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 4px 0;
}

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

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

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

@keyframes typingBounce {
    0%, 80%, 100% {
        transform: scale(0.6);
        opacity: 0.4;
    }
    40% {
        transform: scale(1);
        opacity: 1;
    }
}

.thinking-container {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.thinking-toggle {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    user-select: none;
    font-size: 13px;
    color: var(--text-muted);
    transition: color 0.2s;
    background: none;
    border: none;
    padding: 0;
    font-family: inherit;
}

.thinking-toggle:hover {
    color: var(--text-secondary);
}

.thinking-toggle-icon {
    display: inline-flex;
    transition: transform 0.2s;
}

.thinking-toggle-icon.open {
    transform: rotate(90deg);
}

.thinking-spinner {
    width: 14px;
    height: 14px;
    border: 2px solid var(--border-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    flex-shrink: 0;
}

.thinking-body {
    overflow: hidden;
    transition: max-height 0.3s ease, opacity 0.3s ease;
    max-height: 200px;
    opacity: 1;
}

.thinking-body.collapsed {
    max-height: 0;
    opacity: 0;
}

.thinking-thought {
    font-size: 13px;
    color: var(--text-muted);
    font-style: italic;
    padding: 6px 0 6px 20px;
    border-left: 2px solid var(--border-color);
    margin-left: 2px;
    animation: thoughtFadeIn 0.4s ease;
    line-height: 1.5;
}

#inputArea {
    padding: 0 24px 20px;
    max-width: 768px;
    width: 100%;
    margin: 0 auto;
}

.input-wrapper {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    display: flex;
    align-items: flex-end;
    padding: 8px 8px 8px 16px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-wrapper:focus-within {
    border-color: var(--text-muted);
    box-shadow: 0 0 0 1px var(--text-muted);
}

#messageInput {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    font-size: 15px;
    font-family: inherit;
    line-height: 1.5;
    resize: none;
    max-height: 200px;
    min-height: 24px;
    padding: 4px 0;
}

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

#sendBtn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: var(--text-primary);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.2s, opacity 0.2s;
    flex-shrink: 0;
    margin-left: 8px;
}

#sendBtn:hover {
    background: #ffffff;
}

#sendBtn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

#sendBtn svg {
    width: 18px;
    height: 18px;
    color: var(--bg-primary);
}

.disclaimer {
    text-align: center;
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 10px;
    padding: 0 8px;
}

.mobile-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 999;
    cursor: pointer;
}

.mobile-overlay.visible {
    display: block;
}

@media (max-width: 768px) {
    #sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100vh;
        width: 260px;
        min-width: 260px;
        z-index: 1000;
        box-shadow: 4px 0 20px rgba(0,0,0,0.5);
        margin-left: 0;
        transform: translateX(0);
        transition: transform 0.3s ease;
    }

    #sidebar.collapsed {
        transform: translateX(-100%);
        margin-left: 0;
    }

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

    #inputArea {
        padding: 0 12px 12px;
    }

    .message {
        padding: 16px 12px;
    }

    .welcome-title {
        font-size: 22px;
    }
}

.fade-in {
    animation: fadeIn 0.3s ease;
}

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

@keyframes thoughtFadeIn {
    from { opacity: 0; transform: translateX(-4px); }
    to { opacity: 1; transform: translateX(0); }
}

.empty-conversations {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-muted);
    font-size: 13px;
}

.loading-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-top-color: var(--text-primary);
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ---- PWA Install Banner ---- */
.install-banner {
    display: none;
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 14px 18px;
    z-index: 9999;
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
    max-width: 440px;
    width: calc(100% - 32px);
    animation: installSlideUp 0.4s ease;
}

.install-banner.visible {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

@keyframes installSlideUp {
    from { opacity: 0; transform: translateX(-50%) translateY(20px); }
    to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

.install-banner-content {
    display: flex;
    align-items: center;
    gap: 12px;
}

.install-banner-icon {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    object-fit: cover;
    flex-shrink: 0;
}

.install-banner-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.install-banner-text strong {
    font-size: 14px;
    color: var(--text-primary);
}

.install-banner-text span {
    font-size: 12px;
    color: var(--text-secondary);
}

.install-banner-actions {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
}

.install-btn-dismiss {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 10px;
    font-size: 13px;
    font-family: inherit;
    cursor: pointer;
    transition: background 0.2s, color 0.2s;
}

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

.install-btn-accept {
    background: var(--accent-color);
    border: none;
    color: #fff;
    padding: 8px 20px;
    border-radius: 10px;
    font-size: 13px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: background 0.2s;
}

.install-btn-accept:hover {
    background: var(--accent-hover);
}

.install-btn-accept svg {
    width: 16px;
    height: 16px;
}