*,
        *:before,
        *:after {
            box-sizing: border-box;
            border-width: 0;
            border-style: solid;
            border-color: #e5e7eb;
            margin: 0;
            padding: 0;
        }

        :root {
            --background: 0 0% 100%;
            --foreground: 0 0% 9%;
            --card: 0 0% 100%;
            --card-foreground: 0 0% 9%;
            --shell: 0 0% 100%;
            --chat-surface: 0 0% 100%;
            --primary: 0 0% 9%;
            --primary-foreground: 0 0% 100%;
            --secondary: 240 5% 96%;
            --secondary-foreground: 0 0% 25%;
            --muted: 240 5% 96%;
            --muted-foreground: 0 0% 45%;
            --accent: 240 4% 95%;
            --accent-foreground: 0 0% 9%;
            --border: 0 0% 90%;
            --input: 0 0% 90%;
            --ring: 0 0% 9%;
            --radius: 1rem;
            --input-max-h: 200px;
            --glass: rgba(255, 255, 255, 0.95);
            --glass-border: rgba(0, 0, 0, 0.08);
            --font-brand: 'Cairo', sans-serif;
        }

        html {
            line-height: 1.5;
            -webkit-text-size-adjust: 100%;
            font-family: DM Sans, sans-serif;
            -webkit-tap-highlight-color: transparent;
            height: 100%;
            overflow: hidden;
        }

        body {
            margin: 0;
            background-color: #ffffff;
            color: hsl(var(--foreground));
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            font-family: DM Sans, sans-serif;
            height: 100vh;
            height: 100dvh;
            overflow: hidden;
            width: 100%;
        }

        code, pre {
            font-family: Space Mono, monospace;
        }

        ::-webkit-scrollbar {
            width: 4px;
        }
        ::-webkit-scrollbar-track {
            background: transparent;
        }
        ::-webkit-scrollbar-thumb {
            background: hsl(var(--border));
            border-radius: 2px;
        }

        #app-shell {
            position: fixed;
            left: 0;
            right: 0;
            top: 0;
            height: 100%;
            height: 100dvh;
            display: flex;
            flex-direction: column;
            overflow: hidden;
            background: #ffffff;
            z-index: 1;
        }

        .toolbar-zone {
            flex-shrink: 0;
            z-index: 100;
            display: flex;
            justify-content: center;
            padding: max(0.625rem, env(safe-area-inset-top)) 1rem 0.75rem;
            background: #ffffff;
            pointer-events: none;
        }

        .top-toolbar {
            pointer-events: auto;
            display: grid;
            grid-template-columns: 40px 1fr 40px;
            align-items: center;
            max-width: 42rem;
            width: 100%;
            margin: 0 auto;
            padding: 0.4rem 0.5rem;
            border-radius: 9999px;
            background: #ffffff;
            border: 1px solid rgba(0, 0, 0, 0.08);
            box-shadow:
                0 2px 4px rgba(0, 0, 0, 0.04),
                0 8px 28px rgba(0, 0, 0, 0.1),
                0 16px 48px rgba(0, 0, 0, 0.06);
        }

        .toolbar-brand-name {
            grid-column: 2;
            text-align: center;
            font-family: var(--font-brand);
            font-weight: 800;
            font-size: 1.125rem;
            letter-spacing: -0.02em;
            color: hsl(var(--foreground));
            line-height: 1;
        }

        .toolbar-spacer {
            grid-column: 3;
            width: 40px;
        }

        .menu-btn {
            grid-column: 1;
            width: 38px;
            height: 38px;
            border-radius: 50%;
            background: hsl(var(--secondary));
            border: 0.5px solid rgba(0, 0, 0, 0.06);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: transform 0.2s, background 0.2s;
        }
        .menu-btn:active {
            transform: scale(0.94);
            background: rgba(0, 0, 0, 0.05);
        }
        .menu-btn svg {
            width: 19px;
            height: 19px;
            stroke: hsl(var(--foreground));
            stroke-width: 2;
            fill: none;
        }

        .brand-logo {
            border-radius: 50%;
            object-fit: cover;
            background: #0a0a0a;
            border: 2px solid hsl(0 0% 100%);
            box-shadow:
                0 0 0 1px rgba(0, 0, 0, 0.06),
                0 8px 24px rgba(0, 0, 0, 0.1);
        }

        #app-container {
            flex: 1;
            width: 100%;
            display: flex;
            flex-direction: column;
            min-height: 0;
            overflow: hidden;
            background: #ffffff;
        }

        #chat-view {
            flex: 1;
            min-height: 0;
            flex-direction: column;
        }
        #chat-view:not(.hidden) {
            display: flex;
        }

        .chat-area {
            flex: 1;
            min-height: 0;
            overflow-y: auto;
            overflow-x: hidden;
            -webkit-overflow-scrolling: touch;
            overscroll-behavior: contain;
            background: hsl(var(--chat-surface));
        }

        .input-container {
            flex-shrink: 0;
            position: relative;
            z-index: 50;
            background: transparent;
            padding: 0.625rem 1rem 1rem;
            padding-bottom: max(1rem, env(safe-area-inset-bottom));
        }

        #messages-list {
            max-width: 42rem;
            margin: 0 auto;
            padding: 1.25rem 1rem 0.75rem;
        }
        #messages-list > * + * {
            margin-top: 1rem;
        }

        .input-wrapper {
            max-width: 42rem;
            margin: 0 auto;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            min-height: 52px;
            padding: 0.4rem 0.625rem 0.4rem 0.5rem;
            border-radius: 1.375rem;
            border: 1px solid rgba(0, 0, 0, 0.1);
            background: #ffffff;
            box-shadow:
                0 1px 2px rgba(0, 0, 0, 0.04),
                0 6px 20px rgba(0, 0, 0, 0.06);
            transition: box-shadow 0.2s, border-color 0.2s;
        }
        .input-wrapper:focus-within {
            border-color: rgba(0, 0, 0, 0.16);
            box-shadow:
                0 0 0 3px rgba(0, 0, 0, 0.05),
                0 8px 24px rgba(0, 0, 0, 0.08);
        }

        textarea {
            flex: 1;
            min-width: 0;
            min-height: 28px;
            max-height: var(--input-max-h);
            resize: none;
            overflow-y: auto;
            font-family: inherit;
            background: transparent;
            padding: 0.5rem 0.25rem;
            margin: 0;
            font-size: 0.9375rem;
            color: hsl(var(--foreground));
            outline: none;
            border: none;
            line-height: 1.5;
            scrollbar-width: thin;
            text-align: start;
            align-self: center;
        }
        textarea[dir="rtl"],
        textarea:dir(rtl) {
            text-align: right;
        }
        textarea::placeholder {
            color: hsl(var(--muted-foreground));
        }

        .send-button {
            order: -1;
            flex-shrink: 0;
            width: 2.25rem;
            height: 2.25rem;
            border-radius: 50%;
            display: flex !important;
            align-items: center;
            justify-content: center;
            transition: background-color 0.2s, color 0.2s, transform 0.15s;
            border: none;
            cursor: pointer;
            align-self: center;
        }
        .send-button.active {
            background-color: hsl(var(--foreground));
            color: #ffffff;
            cursor: pointer;
        }
        .send-button.active:active {
            transform: scale(0.94);
        }
        .send-button.inactive {
            background-color: hsl(0 0% 92%);
            color: hsl(0 0% 60%);
            cursor: default;
        }
        .send-button:disabled.inactive {
            opacity: 0.9;
        }
        .send-button svg {
            width: 1.05rem;
            height: 1.05rem;
            stroke: currentColor;
            flex-shrink: 0;
            transform: scaleX(-1);
        }

        .empty-state {
            flex: 1;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: 1.25rem 1.25rem 2rem;
            overflow-y: auto;
            -webkit-overflow-scrolling: touch;
            background: #ffffff;
        }
        .hero {
            width: 100%;
            max-width: 36rem;
            text-align: center;
            margin-bottom: 1.5rem;
        }
        .hero-brand {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.75rem;
            margin-bottom: 0.5rem;
        }
        .hero-logo {
            width: 80px;
            height: 80px;
            display: block;
        }
        .hero-title {
            font-family: var(--font-brand);
            font-size: 1.75rem;
            font-weight: 800;
            letter-spacing: -0.03em;
            color: hsl(var(--foreground));
            line-height: 1.15;
        }
        .hero-tagline {
            font-size: 0.9375rem;
            font-weight: 500;
            color: hsl(var(--muted-foreground));
            margin-bottom: 1.125rem;
            letter-spacing: -0.01em;
        }
        .provider-badges {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 0.35rem;
        }
        .provider-badge {
            font-size: 0.625rem;
            font-weight: 600;
            letter-spacing: 0.04em;
            text-transform: uppercase;
            padding: 0.32rem 0.6rem;
            border-radius: 9999px;
            background: hsl(var(--secondary));
            color: hsl(var(--muted-foreground));
            border: 0.5px solid hsl(var(--border));
        }
        .empty-state .empty-input-wrap,
        .empty-state .input-wrapper {
            width: 100%;
            max-width: 42rem;
            flex-shrink: 0;
        }

        .message-enter {
            animation: message-enter 250ms ease-out forwards;
        }
        @keyframes message-enter {
            0% { opacity: 0; transform: translateY(8px); }
            100% { opacity: 1; transform: translateY(0); }
        }

        @keyframes loading-pulse {
            0% { opacity: 0.3; transform: scale(1); }
            50% { opacity: 1; transform: scale(1.4); }
            100% { opacity: 0.3; transform: scale(1); }
        }
        .loading-dot {
            display: inline-block;
            width: 0.625rem;
            height: 0.625rem;
            border-radius: 9999px;
            background-color: hsl(var(--foreground));
            animation: loading-pulse 1.2s ease-in-out infinite;
        }

        .msg-user-row {
            display: flex;
            justify-content: flex-end;
        }
        .user-bubble {
            max-width: 88%;
            background: hsl(var(--primary));
            color: #ffffff;
            padding: 0.7rem 1rem;
            border-radius: 1.25rem;
            border-bottom-right-radius: 0.3rem;
            font-size: 0.875rem;
            box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
            white-space: pre-wrap;
            word-break: break-word;
            overflow-wrap: anywhere;
        }
        .user-bubble .chat-prose {
            color: #ffffff;
            white-space: pre-wrap;
            word-break: break-word;
            overflow-wrap: anywhere;
        }

        .msg-ai-row {
            width: 100%;
        }
        .msg-ai-wrap {
            max-width: 100%;
            padding: 0.875rem 0;
            background: transparent;
            border: none;
            border-radius: 0;
            box-shadow: none;
        }
        .msg-ai-wrap.msg-ai-wrap--stream {
            padding: 0;
        }

        .chat-prose {
            font-size: 0.875rem;
            line-height: 1.625;
            color: hsl(var(--foreground));
        }
        .chat-prose p { margin-bottom: 0.75rem; }
        .chat-prose p:last-child { margin-bottom: 0; }
        .chat-prose strong { font-weight: 600; }
        .chat-prose em { font-style: italic; }
        .chat-prose ul { margin-left: 1rem; margin-bottom: 0.75rem; list-style: disc; }
        .chat-prose ol { margin-left: 1rem; margin-bottom: 0.75rem; list-style: decimal; }
        .chat-prose li { margin-bottom: 0.375rem; }
        .chat-prose code {
            border-radius: 0.25rem;
            border: 1px solid hsl(var(--border) / 0.4);
            background-color: hsl(var(--secondary));
            padding: 0.125rem 0.375rem;
            font-family: Space Mono, monospace;
            font-size: 0.75rem;
        }
        .chat-prose pre {
            margin-bottom: 0.75rem;
            overflow-x: auto;
            border-radius: 0.625rem;
            background-color: #000000;
            border: 1px solid #2a2a2a;
            padding: 1rem 1.125rem;
            color: #e5e5e5;
        }
        .chat-prose pre code {
            border: none;
            background: transparent;
            padding: 0;
            color: #e5e5e5;
        }
        .chat-prose a.link-button,
        .chat-prose .fmt-link-btn {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            background-color: hsl(var(--primary));
            color: hsl(var(--primary-foreground));
            padding: 0.35rem 0.875rem;
            border-radius: 9999px;
            font-size: 0.75rem;
            font-weight: 500;
            text-decoration: none;
            border: none;
            cursor: pointer;
            font-family: inherit;
            line-height: 1.2;
            -webkit-touch-callout: none;
            -webkit-user-select: none;
            user-select: none;
            touch-action: manipulation;
        }
        .chat-prose .fmt-link-btn:active {
            opacity: 0.88;
            transform: scale(0.98);
        }
        .chat-prose .fmt-link-btn-label {
            pointer-events: none;
        }

        /* Cipher formatting tokens */
        .fmt-hl-yellow {
            background: linear-gradient(180deg, transparent 55%, #fde047 55%);
            color: inherit;
            padding: 0 0.12em;
            border-radius: 0.15em;
            box-decoration-break: clone;
            -webkit-box-decoration-break: clone;
        }
        .fmt-hl-green {
            background: linear-gradient(180deg, transparent 55%, #86efac 55%);
            color: inherit;
            padding: 0 0.12em;
            border-radius: 0.15em;
            box-decoration-break: clone;
            -webkit-box-decoration-break: clone;
        }
        .fmt-bold {
            font-weight: 700;
            color: hsl(var(--foreground));
        }
        .fmt-dark {
            color: hsl(var(--foreground));
            font-weight: 600;
            background: hsl(var(--secondary));
            padding: 0.1em 0.35em;
            border-radius: 0.25rem;
        }
        .fmt-title {
            font-size: 1.05rem;
            font-weight: 700;
            letter-spacing: -0.02em;
            margin: 0.75rem 0 0.35rem;
            color: hsl(var(--foreground));
            line-height: 1.35;
        }
        .fmt-title:first-child {
            margin-top: 0;
        }
        .fmt-math {
            display: block;
            margin: 0.5rem 0;
            padding: 0.65rem 0.85rem;
            border-radius: 0.5rem;
            background: hsl(var(--muted));
            border: 1px solid hsl(var(--border));
            font-family: Space Mono, monospace;
            font-size: 0.8125rem;
            line-height: 1.5;
            color: hsl(var(--foreground));
            white-space: pre-wrap;
            word-break: break-word;
        }
        .fmt-br {
            display: block;
            content: '';
            margin: 0;
        }
        .fmt-step {
            display: flex;
            align-items: flex-start;
            gap: 0.625rem;
            margin: 0.5rem 0;
            padding: 0.5rem 0.65rem;
            border-radius: 0.5rem;
            background: hsl(var(--muted) / 0.55);
            border: 1px solid hsl(var(--border));
        }
        .fmt-step-num {
            flex-shrink: 0;
            min-width: 1.5rem;
            height: 1.5rem;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            border-radius: 9999px;
            background: hsl(var(--primary));
            color: hsl(var(--primary-foreground));
            font-size: 0.6875rem;
            font-weight: 700;
            line-height: 1;
        }
        .fmt-step-body {
            flex: 1;
            min-width: 0;
            font-size: 0.875rem;
            line-height: 1.5;
            color: hsl(var(--foreground));
            word-break: break-word;
        }

        /* Code block — always black background */
        .code-block-wrapper {
            margin: 0.75rem 0;
            border-radius: 0.625rem;
            overflow: hidden;
            background-color: #000000 !important;
            border: 1px solid #2a2a2a;
            direction: ltr;
            opacity: 1;
        }
        .code-block-wrapper.code-block-animate-in {
            animation: code-block-appear 0.35s cubic-bezier(0.22, 1, 0.36, 1) forwards;
        }
        @keyframes code-block-appear {
            from {
                opacity: 0.6;
                transform: translateY(6px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        .code-block-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0.5rem 0.875rem;
            background: #000000;
            color: #9ca3af;
            font-size: 0.6875rem;
            font-family: Space Mono, monospace;
            border-bottom: none;
        }
        .code-block-lang {
            text-transform: uppercase;
            font-weight: 600;
            letter-spacing: 0.05em;
        }
        .code-block-copy {
            background: transparent;
            border: 1px solid #3f3f3f;
            color: #d1d5db;
            cursor: pointer;
            padding: 0.25rem 0.5rem;
            border-radius: 0.375rem;
            font-size: 0.65rem;
            display: inline-flex;
            align-items: center;
            gap: 0.35rem;
            transition: background 0.15s, color 0.15s, border-color 0.15s;
            font-family: DM Sans, sans-serif;
        }
        .code-block-copy:disabled {
            opacity: 0.4;
            cursor: not-allowed;
        }
        .code-block-copy:hover:not(:disabled),
        .code-block-copy:active:not(:disabled) {
            background: #262626;
            color: #fff;
            border-color: #525252;
        }
        code.code-typing::after {
            content: '|';
            color: #22c55e;
            animation: code-caret-blink 0.9s step-end infinite;
        }
        @keyframes code-caret-blink {
            50% { opacity: 0; }
        }
        .code-block-copy svg {
            width: 12px;
            height: 12px;
            stroke: currentColor;
            fill: none;
            stroke-width: 2;
        }
        .code-block-content {
            margin: 0;
            padding: 1rem 1.125rem;
            overflow-x: auto;
            overflow-y: hidden;
            background-color: #000000 !important;
            color: #e5e5e5 !important;
            font-family: Space Mono, monospace;
            font-size: 0.8rem;
            line-height: 1.6;
            white-space: pre;
            scrollbar-color: #333333 #000000;
            scrollbar-width: thin;
        }
        .code-block-content::-webkit-scrollbar {
            height: 5px;
        }
        .code-block-content::-webkit-scrollbar-track {
            background: #000000;
        }
        .code-block-content::-webkit-scrollbar-thumb {
            background: #333333;
            border-radius: 4px;
        }
        .code-block-content::-webkit-scrollbar-thumb:hover {
            background: #444444;
        }
        .code-block-wrapper pre,
        .code-block-wrapper .code-block-content {
            background-color: #000000 !important;
            border: none !important;
            box-shadow: none !important;
        }
        .code-block-wrapper pre code,
        .code-block-wrapper pre code.hljs,
        .code-block-wrapper .code-block-content code,
        .code-block-wrapper .code-block-content .hljs,
        .code-block-wrapper .hljs * {
            background: transparent !important;
            background-color: transparent !important;
            box-shadow: none !important;
        }
        .code-block-content code.hljs {
            display: block;
            padding: 0 !important;
            margin: 0 !important;
            font-family: inherit;
            font-size: inherit;
            line-height: inherit;
            white-space: pre;
        }
        .msg-ai-wrap .code-block-wrapper,
        .msg-ai-wrap .code-block-header,
        .msg-ai-wrap .code-block-content,
        .msg-ai-wrap .code-block-wrapper .hljs {
            background-color: #000000 !important;
            color: #e5e5e5 !important;
        }
        .response-preparing {
            display: flex;
            align-items: center;
            gap: 0.625rem;
            padding: 0.35rem 0;
            color: hsl(var(--muted-foreground));
            font-size: 0.875rem;
        }
        .response-preparing .loading-dot {
            flex-shrink: 0;
        }

        .msg-actions {
            display: flex;
            align-items: center;
            gap: 0.25rem;
            margin-top: 0.5rem;
            transition: opacity 300ms cubic-bezier(0.4, 0, 0.2, 1);
        }
        .msg-action-btn {
            padding: 0.375rem;
            border-radius: calc(var(--radius) - 2px);
            border: none;
            background: transparent;
            cursor: pointer;
            color: hsl(var(--muted-foreground));
            transition: color 150ms cubic-bezier(0.4, 0, 0.2, 1), background-color 150ms cubic-bezier(0.4, 0, 0.2, 1);
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .msg-action-btn:hover {
            color: hsl(var(--foreground));
            background: hsl(var(--secondary));
        }
        .msg-action-btn.is-on {
            color: hsl(var(--foreground));
            background: hsl(var(--secondary));
        }
        .msg-action-svg {
            width: 0.875rem;
            height: 0.875rem;
            display: block;
            fill: none;
            stroke: currentColor;
            stroke-width: 2;
            stroke-linecap: round;
            stroke-linejoin: round;
        }

        .sidebar-footer {
            flex-shrink: 0;
            padding: 0.75rem;
            padding-bottom: max(0.75rem, env(safe-area-inset-bottom));
            border-top: 1px solid hsl(var(--border));
            background: hsl(var(--background));
        }
        .api-key-card {
            border-radius: 0.875rem;
            border: 1px solid hsl(var(--border));
            background: hsl(var(--card));
            padding: 0.875rem;
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
        }
        .api-key-card-head {
            display: flex;
            flex-direction: column;
            gap: 0.125rem;
            margin-bottom: 0.625rem;
        }
        .api-key-title {
            font-size: 0.8125rem;
            font-weight: 600;
            color: hsl(var(--foreground));
            letter-spacing: -0.02em;
        }
        .api-key-subtitle {
            font-size: 0.6875rem;
            color: hsl(var(--muted-foreground));
            line-height: 1.35;
        }
        .api-key-field {
            display: flex;
            align-items: center;
            gap: 0.375rem;
            border: 1px solid hsl(var(--border));
            border-radius: 0.625rem;
            background: hsl(var(--background));
            padding: 0 0.5rem 0 0.75rem;
            transition: border-color 0.2s, box-shadow 0.2s;
        }
        .api-key-field:focus-within {
            border-color: hsl(var(--foreground) / 0.22);
            box-shadow: 0 0 0 3px hsl(var(--foreground) / 0.06);
        }
        .api-key-input {
            flex: 1;
            min-width: 0;
            border: none;
            background: transparent;
            padding: 0.625rem 0;
            color: hsl(var(--foreground));
            font-size: 0.8125rem;
            font-family: Space Mono, monospace;
            outline: none;
        }
        .api-key-input::placeholder {
            color: hsl(var(--muted-foreground));
            font-family: DM Sans, sans-serif;
            font-size: 0.75rem;
        }
        .api-key-toggle {
            flex-shrink: 0;
            width: 32px;
            height: 32px;
            border: none;
            background: transparent;
            border-radius: 0.375rem;
            cursor: pointer;
            color: hsl(var(--muted-foreground));
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 0;
        }
        .api-key-toggle:active {
            background: hsl(var(--secondary));
            color: hsl(var(--foreground));
        }
        .api-key-toggle svg {
            width: 16px;
            height: 16px;
        }
        .api-key-status {
            margin: 0.5rem 0 0;
            font-size: 0.6875rem;
            color: hsl(var(--muted-foreground));
            line-height: 1.4;
        }
        .api-key-status.is-ok {
            color: hsl(142 45% 35%);
        }
        .api-key-status.is-warn {
            color: hsl(38 80% 40%);
        }

        .toast-container {
            position: fixed;
            bottom: max(1rem, env(safe-area-inset-bottom));
            left: 50%;
            transform: translateX(-50%);
            z-index: 500;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.5rem;
            pointer-events: none;
            max-width: 90vw;
        }
        .toast {
            padding: 0.625rem 1rem;
            border-radius: 9999px;
            background: hsl(var(--primary));
            color: hsl(var(--primary-foreground));
            font-size: 0.8125rem;
            font-weight: 500;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
            animation: toast-in 0.25s ease-out forwards;
        }
        @keyframes toast-in {
            from { opacity: 0; transform: translateY(8px); }
            to { opacity: 1; transform: translateY(0); }
        }

        /* Sidebar */
        .sidebar-overlay {
            position: fixed;
            inset: 0;
            z-index: 300;
            background: rgba(0,0,0,0.4);
            opacity: 0;
            pointer-events: none;
            transition: opacity 0.3s ease;
            will-change: opacity;
            -webkit-backdrop-filter: blur(2px);
            backdrop-filter: blur(2px);
        }
        .sidebar-overlay.open {
            opacity: 1;
            pointer-events: auto;
        }

        .sidebar {
            position: fixed;
            top: 0;
            left: 0;
            bottom: 0;
            width: min(320px, 88vw);
            z-index: 301;
            background: hsl(var(--background));
            border-right: 1px solid hsl(var(--border));
            transform: translateX(-100%);
            transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
            display: flex;
            flex-direction: column;
            box-shadow: 4px 0 24px rgba(0,0,0,0.08);
            padding-top: env(safe-area-inset-top);
        }
        .sidebar.open {
            transform: translateX(0);
        }

        .sidebar-header {
            padding: 1.25rem 1rem 1rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            gap: 0.5rem;
        }
        .sidebar-brand {
            display: flex;
            align-items: center;
            gap: 0.625rem;
            min-width: 0;
        }
        .sidebar-logo-img {
            width: 40px;
            height: 40px;
            flex-shrink: 0;
        }
        .sidebar-title {
            font-family: var(--font-brand);
            font-weight: 800;
            font-size: 1.0625rem;
            letter-spacing: -0.02em;
        }
        .sidebar-subtitle {
            font-size: 0.7rem;
            color: hsl(var(--muted-foreground));
            margin-top: 0.125rem;
        }
        .sidebar-close {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            border: 1px solid hsl(var(--border));
            background: hsl(var(--card));
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            color: hsl(var(--foreground));
            flex-shrink: 0;
        }
        .sidebar-close svg {
            width: 18px;
            height: 18px;
            stroke: currentColor;
            stroke-width: 2;
            fill: none;
        }

        .new-chat-btn-sidebar {
            margin: 0 0.75rem 0.75rem;
            padding: 0.75rem 1rem;
            border-radius: 0.75rem;
            border: 1px solid hsl(var(--border));
            background: hsl(var(--primary));
            color: hsl(var(--primary-foreground));
            cursor: pointer;
            font-size: 0.875rem;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            justify-content: center;
            transition: opacity 0.2s;
        }
        .new-chat-btn-sidebar:active {
            opacity: 0.85;
        }

        .sidebar-section-label {
            padding: 0 1rem 0.5rem;
            font-size: 0.7rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.06em;
            color: hsl(var(--muted-foreground));
        }

        .sidebar-chats {
            flex: 1;
            overflow-y: auto;
            padding: 0 0.625rem 1rem;
            -webkit-overflow-scrolling: touch;
        }
        .sidebar-empty {
            text-align: center;
            color: hsl(var(--muted-foreground));
            padding: 2.5rem 1.25rem;
            font-size: 0.875rem;
            line-height: 1.5;
        }
        .sidebar-empty span {
            display: block;
            margin-top: 0.3rem;
            font-size: 0.75rem;
            opacity: 0.8;
        }

        .chat-item {
            padding: 0.75rem 0.625rem 0.75rem 0.75rem;
            border-radius: 0.875rem;
            cursor: pointer;
            transition: background 0.2s, border-color 0.2s, box-shadow 0.2s;
            display: flex;
            align-items: flex-start;
            gap: 0.625rem;
            margin-bottom: 0.375rem;
            border: 1px solid transparent;
            background: transparent;
        }
        .chat-item:hover {
            background: hsl(var(--muted) / 0.65);
        }
        .chat-item:active {
            transform: scale(0.99);
        }
        .chat-item.active {
            background: hsl(var(--secondary));
            border-color: hsl(var(--border));
            box-shadow: 0 1px 0 hsl(var(--border) / 0.5);
        }
        .chat-item.active .chat-item-icon {
            background: hsl(var(--primary));
            color: hsl(var(--primary-foreground));
        }
        .chat-item-icon {
            width: 36px;
            height: 36px;
            border-radius: 0.625rem;
            background: hsl(var(--muted));
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            color: hsl(var(--muted-foreground));
            margin-top: 0.125rem;
            transition: background 0.2s, color 0.2s;
        }
        .chat-item-icon svg {
            width: 16px;
            height: 16px;
            stroke: currentColor;
            stroke-width: 2;
            fill: none;
        }
        .chat-item-body {
            flex: 1;
            min-width: 0;
            display: flex;
            flex-direction: column;
            gap: 0.2rem;
        }
        .chat-item-title {
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            font-weight: 600;
            font-size: 0.8125rem;
            letter-spacing: -0.01em;
            color: hsl(var(--foreground));
            line-height: 1.3;
        }
        .chat-item-preview {
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
            font-size: 0.75rem;
            color: hsl(var(--muted-foreground));
            line-height: 1.35;
        }
        .chat-item-time {
            font-size: 0.6875rem;
            color: hsl(var(--muted-foreground));
            opacity: 0.9;
            margin-top: 0.1rem;
        }
        .chat-item-delete {
            width: 30px;
            height: 30px;
            border-radius: 0.5rem;
            border: none;
            background: transparent;
            cursor: pointer;
            color: hsl(var(--muted-foreground));
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            margin-top: 0.125rem;
            opacity: 0.7;
            transition: opacity 0.15s, background 0.15s, color 0.15s;
        }
        .chat-item:hover .chat-item-delete {
            opacity: 1;
        }
        .chat-item-delete:active {
            background: hsl(var(--border));
            color: hsl(var(--foreground));
        }
        .chat-item-delete svg {
            width: 15px;
            height: 15px;
            stroke: currentColor;
            stroke-width: 2;
            fill: none;
        }

        /* Text stream — plain chars only, then formatted reveal */
        .stream-text-live {
            white-space: pre-wrap;
            word-break: break-word;
            overflow-wrap: anywhere;
        }
        .stream-text-live.is-typing::after {
            content: '';
            display: inline-block;
            width: 2px;
            height: 1.05em;
            background: hsl(var(--foreground));
            margin-left: 1px;
            vertical-align: text-bottom;
            opacity: 0.75;
            animation: stream-caret-blink 0.85s step-end infinite;
        }
        @keyframes stream-caret-blink {
            50% { opacity: 0; }
        }
        .stream-text-live.stream-text-reveal {
            animation: stream-text-reveal 0.22s ease-out forwards;
        }
        @keyframes stream-text-reveal {
            from { opacity: 0.35; }
            to { opacity: 1; }
        }

        .hidden {
            display: none !important;
        }