:root {
    color-scheme: light;
    --bg: #ffffff;
    --bg-soft: #fafafa;
    --panel: #ffffff;
    --panel-soft: #f7f7f8;
    --border: #e6e7eb;
    --border-strong: #d2d6dc;
    --text: #111827;
    --muted: #6b7280;
    --muted-strong: #374151;
    --accent: #111827;
    --accent-soft: #f3f4f6;
    --success: #1f6f46;
    --pending: #8b6a1a;
    --danger: #b42318;
    --code-bg: #f7f7f8;
    --radius-xl: 28px;
    --radius-lg: 22px;
    --radius-md: 18px;
    --radius-sm: 14px;
    --content-max-width: 1140px;
    --font-display: "Space Grotesk", "IBM Plex Sans KR", "Segoe UI", sans-serif;
    --font-body: "IBM Plex Sans KR", "Segoe UI", sans-serif;
}

* {
    box-sizing: border-box;
}

.hidden {
    display: none !important;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

html,
body {
    margin: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: var(--bg);
    color: var(--text);
}

body {
    font-family: var(--font-body);
}

button,
textarea,
select {
    color: inherit;
    font: inherit;
}

button {
    border: 0;
    background: none;
    cursor: pointer;
}

textarea,
select {
    appearance: none;
}

::selection {
    background: #eceef1;
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

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

::-webkit-scrollbar-thumb {
    border: 3px solid transparent;
    border-radius: 999px;
    background: #d7dae0;
    background-clip: padding-box;
}

.app-backdrop {
    display: none;
}

.flex-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.mobile-only {
    display: none !important;
}

.desktop-only {
    display: inline-flex;
}

.btn-icon {
    flex: 0 0 auto;
}

.primary-button .btn-icon,
.ghost-button .btn-icon {
    display: none;
}

.topbar-tool .btn-icon {
    display: block;
}

.btn-text {
    white-space: nowrap;
}

.app-shell {
    position: relative;
    display: flex;
    gap: 16px;
    width: 100vw;
    height: 100vh;
    padding: 16px;
    background: var(--bg);
}

.sidebar-overlay {
    position: fixed;
    inset: 0;
    display: none;
    z-index: 999;
    background: rgba(17, 24, 39, 0.08);
    opacity: 0;
    transition: opacity 180ms ease;
}

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

.sidebar {
    position: relative;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 14px;
    width: 264px;
    min-width: 264px;
    min-height: 0;
    padding: 18px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    background: var(--bg-soft);
    overflow: hidden;
    transition: width 220ms ease, min-width 220ms ease, padding 220ms ease, transform 220ms ease;
}

.sidebar::before,
.topbar::before,
.message-list::before,
.composer-inner::before,
.auth-modal-card::before,
.session-item::after {
    content: none;
}

.flex-header {
    display: flex;
    flex-direction: column;
    gap: 12px;
    align-items: stretch;
}

.sidebar-header-copy {
    min-width: 0;
}

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

#newChatButton {
    flex: 1 1 auto;
}

.sidebar-toggle-button {
    flex: 0 0 auto;
}

.sidebar-toggle-button svg {
    transition: transform 180ms ease;
}

.sidebar-header h1,
.topbar h2,
.empty-state h3,
.auth-modal-header h3 {
    margin: 0;
    font-family: var(--font-display);
    letter-spacing: -0.04em;
}

.sidebar-header h1 {
    font-size: 2.3rem;
}

.sidebar-label,
.topbar-label,
.auth-section-label {
    margin: 0 0 8px;
    color: var(--muted);
    font-size: 0.74rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
}

.primary-button,
.ghost-button,
.icon-button,
.copy-button,
.quick-prompt {
    transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}

.primary-button {
    padding: 13px 18px;
    border: 1px solid var(--accent);
    border-radius: 18px;
    background: var(--accent);
    color: #ffffff;
    font-weight: 600;
}

.primary-button:hover {
    background: #1f2937;
    border-color: #1f2937;
}

.primary-button:disabled,
.ghost-button:disabled,
.icon-button:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

.primary-button.danger {
    border-color: #f5c2c7;
    background: #fff5f5;
    color: var(--danger);
}

.ghost-button {
    min-width: 0;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: var(--panel);
    color: var(--muted-strong);
}

.ghost-button:hover {
    background: var(--accent-soft);
    border-color: var(--border-strong);
}

.icon-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: var(--panel);
    color: var(--muted-strong);
}

.icon-button:hover {
    background: var(--accent-soft);
    border-color: var(--border-strong);
}

.session-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    min-height: 0;
    overflow-y: auto;
    padding-right: 2px;
}

.session-item {
    display: flex;
    flex-direction: column;
    gap: 6px;
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: var(--panel);
    color: inherit;
    text-align: left;
}

.session-item:hover {
    border-color: var(--border-strong);
    background: #fcfcfc;
}

.session-item.active {
    border-color: var(--accent);
    background: #ffffff;
}

.session-title {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.session-abbr {
    display: none;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 12px;
    background: var(--panel-soft);
    color: var(--text);
    font-family: var(--font-display);
    font-size: 0.92rem;
    font-weight: 700;
}

.session-preview {
    color: var(--muted);
    font-size: 0.9rem;
    line-height: 1.45;
}

.main-panel {
    display: flex;
    flex: 1;
    flex-direction: column;
    gap: 10px;
    min-width: 0;
    min-height: 0;
}

.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 24px;
    background: var(--panel);
}

.topbar-left,
.topbar-actions {
    min-width: 0;
}

.topbar-left {
    display: flex;
    align-items: center;
    flex: 1;
    gap: 10px;
}

.topbar-brand,
.topbar-copy {
    min-width: 0;
}

.topbar-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand-mark,
.usage-summary-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex: 0 0 auto;
    width: 36px;
    height: 36px;
    border: 1px solid var(--border);
    border-radius: 12px;
    background: var(--panel-soft);
    color: var(--muted-strong);
}

.topbar-copy {
    display: flex;
    align-items: baseline;
    gap: 10px;
}

.topbar .topbar-label {
    margin: 0;
}

.topbar h2 {
    font-size: clamp(1.05rem, 1.8vw, 1.28rem);
    line-height: 1.1;
    white-space: nowrap;
}

.topbar-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 8px;
    flex-wrap: nowrap;
    white-space: nowrap;
}

.auth-status-button {
    position: relative;
    width: 46px;
    height: 46px;
    min-width: 46px;
    padding: 0;
    justify-content: center;
}

.status-dot {
    position: absolute;
    right: 11px;
    bottom: 10px;
    width: 8px;
    height: 8px;
    border: 2px solid #ffffff;
    border-radius: 999px;
    background: #c7cdd6;
}

.auth-status-button.connected {
    border-color: #cfe6d8;
    background: #f5fbf7;
    color: var(--success);
}

.auth-status-button.connected .status-dot {
    background: var(--success);
}

.auth-status-button.pending {
    border-color: #ecdcb6;
    background: #fffaf0;
    color: var(--pending);
}

.auth-status-button.pending .status-dot {
    background: var(--pending);
}

.model-picker {
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 0;
    height: 46px;
    padding: 0 12px;
    border: 1px solid var(--border);
    border-radius: 16px;
    background: var(--panel);
    color: var(--muted-strong);
}

.model-picker-icon,
.model-picker-chevron {
    flex: 0 0 auto;
}

.model-picker select {
    min-width: 92px;
    max-width: 140px;
    padding: 0;
    border: none;
    background: transparent;
    color: var(--text);
    outline: none;
    font-weight: 600;
    text-overflow: ellipsis;
}

.model-picker select:focus {
    color: var(--accent);
}

.message-list {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    background: var(--panel);
}

.usage-summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 22px;
    background: linear-gradient(180deg, #ffffff 0%, #fbfbfb 100%);
}

.usage-summary-panel {
    display: flex;
}

.usage-summary-copy,
.usage-summary-panel {
    min-width: 0;
}

.usage-summary-copy {
    align-items: center;
    flex: 0 0 auto;
    gap: 10px;
}

.usage-summary-panel {
    align-items: center;
    justify-content: flex-end;
    flex: 1;
    gap: 10px;
    overflow: clip;
    transition: max-height 220ms ease, opacity 220ms ease, transform 220ms ease;
}

.usage-summary-copy-text {
    display: flex;
    align-items: baseline;
    gap: 8px;
}

.usage-summary-kicker {
    margin: 0;
    color: var(--muted);
    font-size: 0.68rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
}

.usage-summary-title {
    margin: 0;
    font-family: var(--font-display);
    font-size: 0.96rem;
    letter-spacing: -0.04em;
    white-space: nowrap;
}

.usage-summary-toggle {
    display: none;
    flex: 0 0 auto;
    align-items: center;
    justify-content: center;
    position: relative;
    width: 38px;
    height: 38px;
    padding: 0;
    border-radius: 999px;
}

.usage-summary-toggle:hover {
    border-color: var(--border-strong);
    background: var(--accent-soft);
}

.usage-toggle-icon {
    position: relative;
    width: 16px;
    height: 16px;
}

.usage-toggle-symbol {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    transition: opacity 180ms ease, transform 180ms ease;
}

.usage-toggle-symbol-minus {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.72);
}

.usage-summary-toggle[aria-expanded="true"] .usage-toggle-symbol-plus {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.72);
}

.usage-summary-toggle[aria-expanded="true"] .usage-toggle-symbol-minus {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
}

.usage-summary[data-collapsed="true"] .usage-summary-panel {
    max-height: 0;
    opacity: 0;
    transform: translateY(-6px);
    pointer-events: none;
}

.usage-summary[data-collapsed="false"] .usage-summary-panel,
.usage-summary[data-compact="false"] .usage-summary-panel {
    max-height: 160px;
    opacity: 1;
    transform: translateY(0);
}

.usage-summary-grid {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 8px;
    min-width: 0;
    flex-wrap: wrap;
}

.usage-card {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 7px;
    min-width: 170px;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 16px;
    background: var(--panel-soft);
}

.usage-label {
    color: var(--muted);
    font-size: 0.66rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.usage-value {
    display: inline-flex;
    align-items: center;
    padding: 5px 10px;
    border-radius: 999px;
    background: #eef1f5;
    color: var(--muted-strong);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0;
}

.usage-chart {
    width: 128px;
    height: 8px;
    border-radius: 999px;
    background: #e7ebf0;
    overflow: hidden;
}

.usage-chart-fill {
    display: block;
    width: 12%;
    height: 100%;
    border-radius: inherit;
    background: #c7cdd6;
    transition: width 220ms ease, background-color 180ms ease;
}

.usage-meta,
.usage-summary-detail,
.auth-usage-detail {
    color: var(--muted);
    font-size: 0.82rem;
    line-height: 1.4;
}

.usage-meta {
    white-space: nowrap;
}

.usage-summary-detail,
.auth-usage-detail {
    margin: 0;
}

.usage-summary-detail {
    flex: 0 1 250px;
    text-align: right;
}

.usage-summary[data-status="ok"] .usage-card {
    border-color: #d7e7dc;
    background: #f7fbf8;
}

.usage-summary[data-status="partial"] .usage-card {
    border-color: #eadfbe;
    background: #fffaf2;
}

.usage-summary[data-status="unavailable"] .usage-card {
    border-color: #e5e7eb;
    background: #fafafa;
}

.usage-card[data-level="high"] .usage-value {
    background: #e7f5ec;
    color: var(--success);
}

.usage-card[data-level="high"] .usage-chart-fill {
    background: #3b915f;
}

.usage-card[data-level="medium"] .usage-value {
    background: #f2f4f7;
    color: var(--muted-strong);
}

.usage-card[data-level="medium"] .usage-chart-fill {
    background: #687385;
}

.usage-card[data-level="indeterminate"] .usage-value {
    background: #eef1f5;
    color: var(--muted-strong);
}

.usage-card[data-level="indeterminate"] .usage-chart-fill {
    background: #9aa3b2;
}

.usage-card[data-level="low"] .usage-value {
    background: #fff3dd;
    color: var(--pending);
}

.usage-card[data-level="low"] .usage-chart-fill {
    background: #c28b1d;
}

.usage-card[data-level="empty"] .usage-value,
.usage-card[data-level="missing"] .usage-value {
    background: #f3f4f6;
    color: var(--muted);
}

.usage-card[data-level="unlimited"] .usage-value {
    background: #eef4ff;
    color: #2f5ea8;
}

.usage-card[data-level="unlimited"] .usage-chart-fill {
    width: 100% !important;
    background: linear-gradient(90deg, #87aef7 0%, #b9d0ff 50%, #87aef7 100%);
    background-size: 200% 100%;
    animation: usageShimmer 2.6s linear infinite;
}

.usage-card[data-level="empty"] .usage-chart-fill,
.usage-card[data-level="missing"] .usage-chart-fill {
    background: #cfd5dd;
}

.message-stack,
.empty-state {
    position: relative;
}

.message-stack {
    display: flex;
    flex-direction: column;
    gap: 12px;
    max-width: min(100%, var(--content-max-width));
    margin: 0 auto;
    padding: 0 4px;
}

.message {
    display: flex;
}

.message::before {
    display: none;
}

.message-user {
    justify-content: flex-end;
}

.message-assistant {
    justify-content: flex-start;
}

.message-body {
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: var(--panel);
    line-height: 1.66;
    word-break: break-word;
}

.message-assistant .message-body {
    max-width: min(860px, calc(100% - 44px));
}

.message-user .message-body {
    background: var(--panel-soft);
    max-width: min(720px, calc(100% - 120px));
}

.message-body p {
    margin: 0 0 14px;
}

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

.message-body strong {
    font-weight: 700;
}

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

.message-body code {
    padding: 0.16em 0.44em;
    border-radius: 8px;
    background: #f3f4f6;
    color: var(--text);
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.94em;
}

.code-block {
    margin: 16px 0;
    border: 1px solid var(--border);
    border-radius: 16px;
    overflow: hidden;
    background: var(--code-bg);
}

.code-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 10px 14px;
    border-bottom: 1px solid var(--border);
    color: var(--muted-strong);
    font-size: 0.84rem;
    background: #f8f8f9;
}

.copy-button {
    padding: 7px 12px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: #ffffff;
    color: var(--text);
}

.copy-button:hover {
    background: #f3f4f6;
}

.code-block pre {
    margin: 0;
    padding: 16px;
    overflow-x: auto;
}

.code-block pre code {
    display: block;
    padding: 0;
    border-radius: 0;
    background: transparent;
    font-size: 0.93rem;
    line-height: 1.7;
    white-space: pre;
}

.pending-text {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--muted);
}

.pending-text::after {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 999px;
    background: var(--text);
    animation: pulse 1s ease-in-out infinite;
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: 8px;
    min-height: auto;
    max-width: min(820px, 100%);
    margin: 0 auto;
    padding: 16px 18px;
    border: 1px dashed var(--border-strong);
    border-radius: 22px;
    background: #fcfcfc;
}

.empty-state-kicker,
.quick-prompts {
    display: none;
}

.empty-state h3 {
    font-size: clamp(1.45rem, 2.6vw, 2.2rem);
    line-height: 1.02;
    max-width: 11ch;
}

.empty-state p {
    margin: 0;
    color: var(--muted);
    font-size: 0.95rem;
    line-height: 1.55;
    max-width: 44ch;
}

.composer {
    flex-shrink: 0;
    padding: 0;
}

.composer-inner {
    display: flex;
    align-items: flex-end;
    gap: 12px;
    max-width: var(--content-max-width);
    margin: 0 auto;
    padding: 12px 14px;
    border: 1px solid var(--border);
    border-radius: 22px;
    background: var(--panel);
}

.composer-meta {
    max-width: var(--content-max-width);
    margin: 8px auto 0;
    padding: 0 4px;
}

.stream-status {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin: 0;
    color: var(--muted);
    font-size: 0.9rem;
    line-height: 1.5;
}

.stream-status::before {
    content: "";
    width: 8px;
    height: 8px;
    border-radius: 999px;
    background: #c7cdd6;
    flex: 0 0 auto;
}

.stream-status[data-tone="pending"] {
    color: var(--pending);
}

.stream-status[data-tone="pending"]::before {
    background: var(--pending);
    animation: pulse 1s ease-in-out infinite;
}

.stream-status[data-tone="stopped"] {
    color: var(--danger);
}

.stream-status[data-tone="stopped"]::before {
    background: var(--danger);
}

.composer textarea,
.send-button {
    position: relative;
}

.composer textarea {
    flex: 1;
    min-height: 28px;
    max-height: 180px;
    padding: 6px 0;
    border: none;
    outline: none;
    background: transparent;
    color: var(--text);
    font-size: 1rem;
    line-height: 1.6;
    resize: none;
    overflow-y: auto;
}

.composer textarea::placeholder {
    color: var(--muted);
}

.send-button {
    flex: 0 0 auto;
    min-width: 96px;
}

.toast-container {
    position: fixed;
    top: 16px;
    right: 16px;
    z-index: 1200;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    min-width: 260px;
    max-width: 360px;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: 16px;
    background: #ffffff;
    color: var(--text);
}

.toast.info {
    border-color: var(--border-strong);
}

.toast.error {
    border-color: #efc7c3;
}

.auth-modal {
    position: fixed;
    inset: 0;
    z-index: 1300;
    display: grid;
    place-items: center;
    padding: 24px;
    background: rgba(255, 255, 255, 0.82);
    backdrop-filter: blur(8px);
}

.auth-modal-card {
    width: min(540px, 100%);
    padding: 24px;
    border: 1px solid var(--border);
    border-radius: 24px;
    background: #ffffff;
}

.auth-modal-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
}

.auth-modal-header h3 {
    font-size: 1.55rem;
}

.auth-description {
    margin: 18px 0 8px;
    color: var(--muted-strong);
    line-height: 1.7;
}

.auth-meta {
    margin: 0;
    color: var(--muted);
    line-height: 1.6;
    font-size: 0.92rem;
}

.auth-code-section,
.auth-connected-section {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-top: 18px;
    padding: 16px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: var(--bg-soft);
}

.auth-connected-section {
    flex-direction: column;
    align-items: stretch;
}

.auth-code {
    font-family: var(--font-display);
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: 0.16em;
}

.auth-link-button {
    white-space: nowrap;
}

.auth-detail-row {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 16px;
}

.auth-modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    margin-top: 22px;
}

.app-shell.sidebar-collapsed {
    gap: 12px;
}

.app-shell.sidebar-collapsed .sidebar {
    width: 84px;
    min-width: 84px;
    padding: 14px 10px;
}

.app-shell.sidebar-collapsed .sidebar-header {
    align-items: center;
}

.app-shell.sidebar-collapsed .sidebar-header-copy,
.app-shell.sidebar-collapsed .session-title,
.app-shell.sidebar-collapsed .session-preview {
    display: none;
}

.app-shell.sidebar-collapsed .sidebar-header-actions {
    flex-direction: column;
    width: 100%;
}

.app-shell.sidebar-collapsed .sidebar-toggle-button svg {
    transform: rotate(180deg);
}

.app-shell.sidebar-collapsed #newChatButton {
    flex: 0 0 auto;
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: 14px;
}

.app-shell.sidebar-collapsed #newChatButton .btn-icon {
    display: block;
}

.app-shell.sidebar-collapsed #newChatButton .btn-text {
    display: none;
}

.app-shell.sidebar-collapsed .session-list {
    gap: 8px;
}

.app-shell.sidebar-collapsed .session-item {
    align-items: center;
    justify-content: center;
    min-height: 52px;
    padding: 8px;
}

.app-shell.sidebar-collapsed .session-abbr {
    display: inline-flex;
}

.secondary-button {
    min-width: 110px;
}

@keyframes pulse {
    0%,
    100% {
        opacity: 0.45;
    }

    50% {
        opacity: 1;
    }
}

@keyframes usageShimmer {
    0% {
        background-position: 100% 0;
    }

    100% {
        background-position: -100% 0;
    }
}

@media (max-width: 1180px) {
    .sidebar {
        width: 244px;
        min-width: 244px;
    }

    .topbar h2 {
        font-size: 1.12rem;
    }

    .usage-summary-detail {
        flex-basis: 200px;
    }

    .message-assistant .message-body {
        max-width: min(780px, calc(100% - 36px));
    }
}

@media (max-width: 960px) {
    .mobile-only {
        display: inline-flex !important;
    }

    .desktop-only {
        display: none !important;
    }

    .app-shell {
        gap: 0;
        padding: 12px;
    }

    .sidebar {
        position: fixed;
        top: 12px;
        bottom: 12px;
        left: 12px;
        width: min(82vw, 286px);
        min-width: auto;
        background: #ffffff;
        transform: translateX(calc(-100% - 18px));
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .main-panel {
        gap: 10px;
    }

    .topbar,
    .usage-summary,
    .message-list,
    .composer-inner,
    .empty-state,
    .auth-modal-card {
        border-radius: 22px;
    }

    .topbar {
        padding: 10px 12px;
    }

    .topbar-copy {
        gap: 8px;
    }

    .topbar-actions {
        flex: 0 0 auto;
        gap: 6px;
    }

    .topbar-label {
        display: none;
    }

    .topbar h2 {
        font-size: 1rem;
    }

    .usage-summary-copy-text {
        gap: 6px;
    }

    .usage-summary-kicker {
        display: none;
    }

    .message-list {
        padding: 14px;
    }

    .usage-summary {
        align-items: flex-start;
        flex-wrap: wrap;
        gap: 8px;
        padding: 10px 12px;
    }

    .usage-summary-toggle {
        display: inline-flex;
        margin-left: auto;
    }

    .usage-summary[data-collapsed="true"] .usage-summary-panel {
        max-height: 0;
    }

    .usage-summary-grid {
        justify-content: flex-start;
    }

    .usage-card {
        min-width: 138px;
        padding: 8px 10px;
    }

    .usage-chart {
        width: 112px;
    }

    .usage-summary-panel {
        width: 100%;
        align-items: flex-start;
        flex-direction: column;
        gap: 8px;
        order: 3;
    }

    .usage-summary-detail {
        max-width: none;
        text-align: left;
    }

    .empty-state {
        padding: 14px 16px;
    }

    .empty-state h3 {
        max-width: 12ch;
        font-size: clamp(1.35rem, 6vw, 1.9rem);
    }

    .composer-inner {
        padding: 12px 14px;
    }

    .composer-meta {
        margin-top: 6px;
    }

    .stream-status {
        font-size: 0.86rem;
    }

    .send-button {
        min-width: 78px;
    }

    .toast-container {
        left: 12px;
        right: 12px;
        top: auto;
        bottom: 12px;
    }

    .toast {
        width: 100%;
        max-width: none;
    }

    .auth-code-section,
    .auth-detail-row,
    .auth-modal-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .auth-link-button,
    .secondary-button,
    .auth-modal-actions .primary-button {
        width: 100%;
        justify-content: center;
    }
}

@media (max-height: 720px) {
    .sidebar {
        padding: 16px;
    }

    .sidebar-header h1 {
        font-size: 2.05rem;
    }

    .sidebar-copy {
        line-height: 1.55;
    }

    .topbar {
        padding: 9px 12px;
    }

    .topbar h2 {
        font-size: 1rem;
    }

    .topbar-label,
    .usage-summary-kicker {
        display: none;
    }

    .message-list {
        padding: 14px;
    }

    .usage-summary {
        gap: 8px;
        padding: 9px 12px;
    }

    .usage-summary-toggle {
        display: inline-flex;
    }

    .usage-summary[data-collapsed="true"] .usage-summary-panel {
        max-height: 0;
    }

    .usage-summary-title {
        font-size: 0.9rem;
    }

    .message-stack {
        padding: 0;
    }

    .message-assistant .message-body,
    .message-user .message-body {
        max-width: 100%;
    }

    .empty-state {
        gap: 7px;
        padding: 12px 14px;
    }

    .empty-state h3 {
        font-size: clamp(1.2rem, 4.1vh, 1.7rem);
    }

    .empty-state p {
        font-size: 0.9rem;
        line-height: 1.5;
    }

    .composer-inner {
        padding: 12px 14px;
    }

    .composer-meta {
        margin-top: 6px;
    }
}