/* ── Porsche Design System–inspired tokens (v4) ── */
:root {
    color-scheme: light dark;

    --pds-font: 'Arial Narrow', Arial, 'Heiti SC', SimHei, sans-serif;
    --pds-leading: calc(6px + 2.125ex);

    --pds-canvas: light-dark(#fff, hsl(225 66.7% 1.2%));
    --pds-surface: light-dark(hsl(240 10% 95%), hsl(240 2% 10%));
    --pds-surface-soft: light-dark(hsl(234 9.8% 60% / 0.06), hsl(240 3.7% 26.5% / 0.154));
    --pds-frosted: light-dark(hsl(240 5% 70% / 0.148), hsl(240 2% 43% / 0.228));

    --pds-text-primary: light-dark(hsl(225 66.7% 1.2%), hsl(225 100% 99%));
    --pds-text-high: light-dark(hsl(240 7.1% 11% / 0.7), hsl(240 12.5% 96.9% / 0.67));
    --pds-text-medium: light-dark(hsl(240 6.1% 7% / 0.6), hsl(240 12.5% 96.9% / 0.56));
    --pds-text-low: light-dark(hsl(240 5.3% 14.9% / 0.5), hsl(240 12.5% 96.9% / 0.45));

    --pds-border: light-dark(hsl(240 6.1% 7% / 0.12), hsl(240 12.5% 96.9% / 0.14));
    --pds-border-strong: light-dark(hsl(240 6.1% 7% / 0.22), hsl(240 12.5% 96.9% / 0.24));

    --pds-focus: #1a44ea;
    --pds-success: light-dark(hsl(115 77.5% 27.8%), hsl(157 84.9% 41.6%));
    --pds-error: light-dark(hsl(357 78% 41%), hsl(0 96.9% 62%));

    --pds-motion: 0.2s cubic-bezier(0.25, 0.1, 0.25, 1);
    --pds-radius: 2px;
    --pds-shadow: light-dark(0 12px 40px hsl(240 6.1% 7% / 0.08), 0 12px 40px hsl(0 0% 0% / 0.35));

    /* Shell aliases */
    --bg-primary: var(--pds-canvas);
    --bg-secondary: var(--pds-surface);
    --text-primary: var(--pds-text-primary);
    --text-secondary: var(--pds-text-medium);
    --border: var(--pds-border);
    --accent: var(--pds-text-primary);
    --accent-hover: light-dark(hsl(240 8.7% 9% / 0.8), hsl(240 12.5% 96.9% / 0.78));
    --success: var(--pds-success);
}

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

body {
    font-family: var(--pds-font);
    font-size: 1rem;
    line-height: var(--pds-leading);
    background: var(--pds-canvas);
    color: var(--pds-text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
}

.container {
    width: min(1200px, 100%);
    margin: 0 auto;
    padding: 0 clamp(1rem, 4vw, 2rem);
}

/* ── Header ── */
.header {
    background: #0989CB;
    border-bottom: 1px solid rgb(0 0 0 / 0.12);
    padding: clamp(2rem, 0.5vw, 3.5rem) 0;
    color: #fff;
}

.header-inner {
    text-align: center;
}

.header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: clamp(1rem, 2vw, 1.5rem);
    text-align: left;
}

.header-brand {
    font-size: 0.875rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: #fff;
    text-decoration: none;
    flex-shrink: 0;
}

.header-brand:hover {
    color: rgb(255 255 255 / 0.88);
}

.header-nav {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-left: auto;
}

.header-nav-link {
    display: inline-block;
    padding: 0.5rem 1.1rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: rgb(255 255 255 / 0.88);
    text-decoration: none;
    border: 1px solid rgb(255 255 255 / 0.28);
    border-radius: 999px;
    transition: background var(--pds-motion), border-color var(--pds-motion), color var(--pds-motion);
}

.header-nav-link:hover {
    background: rgb(255 255 255 / 0.12);
    border-color: rgb(255 255 255 / 0.45);
    color: #fff;
}

.header-nav-link.is-active {
    background: rgb(255 255 255 / 0.18);
    border-color: rgb(255 255 255 / 0.55);
    color: #fff;
}

.header-eyebrow {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: rgb(255 255 255 / 0.82);
    margin-bottom: 0.75rem;
}

.header h1 {
    font-size: clamp(1.6rem, 2.41vw + 1.32rem, 3.16rem);
    font-weight: 600;
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin: 0;
    padding: 0;
    color: #fff;
}

.header-lead {
    margin-top: 0.85rem;
    font-size: clamp(1rem, 0.21vw + 0.98rem, 1.13rem);
    color: rgb(255 255 255 / 0.88);
    max-width: 36ch;
    margin-left: auto;
    margin-right: auto;
}

/* ── Main layout ── */
.main-content {
    flex: 1;
    padding-top: clamp(1.5rem, 4vw, 2.5rem);
    padding-bottom: clamp(2rem, 5vw, 3rem);
}

section {
    padding: 0;
}

/* ── Content pages ── */
.content-page {
    display: grid;
    gap: clamp(1rem, 3vw, 1.5rem);
    max-width: 52rem;
    margin: 0 auto;
}

.content-panel {
    margin-bottom: 0;
}

.content-heading {
    font-size: clamp(1.15rem, 0.3vw + 1.1rem, 1.4rem);
    font-weight: 600;
    margin-bottom: 0.85rem;
}

.content-subheading {
    font-size: 1rem;
    font-weight: 600;
    margin: 1.25rem 0 0.65rem;
}

.content-text {
    color: var(--pds-text-high);
    line-height: 1.6;
}

.content-text a {
    color: var(--pds-focus);
}

.content-list {
    padding-left: 1.25rem;
    color: var(--pds-text-high);
    line-height: 1.6;
}

.content-list li + li {
    margin-top: 0.5rem;
}

.code-block {
    margin: 0.75rem 0 0;
    padding: 1rem 1.1rem;
    background: var(--pds-surface-soft);
    border: 1px solid var(--pds-border);
    border-radius: var(--pds-radius);
    overflow-x: auto;
    font-family: ui-monospace, 'Cascadia Code', 'Segoe UI Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.5;
    white-space: pre-wrap;
    word-break: break-word;
}

.content-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.content-actions .btn {
    text-decoration: none;
    text-align: center;
}

/* ── Panel / demo controls ── */
.panel {
    background: var(--pds-surface);
    border: 1px solid var(--pds-border);
    border-radius: var(--pds-radius);
    padding: clamp(1.25rem, 3vw, 1.75rem);
    margin-bottom: clamp(1rem, 3vw, 1.5rem);
    box-shadow: var(--pds-shadow);
}

.demo-controls .panel-header {
    justify-content: center;
}

.demo-controls .panel-title {
    text-align: center;
    width: 100%;
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 1.25rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--pds-border);
}

.panel-title {
    font-size: clamp(1.13rem, 0.21vw + 1.08rem, 1.33rem);
    font-weight: 600;
    letter-spacing: -0.01em;
}

.input-mode {
    display: inline-flex;
    gap: 0;
    border: 1px solid var(--pds-border-strong);
    border-radius: var(--pds-radius);
    overflow: hidden;
}

.mode-btn {
    padding: 0.45rem 1rem;
    background: transparent;
    border: none;
    border-right: 1px solid var(--pds-border);
    color: var(--pds-text-high);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    transition: background var(--pds-motion), color var(--pds-motion);
}

.mode-btn:last-child {
    border-right: none;
}

.mode-btn:hover {
    background: var(--pds-surface-soft);
}

.mode-btn.active {
    background: var(--pds-text-primary);
    color: var(--pds-canvas);
}

.mode-btn:focus-visible {
    outline: 2px solid var(--pds-focus);
    outline-offset: 2px;
}

.field-label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--pds-text-high);
    letter-spacing: 0.01em;
}

#pgn-input {
    width: 100%;
    padding: 0.85rem 1rem;
    background: var(--pds-canvas);
    border: 1px solid var(--pds-border-strong);
    border-radius: var(--pds-radius);
    color: var(--pds-text-primary);
    font-family: ui-monospace, 'Cascadia Code', 'Segoe UI Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.5;
    resize: vertical;
    min-height: 9rem;
    transition: border-color var(--pds-motion), box-shadow var(--pds-motion);
}

#pgn-input::placeholder {
    color: var(--pds-text-low);
}

#pgn-input:hover {
    border-color: var(--pds-text-low);
}

#pgn-input:focus {
    outline: none;
    border-color: var(--pds-focus);
    box-shadow: 0 0 0 1px var(--pds-focus);
}

.control-buttons {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    margin-top: 1.25rem;
    flex-wrap: wrap;
}

.btn {
    padding: 0.7rem 1.35rem;
    border: 1px solid transparent;
    border-radius: var(--pds-radius);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    transition: background var(--pds-motion), color var(--pds-motion), border-color var(--pds-motion), opacity var(--pds-motion);
}

.btn:focus-visible {
    outline: 2px solid var(--pds-focus);
    outline-offset: 2px;
}

.btn.primary {
    background: var(--pds-text-primary);
    color: var(--pds-canvas);
    border-color: var(--pds-text-primary);
}

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

.btn.secondary {
    background: transparent;
    color: var(--pds-text-primary);
    border-color: var(--pds-border-strong);
}

.btn.secondary:hover:not(:disabled) {
    background: var(--pds-surface-soft);
    border-color: var(--pds-text-low);
}

.btn.secondary.active {
    background: var(--pds-text-primary);
    color: var(--pds-canvas);
    border-color: var(--pds-text-primary);
}

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

.btn.tertiary {
    background: transparent;
    color: var(--pds-text-medium);
    border-color: transparent;
}

.btn.tertiary:hover:not(:disabled) {
    color: var(--pds-text-primary);
    background: var(--pds-surface-soft);
}

.btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

/* ── Demo section layout ── */
.demo-section {
    width: 100%;
}

.demo-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(280px, 360px);
    gap: clamp(1rem, 3vw, 1.75rem);
    align-items: start;
}

.demo-viewer-column {
    min-width: 0;
    --chess-board-size: 50vh;
}

.board-players {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem 1.25rem;
    flex-wrap: wrap;
    width: 100%;
    max-width: calc(var(--chess-board-size) + 48px);
    margin: 0 auto 0.75rem;
    padding: 0.65rem 1rem;
    background: var(--obs-bg-secondary, var(--pds-surface));
    border: 1px solid var(--obs-border, var(--pds-border));
    border-radius: var(--pds-radius);
    color: var(--obs-text-normal, var(--pds-text-primary));
    font-weight: 600;
    font-size: clamp(0.9rem, 2.5vw, 1.05rem);
    text-align: center;
    box-sizing: border-box;
}

.board-players.hidden {
    display: none;
}

.board-player {
    display: flex;
    align-items: baseline;
    gap: 0.45rem;
    min-width: 0;
}

.board-player-label {
    font-size: 0.78em;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--obs-text-muted, var(--pds-text-medium));
    flex-shrink: 0;
}

.board-player-name {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    max-width: min(220px, 38vw);
}

.board-players-vs {
    color: var(--obs-text-muted, var(--pds-text-medium));
    font-weight: 500;
    flex-shrink: 0;
}

.demo-sidebar {
    display: flex;
    flex-direction: column;
    gap: clamp(1rem, 2vw, 1.25rem);
    min-width: 0;
}

.demo-sidebar .demo-controls {
    margin-bottom: 0;
}

.demo-sidebar .control-buttons {
    flex-direction: column;
    align-items: stretch;
}

.demo-sidebar .control-buttons .btn {
    width: 100%;
}

.viewer-container {
    background: var(--pds-surface);
    border: 1px solid var(--pds-border);
    border-radius: var(--pds-radius);
    padding: clamp(0.75rem, 2vw, 1rem);
    margin: 0 auto;
    width: 100%;
    max-width: min(calc(var(--chess-board-size, 50vh) + 80px), 100%);
    box-sizing: border-box;
    box-shadow: var(--pds-shadow);
}

.viewer-status {
    margin-top: 0.85rem;
    font-size: 0.875rem;
    text-align: center;
    color: var(--pds-text-medium);
}

.viewer-status:empty {
    display: none;
    margin: 0;
}

.viewer-status.success {
    color: var(--pds-success);
}

.viewer-status.error {
    color: var(--pds-error);
}

.engine-panel {
    width: 100%;
    margin: 0;
    padding: 1rem 1.15rem;
    background: var(--pds-surface);
    border: 1px solid var(--pds-border);
    border-radius: var(--pds-radius);
    box-shadow: var(--pds-shadow);
}

.engine-panel.hidden {
    display: none;
}

.engine-panel-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 0.75rem;
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.engine-panel:has(.engine-analysis-block:not(.hidden)) .engine-panel-header {
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--pds-border);
}

.engine-panel-title {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--pds-text-medium);
}

.engine-depth {
    font-size: 0.75rem;
    color: var(--pds-text-low);
}

.engine-opening-block {
    margin-bottom: 1rem;
}

.engine-opening-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--pds-text-medium);
    margin-bottom: 0.35rem;
}

.engine-opening {
    font-size: 1rem;
    font-weight: 600;
    line-height: 1.35;
    color: var(--pds-text-primary);
}

.engine-opening-detail {
    margin-top: 0.35rem;
    font-size: 0.8rem;
    line-height: 1.4;
    color: var(--pds-text-low);
}

.engine-analysis-block {
    padding-top: 1rem;
    border-top: 1px solid var(--pds-border);
}

.engine-analysis-block.hidden {
    display: none;
}

.engine-eval-row {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem 0.75rem;
    margin-bottom: 0.5rem;
}

.engine-eval-label {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--pds-text-medium);
}

.engine-eval {
    font-size: clamp(1.6rem, 2vw, 2rem);
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1;
    color: var(--pds-text-primary);
    font-variant-numeric: tabular-nums;
}

.engine-busy {
    font-size: 0.8rem;
    color: var(--pds-text-medium);
}

.engine-line {
    font-family: ui-monospace, 'Cascadia Code', 'Segoe UI Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--pds-text-high);
    word-break: break-word;
}

/* ── Footer ── */
.footer {
    border-top: 1px solid rgb(0 0 0 / 0.12);
    background: #414145;
    padding: clamp(1.5rem, 4vw, 2rem) 0;
    margin-top: auto;
    color: #fff;
}

.footer-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.35rem;
    text-align: center;
}

.footer-copy {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgb(255 255 255 / 0.82);
}

.footer-links {
    font-size: 0.875rem;
    color: rgb(255 255 255 / 0.88);
}

.footer-links a {
    color: #fff;
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: color var(--pds-motion), border-color var(--pds-motion);
}

.footer-links a:hover {
    color: #fff;
    border-bottom-color: rgb(255 255 255 / 0.65);
}

.footer-sep {
    margin: 0 0.5rem;
    color: rgb(255 255 255 / 0.55);
}

/* ══════════════════════════════════════════
   Chess board & PGN viewer — DO NOT restyle
   ══════════════════════════════════════════ */

#chess-viewer cg-resize {
    display: none !important;
}

san {
    cursor: pointer !important;
}

move :hover {
    background-color: gray !important;
}

san.yellow {
    background-color: gray !important;
}

.ranks,
.files {
    font-weight: 900;
}

cg-board {
    border-radius: 8px;
}

.green cg-board {
    background-image: url("/board/150.png") !important;
    background-size: 100% 100% !important;
}

#chess-viewer.analysis-active .error,
#chess-viewer.analysis-active .edit,
#chess-viewer.analysis-active .games,
#chess-viewer.analysis-active [id^="edit"] {
    display: none !important;
}

#chess-viewer {
    --chess-board-size: 50vh;
    --chess-moves-max-height: 250px;
    --obs-bg-secondary: #ebe4d6;
    --obs-bg-secondary-alt: #ddd4c2;
    --obs-border: #d4cbb8;
    --obs-text-normal: #2c2a26;
    --obs-text-muted: #5c574e;
    --obs-accent: #6b7c3a;
    width: 100% !important;
    max-width: calc(var(--chess-board-size) + 48px) !important;
    height: auto !important;
    padding: clamp(12px, 3vw, 24px) !important;
    box-sizing: border-box !important;
    margin-left: auto !important;
    margin-right: auto !important;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
}

#chess-viewer cg-board {
    background-color: #ebecd0;
    background-image: url('data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI4IiBoZWlnaHQ9IjgiPjxnIGlkPSJhIj48ZyBpZD0iYiI+PGcgaWQ9ImMiPjxnIGlkPSJkIj48cmVjdCB3aWR0aD0iMSIgaGVpZ2h0PSIxIiBpZD0iZSIgZmlsbD0iI0VCRUNEMCIvPjx1c2UgeD0iMSIgeT0iMSIgaHJlZj0iI2UiLz48cmVjdCB5PSIxIiB3aWR0aD0iMSIgaGVpZ2h0PSIxIiBpZD0iZiIgZmlsbD0iIzczOTU1MiIvPjx1c2UgeD0iMSIgeT0iLTEiIGhyZWY9IiNmIi8+PC9nPjx1c2UgeD0iMiIgaHJlZj0iI2QiLz48L2c+PHVzZSB4PSI0IiBocmVmPSIjYyIvPjwvZz48dXNlIHk9IjIiIGhyZWY9IiNiIi8+PC9nPjx1c2UgeD0iNCIgaHJlZj0iI2EiLz48L3N2Zz4=');
}

#chess-viewer .buttons,
#chess-viewer .default.buttons,
#chess-viewer [class*="buttons"] {
    display: flex !important;
    flex-direction: row !important;
    flex-wrap: nowrap !important;
    justify-content: center !important;
    align-items: stretch !important;
    gap: 8px !important;
    margin-top: 33px !important;
    margin-bottom: 2px !important;
    width: 100% !important;
    padding: 0 !important;
    box-sizing: border-box !important;
}

#chess-viewer .buttons>*,
#chess-viewer .default.buttons>*,
#chess-viewer [class*="buttons"]>*,
#chess-viewer .pgnvbutton {
    flex: 1 1 auto !important;
    min-width: 0 !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    padding: 5px 4px !important;
    font-size: 14px !important;
    font-weight: 600 !important;
    background-color: var(--obs-bg-secondary) !important;
    border: 1px solid var(--obs-border) !important;
    border-radius: 4px !important;
    color: var(--obs-text-normal) !important;
    white-space: nowrap !important;
    transition: all 0.2s ease !important;
    height: 27px !important;
    margin: 0 !important;
    box-shadow: none !important;
    text-decoration: none !important;
}

#chess-viewer .buttons>*:hover,
#chess-viewer .default.buttons>*:hover,
#chess-viewer .pgnvbutton:hover {
    background-color: var(--obs-bg-secondary-alt) !important;
    border-color: var(--obs-accent) !important;
    color: var(--obs-accent) !important;
}

#chess-viewer .buttons>* i,
#chess-viewer .pgnvbutton i {
    display: inline-block !important;
    font-size: 14px !important;
    line-height: 1 !important;
    color: inherit !important;
    font-style: normal !important;
}

#chess-viewer .moves.inline {
    display: block !important;
    width: 100% !important;
    height: var(--chess-moves-max-height) !important;
    min-height: var(--chess-moves-max-height) !important;
    max-height: var(--chess-moves-max-height) !important;
    overflow-y: auto !important;
    border: 1px solid var(--obs-border) !important;
    border-radius: 4px !important;
    margin-top: 16px !important;
    padding: 8px !important;
    box-sizing: border-box !important;
    text-align: left !important;
    align-self: stretch !important;
}

#chess-viewer .moves.inline * {
    cursor: pointer !important;
}

#chess-viewer .moves.inline::-webkit-scrollbar {
    width: 10px !important;
}

#chess-viewer .moves.inline::-webkit-scrollbar-thumb {
    background-color: var(--obs-text-muted) !important;
    border-radius: 10px !important;
}

#chess-viewer .moves.inline::-webkit-scrollbar-track {
    background-color: var(--obs-bg-secondary) !important;
}

#chess-viewer cg-resize {
    display: none !important;
    visibility: hidden !important;
    opacity: 0 !important;
    pointer-events: none !important;
}

#chess-viewer #chess-viewerInner,
#chess-viewer cg-container {
    width: var(--chess-board-size) !important;
    height: var(--chess-board-size) !important;
    max-width: 100% !important;
}

#chess-viewer .board {
    width: var(--chess-board-size) !important;
    height: var(--chess-board-size) !important;
    max-width: 100% !important;
    margin: 0 !important;
}

#chess-viewer .cg-wrap {
    width: var(--chess-board-size) !important;
    height: var(--chess-board-size) !important;
    max-width: 100% !important;
    flex-shrink: 0;
    overflow: visible !important;
}

#chess-viewer .outerBoard {
    margin: 0 !important;
    padding: 0 !important;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
}

#chess-viewer .pgnvjs {
    display: flex !important;
    flex-direction: column !important;
    align-items: stretch !important;
    width: 100% !important;
    grid-template-columns: none !important;
    grid-template-rows: none !important;
}

#chess-viewer .outerBoard,
#chess-viewer .buttons,
#chess-viewer .default.buttons,
#chess-viewer [class*="buttons"] {
    align-self: center !important;
}

#chess-viewer .outerBoard,
#chess-viewer .pgnvjs {
    max-width: 100% !important;
}

#chess-viewer coords.ranks {
    right: -18px !important;
    top: 0 !important;
    height: 100% !important;
    width: 20px !important;
    display: flex !important;
    flex-direction: column-reverse !important;
    justify-content: space-around !important;
    align-items: center !important;
}

#chess-viewer coords.files {
    bottom: -20px !important;
    left: 0 !important;
    width: 100% !important;
    height: 20px !important;
    display: flex !important;
    flex-direction: row !important;
    justify-content: space-around !important;
    align-items: center !important;
}

#chess-viewer .cg-wrap.orientation-black coords.ranks {
    flex-direction: column !important;
}

#chess-viewer .cg-wrap.orientation-black coords.files {
    flex-direction: row-reverse !important;
}

#chess-viewer coords coord {
    position: static !important;
    color: var(--obs-text-normal) !important;
    font-weight: 800 !important;
    text-shadow: none !important;
    font-size: 10px !important;
}

/* ── Responsive ── */
@media (max-width: 900px) {
    .header-top {
        flex-direction: column;
        align-items: stretch;
    }

    .header-nav {
        margin-left: 0;
        justify-content: center;
    }

    .demo-layout {
        grid-template-columns: 1fr;
    }

    .demo-sidebar {
        order: 1;
    }

    .demo-viewer-column {
        order: 2;
    }

    .demo-sidebar .control-buttons {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
    }

    .demo-sidebar .control-buttons .btn {
        width: auto;
        flex: 1 1 auto;
    }

    .viewer-container {
        margin: 0 auto;
    }

    .viewer-status {
        max-width: min(calc(var(--chess-board-size, 50vh) + 80px), 100%);
        margin-left: auto;
        margin-right: auto;
    }
}

@media (max-width: 768px) {
    .demo-controls .panel-header {
        align-items: center;
    }

    .control-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .control-buttons .btn {
        width: 100%;
    }
}

@media (max-width: 520px) {

    #chess-viewer .buttons,
    #chess-viewer .default.buttons,
    #chess-viewer [class*="buttons"] {
        flex-wrap: wrap !important;
        gap: 6px !important;
    }

    #chess-viewer .buttons>*,
    #chess-viewer .default.buttons>*,
    #chess-viewer [class*="buttons"]>*,
    #chess-viewer .pgnvbutton {
        flex: 1 1 calc(33.33% - 6px) !important;
        height: auto !important;
        min-height: 30px !important;
        font-size: 12px !important;
        padding: 4px 2px !important;
    }

    #chess-viewer coords.ranks {
        right: -14px !important;
        width: 16px !important;
    }

    #chess-viewer coords.files {
        bottom: -16px !important;
        height: 16px !important;
    }

    #chess-viewer coords coord {
        font-size: 9px !important;
    }
}