@media (max-width: 600px) {
        .chord-grid { grid-template-columns: 1fr; }
    }

        .chord-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
            gap: var(--sp-md);
        }

        .chord-page-icon,
        [data-icon] {
            display: inline-flex;
            align-items: center;
            justify-content: center;
        }

        .chord-page-icon svg,
        [data-icon] svg,
        .btn svg {
            width: 1.15em;
            height: 1.15em;
            display: block;
        }

        .btn svg { display: inline-block; vertical-align: -0.15em; }

        .chord-page-icon,
        .mentor-avatar,
        .tip-box [data-icon] {
            color: var(--text-accent);
        }

        .chord-card {
            text-align: center;
            transition: transform var(--t-med) var(--ease-out), box-shadow var(--t-med);
            cursor: default;
        }

        .chord-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-lg);
            border-color: var(--border-hover);
        }

        .chord-name {
            font-size: var(--text-xl);
            font-weight: 800;
            margin-bottom: 0.15rem;
        }

        .chord-name span {
            font-weight: 400;
            font-size: var(--text-sm);
            color: var(--text-muted);
        }

        .chord-svg {
            display: flex;
            justify-content: center;
        }

        .scale-notes {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 0.35rem;
            margin: 0.5rem 0;
        }

        .scale-note {
            display: inline-block;
            min-width: 1.8rem;
            padding: 0.2rem 0.4rem;
            border-radius: 6px;
            background: var(--bg-elevated, #2a2a35);
            border: 1px solid var(--border, #3a3a45);
            font-family: 'JetBrains Mono', monospace;
            font-size: var(--text-sm);
            font-weight: 600;
            color: var(--text-accent);
        }

        .legend {
            display: flex;
            flex-wrap: wrap;
            gap: var(--sp-md);
            justify-content: center;
            margin-bottom: var(--sp-xl);
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: 0.4rem;
            font-size: var(--text-sm);
            color: var(--text-muted);
        }

        .legend-dot {
            width: 12px;
            height: 12px;
            border-radius: 50%;
        }

        .tip-box {
            background: var(--accent-soft);
            border: 1px solid rgba(129, 140, 248, 0.15);
            border-radius: var(--r-md);
            padding: var(--sp-md) var(--sp-lg);
            text-align: center;
            font-size: var(--text-sm);
            color: var(--text-secondary);
            line-height: 1.6;
            margin-bottom: var(--sp-xl);
        }

        .tip-box strong {
            color: var(--text-accent);
        }

        .chord-coach {
            padding: var(--sp-lg);
            margin-bottom: var(--sp-lg);
            background: linear-gradient(135deg, var(--bg-elevated), rgba(129, 140, 248, 0.08));
            border: 1px solid rgba(129, 140, 248, 0.12);
        }

        .chord-status {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            margin-bottom: var(--sp-sm);
        }

        .chord-card.locked {
            opacity: 0.72;
        }

        .chord-summary {
            font-size: var(--text-sm);
            color: var(--text-secondary);
            margin-bottom: var(--sp-md);
            min-height: 2.5rem;
        }

        .placement-guide,
        .checklist,
        .drill-grid {
            display: flex;
            flex-direction: column;
            gap: var(--sp-sm);
        }

        .placement-guide {
            text-align: left;
            margin-top: var(--sp-md);
            padding-top: var(--sp-md);
            border-top: 1px solid var(--border);
        }

        .placement-guide strong,
        .checklist strong {
            font-size: var(--text-sm);
        }

        .placement-guide ul,
        .checklist ul {
            list-style: none;
            margin: 0;
            padding: 0;
            display: flex;
            flex-direction: column;
            gap: 0.45rem;
        }

        .placement-guide li,
        .checklist li {
            font-size: var(--text-sm);
            color: var(--text-secondary);
            display: flex;
            gap: 0.5rem;
            align-items: flex-start;
            text-align: left;
        }

        .drill-section {
            margin-top: var(--sp-xl);
        }

        .drill-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--sp-md);
        }

        .drill-card {
            padding: var(--sp-lg);
            border-radius: var(--r-lg);
            background: var(--bg-card);
            border: 1px solid var(--border);
            box-shadow: var(--shadow-md);
        }

        .drill-card h3 {
            margin-bottom: 0.35rem;
            font-size: var(--text-md);
        }

        /* Switch-drill pair cards are real keyboard-operable toggles
           (role="button" + tabindex, see chords-page.js), so they need the
           same selectable affordance as any other control on the page. */
        .switch-pair-card {
            cursor: pointer;
            transition: border-color var(--t-med) var(--ease-out), box-shadow var(--t-med);
        }
        .switch-pair-card:hover {
            border-color: var(--border-hover);
        }
        .switch-pair-card:focus-visible {
            outline: 2px solid var(--accent);
            outline-offset: 2px;
        }
        .switch-pair-card.selected {
            border-color: var(--accent);
            box-shadow: 0 0 0 1px var(--accent);
        }

        .drill-meta {
            font-size: var(--text-sm);
            color: var(--text-muted);
            margin-bottom: var(--sp-sm);
        }

        .drill-status {
            display: inline-flex;
            margin-bottom: var(--sp-sm);
        }

        .drill-steps {
            list-style: none;
            padding: 0;
            margin: 0 0 var(--sp-md);
            display: flex;
            flex-direction: column;
            gap: 0.45rem;
        }

        .drill-steps li {
            font-size: var(--text-sm);
            color: var(--text-secondary);
            display: flex;
            align-items: flex-start;
            gap: 0.45rem;
        }

        .drill-timer {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: var(--sp-sm);
            padding: var(--sp-sm);
            border-radius: var(--r-sm);
            background: var(--bg-glass);
            border: 1px solid var(--border);
            margin-top: var(--sp-sm);
        }

        .drill-timer .timer-display {
            font-family: 'JetBrains Mono', monospace;
            font-size: var(--text-base);
            font-weight: 700;
            color: var(--text-primary);
            min-width: 64px;
        }

        .drill-input {
            display: flex;
            justify-content: space-between;
            gap: var(--sp-sm);
            align-items: center;
            margin-top: var(--sp-sm);
        }

        .drill-input label {
            font-size: var(--text-xs);
            color: var(--text-muted);
        }

        .drill-input input {
            width: 80px;
            padding: 0.35rem 0.5rem;
            border-radius: var(--r-sm);
            border: 1px solid var(--border);
            background: var(--bg-card);
            color: var(--text-primary);
            font-size: var(--text-sm);
            font-family: inherit;
        }

        .expansion-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--sp-md);
            margin-top: var(--sp-xl);
        }

        .expansion-card {
            padding: var(--sp-lg);
            border-radius: var(--r-lg);
            background: var(--bg-card);
            border: 1px solid var(--border);
        }

        .expansion-card ul {
            list-style: none;
            padding: 0;
            margin: var(--sp-sm) 0 0;
            display: flex;
            flex-direction: column;
            gap: 0.45rem;
        }

        .expansion-card li {
            font-size: var(--text-sm);
            color: var(--text-secondary);
        }

        .chord-check-panel {
            border-top: 1px solid var(--border);
            margin-top: var(--sp-md);
            padding-top: var(--sp-md);
        }

        .chord-detected-note {
            font-family: 'JetBrains Mono', monospace;
            font-size: var(--text-2xl);
            font-weight: 800;
        }

        .chord-detected-note.correct { color: var(--success-text); }
        .chord-detected-note.wrong { color: var(--error-text); }

        /* Chord check feedback (shared with audio-coach) */
        .pitch-detected { font-family: 'JetBrains Mono', monospace; font-size: var(--text-lg); }
        .pitch-detected.correct { color: var(--success-text); }
        .pitch-detected.near { color: var(--warning-text); }
        .pitch-detected.wrong { color: var(--error-text); }
        .feedback-text { font-size: var(--text-sm); }
        .feedback-text.correct { color: var(--success-text); }
        .feedback-text.near { color: var(--warning-text); }
        .feedback-text.wrong { color: var(--error-text); }
        .chord-detected-note.near { color: var(--warning-text); }

        .acoustic-xray-bar {
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: 4px;
            margin: var(--sp-xs) 0;
            min-height: 22px;
        }

        .xray-pill {
            display: inline-flex;
            align-items: center;
            gap: 3px;
            font-size: 10px;
            font-weight: 700;
            padding: 2px 6px;
            border-radius: var(--r-full);
            font-family: 'JetBrains Mono', monospace;
            border: 1px solid transparent;
            transition: all var(--t-fast) var(--ease-out);
        }

        .xray-pill.xray-clean {
            background: rgba(74, 222, 128, 0.15);
            color: var(--success-text);
            border-color: rgba(74, 222, 128, 0.35);
        }

        .xray-pill.xray-buzz {
            background: rgba(251, 191, 36, 0.15);
            color: var(--warning-text);
            border-color: rgba(251, 191, 36, 0.35);
        }

        .xray-pill.xray-muted {
            background: rgba(248, 113, 113, 0.15);
            color: var(--error-text);
            border-color: rgba(248, 113, 113, 0.35);
        }
        .switch-drill-target {
            font-size: var(--text-3xl);
            font-weight: 800;
            text-align: center;
            margin: var(--sp-md) 0;
        }
        .switch-drill-target .active {
            color: var(--text-accent);
            background: var(--accent-soft);
            padding: var(--sp-sm) var(--sp-lg);
            border-radius: var(--r-lg);
            display: inline-block;
        }
        .switch-drill-stats {
            display: flex;
            gap: var(--sp-md);
            justify-content: center;
            margin: var(--sp-md) 0;
        }
        .switch-drill-stats .stat {
            text-align: center;
        }
        .switch-drill-stats .stat .value {
            font-size: var(--text-2xl);
            font-weight: 800;
            color: var(--text-accent);
        }
        .switch-drill-stats .stat .label {
            font-size: var(--text-xs);
            color: var(--text-muted);
        }
        #switchResults { margin-top: var(--sp-md); }

        .legend-dot-1 { background: var(--finger-1); }
        .legend-dot-2 { background: var(--finger-2); }
        .legend-dot-3 { background: var(--finger-3); }
        .legend-dot-4 { background: var(--finger-4); }
        .legend-dot-open { background: #888; border: 2px solid #555; }
        .legend-x { color: var(--error-text); font-weight: 700; font-size: var(--text-lg); }

        .chord-fallback { padding: 40px; text-align: center; color: var(--text-muted); }
        .grid-span-full { grid-column: 1 / -1; text-align: center; padding: var(--sp-lg); }
        .placement-caption { margin-top: 0.25rem; }
        .chord-feedback { margin-top: 0.3rem; }
        .drill-steps { padding-left: 1rem; }
        .drill-title { margin: 0.3rem 0; }
        .drill-svg-row { display: flex; justify-content: space-around; margin-top: var(--sp-sm); }

        .chord-toolbar {
            padding: var(--sp-md);
        }

        .chord-search-row {
            display: flex;
            gap: var(--sp-sm);
            align-items: center;
            flex-wrap: wrap;
        }

        .search-input-wrapper {
            flex: 1;
            min-width: 220px;
        }

        .chord-search-input {
            width: 100%;
            padding: var(--sp-xs) var(--sp-sm);
            border-radius: var(--r-md);
            border: 1px solid var(--border);
            background: var(--bg-card);
            color: var(--text-primary);
            font-size: var(--text-sm);
        }

        .chord-search-input:focus {
            border-color: var(--border-focus);
            outline: none;
        }

        .filter-chips {
            display: inline-flex;
            gap: 4px;
            background: var(--bg-elevated);
            padding: 3px;
            border-radius: var(--r-full);
            border: 1px solid var(--border);
        }

        .filter-chip,
        .mode-chip {
            padding: 4px 10px;
            border-radius: var(--r-full);
            border: 1px solid transparent;
            background: transparent;
            font-size: var(--text-xs);
            font-weight: 600;
            color: var(--text-secondary);
            cursor: pointer;
            transition: all var(--t-fast) var(--ease-out);
        }

        .filter-chip:hover,
        .mode-chip:hover {
            color: var(--text-primary);
        }

        .filter-chip.active,
        .mode-chip.active {
            background: var(--accent-fill);
            color: #ffffff;
            border-color: var(--accent);
        }

        .chord-options-row {
            display: flex;
            align-items: center;
            gap: var(--sp-md);
            flex-wrap: wrap;
        }

        .toolbar-label {
            font-size: var(--text-xs);
            font-weight: 600;
            color: var(--text-secondary);
            margin-right: 4px;
        }

        .play-mode-selector {
            display: inline-flex;
            align-items: center;
            gap: 4px;
            background: var(--bg-elevated);
            padding: 3px;
            border-radius: var(--r-full);
            border: 1px solid var(--border);
        }

        .capo-selector {
            display: inline-flex;
            align-items: center;
            gap: var(--sp-xs);
        }

        .capo-select {
            padding: 4px 8px;
            font-size: var(--text-xs);
            font-weight: 600;
            border-radius: var(--r-sm);
            border: 1px solid var(--border);
            background: var(--bg-card);
            color: var(--text-primary);
        }

        .transposed-badge {
            font-size: var(--text-xs);
            font-weight: 600;
            padding: 2px 6px;
            border-radius: var(--r-sm);
            background: var(--accent-soft);
            color: var(--text-accent);
            display: block;
            margin-top: 2px;
        }

        .chord-toolbar kbd {
            display: inline-block;
            padding: 1px 4px;
            font-size: var(--text-2xs);
            font-family: monospace;
            background: var(--bg-elevated);
            border: 1px solid var(--border);
            border-radius: 4px;
            color: var(--text-primary);
        }