.lesson-diagram { width: min(100%, 480px); margin: 20px auto; min-width: 0; }
.lesson-diagram h3 { margin-bottom: 8px; }
.lesson-diagram-board { width: 100%; max-width: 480px; min-width: 0; overflow: visible; }
.lesson-diagram-intro, .lesson-diagram-caption { line-height: 1.5; overflow-wrap: anywhere; }
.lesson-diagram-caution { padding: 10px 12px; border-left: 3px solid var(--warning, #e6b450); font-size: 14px; line-height: 1.45; }
.lesson-diagram-notation { margin: 12px 0 6px; font-weight: 700; font-variant-numeric: tabular-nums; }
.lesson-diagram-controls { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; margin-top: 12px; }
.lesson-diagram .lesson-diagram-controls button { margin: 0; min-height: 48px; min-width: 0; padding: 8px 10px; }
.lesson-diagram-controls button:disabled { opacity: .5; cursor: default; }
.lesson-diagram-note { display: block; margin-top: 8px; color: var(--muted); line-height: 1.4; }