@import "https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,400;0,9..40,500;0,9..40,600;0,9..40,700;1,9..40,400&family=Source+Serif+4:opsz,wght@8..60,600;8..60,700&display=swap";:root{--font-display:"Source Serif 4", "Georgia", serif;--font-body:"DM Sans", system-ui, -apple-system, "Segoe UI", sans-serif;--clr-bg:#1a1614;--clr-card:#2c2622;--clr-surface:#362f2a;--clr-input:#3e3631;--clr-text:#ede8e3;--clr-text-soft:#a89e94;--clr-border:#fff5e61a;--clr-accent:#e8864a;--clr-accent-soft:#e8864a26;--clr-correct:#5cb87a;--clr-correct-bg:#5cb87a1f;--clr-wrong:#e05a4a;--clr-wrong-bg:#e05a4a1f;--clr-badge:#4a4340;--clr-placeholder:#6b6058;--clr-hover:#fff5e60a;--clr-hover-strong:#fff5e614;--radius:16px;--radius-sm:10px;--shadow-card:0 4px 24px #00000040, 0 1px 3px #00000026;--shadow-btn:0 2px 8px #0003;--transition:.18s 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td.blank-cell{color:var(--clr-accent);background:#e8864a14;border-radius:4px;font-weight:700}.matrix-op{color:var(--clr-accent);-webkit-user-select:none;user-select:none;margin:0 6px;font-size:1.4rem;font-weight:700}.matrix-grid-cell{text-align:center;width:48px;height:40px;font-family:var(--font-body);border:2px solid var(--clr-accent);border-radius:var(--radius-sm);background:var(--clr-input);color:var(--clr-text);transition:border-color var(--transition), box-shadow var(--transition), background var(--transition);outline:none;font-size:1.1rem;font-weight:600}.matrix-grid-cell:focus{border-color:var(--clr-accent);box-shadow:0 0 0 3px var(--clr-accent-soft)}.matrix-grid-cell.small{width:40px;height:34px;font-size:.95rem}.matrix-grid-cell.revealed-correct{background:#4caf5014;border-color:#4caf50}.matrix-grid-cell.revealed-wrong{background:#f4433614;border-color:#f44336}.matrix-grid-fixed{text-align:center;font-family:var(--font-body);color:var(--clr-text);padding:4px 10px;font-size:1.1rem}.dotprod-question{text-align:center;margin:18px 0}.dotprod-question .hint-text{color:var(--clr-dim);margin-bottom:12px;font-size:.92rem}.dotprod-row{flex-wrap:wrap;justify-content:center;align-items:center;gap:8px;display:flex}@media (width<=600px){.matrix-grid-cell{width:38px;height:32px;font-size:.9rem}.matrix-grid-cell.small{width:34px;height:30px;font-size:.85rem}.matrix-bracket td{padding:2px 6px;font-size:.95rem}.matrix-op{margin:0 3px;font-size:1.15rem}}*,:before,:after{box-sizing:border-box;margin:0;padding:0}body{margin:0}#root{min-height:100vh}