.practice-box{margin:28px 0;padding:clamp(18px,4vw,32px);background:#fff;border:1px solid #cbd8ee;border-radius:20px;box-shadow:0 12px 35px #18336109}.practice-box h2{margin-top:0}.practice-tag{display:inline-block;padding:4px 10px;border-radius:50px;background:#e8efff;color:#163d9d;font-size:.8rem;font-weight:750}.practice-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.practice-field label{display:block;font-weight:700;margin-bottom:7px}.practice-pair{display:flex;gap:8px}.practice-pair input{min-width:0;flex:1;width:100%}.practice-pair select{width:82px}.practice-box input,.practice-box select{font:inherit;padding:10px 12px;border:1px solid #98abc9;border-radius:8px;background:#fff;color:#14233b}.practice-box button,.practice-link{font:inherit;font-weight:700;border:0;border-radius:9px;background:#2458df;color:#fff;padding:12px 18px;cursor:pointer;text-decoration:none;display:inline-block}.practice-box button:hover{background:#1744b6}.practice-box button:focus-visible,.practice-box input:focus-visible,.practice-box select:focus-visible,.practice-link:focus-visible{outline:3px solid #d47700;outline-offset:3px}.practice-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}.practice-actions .secondary{background:#e9effb;color:#193d8e}.practice-error{color:#8d3b10;min-height:1.6em;font-size:.94rem}.reaction-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}.reaction-grid p{background:#edf3ff;border-radius:12px;padding:16px;margin:0}.reaction-grid strong{font-size:1.9rem;display:block;line-height:1.4}.beam-figure{margin:20px 0 0}.beam-figure svg{width:100%;height:auto;display:block;background:#f7f9fe;border-radius:14px}.beam-figure text{font:18px system-ui;fill:#14233b}.beam-figure figcaption{font-size:.9rem;margin-top:8px}#beam-steps{white-space:pre-line;line-height:1.95}.practice-quiz fieldset{border:0;padding:0;margin:0}.practice-quiz legend{font-weight:750;margin-bottom:14px}.practice-option{display:flex;align-items:flex-start;gap:10px;padding:12px;border:1px solid #d5deed;border-radius:10px;margin:8px 0;cursor:pointer}.practice-option input{margin-top:5px;accent-color:#2458df}.quiz-feedback{min-height:1.7em;border-left:3px solid #2458df;padding-left:12px;line-height:1.8}.answer-note{font-size:.92rem}.guide-shell pre{overflow:auto;border:1px solid #d5deed;background:#fff;padding:18px;border-radius:12px}.guide-shell details{padding:14px 18px;background:#eef3fd;border-radius:10px;margin:12px 0}.guide-shell summary{cursor:pointer;font-weight:700}.guide-shell .practice-box p{max-width:none}.practice-box [hidden]{display:none}.result-note{font-size:.9rem;color:#465a77}@media(max-width:600px){.practice-grid{grid-template-columns:1fr}.reaction-grid strong{font-size:1.5rem}.practice-box{padding:18px}.practice-actions button{width:100%}}@media print{.practice-box button,.practice-actions{display:none}.practice-box{box-shadow:none;break-inside:avoid}.guide-shell details{display:block}}