:root{--bg:#dbe7ff;--panel:#fff;--bg-soft:#edf3ff;--border:#648de542;--text-strong:#1d2f57;--text-soft:#38507f;--muted:#6379a1;--accent-strong:#648de5;--accent-soft:#e8f0ff;--success:#2d8248;--danger:#b95f46;--shadow-soft:0 20px 40px #445c911f;--shadow-pop:0 16px 30px #648de538;--sans:"Roboto", "Open Sans", "Segoe UI", "Helvetica Neue", Arial, sans-serif;font:17px/1.5 var(--sans);color:var(--text-soft);background:var(--bg);font-synthesis:none;text-rendering:optimizelegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}*,:before,:after{box-sizing:border-box}html{min-height:100%}body{background:0 0;min-height:100vh;margin:0}body,button,input,select,textarea{font:inherit}#root{min-height:100vh}h1,h2{color:var(--text-strong);font-family:var(--sans);letter-spacing:-.03em;margin:0;font-weight:700;line-height:1.05}h1{font-size:clamp(1.5rem,3vw,2.6rem)}h2{font-size:clamp(1.45rem,2vw,2rem)}p{margin:0}button{appearance:none}button:focus-visible{outline-offset:3px;outline:3px solid #648de54d}.app-shell{width:min(1120px,100% - 32px);margin:0 auto;padding:28px 0 48px}.app-header{color:var(--muted);justify-content:space-between;align-items:center;gap:16px;margin-bottom:16px;font-size:1.05rem;display:flex}.app-header__brand{align-items:center;gap:10px;display:inline-flex}.app-header__logo{object-fit:contain;flex-shrink:0;width:36px;height:36px}.app-header__tag{color:var(--text-strong);letter-spacing:-.01em;margin:0;font-size:1.5rem;font-weight:700}.screen{gap:18px;display:grid}.panel{background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow-soft);border-radius:28px;padding:32px}.hero-card,.result-hero{background:var(--panel)}.eyebrow,.section-kicker{color:var(--accent-strong);letter-spacing:.14em;text-transform:uppercase;font-size:.84rem}.eyebrow{margin-bottom:4px}.lead{max-width:64ch;color:var(--text-soft);margin-top:12px}.hero-stats,.choice-grid,.exercise-list,.mistake-list{gap:12px;display:grid}.hero-stats{grid-template-columns:repeat(auto-fit,minmax(150px,1fr));margin-top:16px}.stat-chip{border:1px solid var(--border);background:#fff;border-radius:20px;padding:16px 18px}.stat-chip span,.section-note,.prompt-meta,.mistake-card__meta{color:var(--muted)}.stat-chip strong{color:var(--text-strong);margin-top:8px;font-size:1.45rem;display:block}.feedback{justify-content:space-between;align-items:flex-start;gap:16px;display:flex}.quiz-header,.section-heading{flex-direction:column;justify-content:space-between;align-items:flex-start;gap:8px;display:flex}.choice-grid{grid-template-columns:repeat(auto-fit,minmax(180px,1fr));margin-top:12px}.choice,.exercise-choice,.option-card,.ghost-button,.primary-button{border:1px solid var(--border);border-radius:20px;transition:transform .16s,border-color .16s,background-color .16s,box-shadow .16s}.choice,.exercise-choice,.option-card{color:var(--text-strong);text-align:left;cursor:pointer;background:#fff;padding:12px 16px}.exercise-choice__title{display:block}.choice:hover,.exercise-choice:hover,.option-card:hover,.ghost-button:hover,.primary-button:hover{border-color:var(--accent-strong);box-shadow:var(--shadow-pop);transform:translateY(-1px)}.choice.active,.exercise-choice.active{border-color:var(--accent-strong);background:var(--accent-soft)}.exercise-list{margin-top:20px}.cta-row{align-items:center}.primary-button,.ghost-button{cursor:pointer;font:inherit;padding:14px 22px}.primary-button{background:var(--accent-strong);color:#f8fff1;border-color:#0000;min-width:200px}.primary-button:disabled{cursor:wait;opacity:.7;box-shadow:none;transform:none}.ghost-button{color:var(--text-strong);background:0 0}.quiz-shell{gap:16px;display:grid;position:relative;overflow:hidden}.quiz-close-button{z-index:2;border:1px solid var(--border);width:38px;height:38px;color:var(--muted);cursor:pointer;background:#fffffff0;border-radius:50%;justify-content:center;align-items:center;padding-bottom:2px;font-size:1.5rem;line-height:1;transition:transform .16s,border-color .16s,box-shadow .16s,color .16s;display:inline-flex;position:absolute;top:18px;right:18px}.quiz-close-button:hover{border-color:var(--accent-strong);color:var(--accent-strong);transform:translateY(-1px)}.progress-bar{background:#648de51f;height:8px;position:absolute;inset:0 0 auto}.progress-bar__fill{background:var(--accent-strong);height:100%;transition:width .22s}.prompt-card{border:1px solid var(--border);background:#fff;border-radius:24px;padding:16px}.prompt-row{justify-content:space-between;align-items:flex-start;gap:12px;display:flex}.prompt-body{color:var(--text-strong);word-break:break-word;margin:0;font-size:clamp(1.75rem,3vw,2.4rem);line-height:1.05}.sound-controls{border:1px solid var(--border);background:var(--accent-soft);border-radius:999px;flex-shrink:0;align-items:stretch;display:inline-flex;overflow:hidden}.sound-button{width:42px;height:42px;color:var(--accent-strong);cursor:pointer;background:0 0;border:0;border-radius:0;flex-shrink:0;justify-content:center;align-items:center;font-size:1rem;transition:transform .16s,background-color .16s;display:inline-flex}.sound-button:hover{background:#ffffff75;transform:translateY(-1px)}.sound-button--segmented+.sound-button--segmented{border-left:1px solid var(--border)}.sound-button__icon{object-fit:contain;width:18px;height:18px}.prompt-meta{margin:12px 0 0;font-size:1rem}.option-list{gap:12px;display:grid}.text-answer-form,.text-answer-fields{gap:16px;display:grid}.text-answer-field{gap:8px;display:grid}.text-answer-label{color:var(--text-strong);font-weight:600}.text-answer-input{border:1px solid var(--border);width:100%;color:var(--text-strong);font:inherit;background:#fff;border-radius:18px;padding:14px 16px;transition:border-color .16s,box-shadow .16s}.text-answer-input:focus{border-color:var(--accent-strong);outline:none;box-shadow:0 0 0 4px #648de51f}.text-answer-input:disabled{color:var(--muted);background:#f8f9fceb}.text-answer-actions{flex-wrap:wrap;gap:12px;display:flex}.option-card{font-size:1.05rem}.option-card.is-selected{border-color:var(--accent-strong)}.option-card.is-correct{border-color:var(--success);background:#d6f4e1f0}.option-card.is-wrong{border-color:var(--danger);background:#ffe1dbf0}.feedback{padding:0}.feedback p{margin:6px 0 0}.feedback.success{color:#358a57}.feedback.error{color:#bb4e2f}.result-actions{flex-wrap:wrap;gap:12px;margin-top:24px;display:flex}.mistake-list{margin-top:20px}.mistake-card{border:1px solid var(--border);background:#fff;border-radius:20px;padding:18px 20px}.mistake-card__title,.mistake-card__body,.mistake-card__answer{margin:0}.mistake-card__body{color:var(--text-strong);margin-top:8px;font-size:1.12rem}.mistake-card__meta,.mistake-card__answer{margin-top:10px}@media (width<=760px){.app-shell{width:min(100% - 16px,1120px);padding-top:18px}.app-header,.section-heading,.cta-row,.quiz-header,.feedback{flex-direction:column}.section-kicker{margin-top:16px}.panel{border-radius:24px;padding:16px 16px 24px}.quiz-close-button{top:18px;right:16px}.prompt-row{align-items:center}.primary-button,.ghost-button{width:100%}.text-answer-actions{flex-direction:column}}