:root{color-scheme:light;--primary:#6366f1;--primary-dark:#4f46e5;--accent:#f59e0b;--success:#10b981;--error:#ef4444;--gray-50:#f9fafb;--gray-100:#f3f4f6;--gray-200:#e5e7eb;--gray-500:#6b7280;--gray-900:#111827}body,html{padding:0;margin:0;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial;background:linear-gradient(135deg,#fafafa,#f0f4ff);color:var(--gray-900);min-height:100vh}*{box-sizing:border-box}.container{max-width:820px;margin:0 auto;padding:18px 16px 100px}.h1{font-size:28px;font-weight:800;margin:6px 0 2px;background:linear-gradient(135deg,var(--gray-900) 0,var(--primary) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}.h2{font-size:16px;font-weight:700;margin:18px 0 8px;text-transform:uppercase;letter-spacing:.05em}.h2,.muted{color:var(--gray-500)}.small{font-size:13px}.card{border:1px solid var(--gray-200);border-radius:20px;padding:20px;background:#fff;box-shadow:0 4px 20px rgba(0,0,0,.04),0 1px 3px rgba(0,0,0,.02);transition:transform .2s ease,box-shadow .2s ease}.card:hover{transform:translateY(-2px);box-shadow:0 8px 30px rgba(0,0,0,.08),0 2px 6px rgba(0,0,0,.04)}.term{font-size:48px;font-weight:900;letter-spacing:-.03em;margin:16px 0 20px;background:linear-gradient(135deg,var(--primary) 0,var(--accent) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;animation:fadeInUp .5s ease-out}@keyframes fadeInUp{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}@keyframes pulse{0%,to{transform:scale(1)}50%{transform:scale(1.02)}}@keyframes shake{0%,to{transform:translateX(0)}25%{transform:translateX(-4px)}75%{transform:translateX(4px)}}@keyframes slideIn{0%{opacity:0;transform:translateX(-10px)}to{opacity:1;transform:translateX(0)}}@keyframes shrink{0%{width:100%}to{width:0}}.button{width:100%;border:none;background:linear-gradient(135deg,var(--primary) 0,var(--primary-dark) 100%);color:#fff;border-radius:14px;padding:14px 18px;font-size:16px;font-weight:700;cursor:pointer;transition:all .2s ease;box-shadow:0 4px 14px rgba(99,102,241,.3)}.button:hover{transform:translateY(-1px);box-shadow:0 6px 20px rgba(99,102,241,.4)}.button:active{transform:translateY(0)}.button:disabled{opacity:.5;cursor:not-allowed;transform:none}.button.secondary{background:#fff;color:var(--gray-900);border:2px solid var(--gray-200);box-shadow:0 2px 8px rgba(0,0,0,.04)}.button.secondary:hover{border-color:var(--primary);background:var(--gray-50);box-shadow:0 4px 12px rgba(99,102,241,.15)}.button.ghost{background:transparent;color:var(--gray-500);border:1px dashed var(--gray-200);box-shadow:none}.button.ghost:hover{color:var(--gray-900);border-color:var(--gray-300);background:var(--gray-50)}.button.success{background:linear-gradient(135deg,var(--success) 0,#059669 100%);box-shadow:0 4px 14px rgba(16,185,129,.3)}.buttonRow{display:flex;gap:10px}.hr{border:0;border-top:1px solid var(--gray-200);margin:20px 0}.notice{border:1px solid var(--gray-200);background:linear-gradient(135deg,var(--gray-50) 0,#fff 100%);border-radius:16px;padding:16px;animation:fadeInUp .3s ease-out}.notice.success{border-color:rgba(16,185,129,.3);background:linear-gradient(135deg,#ecfdf5,#fff)}.notice.error{border-color:rgba(239,68,68,.3);background:linear-gradient(135deg,#fef2f2,#fff)}.pill{display:inline-block;padding:8px 14px;background:linear-gradient(135deg,var(--primary) 0,var(--primary-dark) 100%);color:#fff;border-radius:999px;font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;box-shadow:0 2px 8px rgba(99,102,241,.25)}.pill.outline{background:transparent;color:var(--gray-500);border:1px solid var(--gray-200);box-shadow:none}.tabbar{position:fixed;left:0;right:0;bottom:0;background:hsla(0,0%,100%,.95);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-top:1px solid var(--gray-200);padding:12px 12px calc(12px + env(safe-area-inset-bottom))}.tabs{max-width:820px;margin:0 auto;display:flex;gap:10px}.tab{flex:1 1;text-align:center;border:1px solid var(--gray-200);border-radius:14px;padding:12px 8px;font-weight:700;color:var(--gray-500);background:#fff;transition:all .2s ease;text-decoration:none}.tab:hover{border-color:var(--gray-300);color:var(--gray-900)}.tab.active{border-color:var(--primary);background:linear-gradient(135deg,rgba(99,102,241,.1),rgba(99,102,241,.05));color:var(--primary)}.feedback-correct{color:var(--success);animation:pulse .5s ease-out}.feedback-incorrect{color:var(--error);animation:shake .4s ease-out}.choice-btn{animation:slideIn .3s ease-out backwards}.choice-btn:first-child{animation-delay:.05s}.choice-btn:nth-child(2){animation-delay:.1s}.choice-btn:nth-child(3){animation-delay:.15s}.loading-pulse{animation:pulse 1.5s ease-in-out infinite}.notification-banner{background:linear-gradient(135deg,var(--accent) 0,#d97706 100%);color:#fff;padding:12px 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