*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}:root{--indigo: #4B49AC;--indigo-lt: #E8E9FE;--indigo-dk: #3C3AA0;--coral: #F3797E;--coral-lt: #FCDFE0;--green: #34C38F;--green-lt: #D6F5EC;--amber: #F1B44C;--amber-lt: #FDEFC3;--gray-50: #F8F8FD;--gray-100: #F0F0F7;--gray-200: #E2E2EF;--gray-400: #A9A9C8;--gray-600: #6B6B8A;--text: #2C2C54;--text-light: #6B6B8A;--radius: 12px;--radius-sm: 8px;--shadow: 0 4px 24px rgba(0, 0, 0, .08);--shadow-sm: 0 1px 6px rgba(0, 0, 0, .06)}body{font-family:Nunito,sans-serif;background:#eaeaf5;min-height:100vh;display:flex;align-items:flex-start;justify-content:center;padding:clamp(24px,6vh,80px) 16px 32px;color:var(--text)}.screen{display:none;width:80vw;max-width:900px;min-width:0;animation:fadeIn .35s ease}.screen.active{display:flex;justify-content:center}@media(max-width:768px){.screen{width:92vw}}@media(max-width:480px){.screen{width:98vw}body{padding:8px}}@keyframes 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.card-body{text-align:center}.welcome-top{display:flex;align-items:flex-start;justify-content:space-between}.user-badge{display:flex;flex-direction:column;align-items:flex-end;gap:6px}#user-greeting{font-size:1rem;font-weight:700;color:#fff}.btn-logout{background:#fff3;border:1px solid rgba(255,255,255,.4);color:#fff;font-family:Nunito,sans-serif;font-size:.75rem;font-weight:700;padding:4px 12px;border-radius:50px;cursor:pointer;transition:background .2s}.btn-logout:hover{background:#ffffff59}.difficulty-section{margin-bottom:20px}.label{font-size:.8rem;font-weight:700;color:var(--gray-600);text-transform:uppercase;letter-spacing:.8px;margin-bottom:12px}.difficulty-buttons{display:flex;gap:12px}.diff-btn{flex:1;display:flex;flex-direction:column;align-items:center;gap:6px;padding:20px 12px;border:2px solid var(--gray-200);border-radius:var(--radius-sm);background:var(--gray-50);cursor:pointer;transition:all 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var(--coral);color:var(--coral);font-family:Nunito,sans-serif;font-size:.9rem;font-weight:700;padding:8px 18px;border-radius:8px;cursor:pointer;transition:background .2s}.btn-danger:hover{background:var(--coral-lt)}.btn-ghost{background:transparent;border:2px solid var(--gray-200);font-family:Nunito,sans-serif;font-size:.9rem;font-weight:700;color:var(--gray-600);cursor:pointer;padding:10px 16px;border-radius:8px;transition:color .2s,background .2s,border-color .2s;text-align:center}.btn-ghost:hover{color:var(--indigo);background:var(--indigo-lt);border-color:var(--indigo)}.btn-link{background:none;border:none;color:var(--indigo);font-family:Nunito,sans-serif;font-size:inherit;font-weight:700;cursor:pointer;padding:0;text-decoration:underline}.game-card .card-body{padding:24px 32px 28px}.game-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:28px;gap:16px}.stat-box{display:flex;flex-direction:column;align-items:center;gap:2px;background:var(--indigo-lt);border-radius:var(--radius-sm);padding:10px 20px;min-width:80px}.stat-label{font-size:.65rem;font-weight:700;color:var(--indigo);text-transform:uppercase;letter-spacing:.8px}.stat-value{font-size:clamp(1.3rem,2.5vw,1.7rem);font-weight:800;color:var(--indigo-dk);line-height:1.1}.progress-dots{display:flex;gap:8px}.dot{width:12px;height:12px;border-radius:50%;background:var(--gray-200);transition:background .3s,transform .3s}.dot.correct{background:var(--green);transform:scale(1.2)}.dot.wrong{background:var(--coral);transform:scale(1.2)}.dot.current{background:var(--amber);box-shadow:0 0 0 3px #f1b44c59}.question-area{text-align:center;margin-bottom:24px}.q-label{font-size:.78rem;font-weight:700;color:var(--gray-400);text-transform:uppercase;letter-spacing:.8px;margin-bottom:14px}.equation{font-size:clamp(1.8rem,3.5vw,2.8rem);font-weight:900;color:#fff;background:var(--indigo-dk);border-radius:var(--radius-sm);padding:28px 20px;letter-spacing:2px;margin-bottom:10px;transition:background .3s;box-shadow:0 2px 10px #0000001f}.badge-op{display:inline-block;vertical-align:middle;position:relative;top:-2px;margin:0 2px}.op-mult{font-size:1.1em;position:relative;top:3px}.find-x{font-size:.9rem;color:var(--gray-600)}.input-area{margin-bottom:16px}.input-wrap{display:flex;align-items:center;gap:12px;justify-content:center;margin-bottom:12px}.input-label{font-size:clamp(1.3rem,2vw,1.6rem);font-weight:700;color:var(--indigo)}.answer-input{width:33%;height:72px;font-family:Nunito,sans-serif;font-size:2.2rem;font-weight:700;text-align:center;border:2px solid var(--gray-200);border-radius:var(--radius-sm);color:var(--text);outline:none;background:var(--gray-50);transition:border-color .2s,box-shadow .2s;-moz-appearance:textfield;letter-spacing:2px}.answer-input::-webkit-inner-spin-button,.answer-input::-webkit-outer-spin-button{-webkit-appearance:none}.answer-input:focus{border-color:var(--indigo);background:#fff;box-shadow:0 0 0 3px #4b49ac26}.answer-input.correct-anim{border-color:var(--green);box-shadow:0 0 0 3px #34c38f4d;animation:bounceInput .5s ease}.answer-input.wrong-anim{border-color:var(--coral);box-shadow:0 0 0 3px #f3797e4d;animation:shakeInput .4s ease}@keyframes bounceInput{0%{transform:scale(1)}30%{transform:scale(1.12)}60%{transform:scale(.96)}to{transform:scale(1)}}@keyframes shakeInput{0%,to{transform:translate(0)}20%{transform:translate(-8px)}40%{transform:translate(8px)}60%{transform:translate(-6px)}80%{transform:translate(6px)}}.feedback{border-top:2px solid var(--gray-100);padding-top:16px;animation:fadeIn .25s ease}.feedback.hidden{display:none}.feedback-correct,.feedback-wrong{display:flex;align-items:center;gap:10px;border-radius:var(--radius-sm);padding:12px 16px;font-size:1rem;font-weight:700;margin-bottom:12px}.feedback-correct.hidden,.feedback-wrong.hidden{display:none}.feedback-correct{background:var(--green-lt);color:#0a6448}.feedback-wrong{background:var(--coral-lt);color:#9b2226}.feedback-icon{font-size:1.3rem}.steps-panel{background:var(--amber-lt);border-radius:var(--radius-sm);padding:14px 18px;margin-bottom:12px;border-left:4px solid var(--amber)}.steps-panel.hidden{display:none}.steps-title{font-size:.78rem;font-weight:700;color:#7a4f03;text-transform:uppercase;letter-spacing:.6px;margin-bottom:8px}.steps-list{padding-left:18px}.steps-list li{font-size:.92rem;color:#6d4000;line-height:1.7;font-weight:600}.end-card .card-banner{padding:40px 40px 32px}.end-stars{font-size:clamp(2rem,4vw,3rem);margin-bottom:8px;letter-spacing:4px;animation:starPop .5s ease 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28px}.history-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:20px}.history-title{font-size:1.2rem;font-weight:900;color:#fff}.trend-section{margin-bottom:24px}.section-label{font-size:.75rem;font-weight:700;color:var(--gray-600);text-transform:uppercase;letter-spacing:.8px;margin-bottom:10px}.trend-chart{background:var(--gray-50);border:1px solid var(--gray-200);border-radius:var(--radius-sm);padding:8px;height:200px}.history-list{display:flex;flex-direction:column;gap:10px}.history-item{border:1.5px solid var(--gray-200);border-radius:var(--radius-sm);overflow:hidden;transition:border-color .2s,box-shadow .2s}.history-item:hover{border-color:var(--indigo);box-shadow:var(--shadow-sm)}.history-item-header{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;cursor:pointer;background:#fff;gap:10px}.hi-left{display:flex;flex-direction:column;gap:4px}.hi-date{font-size:.78rem;color:var(--gray-400);font-weight:600}.hi-diff{display:inline-block;font-size:.72rem;font-weight:700;padding:2px 10px;border-radius:4px}.hi-diff.easy,.hi-diff.beginner{background:var(--green-lt);color:#0a6448}.hi-diff.medium,.hi-diff.advanced{background:var(--indigo-lt);color:var(--indigo-dk)}.hi-diff.hard{background:var(--coral-lt);color:#9b2226}.hi-right{display:flex;flex-direction:column;align-items:flex-end;gap:2px}.hi-stars{font-size:.95rem;letter-spacing:1px}.hi-score{font-size:.78rem;color:var(--gray-400);font-weight:700}.hi-time{font-size:.72rem;color:var(--gray-400)}.hi-chevron{color:var(--gray-400);font-size:.75rem;transition:transform .2s}.history-item.expanded .hi-chevron{transform:rotate(180deg)}.history-details{display:none;background:var(--gray-50);padding:10px 16px 14px;border-top:1px solid var(--gray-200)}.history-item.expanded .history-details{display:block}.hd-question{display:flex;align-items:center;gap:10px;padding:7px 0;font-size:.88rem;border-bottom:1px solid var(--gray-200)}.hd-question:last-child{border-bottom:none}.hd-num{width:20px;font-weight:800;color:var(--gray-400);flex-shrink:0}.hd-eq{flex:1;font-weight:700;color:var(--indigo-dk);font-size:.92rem}.hd-result{font-size:.78rem;font-weight:700;padding:2px 10px;border-radius:4px;flex-shrink:0}.hd-result.ok{background:var(--green-lt);color:#0a6448}.hd-result.bad{background:var(--coral-lt);color:#9b2226}.no-history{text-align:center;padding:32px 16px;color:var(--gray-400)}.no-history.hidden{display:none}.no-history-icon{font-size:3rem;display:block;margin-bottom:8px}.login-card .card-banner{padding:36px 40px 28px}.login-card .card-body{padding:28px 40px 32px}.login-tabs{display:flex;background:var(--gray-100);border-radius:8px;padding:4px;margin-bottom:22px}.tab-btn{flex:1;padding:9px 12px;border:none;background:transparent;font-family:Nunito,sans-serif;font-size:.92rem;font-weight:700;color:var(--gray-600);border-radius:6px;cursor:pointer;transition:background .2s,color .2s}.tab-btn.active{background:#fff;color:var(--indigo);box-shadow:0 2px 8px #0000001a}.tab-panel{text-align:left}.tab-panel.hidden{display:none}.field{width:100%;height:50px;padding:0 16px;font-family:Nunito,sans-serif;font-size:1rem;font-weight:700;border:2px solid var(--gray-200);border-radius:var(--radius-sm);color:var(--text);background:var(--gray-50);outline:none;transition:border-color .2s,box-shadow .2s}.field::placeholder{color:var(--gray-400);font-weight:400;opacity:1;letter-spacing:0}.field:focus{border-color:var(--indigo);background:#fff;box-shadow:0 0 0 3px #4b49ac1f}.pin-field{letter-spacing:6px;text-align:center}.field-label{display:block;font-size:.75rem;font-weight:700;color:var(--gray-600);margin-bottom:6px;text-transform:uppercase;letter-spacing:.6px}.field-input{width:100%;height:50px;padding:0 16px;font-family:Nunito,sans-serif;font-size:1rem;font-weight:700;border:2px solid var(--gray-200);border-radius:var(--radius-sm);color:var(--text);background:var(--gray-50);outline:none;transition:border-color .2s,box-shadow .2s}.field-input::placeholder{color:var(--gray-400);font-weight:400;opacity:1}.field-input:focus{border-color:var(--indigo);background:#fff;box-shadow:0 0 0 3px #4b49ac1f}.auth-error{font-size:.85rem;font-weight:700;color:#9b2226;background:var(--coral-lt);border-radius:var(--radius-sm);padding:10px 14px;margin-bottom:10px;text-align:center}.guest-banner{display:flex;align-items:center;justify-content:space-between;gap:10px;background:var(--amber-lt);border-radius:var(--radius-sm);padding:10px 14px;margin-bottom:16px;font-size:.83rem;font-weight:700;color:#7a4f03;flex-wrap:wrap;border-left:4px solid var(--amber)}.guest-banner.hidden{display:none}.btn-create-account{background:var(--amber);border:none;font-family:Nunito,sans-serif;font-size:.8rem;font-weight:700;color:#4a2f00;padding:5px 14px;border-radius:6px;cursor:pointer;white-space:nowrap;transition:opacity .2s}.btn-create-account:hover{opacity:.85}.confetti-container{position:fixed;top:0;left:0;width:100%;height:100%;pointer-events:none;overflow:hidden;z-index:999}.confetti-piece{position:absolute;top:-12px;width:10px;height:10px;border-radius:2px;animation:confettiFall linear forwards}@keyframes confettiFall{0%{transform:translateY(0) rotate(0);opacity:1}80%{opacity:1}to{transform:translateY(105vh) rotate(720deg);opacity:0}}#confetti-container{position:fixed;top:0;left:0;width:100%;height:100%;pointer-events:none;overflow:hidden;z-index:999}.app-title{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:900;color:#fff;letter-spacing:-.5px}.app-subtitle{font-size:clamp(.9rem,1.5vw,1.05rem);color:#ffffffbf;margin-top:4px}.tabs{display:flex;background:var(--gray-100);border-radius:8px;padding:4px;margin-bottom:22px}.field-group{display:flex;flex-direction:column;gap:10px;margin-bottom:16px}.error-msg{font-size:.85rem;font-weight:700;color:#9b2226;background:var(--coral-lt);border-radius:var(--radius-sm);padding:10px 14px;margin-bottom:10px;text-align:center}.divider{display:flex;align-items:center;gap:12px;margin:16px 0;color:var(--gray-400);font-size:.85rem;font-weight:700}.divider:before,.divider:after{content:"";flex:1;border-top:1px solid var(--gray-200)}.diff-buttons{display:flex;gap:12px;margin-bottom:12px}.addon-label{flex:1;display:flex;align-items:center;gap:8px;padding:10px 14px;border:2px solid var(--gray-200);border-radius:var(--radius-sm);background:var(--gray-50);cursor:pointer;transition:all .2s;font-size:.88rem;font-weight:700;color:var(--text);-webkit-user-select:none;user-select:none}.addon-label:hover{border-color:var(--indigo);background:var(--indigo-lt)}.addon-label:has(input:checked){border-color:var(--indigo);background:var(--indigo-lt);box-shadow:0 0 0 3px #4b49ac33}.addon-label input[type=checkbox]{accent-color:var(--indigo);width:16px;height:16px;cursor:pointer}.welcome-footer{display:flex;gap:8px;margin-top:8px}.welcome-footer .btn-ghost{flex:1;text-align:center}.game-banner{display:flex;flex-direction:column;gap:12px}.game-header{display:flex;align-items:center;justify-content:space-between;color:#fff;gap:12px}#score-display,#timer-display{background:#fff3;padding:6px 14px;border-radius:50px;font-size:1rem;font-weight:800;min-width:56px;text-align:center}#q-label{font-size:.9rem;font-weight:700;color:#ffffffd9}.equation-display{font-size:clamp(1.8rem,3.5vw,2.8rem);font-weight:900;color:#fff;background:var(--indigo-dk);border-radius:var(--radius-sm);padding:28px 20px;letter-spacing:2px;margin-bottom:20px;text-align:center;box-shadow:0 2px 10px #0000001f}.answer-row{display:flex;flex-direction:column;align-items:center;gap:12px;margin-bottom:16px}.answer-row .btn-primary{display:block;width:100%;align-self:stretch;margin-top:0;padding:16px 24px;font-size:1.1rem}.stat-row{display:flex;justify-content:space-between;align-items:center;padding:10px 0;border-bottom:1px solid var(--gray-100);font-size:.95rem}.stat-row:last-child{border-bottom:none}.stat-row span{color:var(--gray-600);font-weight:700}.stat-row strong{color:var(--indigo-dk);font-weight:900}.end-actions{display:flex;flex-direction:column;gap:4px}.history-footer{display:flex;justify-content:space-between;align-items:center;margin-top:20px;padding-top:16px;border-top:1px solid var(--gray-200)}.hidden{display:none!important}