@font-face{font-family:system-korean;src:local('Apple SD Gothic Neo'),local('Malgun Gothic')}
:root{--ink:#203d35;--muted:#66766f;--green:#175d50;--soft:#edf4e9;--cream:#f8f7f2;--line:#dde4dc;--gold:#f4ce79;--red:#9b422e;--shadow:0 8px 32px #193e2910}
*{box-sizing:border-box}body{margin:0;color:var(--ink);background:var(--cream);font:16px/1.6 system-korean,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;word-break:keep-all}button,input,select,textarea{font:inherit}button,select,summary{cursor:pointer}button{line-height:1.35;transition:background .16s,transform .16s}button:hover:not(:disabled){transform:translateY(-1px)}button:disabled{opacity:.48;cursor:not-allowed}a{color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #dc9c28;outline-offset:4px}input,select,textarea{max-width:100%}select,textarea{background:#fff;border:1px solid #ced9d0;border-radius:9px;color:var(--ink);padding:9px 10px;min-height:44px}select{font-size:14px}textarea{width:100%;resize:vertical;min-height:100px}button{min-height:44px;border:0;border-radius:11px;font-weight:650}h1,h2,h3,p{margin:0}h2{font-size:18px;letter-spacing:-.5px}h3{font-size:25px;letter-spacing:-.9px}[hidden]{display:none!important}.wrap{width:min(1120px,calc(100% - 64px));margin:auto}.topbar{display:flex;justify-content:space-between;align-items:center;height:96px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-size:24px;font-weight:800;letter-spacing:-1px}.beta{font-size:11px;letter-spacing:0;background:#e5ebdf;padding:3px 8px;border-radius:5px;font-weight:600;color:#62715d}.help-link{font-size:14px;text-decoration:none}.help-link span{padding-left:8px}.intro{display:flex;align-items:center;justify-content:space-between;padding:46px 18px 39px}.eyebrow{font-size:13px;color:var(--green);font-weight:700;letter-spacing:.5px;margin-bottom:9px}h1{font-size:42px;line-height:1.25;letter-spacing:-1.8px;font-weight:800}.lead{color:var(--muted);margin-top:17px;font-size:15px;line-height:1.8}.mobile-break{display:none}.abacus-art{position:relative;width:250px;height:170px;transform:rotate(-5deg);margin-right:32px}.abacus{position:absolute;inset:9px 20px 33px;border:9px solid var(--green);border-radius:17px;display:flex;justify-content:space-evenly;background:#e6e9d8;box-shadow:7px 9px 0 #e4e6da}.abacus i{height:100%;width:4px;background:#90a188;position:relative}.abacus i:before,.abacus i:after{content:'';position:absolute;left:50%;transform:translateX(-50%);width:26px;height:14px;border-radius:50%;background:var(--gold);border:2px solid #dfb76c;top:12px;box-shadow:0 53px 0 #eabd67,0 68px 0 #eabd67}.abacus i:after{top:50px;box-shadow:none}.abacus i:nth-child(2n):after{top:40px}.abacus b{position:absolute;top:35px;height:6px;width:100%;background:var(--green)}.spark{position:absolute;color:#b28e43;font-size:28px}.one{right:-12px;top:-14px}.two{left:0;bottom:24px}.art-label{position:absolute;bottom:0;width:100%;text-align:center;font-size:11px;color:var(--muted);letter-spacing:1px;transform:rotate(5deg)}.mode-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:0 0 24px}.mode{display:flex;align-items:center;gap:17px;text-align:left;background:#fff;border:1.5px solid var(--line);padding:20px 24px;min-width:0}.mode.active{border-color:var(--green);background:#eef4e9;box-shadow:0 0 0 1px var(--green)}.mode-icon{display:grid;place-items:center;background:#f2f3ec;color:var(--green);border-radius:12px;width:45px;height:45px;flex-shrink:0;font-size:27px}.active .mode-icon{background:#dbe8d4}.mode strong{display:block;font-size:19px}.mode small{display:block;font-size:12px;font-weight:400;color:var(--muted);margin-top:4px}.mode-check{margin-left:auto;background:#dce6d9;color:transparent;font-size:12px;border-radius:50%;width:22px;height:22px;text-align:center;padding-top:3px;flex-shrink:0}.active .mode-check{color:#fff;background:var(--green)}.workspace{display:grid;grid-template-columns:326px 1fr;gap:24px;align-items:start}.card{background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow)}.settings{padding:26px 24px}.section-title{display:flex;align-items:center;justify-content:space-between;gap:10px}.tiny{font-size:11px;color:#6d7c71;white-space:nowrap}.field-label{display:block;font-size:13px;font-weight:700;margin:23px 0 10px}.preset-group{display:flex;background:#f4f5f0;border-radius:9px;padding:4px;gap:4px}.preset-group button{width:33.333%;background:transparent;color:var(--muted);font-size:14px;min-height:39px;border-radius:7px}.preset-group .selected{background:var(--green);color:white}.setting-summary{font-size:13px;margin:14px 0 5px;color:var(--green);font-weight:650}.micro{font-size:11px;line-height:1.65;color:var(--muted)}.setting-line{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-top:19px}.setting-line label{font-size:13px;font-weight:600;flex-shrink:0}.setting-line select{max-width:165px}.range-heading{display:flex;justify-content:space-between;font-size:13px;font-weight:600;margin:23px 0 9px}.range-heading output{color:var(--green);font-variant-numeric:tabular-nums}input[type=range]{width:100%;accent-color:var(--green);height:20px;margin:0;cursor:pointer}.range-ends{display:flex;justify-content:space-between;font-size:10px;color:var(--muted)}.teacher{border-top:1px solid var(--line);margin-top:22px;padding-top:17px}.teacher summary{font-size:13px;display:flex;justify-content:space-between;list-style:none;font-weight:650}.teacher summary::-webkit-details-marker{display:none}.teacher[open] summary span{transform:rotate(45deg)}.teacher-content{padding-top:2px}.check{display:flex;align-items:start;gap:7px;font-size:12px;margin:14px 0}.check input{accent-color:var(--green);width:16px;height:16px;flex-shrink:0}.optional{font-weight:400;font-size:11px;color:var(--muted)}.reset-note{margin-top:17px;font-size:10px}.practice{padding:26px 32px;min-height:581px;display:flex;flex-direction:column}.progress-track{height:4px;border-radius:3px;background:#f0f3ed;margin-top:22px;overflow:hidden}#round-progress{height:100%;width:0;background:#a5c59a;transition:width .3s}.practice-stage{text-align:center;padding:28px 0 19px}.listening-orb{display:flex;justify-content:center;align-items:center;gap:5px;margin:0 auto 17px;width:96px;height:96px;background:var(--soft);border-radius:50%;outline:1px solid #e5eddf;outline-offset:7px}.listening-orb span{background:var(--green);width:5px;border-radius:8px;height:18px}.listening-orb span:nth-child(2),.listening-orb span:nth-child(4){height:31px}.listening-orb span:nth-child(3){height:44px}.listening-orb.playing span{animation:wave .8s ease-in-out infinite alternate}.listening-orb.playing span:nth-child(2){animation-delay:-.3s}.listening-orb.playing span:nth-child(3){animation-delay:-.6s}.listening-orb.playing span:nth-child(4){animation-delay:-.2s}.stage-kicker{font-size:12px;color:var(--green);font-weight:700;margin-bottom:9px}.stage-description{font-size:14px;color:var(--muted);line-height:1.8;margin-top:12px}.primary{background:var(--green);color:#fff;padding:13px 24px;box-shadow:0 4px 8px #175d5010}.primary:hover:not(:disabled){background:#104b40}.start-button{margin-top:23px;min-width:230px}.start-button span{font-size:11px;margin-right:10px}.secondary{border:1px solid #cbd8cd;background:#fff;padding:10px 17px;color:var(--green);font-size:13px}.text-button{color:var(--muted);background:transparent;padding:9px 12px;font-size:12px}.play-controls{display:flex;justify-content:center;gap:10px;margin:18px 0 0}.term-dots{display:flex;gap:8px;justify-content:center;margin:16px 0 0}.term-dots:empty{display:none}.term-dots span{width:8px;height:8px;border-radius:50%;background:#e3eade}.term-dots .heard{background:#67a082}.term-dots .current{outline:2px solid #67a082;outline-offset:3px}.practice-bottom{margin-top:auto;border-top:1px solid #edf0e9;padding-top:18px;display:flex;align-items:center;justify-content:space-between;font-size:12px;color:var(--muted)}.practice-bottom .text-button{min-height:32px;padding:3px 0}.message{font-size:13px;background:#f9f1d9;color:#705524;padding:12px 15px;border-radius:10px;margin-bottom:16px}#answer-form{border-top:1px solid var(--line);padding:19px 0 16px}#answer-form>label{font-size:13px;font-weight:650;display:block;margin-bottom:10px}.answer-row{display:flex;gap:10px}.answer-row input{font-size:30px;min-width:0;width:100%;border:1.5px solid #cad6cc;border-radius:12px;padding:8px 16px;font-weight:700;line-height:1.3;font-variant-numeric:tabular-nums;color:var(--ink);background:#fdfefb}.answer-row .primary{flex-shrink:0;font-size:14px;padding:12px 20px}.answer-row input:disabled{background:#f1f3ee}.answer-row+p{margin-top:7px}.feedback{padding:14px 17px;background:#edf5e7;border-radius:11px;font-size:15px;margin:0 0 12px}.feedback.wrong{background:#fff0e5;color:var(--red)}.feedback strong{font-weight:800}.review-sequence{border:1px solid var(--line);padding:17px;border-radius:12px;margin-bottom:16px}.review-sequence p{font-size:11px;color:var(--muted);margin-bottom:9px}.equation{display:flex;flex-wrap:wrap;align-items:center;gap:7px;font-size:21px;font-weight:700;font-variant-numeric:tabular-nums}.equation span{background:#f4f6f0;padding:3px 9px;border-radius:6px}.equation b{color:var(--green);margin-left:4px}.full{width:100%;margin:0 0 19px}.result-number{font-size:56px;line-height:1.2;font-weight:800;text-align:center;color:var(--green);margin:15px 0}.result-number small{font-size:20px;color:var(--muted)}.result-caption{text-align:center;font-size:14px;color:var(--muted);margin-bottom:20px}.review-item{border-top:1px solid var(--line);padding:14px 0}.review-item-top{display:flex;justify-content:space-between;align-items:center;font-size:13px}.review-item-top span{color:var(--red)}.review-item .equation{font-size:16px;margin-top:8px}.review-item .text-button{min-height:32px;padding:4px 0}.review-heading{font-size:15px;margin-bottom:10px}.voice-card{margin:24px 0;display:flex;align-items:center;justify-content:space-between;gap:18px;background:#edeFE6;border-radius:15px;padding:20px 24px}.voice-card h2{font-size:14px}.voice-card h2 span{margin-right:8px}.voice-card p{font-size:11px;color:var(--muted);margin-top:5px;max-width:450px}.voice-actions{display:flex;align-items:center;gap:8px;flex-wrap:wrap;justify-content:flex-end}.voice-actions select{max-width:190px;font-size:12px}.voice-actions .secondary{font-size:12px;white-space:nowrap}.help{padding:10px 3px 28px;border-bottom:1px solid var(--line);font-size:13px;color:var(--muted)}.help summary{font-weight:650;color:var(--ink);padding:10px 0}.help-grid{display:grid;grid-template-columns:1fr 1fr 1fr;gap:30px;margin-top:20px}.help h3{font-size:15px;letter-spacing:0;color:var(--ink);margin-bottom:8px}.help p{font-size:12px;line-height:1.8;margin-bottom:10px}footer{display:flex;align-items:center;gap:20px;padding-top:26px;padding-bottom:32px;font-size:11px;color:var(--muted)}footer span:last-child{margin-left:auto}.footer-brand{font-size:16px;font-weight:800;color:#496355}.skip{position:absolute;top:-100px;left:20px;background:#fff;padding:10px;z-index:10}.skip:focus{top:5px}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}@keyframes wave{to{transform:scaleY(.5)}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important}}
@media(max-width:850px){.wrap{width:calc(100% - 40px)}.intro{padding-left:0;padding-right:0}h1{font-size:35px}.abacus-art{transform:scale(.85) rotate(-5deg);margin-right:0;width:210px}.workspace{grid-template-columns:280px 1fr;gap:16px}.settings{padding:23px 19px}.practice{padding:23px;min-height:587px}.tiny{font-size:10px}.mode{padding:17px;gap:12px}.mode small{font-size:11px}.voice-card{flex-wrap:wrap}.voice-actions{justify-content:flex-start}h3{font-size:22px}.answer-row{flex-wrap:wrap}.answer-row .primary{width:100%}}
@media(max-width:640px){.wrap{width:calc(100% - 32px)}.topbar{height:74px}.brand{font-size:22px}.help-link{font-size:12px}.intro{padding:29px 3px 27px}.eyebrow{font-size:11px}h1{font-size:34px;line-height:1.3}.mobile-break{display:block}.lead{font-size:12px;margin-top:13px}.abacus-art{display:none}.mode-grid{gap:10px;margin-bottom:16px}.mode{padding:14px 12px;gap:9px;align-items:flex-start;position:relative}.mode-icon{font-size:22px;width:31px;height:31px;border-radius:8px;flex-shrink:0}.mode strong{font-size:17px;line-height:31px}.mode small{font-size:10px;line-height:1.65;margin-top:4px}.mode-check{display:none}.workspace{grid-template-columns:1fr;gap:16px}.settings{padding:22px}.setting-line{margin-top:16px}.range-heading{margin-top:17px}.teacher{margin-top:18px}.reset-note{margin-top:12px}.practice{padding:22px;min-height:550px}.practice-stage{padding:26px 0 20px}.stage-description{font-size:13px}h3{font-size:23px}.answer-row{flex-wrap:nowrap}.answer-row .primary{width:auto;padding:11px 16px}.voice-card{padding:18px;gap:13px}.voice-actions{gap:8px;width:100%}.voice-actions select{max-width:none;width:100%}.voice-actions .secondary{flex:1}.help-grid{grid-template-columns:1fr;gap:14px}footer{flex-wrap:wrap;gap:6px 14px;padding-top:22px}footer span:last-child{width:100%;margin-left:0}.feedback{font-size:14px}.equation{font-size:20px}.tiny{font-size:11px}.start-button{width:100%;min-width:0}}