:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:#182640;background:#f6f8fc;font-synthesis:none;--blue:#234cd0;--muted:#62708a;--border:#dce3f0}*{box-sizing:border-box}body{margin:0}button,input{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible{outline:3px solid #f3ad28;outline-offset:4px}button:disabled{cursor:default;opacity:.55}header{max-width:1180px;margin:auto;padding:26px 30px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--border)}.brand{display:flex;align-items:center;border:0;background:none;padding:0;font-size:21px;font-weight:750;letter-spacing:-.7px;color:#192842}.brand>span:last-child{color:var(--blue)}.mark{display:grid;place-items:center;background:var(--blue);color:white;border-radius:12px;width:36px;height:36px;font-size:30px;margin-right:10px}nav{display:flex;align-items:center;gap:22px}.quiet{border:0;background:transparent;color:#465779;font-weight:600;padding:10px}.quiet span{border-radius:20px;background:#e8edfa;padding:2px 7px;margin-left:5px;font-size:12px}.local{color:var(--muted);font-size:12px;display:flex;align-items:center;gap:7px}.local i{width:6px;height:6px;border-radius:50%;background:#368763}main{max-width:1120px;margin:auto;padding:60px 30px;min-height:75vh}h1,h2,h3,p{margin-top:0}h1{font-size:clamp(36px,5vw,62px);line-height:1.1;letter-spacing:-2.4px;margin-bottom:22px;font-weight:750}h2{font-size:26px;letter-spacing:-.8px}h3{font-size:17px}.eyebrow{color:var(--blue);font-size:11px;letter-spacing:1.8px;font-weight:750;text-transform:uppercase;margin-bottom:20px}.lede{font-size:17px;color:var(--muted);line-height:1.8;max-width:460px}.hero{display:grid;grid-template-columns:1.15fr 1fr;gap:64px;align-items:center;padding:25px 0 42px}.hero h1 em{font-style:normal;color:var(--blue)}.primary{border:0;background:var(--blue);color:white;border-radius:10px;padding:15px 23px;font-weight:650;box-shadow:0 3px 5px #234cd015}.secondary{background:white;color:#344563;border:1px solid var(--border);border-radius:10px;padding:13px 19px;font-weight:600}.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}.micro{font-size:12px;color:var(--muted);margin-top:17px}.card{background:white;border:1px solid var(--border);border-radius:19px;padding:28px;box-shadow:0 12px 38px #26375f05}.example{background:white;position:relative}.example:after{content:"";position:absolute;z-index:-1;inset:10px -10px -10px 10px;background:#e6ecfa;border-radius:20px;}.cardtop{display:flex;justify-content:space-between;align-items:center;color:var(--muted);font-size:12px}.pill{display:inline-flex;border-radius:6px;background:#edf1ff;color:var(--blue);font-size:11px;padding:6px 9px;font-weight:650}.equation{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:clamp(27px,4vw,40px);letter-spacing:-1px;padding:25px 0;text-align:center}.sample-line{padding:13px 15px;border:1px solid var(--border);border-radius:9px;font-family:ui-monospace,monospace;font-size:16px;margin-bottom:10px;display:flex;justify-content:space-between}.wrong-line{border-color:#ecd0c9;background:#fff8f5}.good-line{border-color:#bddccd;background:#f4faf7}.sample-feedback{color:#77574f;font-size:13px;line-height:1.7;margin:15px 0 24px}.features{border-top:1px solid var(--border);padding-top:30px;display:grid;grid-template-columns:repeat(3,1fr);gap:30px}.features>div{display:flex;gap:13px}.number{display:grid;place-items:center;background:#e9eefb;color:var(--blue);min-width:31px;height:31px;border-radius:9px;font-size:12px;font-weight:700}.features h3{font-size:14px;margin-bottom:7px}.features p{font-size:13px;line-height:1.6;color:var(--muted);margin:0}.topline{display:flex;align-items:center;justify-content:space-between;margin-bottom:24px;gap:16px}.topline h1{font-size:34px;letter-spacing:-1px;margin-bottom:7px}.subtitle{font-size:14px;color:var(--muted);margin:0}.practice-grid{display:grid;grid-template-columns:1.35fr .85fr;gap:24px;align-items:start}.problem .equation{text-align:left;margin-top:8px;padding-bottom:26px}.steps{list-style:none;padding:0;margin:0 0 24px}.steps li{border-top:1px solid #edf0f7;padding:14px 0;display:flex;align-items:start;gap:12px}.step-dot{font-size:12px;border-radius:50%;background:#eff3fb;min-width:24px;height:24px;display:grid;place-items:center;color:var(--muted)}.steps code{font-size:17px;white-space:pre-wrap;overflow-wrap:anywhere}.steps small{display:block;margin-top:7px;font-size:12px;line-height:1.6;color:var(--muted)}.steps .incorrect code{color:#a44432;text-decoration:line-through}.steps .incorrect .step-dot{background:#faece7;color:#a44432}label{display:block;font-weight:600;font-size:13px;margin:14px 0 9px}input{display:block;width:100%;border:1px solid #b4c2df;border-radius:9px;padding:15px;color:#182640;font-family:ui-monospace,monospace;font-size:20px;background:#fafbff}input:focus{outline:2px solid #234cd033;border-color:var(--blue)}.format{color:var(--muted);font-size:12px;line-height:1.7;margin-top:10px}.feedback{background:#f0f4ff;border:1px solid #d9e3fa;border-radius:12px;padding:18px;font-size:14px;line-height:1.8;min-height:110px}.feedback[data-kind=wrong]{background:#fff5ef;border-color:#f0d7c6;color:#764931}.feedback[data-kind=complete],.feedback[data-kind=valid]{background:#f0f9f4;border-color:#cbe4d5;color:#265c42}.helper h3{margin:0 0 16px}.helper .rule{padding-top:20px;margin-top:24px;border-top:1px solid var(--border);color:var(--muted);font-size:13px;line-height:1.8}.done{background:#f0f9f4;border:1px solid #cbe4d5;border-radius:12px;padding:21px;margin-top:20px}.done h3{color:#265c42;margin-bottom:9px}.done p{font-size:13px;line-height:1.7;color:#4c685b}.stat-row{display:flex;gap:25px;margin:18px 0}.stat-row strong{font-size:25px;display:block}.stat-row small{color:var(--muted);font-size:11px}.review-list{display:grid;gap:15px}.review-card{display:flex;justify-content:space-between;align-items:center;gap:20px}.review-card code{font-size:18px}.review-card p{font-size:13px;color:var(--muted);line-height:1.7;margin:12px 0}.empty{max-width:600px;text-align:center;margin:40px auto;padding:45px}.empty p{color:var(--muted);line-height:1.8}.danger{border:0;background:none;color:#934735;font-size:12px;padding:12px}.skip{position:absolute;left:10px;top:-80px;background:white;padding:10px;z-index:10}.skip:focus{top:10px}footer{max-width:1120px;margin:auto;border-top:1px solid var(--border);padding:24px 30px;color:#77849a;font-size:11px;display:flex;justify-content:space-between;gap:15px}#storage-warning{position:sticky;bottom:0;padding:14px 25px;background:#fff1da;color:#735029;border-top:1px solid #e0bf83;font-size:13px}.confirm{background:#fff6ec;border:1px solid #ecd5be;padding:20px;border-radius:12px;margin:20px 0}.confirm p{font-size:14px;line-height:1.6} [hidden]{display:none!important}@media(max-width:760px){header{padding:20px}.local{display:none}nav{gap:0}.brand{font-size:18px}.mark{width:30px;height:30px;font-size:24px}main{padding:32px 20px}.hero{grid-template-columns:1fr;gap:35px;padding-top:0}.example{transform:none}.features{grid-template-columns:1fr;gap:22px}.practice-grid{grid-template-columns:1fr}.card{padding:22px}.topline{align-items:start}.topline h1{font-size:28px}.review-card{flex-direction:column;align-items:start}footer{padding:22px 20px;flex-direction:column}.equation{font-size:29px}h1{letter-spacing:-1.5px}}
.review-card{display:block}.review-card h3{margin:16px 0}.review-card p{margin:12px 0}.review-card code{font-size:18px}.review-card button{margin-top:8px}.actions{display:flex;flex-wrap:wrap;gap:8px}.steps code{overflow-wrap:anywhere}.topline{gap:14px;flex-wrap:wrap}
.practice-grid{display:block;max-width:720px;margin:0 auto}.topline{max-width:720px;margin-left:auto;margin-right:auto}.working{margin:16px 0}.working summary{cursor:pointer;color:#465779;font-size:14px}.problem>.equation{margin:22px 0}.problem .fine{line-height:1.6;font-size:14px}
#question-form{max-width:460px;margin:24px 0}#question-error{color:#9a382d;font-size:14px;line-height:1.5}.lesson{background:#edf2ff;padding:20px;border-radius:14px;margin:20px 0}.lesson h2{font-size:18px;margin:0}.lesson p{line-height:1.7}.lesson .equation{font-size:26px;margin:16px 0}
.explanation-steps{padding-left:22px;margin:10px 0}.explanation-steps li{padding:6px 0;line-height:1.65}.next-practice{border-top:1px solid var(--border);margin-top:22px;padding-top:14px}.next-practice p{font-size:14px;color:#465779}
.equation{overflow-wrap:anywhere}.lesson code,.review-card code{overflow-wrap:anywhere}
