:root{--ink:#213f37;--muted:#60756c;--green:#185244;--mint:#e6efdf;--lime:#e0efa9;--paper:#f7f7f0;--line:#dde3d8;--mono:ui-monospace,SFMono-Regular,Consolas,monospace}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.65 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}button,input,textarea{font:inherit}button,a,input,textarea,summary{touch-action:manipulation}button{cursor:pointer}a{color:var(--green)}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #a85a20;outline-offset:4px}button:disabled{cursor:default;opacity:.45}.skip{position:absolute;top:-100px;left:20px;background:white;z-index:10;padding:10px}.skip:focus{top:10px}.topbar{height:98px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding:0 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0;border-bottom:1px solid var(--line)}.question:last-child{border:0;padding-bottom:0}.question label{display:block;font-weight:650;font-size:14px;margin-bottom:9px}.answer-row{display:flex;gap:10px}.answer-row input{width:150px;min-width:0;padding:9px 12px;border:1px solid #c9d5c3;border-radius:9px;background:white}.button{border:1px solid var(--line);border-radius:9px;padding:10px 16px;font-size:13px;font-weight:650;background:white;color:var(--green);text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:7px}.button:hover:not(:disabled){filter:brightness(.96)}.button.primary{background:var(--green);color:white;border-color:var(--green)}.button.lime{background:var(--lime);border-color:var(--lime);color:var(--green)}.button.quiet{background:transparent}.feedback{font-size:12px;margin:9px 0 0;min-height:20px}.feedback.success{color:#236440}.feedback.error{color:#994b28}code{font-family:var(--mono);font-size:.9em;background:#eaf0e4;border-radius:4px;padding:2px 5px}details{border-top:1px solid var(--line);padding-top:15px;margin-top:18px;font-size:13px}summary{cursor:pointer;font-weight:650}pre{white-space:pre-wrap;overflow-wrap:anywhere;font:12px/1.7 var(--mono);background:#eef2e8;padding:18px;border-radius:10px;tab-size:4}pre code{background:none;padding:0;font-size:inherit}.workspace{border:1px solid #294f43;border-radius:16px;overflow:hidden;margin:18px 0;background:#19362f;color:#e0eadc}.workspace-top{display:flex;justify-content:space-between;align-items:center;padding:13px 18px;background:#23473d;gap:10px}.workspace-top label{font:12px var(--mono);color:#d2e2c4}.workspace-top .small{color:#b4c8b7}.editor-wrap{position:relative}.editor{width:100%;display:block;resize:vertical;min-height:280px;border:0;padding:22px;background:#19362f;color:#e3f1c9;font:13px/1.85 var(--mono);tab-size:4;outline-offset:-4px;white-space:pre;overflow:auto}.toolbar{padding:12px 16px;display:flex;flex-wrap:wrap;gap:8px;border-top:1px solid #36544b}.toolbar .button.quiet{color:#e2e9dd;border-color:#517063}.console-section{border-top:1px solid #36544b;background:#132c26;padding:16px 18px}.console-top{display:flex;justify-content:space-between;font-size:10px;letter-spacing:1.2px;color:#a4b9a5}.console{min-height:80px;max-height:330px;overflow:auto;margin:10px 0 0;padding:0;background:none;color:#e4ebdc;font-size:12px;white-space:pre-wrap;overflow-wrap:anywhere}.input-form{display:flex;gap:8px;margin-top:12px;flex-wrap:wrap}.input-form[hidden]{display:none}.input-form label{font-size:11px;color:#c7d9b4;width:100%}.input-form input{flex:1;min-width:120px;padding:9px 12px;background:#24463c;border:1px solid #6f9479;border-radius:8px;color:white;font:13px var(--mono)}.runtime-status{font-size:11px;color:#9fb79e;margin:0;padding:0 18px 12px}.test-results{background:white;padding:18px 23px;border:1px solid var(--line);border-radius:12px;font-size:13px;margin:14px 0}.test-results:empty{display:none}.test-results p{margin:5px 0}.lesson-footer{display:flex;justify-content:space-between;align-items:center;gap:12px;border-top:1px solid var(--line);padding-top:24px;margin-top:28px}.lesson-footer #completion{font-size:11px;color:var(--muted);text-align:center}.page-note{text-align:center;font-size:11px;color:var(--muted);margin-top:24px}.finish-banner{background:var(--mint);border-radius:15px;padding:22px;margin-top:16px}.finish-banner h2{font:27px Georgia,serif;margin:0}.hint{font-size:13px;color:var(--muted)}.practice-label{display:flex;align-items:center;gap:8px;margin-bottom:10px}.practice-label span{display:grid;place-items:center;width:26px;height:26px;border-radius:50%;background:var(--lime);font:15px Georgia,serif}
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@media(max-width:850px){.layout{grid-template-columns:215px minmax(0,1fr)}.sidebar{padding:25px 14px}.journey h2{font-size:24px}main{padding:25px 22px}.equation{gap:7px;font-size:20px}.fraction{font-size:16px}.card{padding:20px}}
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@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}
