:root{color-scheme:light;--ink:#233d38;--muted:#708079;--green:#24705b;--green-light:#eaf2e9;--line:#dce2d8;--paper:#f6f7f2;--white:#fff;--orange:#aa5a36;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans JP",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}*{box-sizing:border-box}body{margin:0}button,a,summary{-webkit-tap-highlight-color:transparent}button{font:inherit;cursor:pointer}button:disabled{cursor:default}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #ba752d;outline-offset:4px}[hidden]{display:none!important}.site-header{max-width:1320px;margin:auto;padding:25px 48px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between}.brand{font-weight:750;font-size:16px;letter-spacing:.06em;text-decoration:none;color:var(--ink);display:flex;align-items:center;gap:10px}.brand-icon{background:var(--green);color:white;width:30px;height:30px;display:grid;place-items:center;border-radius:9px;font-size:24px}.header-caption{font-size:10px;letter-spacing:.18em;color:var(--muted)}main{max-width:1216px;margin:auto;padding:48px 40px 24px}.intro{margin-bottom:37px}.eyebrow{font-size:11px;font-weight:700;letter-spacing:.14em;color:var(--green);margin:0 0 14px}h1{font-size:clamp(28px,3.4vw,40px);line-height:1.45;letter-spacing:.04em;margin:0 0 14px;font-weight:750}.mobile-break{display:none}.lead{font-size:14px;line-height:1.95;color:#66746e;margin:0}.question-bar{border-top:1px solid var(--line);padding-top:25px;display:flex;align-items:center;justify-content:space-between;gap:14px}.question-counter{font-size:14px;font-weight:750}.difficulty{font-size:11px;color:var(--muted);margin-left:18px}.progress{display:flex;gap:6px}.progress span{display:block;width:25px;height:5px;border-radius:5px;background:#dfe5dc}.progress .current{background:var(--green)}.progress .done{background:#98b9a0}h2{font-size:20px;line-height:1.6;letter-spacing:.02em;margin:22px 0 8px}h2:focus{outline:none}.interaction-hint{font-size:12px;color:var(--muted);margin:0 0 25px}.interaction-hint>span:first-child{color:var(--green);font-size:19px;margin-right:6px}.hint-detail{margin-left:5px}.workspace{display:grid;grid-template-columns:minmax(0,.95fr) minmax(0,1.45fr);gap:28px;align-items:start}.source-panel{border:1px solid var(--line);background:#eef2e9;border-radius:16px;padding:22px;position:sticky;top:20px}.panel-top{display:flex;align-items:center;justify-content:space-between}h3{font-size:13px;letter-spacing:.04em;margin:0}.count-tag{font-size:10px;padding:5px 9px;border:1px solid #d3ddce;border-radius:20px;color:#687864}.graph{display:block;width:100%;height:auto;aspect-ratio:4/3;overflow:hidden;user-select:none;-webkit-user-select:none}.source-panel .graph{margin:24px 0 18px}.graph line{stroke:#748c7f;stroke-width:2.3;stroke-linecap:round;pointer-events:none}.vertex{cursor:grab;touch-action:none;outline:none}.vertex.dragging{cursor:grabbing}.vertex .hit-area{fill:transparent}.vertex .dot{fill:#fff;stroke:var(--green);stroke-width:2.5;transition:fill .12s}.vertex:hover .dot,.vertex:focus-visible .dot,.vertex.dragging .dot{fill:#d9edda;stroke:#164b3c;stroke-width:3.5}.vertex:focus-visible .focus-ring{stroke:#ba752d;stroke-width:2;fill:none}.focus-ring{fill:none;pointer-events:none}.vertex text{font-size:13px;font-weight:750;fill:var(--green);pointer-events:none;dominant-baseline:central;text-anchor:middle}.source-note{display:flex;align-items:center;gap:12px;border-top:1px solid #d9e1d3;padding-top:16px}.note-icon{font-size:25px;color:var(--green)}.source-note p{font-size:12px;line-height:1.9;margin:0}.source-note p span{color:var(--muted);font-size:11px}.text-button{border:0;background:none;color:var(--green);font-size:11px;margin:14px 0 0;padding:7px 0;text-decoration:underline;text-underline-offset:4px}.options-heading{display:flex;align-items:center;justify-content:space-between;margin:1px 1px 13px}.options-heading>span{font-size:10px;color:var(--muted)}.choices{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.choice{border:1px solid var(--line);border-radius:13px;background:var(--white);padding:13px 14px 12px;transition:border-color .15s,box-shadow .15s}.choice:hover{border-color:#a1b8a5}.choice-header{display:flex;justify-content:space-between;align-items:center;min-height:25px}.choice-letter{font-size:14px;width:26px;height:26px;border-radius:7px;background:#f1f4ee;display:grid;place-items:center;font-weight:750}.choice-status{font-size:10px;color:var(--muted)}.choice .graph{margin:0 0 5px}.choice-button{width:100%;border:1px solid #e0e7dc;background:#f6f8f3;border-radius:7px;color:#49614f;font-size:11px;font-weight:650;padding:10px 4px;min-height:40px}.choice-button:hover:enabled{background:#e6efdf}.choice.incorrect{border-color:#d7a48a}.choice.incorrect .choice-status{color:var(--orange)}.choice.correct{border:2px solid var(--green);padding:12px 13px 11px;background:#f5faf2;box-shadow:0 0 0 3px #e7efe2}.choice.correct .choice-letter{background:var(--green);color:white}.choice.correct .choice-status{color:var(--green);font-weight:700}.choice.correct .choice-button{background:var(--green);border-color:var(--green);color:white}.choice-button:disabled{opacity:.65}.choice.correct .choice-button:disabled{opacity:1}.feedback{margin-top:24px;padding:19px 22px;border:1px solid var(--line);border-radius:12px;display:flex;align-items:center;justify-content:space-between;gap:20px;background:#eff2eb}.feedback p{margin:0;font-size:13px;font-weight:650;line-height:1.7}.feedback #feedback-detail{font-size:11px;font-weight:400;margin-top:3px;color:#647467}.feedback.success{border-color:#b7cfb3;background:#e9f2e4}.feedback.error{background:#fff3eb;border-color:#e5c7b5}.feedback.error #feedback-title{color:#94522f}.primary-button{border:0;background:var(--green);color:white;border-radius:8px;padding:13px 19px;white-space:nowrap;min-height:45px;font-weight:650;font-size:12px}.primary-button:hover{background:#195541}.primary-button span{margin-left:22px}.explanation{font-size:12px;line-height:1.95;padding:17px 22px;border-left:3px solid #aec7a6;margin:20px 0 0;color:#526653}.explanation strong{display:block;color:var(--ink);margin-bottom:4px}footer{margin-top:32px;padding-top:20px;border-top:1px solid var(--line);color:var(--muted);font-size:10px;line-height:1.8}details{margin-top:10px}summary{cursor:pointer;width:fit-content}details p{max-width:660px}.completion{text-align:center;border:1px solid var(--line);background:white;border-radius:18px;padding:55px 22px}.completion:focus{outline:none}.completion-mark{margin:0 auto 22px;display:grid;place-items:center;width:65px;height:65px;border-radius:50%;background:var(--green-light);color:var(--green);font-size:30px}.completion h2{font-size:25px}.completion>p:not(.eyebrow){font-size:14px;line-height:2;color:var(--muted)}.completion-summary{font-size:18px;font-weight:750;margin:24px}.completion .primary-button{margin-top:8px}@media(min-width:1300px){main{padding-top:54px}.intro{margin-bottom:42px}}@media(max-width:760px){.site-header{padding:18px 22px}.header-caption{font-size:8px}.brand{font-size:13px}main{padding:30px 20px 24px}.intro{margin-bottom:27px}.lead{font-size:12px}.workspace{grid-template-columns:1fr;gap:24px}.source-panel{position:static;padding:18px}.source-panel .graph{max-width:420px;margin:10px auto}.source-note{padding-top:12px}.difficulty{font-size:10px;margin-left:10px}.progress span{width:16px}.question-bar{padding-top:20px}h2{font-size:18px}.feedback{padding:17px;align-items:stretch;flex-direction:column;gap:14px}.feedback .primary-button{align-self:flex-end}.choice{padding:11px}.choice.correct{padding:10px}.choice .graph{min-width:0}.choices{gap:10px}.choice-status{font-size:9px}.choice-button{font-size:10px;min-height:43px}.hint-detail{display:none}.completion h2{font-size:21px}}@media(max-width:390px){main{padding-left:14px;padding-right:14px}.site-header{padding-left:14px;padding-right:14px}.header-caption{display:none}.difficulty{display:block;margin:6px 0 0}.mobile-break{display:block}.choice{padding:8px}.choice.correct{padding:7px}}
@media(max-width:560px){.choices{grid-template-columns:1fr;gap:14px}.choice{padding:15px 18px}.choice.correct{padding:14px 17px}.choice .graph{max-width:360px;margin:0 auto 8px}.choice-button{font-size:12px}.choice-status{font-size:11px}.choice-letter{width:30px;height:30px}}