.selfcheck{--b50:#fef3f0;--b100:#fde2d9;--b600:#f1592a;--b700:#cc4218;--ink:#111827;--muted:#4b5563;--line:#eef0f3;--ok:#e8f5ec;--ok-ink:#1f7a3d;--ok-bd:#bfe3c8;--no:#fdecec;--no-ink:#b5302f;--no-bd:#f3cdcb}.selfcheck .ic{width:30px;height:30px;border-radius:50%;background:var(--b600);display:inline-flex;align-items:center;justify-content:center;flex:0 0 auto}.selfcheck .ic svg{width:17px;height:17px;stroke:#fff;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}.selfcheck .acc{background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 1px 3px #1118270f,0 10px 26px #cc42180f;margin-bottom:14px;overflow:hidden}.selfcheck .acc-head{display:flex;align-items:center;gap:12px;padding:14px 16px;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;user-select:none}.selfcheck .acc-title{font-size:16.5px;margin:0;flex:1;letter-spacing:-.01em;font-weight:700;color:var(--ink)}.selfcheck .tracker{display:inline-flex;align-items:center;font-size:12.5px;font-weight:500;color:var(--b700);background:var(--b50);border:1px solid var(--b100);border-radius:999px;padding:3px 11px;white-space:nowrap}.selfcheck .chev{width:18px;height:18px;stroke:var(--muted);fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;transition:transform .2s;flex:0 0 auto}.selfcheck .acc.open .chev{transform:rotate(180deg)}.selfcheck .acc-body{display:none;padding:2px 16px 18px}.selfcheck .acc.open .acc-body{display:block}.selfcheck .hint{font-size:13px;color:var(--muted);margin:0 0 14px}.selfcheck .cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(205px,1fr));gap:13px}.selfcheck .card{perspective:1000px;height:180px;cursor:pointer}.selfcheck .card-inner{position:relative;width:100%;height:100%;transition:transform .5s;transform-style:preserve-3d}.selfcheck .card.flipped .card-inner{transform:rotateY(180deg)}.selfcheck .face{position:absolute;inset:0;backface-visibility:hidden;border-radius:12px;padding:14px;display:flex;align-items:center;justify-content:center;text-align:center;overflow:auto}.selfcheck .front{background:var(--b50);border:1px solid var(--b100);color:var(--b700);font-weight:600;font-size:15px}.selfcheck .card:hover .front{background:var(--b100)}.selfcheck .back{background:#fff;border:1px solid var(--b100);transform:rotateY(180deg);font-size:12.5px;color:var(--ink);line-height:1.4}.selfcheck .tf{border:1px solid var(--line);border-radius:12px;padding:15px 16px;margin-bottom:11px}.selfcheck .tf-q{font-weight:600;margin:0 0 11px;font-size:15px;color:var(--ink)}.selfcheck .tf-btns{display:grid;grid-template-columns:1fr 1fr;gap:10px}.selfcheck .tf-btns button{padding:10px;border:1px solid var(--b100);background:#fff;border-radius:10px;font-size:14.5px;font-weight:600;color:var(--ink);cursor:pointer;transition:.15s;font-family:inherit}.selfcheck .tf-btns button:hover:not(:disabled){background:var(--b50);border-color:var(--b600);color:var(--b700)}.selfcheck .tf-btns button:disabled{cursor:default;opacity:.97}.selfcheck .tf.answered .pick-correct{background:var(--ok);border-color:var(--ok-bd);color:var(--ok-ink)}.selfcheck .tf.answered .pick-wrong{background:var(--no);border-color:var(--no-bd);color:var(--no-ink)}.selfcheck .tf-exp{margin:11px 0 0;font-size:13px;color:var(--muted);display:none}.selfcheck .tf.answered .tf-exp{display:block}.selfcheck .tf-exp b{color:var(--ink)}.selfcheck .clabel{display:flex;gap:12px;align-items:flex-start;padding:11px 2px;cursor:pointer;border-top:1px solid var(--line);font-size:14.5px;color:var(--ink)}.selfcheck .clabel:first-child{border-top:0}.selfcheck .clabel input{margin-top:3px;width:17px;height:17px;accent-color:var(--b600);flex:0 0 auto}.selfcheck .clabel.on{color:var(--muted);text-decoration:line-through;text-decoration-color:var(--b100)}.interactive{--b50:#fef3f0;--b100:#fde2d9;--b600:#f1592a;--b700:#cc4218;--ink:#111827;--muted:#4b5563;--line:#eef0f3;--ok:#e8f5ec;--ok-ink:#1f7a3d;--ok-bd:#bfe3c8;--no:#fdecec;--no-ink:#b5302f;--no-bd:#f3cdcb}.interactive .ic{width:30px;height:30px;border-radius:50%;background:var(--b600);display:inline-flex;align-items:center;justify-content:center;flex:0 0 auto}.interactive .ic svg{width:17px;height:17px;stroke:#fff;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}.interactive .acc{background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 1px 3px #1118270f,0 10px 26px #cc42180f;margin-bottom:14px;overflow:hidden}.interactive .acc-head{display:flex;align-items:center;gap:12px;padding:14px 16px;cursor:pointer;-webkit-user-select:none;-moz-user-select:none;user-select:none}.interactive .acc-title{font-size:16.5px;margin:0;flex:1;letter-spacing:-.01em;font-weight:700;color:var(--ink)}.interactive .chip{display:inline-flex;align-items:center;font-size:12.5px;font-weight:500;color:var(--b700);background:var(--b50);border:1px solid var(--b100);border-radius:999px;padding:3px 11px;white-space:nowrap}.interactive .chev{width:18px;height:18px;stroke:var(--muted);fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;transition:transform .2s;flex:0 0 auto}.interactive .acc.open .chev{transform:rotate(180deg)}.interactive .acc-body{display:none;padding:2px 16px 18px}.interactive .acc.open .acc-body{display:block}.interactive .hint{font-size:13px;color:var(--muted);margin:0 0 14px}.interactive .algo-q{font-weight:700;font-size:16px;color:var(--ink);margin:0 0 13px}.interactive .algo-opts{display:flex;flex-direction:column;gap:9px}.interactive .algo-opts button{text-align:left;padding:12px 14px;border:1px solid var(--b100);background:#fff;border-radius:11px;font-size:14.5px;font-weight:600;color:var(--ink);cursor:pointer;transition:.15s;font-family:inherit}.interactive .algo-opts button:hover{background:var(--b50);border-color:var(--b600);color:var(--b700)}.interactive .algo-path{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 13px}.interactive .algo-path span{font-size:12px;color:var(--muted);background:var(--line);border-radius:999px;padding:2px 9px}.interactive .algo-result{border:1px solid var(--ok-bd);background:var(--ok);border-radius:12px;padding:16px}.interactive .algo-result .r-name{font-weight:800;font-size:17px;color:var(--ok-ink);margin:0 0 4px}.interactive .algo-result .r-level{font-size:13px;font-weight:600;color:var(--b700);margin:0 0 8px}.interactive .algo-result .r-detail{font-size:13.5px;color:var(--ink);line-height:1.5;margin:0 0 12px}.interactive .algo-restart{padding:9px 14px;border:1px solid var(--b100);background:#fff;border-radius:10px;font-size:13.5px;font-weight:600;color:var(--b700);cursor:pointer;font-family:inherit}.interactive .algo-restart:hover{background:var(--b50);border-color:var(--b600)}.interactive .match-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}.interactive .match-grid>div{display:flex;flex-direction:column;gap:9px}.interactive .mbtn{text-align:left;padding:11px 13px;border:1px solid var(--b100);background:#fff;border-radius:10px;font-size:13.5px;font-weight:600;color:var(--ink);cursor:pointer;transition:.15s;font-family:inherit}.interactive .mbtn:hover:not(:disabled){background:var(--b50);border-color:var(--b600);color:var(--b700)}.interactive .mbtn.sel{background:var(--b50);border-color:var(--b600);color:var(--b700)}.interactive .mbtn.done{background:var(--ok);border-color:var(--ok-bd);color:var(--ok-ink);cursor:default}.interactive .mbtn.miss{animation:mshake .3s}@keyframes mshake{0%,to{transform:translate(0)}25%{transform:translate(-4px)}75%{transform:translate(4px)}}.interactive .case{border:1px solid var(--line);border-radius:12px;padding:15px 16px;margin-bottom:11px}.interactive .case-s{font-size:14.5px;color:var(--ink);line-height:1.5;margin:0 0 12px}.interactive .case-opts{display:flex;flex-direction:column;gap:8px}.interactive .case-opts button{text-align:left;padding:10px 13px;border:1px solid var(--b100);background:#fff;border-radius:10px;font-size:14px;font-weight:600;color:var(--ink);cursor:pointer;transition:.15s;font-family:inherit}.interactive .case-opts button:hover:not(:disabled){background:var(--b50);border-color:var(--b600);color:var(--b700)}.interactive .case-opts button:disabled{cursor:default}.interactive .case.answered .pick-correct{background:var(--ok);border-color:var(--ok-bd);color:var(--ok-ink)}.interactive .case.answered .pick-wrong{background:var(--no);border-color:var(--no-bd);color:var(--no-ink)}.interactive .case-exp{margin:12px 0 0;font-size:13px;color:var(--muted);display:none}.interactive .case.answered .case-exp{display:block}.interactive .case-exp b{color:var(--ink)}.prose-article{color:#1f2937;font-size:1.0625rem;line-height:1.75}.prose-article h2{font-size:1.5rem;font-weight:700;color:#111827;margin-top:2.5rem;margin-bottom:1rem;line-height:1.3}.prose-article h3{font-size:1.25rem;font-weight:600;color:#111827;margin-top:1.75rem;margin-bottom:.75rem}.prose-article p{margin-bottom:1.25rem}.prose-article ul,.prose-article ol{margin:1.25rem 0;padding-left:1.5rem}.prose-article ul{list-style:disc}.prose-article ol{list-style:decimal}.prose-article li{margin-bottom:.5rem}.prose-article strong{font-weight:600;color:#111827}.prose-article em{font-style:italic}.prose-article blockquote{border-left:4px solid #f1592a;padding:.5rem 0 .5rem 1.25rem;margin:1.5rem 0;color:#4b5563;font-style:italic;background:#fff7f1;border-radius:0 .5rem .5rem 0}.prose-article hr{border:0;border-top:1px solid #e5e7eb;margin:2.5rem 0}.prose-article table{width:100%;border-collapse:collapse;margin:1.5rem 0;font-size:.95rem}.prose-article th,.prose-article td{border:1px solid #e5e7eb;padding:.625rem .875rem;text-align:left;vertical-align:top}.prose-article th{background:#f9fafb;font-weight:600;color:#111827}.prose-article a{color:#c84d20;text-decoration:underline;text-underline-offset:2px}.prose-article a:hover{color:#a93d18}.prose-article img{border-radius:1rem;margin:1.5rem 0;width:100%;height:auto}.prose-article code{background:#f3f4f6;padding:.125rem .375rem;border-radius:.25rem;font-size:.9em;font-family:ui-monospace,SFMono-Regular,Menlo,monospace}