:root{--bg:#f4f5f7;--ink:#17212c;--muted:#657381;--line:#dbe1e6;--green:#245c70;--lime:#bfe9f2;--paper:#ffffff;--mono:ui-monospace,SFMono-Regular,Consolas,monospace}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}button,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}button:focus-visible,input:focus-visible,select:focus-visible,a:focus-visible{outline:3px solid #3b8caa;outline-offset:3px}aside{position:fixed;inset:0 auto 0 0;width:235px;background:#e9eef2;border-right:1px solid var(--line);padding:35px 23px;display:flex;flex-direction:column}.brand{display:flex;align-items:center;gap:10px;white-space:nowrap;color:var(--ink);text-decoration:none;font-size:14px;letter-spacing:1px;font-weight:800}.brandmark{background:var(--ink);color:var(--lime);font:20px var(--mono);padding:7px;border-radius:7px}.edition{font:9px var(--mono);letter-spacing:2px;margin:15px 0 50px;color:var(--muted)}nav{display:grid;gap:10px}.nav{background:none;border:0;text-align:left;padding:12px;border-radius:6px;color:var(--muted);font-size:14px}.nav.active{background:#d7e6ed;color:#204f62;font-weight:650}.nav span{float:right;font-size:11px}.sidebar-bottom{margin-top:auto}.small-label,.eyebrow{font:10px var(--mono);letter-spacing:1.6px;font-weight:600}.sidebar-bottom p{font-size:22px;line-height:1.4}.version{border-top:1px solid var(--line);padding-top:20px;font:9px var(--mono);color:var(--muted)}main{margin-left:235px;padding:0 54px;max-width:1560px}header{height:86px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);gap:12px}#breadcrumb{font:10px var(--mono);letter-spacing:1px;color:var(--muted)}.quiet{border:0;background:none;color:var(--green);padding:8px;font-size:13px}.intro{padding:58px 0 38px;position:relative}.intro .eyebrow{color:var(--green)}h1{font-size:clamp(36px,4.3vw,64px);line-height:1.06;letter-spacing:-2.4px;font-weight:550;margin:23px 0}h1 span{color:#3b8caa}.intro p{color:var(--muted);font-size:16px;line-height:1.8}.intro-actions{display:flex;align-items:center;gap:23px;margin-top:26px}.primary{background:var(--green);color:white;border:0;border-radius:5px;padding:12px 20px;font-weight:550;font-size:13px}.primary span{margin-left:25px}#progressLabel{font:11px var(--mono);color:var(--muted)}.stats{display:grid;grid-template-columns:repeat(3,1fr);padding:25px 0;border-block:1px solid var(--line);margin-bottom:25px}.stats div{display:flex;align-items:center;gap:14px;padding-right:10px}.stats div+div{border-left:1px solid var(--line);padding-left:25px}.stats strong{font-size:29px;font-weight:450}.stats span{font:9px/1.7 var(--mono);letter-spacing:1px;max-width:125px}.notice{padding:12px 16px;background:#eaf0f4;border:1px solid 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h2{font-size:29px;line-height:1.2;margin:12px 0}.challenge p{font-size:14px}.tags{display:flex;gap:6px;flex-wrap:wrap;margin:18px 0}.tag{font:11px var(--mono);padding:3px 8px;background:#eaf0f4;border-radius:4px}.lab-actions{display:flex;align-items:center;gap:10px;margin:20px 0}.console{background:#15212b;border-radius:6px;padding:15px;color:#d4e9f2;margin:18px 0}.console-header{display:flex;justify-content:space-between;font:9px var(--mono);color:#94b4c5;border-bottom:1px solid #304957;padding-bottom:12px}.console pre{white-space:pre-wrap;overflow-wrap:anywhere;font:12px/1.7 var(--mono);max-height:300px;overflow:auto;min-height:65px}.command-row{display:flex;align-items:center;gap:8px}.command-row span{color:var(--lime);font-family:var(--mono)}.command-row input{min-width:0;background:none;color:#f0f5f8;border:0;border-bottom:1px solid #416375;border-radius:0;font:12px var(--mono);padding:7px;flex:1}.command-row button{background:#2b5266;border:0;color:#d4e9f2;padding:5px 10px;border-radius:3px;font-size:11px}.console-note{font:10px/1.6 var(--mono);color:#94b4c5;margin-top:12px}.answer-row{display:flex;gap:9px}.answer-row input{flex:1;min-width:0}input,select{background:white;border:1px solid var(--line);padding:10px 12px;border-radius:5px;color:var(--ink)}.subheading{font:10px var(--mono);letter-spacing:1px;margin:24px 0 10px}.hint{border-top:1px solid var(--line);padding:11px 0}.hint summary{font-size:12px;cursor:pointer;color:var(--green)}.hint p{font-size:12px;font-family:var(--mono);overflow-wrap:anywhere}.study-links{display:flex;flex-wrap:wrap;gap:10px}.study-links a{font-size:12px;color:var(--green);text-underline-offset:3px}.filters{display:flex;gap:15px;margin:25px 0}.filters input{flex:1;min-width:0}.skill-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:18px}.skill{background:var(--paper);border:1px solid var(--line);padding:20px;border-radius:6px;min-width:0}.skill h3{font:20px var(--mono);margin:8px 0}.skill .eyebrow{color:var(--muted);font-size:9px}.skill p{font-size:13px}.skill pre{font:11px/1.6 var(--mono);padding:10px;background:#edf2f5;white-space:pre-wrap;overflow-wrap:anywhere}.skill details{font-size:12px}.skill details p{font-size:12px}footer{display:flex;justify-content:space-between;gap:20px;border-top:1px solid var(--line);margin-top:50px;padding:23px 0;color:var(--muted);font-size:10px}dialog{border:1px solid var(--line);border-radius:10px;max-width:440px;padding:35px;background:var(--paper);color:var(--ink)}dialog::backdrop{background:#111b28c0}dialog p{font-size:13px;color:var(--muted)}dialog label{display:grid;gap:5px;font-size:12px;margin:16px 0}dialog label[hidden]{display:none}.close{float:right;background:none;border:0;font-size:25px;color:var(--muted)}.error{color:#a1392d!important;min-height:1em}#toast{position:fixed;bottom:24px;right:24px;background:var(--ink);color:white;border-radius:6px;padding:16px 24px;max-width:420px;z-index:10;font-size:13px}[hidden]{display:none!important}@media(min-width:1400px){main{padding-inline:70px}.workspace{grid-template-columns:290px minmax(0,1fr)}}@media(max-width:1000px){aside{width:190px;padding-inline:17px}main{margin-left:190px;padding:0 28px}.workspace{grid-template-columns:190px minmax(0,1fr);gap:15px}.challenge{padding:20px}.stats div{display:block}.stats div+div{padding-left:18px}.stats span{display:block}}@media(max-width:760px){aside{position:static;width:auto;padding:18px 20px;display:block;border-right:0;border-bottom:1px solid var(--line)}.brand{font-size:13px}.edition,.sidebar-bottom{display:none}nav{display:flex;margin-top:15px}.nav{padding:8px 14px}.nav span{margin-left:15px}main{margin-left:0;padding:0 20px}header{height:65px}#breadcrumb{font-size:8px}.intro{padding-top:35px}h1{letter-spacing:-1.7px}.intro-actions{align-items:start;flex-direction:column;gap:14px}.stats{gap:10px}.stats span{font-size:8px}.workspace{display:block}.level-list{display:flex;overflow:auto;max-height:none;padding-bottom:12px;margin-bottom:15px}.level{min-width:180px}.section-heading>.muted{display:none}.skill-grid{grid-template-columns:1fr}.filters{flex-direction:column}.answer-row{flex-wrap:wrap}.answer-row input{width:100%}.console pre{font-size:11px}footer{flex-direction:column;gap:5px}}

.ssh-panel{margin:20px 0;padding:18px;background:#eaf1f5;border:1px solid #cbdce5;border-radius:6px}.ssh-panel pre{font:12px/1.7 var(--mono);white-space:pre-wrap;overflow-wrap:anywhere;background:#dceaf1;padding:12px;border-radius:4px}.ssh-panel p{font-size:12px}.ssh-panel code{font-family:var(--mono);overflow-wrap:anywhere}.ssh-buttons{display:flex;gap:8px;flex-wrap:wrap}.ssh-panel .fingerprint{font-size:10px;color:var(--muted)}

.trail-sidebar{min-width:0}.trail-sidebar select{width:100%;font-size:11px;margin:8px 0 15px}.checkpoint-note{padding:12px;background:#eaf0f4;border-radius:5px}.level .number{min-width:32px;font-size:11px}#checkWork{margin-bottom:15px}@media(max-width:760px){.trail-sidebar select{max-width:100%}}

.case-briefing{padding:17px 18px;background:#f1f5f8;border-left:3px solid #4d8da9;margin:20px 0}.case-briefing p{margin:8px 0 0;color:#455c6c}.objective-label{margin-top:22px;color:#476b7f}.brand{letter-spacing:1.6px}.intro h1{font-weight:600}