:root{color-scheme:light;--bg:#f7f8fa;--panel:#ffffff;--line:#dce2e8;--muted:#526171;--cyan:#245c99;--amber:#925b12}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:#202b38;font:16px/1.6 system-ui,sans-serif}aside{position:fixed;inset:0 auto 0 0;width:252px;padding:35px 24px;border-right:1px solid var(--line);background:#ffffff}.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:inherit;font-size:17px;letter-spacing:1px}.brand small{display:block;font-size:9px;letter-spacing:1.8px;color:var(--muted)}.brand-icon{display:grid;place-items:center;width:43px;height:43px;background:var(--cyan);color:#ffffff;font-weight:900;font-size:24px;border-radius:12px;position:relative}.brand-icon span{position:absolute;right:4px;top:0;font-size:14px}.nav-label{font-size:10px;color:var(--muted);letter-spacing:2px;margin-top:60px}nav a{display:flex;gap:14px;color:#59697a;text-decoration:none;margin:10px 0;padding:13px 10px;border-radius:8px;font-size:12px}nav a span{color:#405164;font-size:14px}nav a.active{background:#eaf1f8;color:var(--cyan)}nav a.active span{color:var(--cyan)}.side-bottom{position:absolute;bottom:35px;font-size:10px;letter-spacing:1px}.side-bottom small{color:var(--muted);letter-spacing:0}.dot{display:inline-block;width:6px;height:6px;background:var(--cyan);border-radius:50%;margin-right:7px}main{margin-left:252px;padding:0 5vw}header{display:flex;justify-content:space-between;align-items:center;padding:25px 0;border-bottom:1px solid var(--line);color:var(--muted);font-size:11px;letter-spacing:1.5px}.pill{border:1px solid var(--line);border-radius:24px;padding:6px 12px;font-size:10px;color:var(--muted)}section{padding-top:55px;min-height:75vh}.eyebrow{font-size:11px;letter-spacing:2px;color:var(--cyan)}h1{font-size:clamp(36px,5vw,70px);line-height:1.12;font-weight:650;letter-spacing:-2px;margin:18px 0 25px}em{color:var(--cyan);font-style:normal}h2{font-size:24px;font-weight:550;letter-spacing:-.6px}h3{font-weight:550}.lead{color:var(--muted);max-width:640px;font-size:17px;line-height:1.8}.button{display:inline-flex;align-items:center;gap:30px;background:var(--cyan);color:#ffffff;text-decoration:none;border:0;padding:14px 21px;border-radius:7px;font-size:14px;font-weight:650;cursor:pointer;margin:14px 12px 14px 0}.text-link{color:var(--cyan);text-decoration:none;font-size:13px}.metrics{display:flex;gap:65px;margin:37px 0 8px;padding-top:28px;border-top:1px solid var(--line)}.metrics b{display:block;font-size:29px;font-weight:500}.metrics span{font-size:11px;color:var(--muted)}.fine{font-size:11px;color:var(--muted)}.section-head{display:flex;align-items:center;justify-content:space-between;margin-top:45px}.fleet{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}.robot-card,.panel{border:1px solid var(--line);background:var(--panel);border-radius:12px;padding:20px}.robot-card h3{margin:18px 0 3px}.robot-card p{font-size:12px;color:var(--muted);margin:7px 0}.robot{height:65px;position:relative;width:68px;margin:10px auto;border:2px solid #9cadbf;border-radius:16px;background:#edf2f7}.robot:before{content:'••';display:block;text-align:center;letter-spacing:13px;padding-left:12px;font-size:28px;color:var(--cyan);line-height:45px}.robot:after{content:'';position:absolute;width:42px;height:5px;background:#aebdcd;bottom:-8px;left:11px;border-radius:5px}.battery{height:4px;background:#e3e9f0;border-radius:5px}.battery span{display:block;height:100%;background:var(--cyan);border-radius:5px}.battery.low span{background:var(--amber)}.lessons{display:grid;gap:12px;margin:32px 0}.lesson-row{padding:19px 22px;display:flex;gap:22px;align-items:center;background:var(--panel);border:1px solid var(--line);border-radius:9px}.lesson-row strong{flex:1;font-weight:500}.lesson-row span{font-size:12px;color:var(--muted)}.lesson-row a{font-size:12px;color:var(--cyan)}.callout{border-left:2px solid var(--amber);background:#f2f5f8;color:#405164;padding:16px;font-size:13px;margin:20px 0}.lab-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:20px}.panel{margin:15px 0}.panel-head{display:flex;justify-content:space-between;font-size:10px;letter-spacing:1.2px;color:var(--muted);border-bottom:1px solid var(--line);padding-bottom:16px}.panel p{font-size:14px;color:#405164}pre{font:15px/1.9 monospace;overflow:auto;tab-size:4}code{font-family:monospace}.purple{color:#6b458c}.cyan{color:#245c99}.green{color:#27633c}label{display:flex;gap:12px;padding:13px;border:1px solid var(--line);border-radius:7px;margin:10px 0;font-size:14px;cursor:pointer}input{accent-color:var(--cyan)}.secondary{background:#eaf1f8;color:var(--cyan)}.text-button{border:0;background:none;color:var(--cyan);cursor:pointer;padding:10px}.trace #trace-state{min-height:100px;padding-top:20px;font-family:monospace}.command{background:#f1f4f7;padding:16px;font-size:12px}summary{cursor:pointer;color:var(--cyan);font-size:14px}footer{display:flex;justify-content:space-between;padding:40px 0;color:var(--muted);font-size:10px;margin-top:30px;border-top:1px solid var(--line)}a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--amber);outline-offset:4px}@media(max-width:1100px){.fleet{grid-template-columns:repeat(3,1fr)}.lab-grid{grid-template-columns:1fr}.metrics{gap:30px}}@media(max-width:700px){aside{position:static;width:auto;padding:18px;border-right:0}.nav-label,.side-bottom{display:none}nav{display:flex;flex-wrap:wrap;margin-top:15px}nav a{margin:0;padding:8px}nav a span{font-size:11px}main{margin:0;padding:0 6vw}section{padding-top:30px}.fleet{grid-template-columns:repeat(2,1fr)}.metrics{gap:18px}.metrics b{font-size:24px}header{letter-spacing:0}.section-head{display:block}footer{display:block}.lesson-row{gap:12px;font-size:13px}h1{letter-spacing:-1px}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}}

textarea{display:block;width:100%;background:#ffffff;color:#202b38;border:1px solid #b4c0cd;border-radius:6px;padding:12px;font:14px/1.6 monospace;resize:vertical}label:has(textarea){display:block}textarea:focus-visible{outline:3px solid var(--amber);outline-offset:3px}

pre{background:#f4f6f8;color:#283746;border:1px solid var(--line);border-radius:7px;padding:16px}a{color:var(--cyan)}button:disabled{opacity:.55;cursor:default}.panel details{padding:14px 0;border-bottom:1px solid var(--line)}.panel details:last-child{border-bottom:0}.robot-card,.panel{box-shadow:0 1px 3px rgb(32 43 56 / 3%)}header{gap:16px;flex-wrap:wrap}.pill a{color:var(--cyan)}

.workspace-toolbar{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:12px 0}.workspace-toolbar label{border:0;margin:0;padding:0;font-size:13px}.workspace-toolbar .button{margin:0;padding:9px 13px;font-size:12px}.workspace-toolbar select,.workspace-toolbar input{padding:10px;background:#fff;border:1px solid #b4c0cd;border-radius:6px;color:#202b38;font:13px system-ui}.workspace #workspace-code{font:14px/1.7 monospace;min-height:360px;tab-size:4;white-space:pre;overflow:auto}.workspace-toolbar #workspace-status{flex:1;min-width:220px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}select:focus-visible{outline:3px solid var(--amber);outline-offset:3px}

.guided-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:24px}.guided-grid>div{min-width:0}.guided-source{overflow:auto;background:#f4f6f8;border:1px solid var(--line);border-radius:8px;padding:16px 16px 16px 48px;font:13px/1.8 monospace;max-height:560px}.guided-source li{padding:2px 8px;white-space:pre;min-width:max-content}.guided-source .trace-current{background:#dceaf8;outline:2px solid #245c99;outline-offset:-2px;font-weight:650}.guided-table-scroll{overflow-x:auto}.guided-memory{width:100%;border-collapse:collapse;font-size:13px}.guided-memory caption{text-align:left;color:var(--muted);padding:8px 0}.guided-memory th,.guided-memory td{padding:9px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line);overflow-wrap:anywhere}.guided-memory th{background:#f4f6f8}.trace-changed{background:#edf5fc}.guided-grid h4{margin:12px 0}.guided-grid pre{white-space:pre-wrap;overflow-wrap:anywhere}@media(max-width:1100px){.guided-grid{grid-template-columns:1fr}}

.simulation-fleet{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:12px}.simulation-robot{padding:14px;border:1px solid var(--line);border-radius:8px;background:#f8fafc}.simulation-robot h4{margin:0 0 6px}.simulation-robot p{font-size:12px}.simulation-robot progress{width:100%;height:14px;accent-color:var(--cyan)}

.roadmap-step{background:var(--panel);border:1px solid var(--line);border-radius:9px;overflow:hidden}.roadmap-summary{padding:19px 22px;cursor:pointer;display:flex;gap:18px;align-items:baseline;flex-wrap:wrap}.roadmap-summary::after{content:'Details +';font-size:12px;color:var(--cyan)}.roadmap-step[open]>.roadmap-summary::after{content:'Details −'}.roadmap-summary strong{flex:1;min-width:160px;font-weight:500}.roadmap-summary>span{font-size:12px;color:var(--muted)}.roadmap-detail{padding:0 22px 20px;border-top:1px solid var(--line)}.roadmap-detail h4{margin-bottom:8px}.roadmap-detail ul{padding-left:22px}.roadmap-detail li{margin:8px 0}.roadmap-summary:focus-visible{outline:3px solid var(--amber);outline-offset:-3px}#lesson-tutor{scroll-margin-top:24px}
#lesson-tutor .tutor-note-label{display:block;border:0;padding:0;cursor:default;font-weight:550}
#lesson-tutor textarea{margin-top:10px;font:inherit;font-weight:400;min-height:120px}
#lesson-tutor .fine{font-size:13px;color:var(--muted)}
.tutor-controls{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:16px 0}
.tutor-controls .button,.tutor-controls .text-button{margin:0;min-height:44px;white-space:normal}
.tutor-controls .text-button{border:1px solid var(--line);border-radius:7px;padding:12px 16px;font:inherit;font-size:14px}
.tutor-status{padding:12px 14px;background:#f2f6fa;border-radius:7px}
.tutor-hints:not([hidden]){display:grid;gap:12px;margin:20px 0}
.tutor-hints article{padding:16px;border:1px solid var(--line);border-left:3px solid var(--cyan);border-radius:7px;overflow-wrap:anywhere}
.tutor-hints h4{margin:0;color:var(--cyan)}.tutor-hints p{margin:8px 0}
@media(max-width:420px){.tutor-controls>*{flex:1 1 100%;justify-content:center}}

/* Learning tools and extension tracks use native semantic controls. */
.skip-link{position:fixed;top:8px;left:8px;transform:translateY(-180%);z-index:1000;background:#fff;color:#174d80;padding:12px 18px;border:2px solid #245f99;border-radius:8px}
.skip-link:focus{transform:none}
:focus-visible{outline:3px solid #174d80;outline-offset:4px}
#advanced-tracks .lesson-row{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px}
#account-tools form{margin:24px 0}#account-tools label{display:block}#account-tools input{display:block;width:min(100%,32rem);margin:12px 0;padding:12px;box-sizing:border-box}
#instructor-analytics table{border-collapse:collapse;width:100%}#instructor-analytics th,#instructor-analytics td{padding:12px;text-align:left;border-bottom:1px solid #b9c4cf;overflow-wrap:anywhere}
.panel pre{max-width:100%;overflow:auto}main,section,.panel{min-width:0}button,a,input,select,summary{touch-action:manipulation}button,summary{min-height:44px}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation:none!important;transition:none!important}}

.journey-feature .section-head{margin-top:0;gap:12px;flex-wrap:wrap}.journey-feature h2{margin:0}.journey-feature .fine{font-size:13px}.journey-feature .pill{white-space:normal}.journey-feature .button{max-width:100%}#robot-simulation{scroll-margin-top:24px}
@media(max-width:700px){.journey-feature .section-head{display:flex}.journey-feature .pill{margin-top:4px}}

.practice-review-link{display:block;margin:10px 0}.topic-review-links{display:flex;flex-wrap:wrap;gap:10px 16px}.topic-review-links a{display:inline-block;padding:8px 0;font-size:14px}.topic-review-detail{margin-top:24px;border-top:1px solid var(--line);padding-top:20px;scroll-margin-top:24px}#practice-tutor{scroll-margin-top:24px}#practice-tutor label{display:block}#practice-tutor select{display:block;max-width:100%;padding:10px;margin-top:8px;font:inherit}#practice-tutor .fine{font-size:13px}