@import url('https://fonts.googleapis.com/css2?family=Archivo:ital,wght@0,200..800;1,200..800&display=swap');
.sidebar-title{max-width:220px;margin:5px 0 30px;color:var(--text);font-size:15px;font-weight:800;line-height:1.4;letter-spacing:1.25px;text-transform:uppercase;text-wrap:balance}
:root{color-scheme:dark;--bg:#0d0e10;--panel:#141517;--raised:#1b1c20;--line:#2b2c31;--red:#ff343b;--text:#f5f3f1;--muted:#aaaab2;--green:#9fe0b7;font-family:'DM Sans',Arial,sans-serif;font-size:16px}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text)}button,input,textarea,select{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer;color:inherit}button:disabled{cursor:default;opacity:.42}button:focus-visible,a:focus-visible,textarea:focus-visible,select:focus-visible{outline:2px solid #ff8589;outline-offset:5px}button{border:0}a{color:inherit}h1,h2,h3,p{margin:0}h1,h2,h3{text-wrap:balance}p{line-height:1.75}button{line-height:1.4}.skip{position:fixed;top:-70px;left:20px;z-index:99;background:var(--red);padding:12px}.skip:focus{top:12px}.sidebar{width:274px;position:fixed;inset:0 auto 0 0;background:#111214;border-right:1px solid var(--line);padding:30px 22px;display:flex;flex-direction:column;z-index:20;overflow-y:auto}.brand{display:flex;align-items:center;gap:10px;font-size:23px;font-weight:700;letter-spacing:-1px}.brand-mark{width:31px;height:31px;display:grid;place-items:center;background:var(--red);border-radius:8px;font-size:15px;letter-spacing:0}.brand small{font-weight:400}.sidebar-sub{font-size:12px;letter-spacing:2.2px;color:var(--muted);margin:14px 0 30px;text-transform:uppercase}.course-label,.eyebrow{font-size:12px;letter-spacing:1.8px;font-weight:650;text-transform:uppercase;color:var(--muted)}.course-label{margin:0 12px 17px}.nav-list{display:grid;gap:5px}.nav-level{display:flex;width:100%;gap:12px;align-items:center;text-align:left;border-radius:9px;background:none;padding:12px 10px;border:1px solid transparent}.nav-level.active{background:#29171a;border-color:#613036}.nav-num{height:30px;width:30px;flex-shrink:0;border:1px solid #44444d;border-radius:50%;display:grid;place-items:center;color:var(--muted);font-size:12px}.active .nav-num{background:var(--red);border-color:var(--red);color:white}.nav-level.done .nav-num{color:var(--green);border-color:#486554}.nav-text{font-size:14px;font-weight:500}.nav-text small{display:block;color:var(--muted);font-size:12px;margin-top:4px;font-weight:400}.lock{margin-left:auto;color:#7d7d86;font-size:12px}.sidebar-bottom{margin-top:auto;padding-top:30px}.progress-title{display:flex;justify-content:space-between;font-size:12px;color:var(--muted);margin-bottom:10px}.progress-track{height:4px;background:#33343b;overflow:hidden;border-radius:5px}.progress-fill{height:100%;background:var(--red);transition:width .4s}.local-note{font-size:12px;color:#92929d;line-height:1.5;margin-top:12px}.shell{margin-left:274px}.topbar{height:82px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding:0 48px;gap:16px}.breadcrumb{font-size:14px;color:var(--muted)}.breadcrumb b{color:var(--text);font-weight:500}.breadcrumb span{padding:0 10px;color:#62626d}.top-actions{display:flex;align-items:center;gap:18px}.quiet-btn,.icon-btn{background:transparent;color:var(--muted);font-size:14px}.quiet-btn:hover{color:white}.icon-btn{padding:9px 12px;border:1px solid var(--line);border-radius:8px}.mobile-menu{display:none}.main{max-width:1220px;padding:42px 48px 34px;margin:auto;min-height:calc(100vh - 82px)}.level-meta{display:flex;gap:12px;align-items:center;margin-bottom:23px}.pill{font-size:12px;letter-spacing:1.3px;text-transform:uppercase;padding:7px 10px;border:1px solid #6d3035;border-radius:5px;color:#ff777c;background:#2b1518}.time{font-size:12px;color:var(--muted)}.lesson-title{font-family:'Barlow Condensed','Arial Narrow',Impact,sans-serif;font-size:clamp(44px,4.8vw,70px);line-height:1.04;font-weight:700;letter-spacing:-.5px;text-transform:uppercase;max-width:780px}.lesson-title em{color:var(--red);font-style:normal}.lead{color:var(--muted);max-width:690px;margin-top:20px;font-size:16px;line-height:1.7}.lesson-tabs{display:flex;margin:32px 0 27px;gap:6px;border-bottom:1px solid var(--line);overflow-x:auto}.lesson-tab{background:none;padding:0 19px 15px;white-space:nowrap;border-bottom:2px solid transparent;color:var(--muted);font-size:14px}.lesson-tab:first-child{padding-left:0}.lesson-tab.active{border-color:var(--red);color:var(--text)}.lesson-tab span{margin-right:7px;font-size:12px;color:#909099}.lesson-grid{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(245px,1fr);gap:25px}.lesson-panel{background:linear-gradient(130deg,#1a1b1f,#151518);border:1px solid var(--line);border-radius:14px;padding:28px 30px;min-width:0}.lesson-panel .eyebrow{color:#ff777c}.lesson-panel h2{font-size:25px;letter-spacing:-.6px;line-height:1.25;margin:15px 0}.lesson-panel .intro{color:#c7c6ce;font-size:16px;line-height:1.7}.concept-label{margin:25px 0 11px;color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:1.4px}.reveal-list{display:grid;gap:10px}.reveal{border:1px solid #3c3c45;border-radius:8px;overflow:hidden;background:#1d1e22}.reveal button{display:flex;align-items:center;justify-content:space-between;gap:12px;width:100%;text-align:left;padding:14px 17px;background:none;font-size:14px}.reveal button .plus{font-size:21px;color:var(--red);line-height:1}.reveal.open{border-color:#774046;background:#281c20}.reveal-body{padding:0 17px 17px;color:#d0ccd0;font-size:15px;line-height:1.65;animation:reveal .25s ease}.aside-card{border-radius:14px;border:1px solid #512c30;padding:26px;position:relative;overflow:hidden;background:radial-gradient(ellipse at 90% 100%,#401519,transparent 70%),#161315;align-self:start}.aside-card .eyebrow{font-size:12px;color:#d8a2a5}.aside-card h3{font-family:'Barlow Condensed',Impact,sans-serif;font-size:30px;text-transform:uppercase;margin:22px 0 18px}.example-label{font-size:12px;color:var(--muted);display:block;margin:15px 0 8px}.example-bad{font-size:16px;color:#a9a3aa;line-height:1.5;text-decoration:line-through;text-decoration-color:#815055}.example-good{padding-left:15px;border-left:2px solid var(--red);font-size:16px;line-height:1.8;color:#f0dfe1}.aside-note{margin-top:24px;font-size:13px;color:#b99da2;line-height:1.65}.source-btn{margin-top:24px;display:flex;align-items:center;gap:8px;background:none;color:var(--muted);font-size:13px;text-decoration:underline;text-underline-offset:4px}.step-footer{display:flex;align-items:center;justify-content:space-between;gap:20px;border-top:1px solid var(--line);padding-top:24px;margin-top:28px}.step-status{color:var(--muted);font-size:13px;line-height:1.5}.footer-buttons{display:flex;gap:12px;align-items:center}.primary{background:var(--red);border:1px solid var(--red);border-radius:7px;padding:13px 22px;color:white;font-size:14px;font-weight:600;transition:background .2s}.primary:hover:not(:disabled){background:#e8252c}.secondary{background:none;border:1px solid #43434b;border-radius:7px;padding:12px 18px;font-size:14px}.primary .arrow{margin-left:20px}.bottom-caption{display:flex;justify-content:space-between;gap:20px;font-size:12px;color:#858590;margin-top:30px}.quiz{max-width:770px}.question{padding:25px 0;border-bottom:1px solid var(--line)}.question h3{font-size:19px;line-height:1.5;margin-bottom:15px}.option{width:100%;display:flex;gap:13px;align-items:center;text-align:left;padding:15px 18px;border:1px solid #3c3c46;border-radius:8px;background:#191a1f;margin:9px 0;font-size:16px;line-height:1.5}.option .letter{flex-shrink:0;border:1px solid #50515c;border-radius:5px;display:grid;place-items:center;width:26px;height:26px;font-size:12px}.option.correct{border-color:#73b88b;background:#17251d}.option.incorrect{border-color:#ee7278;background:#311c20}.feedback{font-size:14px;line-height:1.6;margin-top:14px;color:var(--green)}.feedback.retry{color:#ffafb2}.complete{padding:45px 0;max-width:780px}.complete-icon{font-size:38px;color:var(--green);margin-bottom:22px}.summary-list{padding:0;list-style:none;display:grid;gap:15px;margin:25px 0 30px}.summary-list li{display:flex;gap:12px;line-height:1.7;color:#c6c6cf}.summary-list li:before{content:'✓';color:var(--green)}.practice{margin-top:23px;border-top:1px solid var(--line);padding-top:23px}.practice label{display:block;font-size:14px;margin-bottom:10px}.practice textarea{resize:vertical;width:100%;min-height:135px;background:#101114;border:1px solid #50515b;border-radius:8px;padding:15px;color:white;line-height:1.65;font-size:16px}.practice-tools{display:flex;flex-wrap:wrap;gap:10px;margin-top:12px}.practice-message{font-size:13px;color:var(--muted);line-height:1.6;margin-top:12px}.checklist{display:flex;flex-wrap:wrap;gap:7px;margin:12px 0}.checklist span{font-size:12px;padding:5px 8px;border:1px solid var(--line);border-radius:4px}.map-shade{display:none}dialog{width:min(1080px,94vw);max-height:90vh;background:#141518;color:white;border:1px solid #454550;border-radius:14px;padding:24px}dialog::backdrop{background:#000c;backdrop-filter:blur(5px)}.dialog-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.dialog-head h2{font-size:21px}.source-page{width:100%;display:block;margin-top:10px;border-radius:5px}.source-caption{font-size:13px;color:var(--muted);margin:20px 0 5px}#toast{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);padding:14px 22px;border:1px solid #595964;border-radius:8px;background:#24252c;z-index:99;display:none;max-width:90vw;font-size:14px}.focus .sidebar{display:none}.focus .shell{margin-left:0}.focus .main{max-width:1190px}.focus .lesson-title{font-size:72px}@keyframes reveal{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:translateY(0)}}
@media(min-width:1600px){.main{padding-top:60px}.lesson-panel{padding:35px}.lesson-grid{gap:32px}.lesson-title{font-size:78px}}@media(max-width:1100px){.sidebar{width:236px;padding:25px 14px}.shell{margin-left:236px}.main{padding:30px 28px}.topbar{padding:0 28px}.lesson-grid{grid-template-columns:1fr}.aside-card{display:grid;grid-template-columns:1fr 1fr;gap:5px 25px}.aside-card h3{margin:8px 0}.aside-card .eyebrow,.aside-note{grid-column:1/-1}.lesson-panel{padding:25px}.nav-text{font-size:13px}}@media(max-width:760px){.sidebar{transform:translateX(-100%);transition:transform .2s;width:274px}.nav-open .sidebar{transform:translateX(0)}.nav-open .map-shade{display:block;position:fixed;inset:0;background:#0009;z-index:19}.shell{margin-left:0}.topbar{height:68px;padding:0 18px;gap:10px}.mobile-menu{display:inline-block}.top-actions{gap:10px}.breadcrumb{font-size:12px}.breadcrumb span,.breadcrumb b{display:none}.quiet-btn{font-size:12px}.main{padding:28px 20px}.lesson-title,.focus .lesson-title{font-size:49px}.lead{font-size:16px}.lesson-tabs{margin-top:25px}.lesson-tab{font-size:13px;padding-right:13px;padding-left:10px}.lesson-panel{padding:23px 20px}.lesson-panel h2{font-size:24px}.aside-card{display:block;padding:23px}.aside-card h3{margin:17px 0}.step-footer{align-items:stretch;flex-direction:column;gap:15px}.footer-buttons{justify-content:space-between}.footer-buttons .primary{flex:1}.bottom-caption{flex-direction:column;gap:8px}.level-meta{flex-wrap:wrap}.complete{padding-top:20px}.option{font-size:15px}.top-actions .source-top{display:none}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
.checkpoint{margin-top:25px;padding-top:22px;border-top:1px solid #474047}.checkpoint h3{font-size:18px;line-height:1.5;margin:10px 0 15px}.checkpoint .eyebrow{color:#ff8589}.checkpoint .option{font-size:14px;padding:12px 14px}.checkpoint-locked{margin-top:22px;border:1px dashed #53535d;padding:15px;border-radius:7px;font-size:13px;line-height:1.65;color:#b2b2bd}.checkpoint .feedback{font-size:14px}.reveal button:disabled{opacity:.55}.nav-guidance{font-size:12px;line-height:1.6;color:#9999a4;margin:16px 10px 0}
/* Learning feedback: tiny celebrations and clear, gentle error states. */
.topic-icon{display:inline-block;width:1.6em;text-align:center;margin-right:5px;font-size:1.05em;vertical-align:middle;line-height:1.4}.nav-text>.topic-icon{width:1.3em;margin-right:4px;font-size:15px}.concept-with-icon{display:flex;align-items:center;gap:8px}.concept-with-icon .topic-icon{margin:0;flex-shrink:0}.option.answer-celebrate{opacity:1;animation:answer-glow 850ms ease-out}.option.answer-retry{animation:answer-shake 440ms ease-in-out}.celebration-layer{position:fixed;inset:0;overflow:hidden;pointer-events:none;z-index:95}.confetti-piece{position:absolute;width:7px;height:12px;border-radius:2px;will-change:transform,opacity;animation:confetti-fly var(--duration,850ms) cubic-bezier(.16,.64,.38,1) both}.confetti-piece:nth-child(3n){border-radius:50%;width:7px;height:7px}.learning-popup{position:fixed;z-index:100;pointer-events:none;color:#fff;box-shadow:0 16px 60px #0008;animation:popup-enter 180ms ease-out;max-width:calc(100vw - 36px);text-align:center}.retry-popup{bottom:34px;left:50%;transform:translateX(-50%);display:flex;align-items:center;gap:10px;padding:15px 23px;background:#30191d;border:1px solid #bf5259;border-radius:12px;white-space:nowrap;font-size:16px}.retry-popup .popup-icon{color:#ff959c;font-size:23px}.level-celebration{left:50%;top:38%;transform:translate(-50%,-50%);width:390px;padding:27px 30px;background:radial-gradient(ellipse at top,#522029,#19171c 75%);border:1px solid #dc555e;border-radius:18px}.level-celebration .popup-icon{display:block;font-size:43px;margin-bottom:10px}.level-celebration strong{font-family:'Barlow Condensed',Impact,sans-serif;font-size:38px;letter-spacing:.8px}.level-celebration p{font-size:15px;line-height:1.6;color:#e1ccd0;margin-top:8px}.complete-icon{display:flex;align-items:center;gap:12px}.complete-icon .topic-icon{font-size:39px;width:auto}
@keyframes answer-glow{0%{box-shadow:0 0 0 1px #ade9b9,0 0 28px #75e89c77;background:#28533a}100%{box-shadow:0 0 0 0 transparent,0 0 0 transparent;background:#17251d}}
@keyframes answer-shake{0%,100%{transform:translateX(0)}15%,45%,75%{transform:translateX(-4px);box-shadow:0 0 20px #ff343b80;background:#632831;border-color:#ff7880}30%,60%,90%{transform:translateX(4px);box-shadow:0 0 14px #ff343b66;background:#4e2028;border-color:#ff7880}}
@keyframes confetti-fly{0%{transform:translate(0,0) rotate(0deg) scale(.6);opacity:1}65%{opacity:1}100%{transform:translate(var(--dx),var(--dy)) rotate(var(--spin)) scale(.85);opacity:0}}
@keyframes popup-enter{from{opacity:0;filter:blur(2px)}to{opacity:1;filter:blur(0)}}
@media(prefers-reduced-motion:reduce){.option.answer-celebrate,.option.answer-retry,.confetti-piece,.learning-popup{animation:none!important}.option.answer-celebrate{box-shadow:0 0 0 2px #a8efc0}.option.answer-retry{box-shadow:0 0 0 2px #ff7880}.confetti-piece{opacity:.75;will-change:auto}}

/* Paint the complete embedded document, including short lesson screens. */
html{min-height:100%;background:#0d0e10}body,#app{min-height:100vh;background:#0d0e10}