:root{
  --bg:#f5f5f7;--surface:rgba(255,255,255,.82);--surface-solid:#fff;--surface-2:#f2f2f5;--text:#1d1d1f;--muted:#6e6e73;--faint:#9a9aa0;--line:rgba(0,0,0,.08);--line-strong:rgba(0,0,0,.13);--accent:#0071e3;--accent-2:#2997ff;--green:#2da44e;--orange:#ff9f0a;--red:#ff3b30;--purple:#7d5cff;--code:#101114;--code-text:#f5f5f7;--shadow:0 18px 50px rgba(0,0,0,.08);--shadow-soft:0 8px 30px rgba(0,0,0,.06);--radius:24px;--radius-sm:16px;--blur:24px;font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","Helvetica Neue",Arial,sans-serif;color-scheme:light;
}
html[data-theme="dark"]{--bg:#000;--surface:rgba(28,28,30,.82);--surface-solid:#1c1c1e;--surface-2:#242426;--text:#f5f5f7;--muted:#a1a1a6;--faint:#737378;--line:rgba(255,255,255,.1);--line-strong:rgba(255,255,255,.16);--accent:#0a84ff;--accent-2:#64b5ff;--green:#32d74b;--orange:#ff9f0a;--red:#ff453a;--purple:#bf5af2;--shadow:0 20px 60px rgba(0,0,0,.36);--shadow-soft:0 8px 30px rgba(0,0,0,.2);color-scheme:dark}
@media (prefers-color-scheme:dark){html[data-theme="system"]{--bg:#000;--surface:rgba(28,28,30,.82);--surface-solid:#1c1c1e;--surface-2:#242426;--text:#f5f5f7;--muted:#a1a1a6;--faint:#737378;--line:rgba(255,255,255,.1);--line-strong:rgba(255,255,255,.16);--accent:#0a84ff;--accent-2:#64b5ff;--green:#32d74b;--orange:#ff9f0a;--red:#ff453a;--purple:#bf5af2;--shadow:0 20px 60px rgba(0,0,0,.36);--shadow-soft:0 8px 30px rgba(0,0,0,.2);color-scheme:dark}}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);min-height:100vh;-webkit-font-smoothing:antialiased}button,input,textarea{font:inherit}button{color:inherit}.hidden{display:none!important}.topbar{height:64px;position:sticky;top:0;z-index:100;display:flex;align-items:center;padding:0 max(22px,env(safe-area-inset-left));border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--bg) 72%,transparent);backdrop-filter:saturate(180%) blur(var(--blur));-webkit-backdrop-filter:saturate(180%) blur(var(--blur))}.brand{border:0;background:none;display:flex;align-items:center;gap:10px;padding:0;cursor:pointer}.brand-icon,.app-icon{display:grid;place-items:center;background:linear-gradient(145deg,#58a9ff,#0066d6);color:#fff;font-weight:800;box-shadow:inset 0 1px rgba(255,255,255,.35),0 8px 24px rgba(0,113,227,.2)}.brand-icon{width:35px;height:35px;border-radius:10px;font-size:18px}.brand-text{text-align:left}.brand-text strong{display:block;font-size:13px;line-height:1.05}.brand-text small{display:block;color:var(--muted);font-size:10px;margin-top:3px}.desktop-nav{height:100%;display:flex;align-items:center;gap:3px;margin-left:48px}.nav-item{height:100%;padding:0 14px;border:0;background:none;color:var(--muted);font-size:13px;cursor:pointer;position:relative}.nav-item.active,.nav-item:hover{color:var(--text)}.nav-item.active:after{content:"";position:absolute;bottom:-1px;left:14px;right:14px;height:2px;background:var(--accent);border-radius:2px}.top-actions{margin-left:auto;display:flex;gap:8px;align-items:center;position:relative}.sync-pill{display:flex;align-items:center;gap:7px;font-size:11px;color:var(--muted);padding:7px 10px;border:1px solid var(--line);border-radius:999px;background:var(--surface)}.sync-pill i{width:6px;height:6px;border-radius:50%;background:var(--green)}.sync-pill.saving i{background:var(--orange)}.sync-pill.error i{background:var(--red)}.icon-button,.avatar-button{width:34px;height:34px;border:1px solid var(--line);border-radius:50%;background:var(--surface);display:grid;place-items:center;cursor:pointer}.avatar-button{background:linear-gradient(145deg,#4f4f54,#222225);color:white;font-size:12px;font-weight:700}.account-menu{position:absolute;right:0;top:43px;width:190px;padding:7px;background:var(--surface-solid);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);z-index:110}.account-menu button,.account-menu label{width:100%;display:block;border:0;background:none;padding:9px 10px;border-radius:9px;text-align:left;font-size:12px;cursor:pointer}.account-menu button:hover,.account-menu label:hover{background:var(--surface-2)}.danger-text{color:var(--red)!important}.mobile-nav{display:none}.shell{width:min(1180px,calc(100% - 40px));margin:0 auto;padding:34px 0 78px}.eyebrow{font-size:10px;letter-spacing:.15em;font-weight:750;color:var(--accent);margin:0 0 10px;text-transform:uppercase}.hero{display:grid;grid-template-columns:1.6fr .7fr;gap:18px;align-items:stretch}.hero-main,.hero-progress,.card{background:var(--surface);border:1px solid var(--line);box-shadow:var(--shadow-soft);border-radius:var(--radius)}.hero-main{padding:46px 48px;min-height:320px;position:relative;overflow:hidden}.hero-main:after{content:"";position:absolute;width:420px;height:420px;border-radius:50%;right:-240px;top:-260px;background:radial-gradient(circle,rgba(0,113,227,.16),transparent 66%)}.hero-main h1{font-size:clamp(44px,6vw,72px);line-height:.98;letter-spacing:-.055em;margin:0;max-width:780px;font-weight:750}.hero-main h1 .accent{color:var(--accent)}.hero-main p.lead{font-size:17px;line-height:1.55;color:var(--muted);max-width:720px;margin:20px 0 28px}.button-row{display:flex;gap:10px;flex-wrap:wrap}.primary-button,.secondary-button,.ghost-button{border-radius:999px;padding:11px 17px;border:1px solid transparent;font-weight:650;font-size:13px;cursor:pointer}.primary-button{background:var(--accent);color:#fff}.primary-button:hover{background:var(--accent-2)}.primary-button:disabled{opacity:.45;cursor:not-allowed}.secondary-button{background:var(--surface-2);border-color:var(--line);color:var(--text)}.ghost-button{background:none;border-color:var(--line);color:var(--muted)}.hero-progress{padding:34px;display:flex;flex-direction:column;justify-content:space-between}.progress-ring{width:138px;height:138px;border-radius:50%;display:grid;place-items:center;margin:2px auto 18px;background:conic-gradient(var(--accent) var(--angle,0deg),var(--surface-2) 0)}.progress-ring:before{content:"";width:112px;height:112px;border-radius:50%;background:var(--surface-solid);position:absolute}.progress-ring div{position:relative;text-align:center}.progress-ring strong{display:block;font-size:31px;letter-spacing:-.045em}.progress-ring span{font-size:10px;color:var(--muted)}.hero-progress .next-label{font-size:11px;color:var(--muted)}.hero-progress h3{font-size:17px;margin:5px 0 4px}.hero-progress p{font-size:12px;color:var(--muted);margin:0}.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:14px 0}.stat{padding:20px 21px}.stat small{display:block;color:var(--muted);font-size:11px}.stat strong{display:block;font-size:26px;letter-spacing:-.04em;margin:7px 0 2px}.stat span{font-size:11px;color:var(--faint)}.grid-2{display:grid;grid-template-columns:1.2fr .8fr;gap:14px}.section-card{padding:26px}.section-head{display:flex;justify-content:space-between;align-items:flex-start;gap:16px;margin-bottom:18px}.section-head h2{margin:0;font-size:22px;letter-spacing:-.025em}.section-head p{margin:5px 0 0;color:var(--muted);font-size:13px}.link-button{border:0;background:none;color:var(--accent);cursor:pointer;font-size:12px}.next-card{display:flex;flex-direction:column;min-height:250px}.topic-chips{display:flex;flex-wrap:wrap;gap:7px;margin:14px 0}.chip{padding:6px 9px;background:var(--surface-2);border-radius:999px;font-size:10px;color:var(--muted);border:1px solid var(--line)}.next-card .primary-button{margin-top:auto;align-self:flex-start}.rhythm{display:grid;gap:1px;border:1px solid var(--line);border-radius:15px;overflow:hidden;background:var(--line)}.rhythm div{background:var(--surface-solid);padding:13px 15px;display:flex;align-items:center;justify-content:space-between;font-size:12px}.rhythm b{color:var(--accent);font-size:11px}.phase-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.phase-mini{padding:17px;border-radius:16px;background:var(--surface-2);border:1px solid var(--line);cursor:pointer}.phase-mini span{font-size:10px;color:var(--muted)}.phase-mini strong{display:block;margin:6px 0 4px;font-size:14px}.phase-mini small{font-size:10px;color:var(--faint)}
.page-head{padding:12px 0 30px}.page-head h1{font-size:clamp(38px,5vw,58px);letter-spacing:-.05em;line-height:1.02;margin:0}.page-head p{font-size:16px;color:var(--muted);max-width:700px;line-height:1.6;margin:14px 0 0}.roadmap{display:grid;gap:14px}.phase-block{padding:25px}.phase-title{display:grid;grid-template-columns:52px 1fr auto;gap:16px;align-items:center;margin-bottom:17px}.phase-num{width:48px;height:48px;border-radius:14px;background:var(--surface-2);display:grid;place-items:center;font-size:15px;font-weight:700;color:var(--accent)}.phase-title h2{margin:0;font-size:20px}.phase-title p{margin:3px 0 0;color:var(--muted);font-size:12px}.phase-title>span{font-size:11px;color:var(--muted)}.days-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}.day-tile{border:1px solid var(--line);background:var(--surface-solid);border-radius:13px;padding:13px;text-align:left;cursor:pointer;display:flex;gap:10px;min-height:70px}.day-tile:hover{border-color:var(--line-strong);transform:translateY(-1px)}.day-tile.done{background:color-mix(in srgb,var(--green) 8%,var(--surface-solid));border-color:color-mix(in srgb,var(--green) 24%,var(--line))}.day-badge{flex:0 0 28px;height:28px;border-radius:50%;display:grid;place-items:center;background:var(--surface-2);font-size:10px;font-weight:700}.day-tile.done .day-badge{background:var(--green);color:#fff}.day-tile strong{font-size:12px;display:block}.day-tile small{font-size:10px;color:var(--muted);display:block;margin-top:4px}
.course-layout{display:grid;grid-template-columns:300px minmax(0,1fr);min-height:calc(100vh - 64px)}.lesson-sidebar{border-right:1px solid var(--line);background:var(--surface);position:sticky;top:64px;height:calc(100vh - 64px);overflow:auto;padding:20px 14px}.search-box{position:sticky;top:0;background:var(--surface);padding:0 0 14px;z-index:2}.search-box input{width:100%;border:1px solid var(--line);border-radius:12px;background:var(--surface-2);padding:10px 12px;color:var(--text);outline:none;font-size:12px}.lesson-group{margin:6px 0 18px}.lesson-group h4{font-size:10px;letter-spacing:.1em;color:var(--faint);text-transform:uppercase;margin:0 8px 7px}.lesson-link{width:100%;border:0;background:none;border-radius:11px;padding:9px 9px;text-align:left;display:flex;gap:9px;align-items:flex-start;cursor:pointer}.lesson-link:hover{background:var(--surface-2)}.lesson-link.active{background:color-mix(in srgb,var(--accent) 10%,var(--surface-2));color:var(--accent)}.lesson-link .lesson-dot{width:22px;height:22px;border-radius:50%;flex:0 0 22px;background:var(--surface-2);display:grid;place-items:center;font-size:9px;color:var(--muted);border:1px solid var(--line)}.lesson-link.done .lesson-dot{background:var(--green);color:#fff;border-color:transparent}.lesson-link strong{display:block;font-size:11px;line-height:1.3}.lesson-link small{display:block;color:var(--muted);font-size:9px;margin-top:3px}.lesson-workspace{min-width:0;padding:0 28px 80px}.lesson-top{max-width:920px;margin:0 auto;height:70px;display:flex;align-items:center;justify-content:space-between;gap:15px;border-bottom:1px solid var(--line)}.lesson-top .crumb{font-size:11px;color:var(--muted)}.lesson-top-actions{display:flex;align-items:center;gap:7px}.tiny-button{width:34px;height:34px;border-radius:50%;border:1px solid var(--line);background:var(--surface);cursor:pointer}.lesson-content{max-width:920px;margin:0 auto;padding-top:44px}.lesson-content h1{font-size:clamp(36px,5vw,54px);letter-spacing:-.05em;line-height:1.02;margin:0 0 15px}.lesson-summary{font-size:17px;line-height:1.65;color:var(--muted);max-width:790px;margin:0 0 28px}.lesson-meta{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:34px}.meta-pill{font-size:10px;border:1px solid var(--line);border-radius:999px;padding:6px 9px;color:var(--muted)}.lesson-section{margin:0 0 34px}.lesson-section h2{font-size:20px;letter-spacing:-.02em;margin:0 0 12px}.lesson-section p{font-size:14px;line-height:1.75;color:var(--muted);margin:0}.concept-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:8px;margin-top:15px}.concept{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:13px;font-size:12px}.code-block{background:var(--code);color:var(--code-text);border-radius:18px;padding:18px 20px;overflow:auto;font:12px/1.65 ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;white-space:pre;box-shadow:inset 0 1px rgba(255,255,255,.06)}.drill-list{display:grid;gap:8px;padding:0;list-style:none}.drill-list li{background:var(--surface);border:1px solid var(--line);border-radius:13px;padding:13px 15px;font-size:12px;color:var(--muted)}.drill-list li:before{content:"✓";color:var(--green);font-weight:700;margin-right:9px}.minecraft-card{border-radius:20px;padding:22px;background:linear-gradient(145deg,color-mix(in srgb,var(--green) 10%,var(--surface)),var(--surface));border:1px solid color-mix(in srgb,var(--green) 25%,var(--line));margin:32px 0}.minecraft-card.real{background:linear-gradient(145deg,color-mix(in srgb,var(--green) 13%,var(--surface)),color-mix(in srgb,var(--accent) 6%,var(--surface)))}.minecraft-card .mc-label{font-size:10px;font-weight:750;letter-spacing:.12em;color:var(--green);text-transform:uppercase}.minecraft-card h3{margin:7px 0 8px;font-size:18px}.minecraft-card p{font-size:13px;color:var(--muted);line-height:1.65;margin:0}.minecraft-card .code-block{margin-top:15px}.challenge-card{border:1px solid var(--line);border-radius:24px;overflow:hidden;background:var(--surface);box-shadow:var(--shadow-soft);margin:40px 0}.challenge-head{padding:22px 24px;border-bottom:1px solid var(--line)}.challenge-head .eyebrow{margin-bottom:7px}.challenge-head h2{font-size:21px;margin:0 0 8px}.challenge-head p{font-size:13px;color:var(--muted);line-height:1.6;margin:0}.editor-shell{background:var(--code);border-bottom:1px solid rgba(255,255,255,.08)}.editor-bar{height:42px;display:flex;align-items:center;padding:0 14px;border-bottom:1px solid rgba(255,255,255,.08);color:#8e8e93;font-size:10px}.editor-dots{display:flex;gap:6px;margin-right:12px}.editor-dots i{width:8px;height:8px;border-radius:50%;background:#3a3a3c}.editor{display:flex;min-height:340px;max-height:600px}.line-numbers{width:46px;padding:16px 10px 16px 0;text-align:right;color:#55565c;background:#0b0c0e;font:12px/1.65 ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;white-space:pre;user-select:none;overflow:hidden}.code-input{flex:1;resize:vertical;min-height:340px;padding:16px;border:0;outline:none;background:transparent;color:#f5f5f7;caret-color:#fff;font:12px/1.65 ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;tab-size:4;white-space:pre}.runner-bar{padding:12px 14px;display:flex;align-items:center;gap:8px;background:#151619}.runner-bar .run-button{background:#f5f5f7;color:#111;border:0;border-radius:9px;padding:8px 12px;font-size:11px;font-weight:700;cursor:pointer}.runner-bar .reset-code{border:1px solid rgba(255,255,255,.12);color:#aaa;background:none;border-radius:9px;padding:7px 10px;font-size:10px;cursor:pointer}.runner-bar .shortcut{margin-left:auto;font-size:9px;color:#666}.terminal{min-height:90px;max-height:220px;overflow:auto;background:#070708;color:#d7d7dc;padding:14px 16px;font:11px/1.6 ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;white-space:pre-wrap}.terminal.success{color:#8ce99a}.terminal.error{color:#ff8d87}.challenge-foot{display:flex;align-items:center;gap:8px;padding:14px 18px}.status-badge{font-size:10px;border-radius:999px;padding:6px 9px;background:var(--surface-2);color:var(--muted)}.status-badge.pass{background:color-mix(in srgb,var(--green) 12%,var(--surface));color:var(--green)}.hint-button{margin-left:auto;border:0;background:none;color:var(--accent);font-size:11px;cursor:pointer}.hints{padding:0 18px 16px;display:grid;gap:7px}.hint{padding:10px 12px;border-radius:11px;background:var(--surface-2);font-size:11px;color:var(--muted)}.quiz-card,.notes-card,.complete-card{padding:24px;margin:28px 0}.quiz-options{display:grid;gap:8px;margin:15px 0}.quiz-option{border:1px solid var(--line);background:var(--surface-solid);border-radius:12px;padding:12px 13px;text-align:left;font-size:12px;cursor:pointer}.quiz-option.selected{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 8%,var(--surface-solid))}.quiz-option.correct{border-color:var(--green);background:color-mix(in srgb,var(--green) 9%,var(--surface-solid))}.quiz-option.wrong{border-color:var(--red);background:color-mix(in srgb,var(--red) 8%,var(--surface-solid))}.quiz-feedback{font-size:11px;color:var(--muted);min-height:18px}.notes-card textarea{width:100%;min-height:120px;border:1px solid var(--line);border-radius:13px;background:var(--surface-2);color:var(--text);padding:13px;resize:vertical;outline:none;font-size:12px;line-height:1.6}.complete-card{display:flex;align-items:center;justify-content:space-between;gap:20px}.complete-card h3{margin:0 0 5px;font-size:17px}.complete-card p{margin:0;font-size:11px;color:var(--muted)}.complete-card.done{border-color:color-mix(in srgb,var(--green) 30%,var(--line));background:color-mix(in srgb,var(--green) 6%,var(--surface))}.reference-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.reference-card{padding:20px}.reference-card h3{margin:0 0 12px;font-size:15px}.reference-card .code-block{font-size:11px}.resource-list{display:grid;grid-template-columns:repeat(2,1fr);gap:8px;margin-top:20px}.resource-link{display:block;text-decoration:none;color:var(--text);background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:14px;font-size:12px}.resource-link:hover{border-color:var(--accent);color:var(--accent)}.auth-shell{min-height:100vh;display:grid;place-items:center;padding:28px;background:radial-gradient(circle at 50% -20%,rgba(0,113,227,.12),transparent 40%),var(--bg)}.auth-card{width:min(520px,100%);background:var(--surface);border:1px solid var(--line);border-radius:30px;box-shadow:var(--shadow);padding:44px}.app-icon{width:54px;height:54px;border-radius:15px;font-size:27px;margin-bottom:24px}.auth-card h1{font-size:38px;letter-spacing:-.045em;margin:0}.auth-copy{font-size:14px;color:var(--muted);line-height:1.65;margin:14px 0 27px}.auth-form label{display:block;font-size:11px;color:var(--muted);margin:0 0 7px}.password-row{display:flex;gap:8px}.password-row input{min-width:0;flex:1;border:1px solid var(--line-strong);border-radius:12px;padding:11px 13px;background:var(--surface-solid);color:var(--text);outline:none}.password-row input:focus{border-color:var(--accent);box-shadow:0 0 0 3px color-mix(in srgb,var(--accent) 15%,transparent)}.form-error{font-size:11px;color:var(--red);min-height:16px}.auth-foot{font-size:10px;color:var(--faint);line-height:1.5;margin:18px 0 0}.toast{position:fixed;left:50%;bottom:28px;z-index:300;transform:translate(-50%,20px);opacity:0;pointer-events:none;background:rgba(30,30,32,.94);color:white;padding:10px 14px;border-radius:999px;font-size:11px;box-shadow:var(--shadow);transition:.2s}.toast.show{opacity:1;transform:translate(-50%,0)}
@media(max-width:900px){.desktop-nav{display:none}.shell{width:min(100% - 26px,1180px);padding-top:20px}.hero{grid-template-columns:1fr}.hero-main{padding:34px 28px;min-height:auto}.hero-progress{display:grid;grid-template-columns:150px 1fr;align-items:center}.stats{grid-template-columns:repeat(2,1fr)}.grid-2{grid-template-columns:1fr}.phase-strip{grid-template-columns:repeat(2,1fr)}.days-grid{grid-template-columns:repeat(2,1fr)}.course-layout{grid-template-columns:1fr}.lesson-sidebar{display:none}.lesson-workspace{padding:0 18px 90px}.reference-grid{grid-template-columns:1fr}.resource-list{grid-template-columns:1fr}.mobile-nav{position:fixed;bottom:0;left:0;right:0;height:66px;padding-bottom:env(safe-area-inset-bottom);z-index:100;background:color-mix(in srgb,var(--bg) 80%,transparent);backdrop-filter:blur(22px);border-top:1px solid var(--line);display:flex;justify-content:space-around}.mobile-nav button{flex:1;border:0;background:none;color:var(--muted);font-size:9px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px}.mobile-nav button span{font-size:17px}.mobile-nav button.active{color:var(--accent)}}
@media(max-width:620px){.topbar{height:58px}.brand-text small{display:none}.sync-pill{display:none}.brand-text strong{font-size:12px}.hero-main h1{font-size:42px}.hero-main{padding:29px 23px}.hero-main p.lead{font-size:14px}.hero-progress{grid-template-columns:120px 1fr;padding:22px}.progress-ring{width:112px;height:112px}.progress-ring:before{width:90px;height:90px}.progress-ring strong{font-size:25px}.stats{gap:8px}.stat{padding:16px}.stat strong{font-size:22px}.phase-strip{grid-template-columns:1fr 1fr}.days-grid{grid-template-columns:1fr}.phase-title{grid-template-columns:45px 1fr}.phase-title>span{display:none}.lesson-workspace{padding:0 14px 86px}.lesson-top{height:58px}.lesson-content{padding-top:30px}.lesson-content h1{font-size:38px}.concept-grid{grid-template-columns:1fr}.editor{min-height:300px}.code-input{min-height:300px;font-size:11px}.line-numbers{font-size:11px;width:39px}.runner-bar .shortcut{display:none}.complete-card{align-items:flex-start;flex-direction:column}.reference-grid{grid-template-columns:1fr}.auth-card{padding:30px 24px}.password-row{flex-direction:column}.password-row .primary-button{width:100%}}

/* ---- v2: logo, icons, lesson prose, IDE ---- */
:root{--ide-bg:#fff;--ide-chrome:#f7f8fa;--ide-line:#ebecf0;--ide-text:#080808;--ide-muted:#6c707e;--tok-text:#080808;--tok-bg:#fff;--tok-keyword:#0033b3;--tok-string:#067d17;--tok-number:#1750eb;--tok-comment:#8c8c8c;--tok-call:#00627a;--tok-def:#080808;--tok-type:#080808;--tok-field:#871094;--tok-annotation:#9e880d;--tok-gutter:#aeb3c2;--tok-gutter-active:#5a5d6b;--tok-active-line:#f5f8fe;--tok-selection:#a6d2ff;--tok-bracket:#93d9d9;--tok-match:#e2e6f5;--tok-caret:#000;--tok-popup:#fff;--tok-popup-border:#dfe1e5;--tok-error:#e0393e}
html[data-theme="dark"]{--ide-bg:#1e1f22;--ide-chrome:#2b2d30;--ide-line:#393b40;--ide-text:#bcbec4;--ide-muted:#868a91;--tok-text:#bcbec4;--tok-bg:#1e1f22;--tok-keyword:#cf8e6d;--tok-string:#6aab73;--tok-number:#2aacb8;--tok-comment:#7a7e85;--tok-call:#56a8f5;--tok-def:#bcbec4;--tok-type:#bcbec4;--tok-field:#c77dbb;--tok-annotation:#b3ae60;--tok-gutter:#4b5059;--tok-gutter-active:#a1a3ab;--tok-active-line:#26282e;--tok-selection:#214283;--tok-bracket:#43454a;--tok-match:#373b39;--tok-caret:#ced0d6;--tok-popup:#2b2d30;--tok-popup-border:#43454a;--tok-error:#f75464}
@media (prefers-color-scheme:dark){html[data-theme="system"]{--ide-bg:#1e1f22;--ide-chrome:#2b2d30;--ide-line:#393b40;--ide-text:#bcbec4;--ide-muted:#868a91;--tok-text:#bcbec4;--tok-bg:#1e1f22;--tok-keyword:#cf8e6d;--tok-string:#6aab73;--tok-number:#2aacb8;--tok-comment:#7a7e85;--tok-call:#56a8f5;--tok-def:#bcbec4;--tok-type:#bcbec4;--tok-field:#c77dbb;--tok-annotation:#b3ae60;--tok-gutter:#4b5059;--tok-gutter-active:#a1a3ab;--tok-active-line:#26282e;--tok-selection:#214283;--tok-bracket:#43454a;--tok-match:#373b39;--tok-caret:#ced0d6;--tok-popup:#2b2d30;--tok-popup-border:#43454a;--tok-error:#f75464}}
:root{--mono:"JetBrains Mono",ui-monospace,"Cascadia Code",SFMono-Regular,Consolas,Menlo,monospace}
img.brand-icon,img.app-icon{background:none;box-shadow:0 6px 18px rgba(0,96,208,.22);display:block}
img.brand-icon{width:35px;height:35px;border-radius:9px}
img.app-icon{width:64px;height:64px;border-radius:16px;margin-bottom:24px}
.icon-button svg{width:17px;height:17px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;display:none}
.icon-button[data-mode="system"] .ti-system,.icon-button[data-mode="light"] .ti-light,.icon-button[data-mode="dark"] .ti-dark{display:block}
.mobile-nav button svg{width:21px;height:21px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.mobile-nav button{font-size:10px}

/* lesson reading */
.lesson-content{max-width:860px}
.lesson-summary{font-size:18px!important;line-height:1.55!important}
.lesson-section{margin:0 0 40px;scroll-margin-top:84px}
.lesson-section h2{display:flex;align-items:center;gap:11px;font-size:22px}
.sec-num{flex:none;width:28px;height:28px;border-radius:9px;display:grid;place-items:center;font-size:13px;font-weight:700;background:color-mix(in srgb,var(--accent) 13%,transparent);color:var(--accent)}
.sec-num.warn{background:color-mix(in srgb,var(--orange) 16%,transparent);color:var(--orange)}
.prose{font-size:16px;line-height:1.72;color:var(--text)}
.prose p{margin:0 0 14px;font-size:16px!important;line-height:1.72!important;color:var(--text)!important}
.prose ul{margin:0 0 14px;padding-left:22px}.prose li{margin:6px 0}
.prose :not(pre)>code,.goals-card code,.key-idea code,.recap-card code,.drill-list code,.hint code,.quiz-question code,.quiz-option code,.quiz-feedback code,.mistake p code,.t-err code{font-family:var(--mono);font-size:.88em;padding:.1em .32em;border-radius:5px;background:color-mix(in srgb,var(--text) 7%,transparent);color:var(--text);overflow-wrap:anywhere}
.prose strong{font-weight:650}
.goals-card{border:1px solid var(--line);background:var(--surface);border-radius:18px;padding:18px 22px;margin:24px 0}
.goals-card h3{margin:0 0 8px;font-size:15px}.goals-card ul{margin:0;padding-left:20px}.goals-card li{margin:5px 0;font-size:15px;line-height:1.55}
.key-idea{border-left:4px solid var(--accent);background:color-mix(in srgb,var(--accent) 7%,var(--surface));border-radius:0 16px 16px 0;padding:16px 20px;margin:0 0 40px}
.key-idea span{font-size:11px;font-weight:750;letter-spacing:.12em;color:var(--accent)}.key-idea p{margin:6px 0 0;font-size:17px;line-height:1.6}
.code-block{background:var(--ide-bg);color:var(--tok-text);border:1px solid var(--ide-line);font:13.5px/1.65 var(--mono);border-radius:14px;padding:16px 18px;box-shadow:none;margin:0}
.code-block.small{font-size:13px;margin:8px 0 10px}
.example{margin-top:6px;border-radius:14px;overflow:hidden;border:1px solid var(--ide-line)}
.example .code-block{border:0;border-radius:0}
.example-bar{display:flex;align-items:center;justify-content:space-between;background:var(--ide-chrome);border-bottom:1px solid var(--ide-line);padding:6px 8px 6px 14px;font:12px var(--mono);color:var(--ide-muted)}
.example-run,.ide-run{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;display:inline-flex;align-items:center;gap:6px;border:0;border-radius:7px;background:#3d9a50;color:#fff;font-size:12.5px;font-weight:600;padding:6px 12px;cursor:pointer}
.example-run:hover,.ide-run:hover{background:#358a46}.example-run:disabled,.ide-run:disabled{opacity:.6;cursor:wait}
.example-out{background:var(--ide-bg);border-top:1px solid var(--ide-line);padding:10px 18px 14px;color:var(--ide-text);font:13px/1.6 var(--mono)}
.example-out-head{font:600 11px/1 -apple-system,BlinkMacSystemFont,sans-serif;letter-spacing:.08em;text-transform:uppercase;color:var(--ide-muted);margin-bottom:8px}
.mistakes{display:grid;gap:10px}
.mistake{border:1px solid var(--line);border-radius:14px;padding:13px 16px;background:var(--surface)}
.mistake>code{display:block;font:12.5px/1.5 var(--mono);color:var(--tok-error);white-space:pre-wrap;word-break:break-word}
.mistake p{margin:7px 0 0;font-size:15px;line-height:1.6}
.minecraft-card .prose p{font-size:15px!important;color:var(--text)!important}
.minecraft-card{margin:10px 0 36px}

/* challenge + IDE */
.challenge-card{margin:36px 0}
.challenge-head .prose p{font-size:16px!important}
.stdin-note{font-size:13px;color:var(--muted);margin:4px 0 6px}
.stdin-block{font:13px/1.5 var(--mono);background:var(--surface-2);border-radius:10px;padding:10px 14px;margin:0}
.ide{background:var(--ide-bg);border-top:1px solid var(--ide-line);border-bottom:1px solid var(--ide-line)}
.ide-tabs{display:flex;align-items:stretch;justify-content:space-between;background:var(--ide-chrome);border-bottom:1px solid var(--ide-line);height:40px}
.ide-tab{display:flex;align-items:center;gap:8px;padding:0 16px;font:12.5px var(--mono);color:var(--ide-text);background:var(--ide-bg);border-right:1px solid var(--ide-line);box-shadow:inset 0 -2px 0 var(--accent)}
.java-file{width:14px;height:14px;border-radius:3px;background:linear-gradient(145deg,#f89820,#e76f00);position:relative}
.java-file:after{content:"J";position:absolute;inset:0;display:grid;place-items:center;font:700 9px/1 sans-serif;color:#fff}
.ide-actions{display:flex;align-items:center;gap:8px;padding:0 8px}
.ide-run i{width:0;height:0;border-left:8px solid #fff;border-top:5px solid transparent;border-bottom:5px solid transparent}
.ide-btn{border:1px solid var(--ide-line);background:transparent;color:var(--ide-text);border-radius:7px;padding:5px 11px;font-size:12px;cursor:pointer}.ide-btn:hover{background:color-mix(in srgb,var(--ide-text) 8%,transparent)}
.ide-editor .cm-editor{min-height:320px;max-height:560px}
.ide-editor .cm-editor.cm-focused{outline:none}
.ide-editor .cm-scroller{overflow:auto}
.ide-console{border-top:1px solid var(--ide-line);background:var(--ide-bg)}
.console-head{display:flex;align-items:center;gap:10px;height:32px;padding:0 14px;background:var(--ide-chrome);border-bottom:1px solid var(--ide-line);font-size:12px;color:var(--ide-muted)}
.console-head span:first-child{font-weight:600;color:var(--ide-text)}
.console-state{font:11px var(--mono);padding:2px 8px;border-radius:20px}
.console-state.busy{background:color-mix(in srgb,var(--accent) 18%,transparent);color:var(--accent)}
.console-state.ok{background:color-mix(in srgb,var(--green) 18%,transparent);color:var(--green)}
.console-state.bad{background:color-mix(in srgb,var(--tok-error) 18%,transparent);color:var(--tok-error)}
.terminal{background:var(--ide-bg)!important;color:var(--ide-text)!important;font:13px/1.6 var(--mono)!important;white-space:normal!important;min-height:110px!important;max-height:420px!important;padding:12px 16px!important}
.t-pre{margin:0 0 6px;white-space:pre-wrap;word-break:break-word;font:inherit}
.t-muted{color:var(--ide-muted)}.t-ok{color:var(--green);font-weight:600;margin-top:6px}
.t-err{color:var(--tok-error);margin:6px 0;font-family:-apple-system,BlinkMacSystemFont,sans-serif;font-size:13.5px}
.goto{color:var(--tok-call);text-decoration:underline}
.diff{margin-top:8px;border:1px solid var(--ide-line);border-radius:8px;overflow:hidden}
.diff-row{display:grid;grid-template-columns:34px minmax(0,1fr) minmax(0,1fr);border-top:1px solid var(--ide-line)}
.diff-row:first-child{border-top:0}
.diff-row.head{background:var(--ide-chrome);color:var(--ide-muted);font-family:-apple-system,BlinkMacSystemFont,sans-serif;font-size:12px}
.diff-row .ln{color:var(--tok-gutter);text-align:right;padding:3px 8px}
.diff-row .cell{padding:3px 10px;white-space:pre-wrap;word-break:break-word;border-left:1px solid var(--ide-line)}
.diff-row.bad .cell{background:color-mix(in srgb,var(--tok-error) 10%,transparent)}
.diff-row i{color:var(--ide-muted)}
.ide-keys{display:flex;flex-wrap:wrap;gap:6px 16px;padding:10px 18px;font-size:12px;color:var(--muted);border-bottom:1px solid var(--line)}
kbd{font:11px var(--mono);padding:1px 5px;border-radius:5px;border:1px solid var(--line-strong);background:var(--surface-2);color:var(--text)}
.challenge-foot{padding:12px 18px!important}
.hint-button{font-size:13px!important}
.hints{gap:8px!important}
.hint{font-size:14px!important;line-height:1.6;color:var(--text)!important}
.solution{border:1px solid var(--line);border-radius:12px;padding:12px;background:var(--surface)}
.solution-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;font-size:14px}
.solution .ide-btn{color:var(--text);border-color:var(--line-strong)}
.solution p{font-size:13px;color:var(--muted);margin:10px 0 0}

/* checkpoint, recap, drills, pager */
.quiz-q{padding:16px 0;border-top:1px solid var(--line)}
.quiz-q:first-of-type{border-top:0}
.quiz-question{font-size:16px;line-height:1.55;margin:0 0 4px}
.quiz-option{font-size:14.5px!important;line-height:1.45;padding:12px 14px!important}
.quiz-options{margin:10px 0 6px!important}
.quiz-feedback{font-size:14px!important;line-height:1.55;margin:6px 0 0}
.quiz-feedback.ok{color:var(--green)}.quiz-feedback.bad{color:var(--red)}
.recap-card,.drills-card{padding:24px;margin:28px 0}
.recap-card h2,.drills-card h2{margin:4px 0 10px;font-size:20px}
.recap-card ul,.drill-list{margin:0;padding-left:22px}
.recap-card li,.drill-list li{margin:8px 0;font-size:15px;line-height:1.6}
.muted-p{color:var(--muted);font-size:14px;margin:0 0 6px}
.lesson-pager{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:28px 0 60px}
.pager-btn{border:1px solid var(--line);background:var(--surface);border-radius:16px;padding:14px 16px;text-align:left;cursor:pointer;font-size:14px;font-weight:600}
.pager-btn small{display:block;color:var(--muted);font-weight:400;font-size:12px;margin-bottom:3px}
.pager-btn.next{text-align:right;grid-column:2}
.pager-btn:hover{border-color:var(--accent)}
@media(max-width:620px){.prose,.prose p{font-size:15.5px!important}.lesson-section h2{font-size:19px}.ide-keys span:nth-child(n+4){display:none}.lesson-pager{grid-template-columns:1fr}.pager-btn.next{grid-column:1}.code-block{font-size:12.5px}}
.reference-card .code-block{font-size:13px}
.meta-pill{white-space:nowrap;font-size:11px}
.example-stdin{border-top:1px dashed var(--ide-line);background:var(--ide-bg);padding:8px 18px 10px;color:var(--ide-muted);font-size:12px}
.example-stdin pre{margin:4px 0 0;font:13px/1.5 var(--mono);color:var(--tok-string)}

/* ---- v3: wide-screen lesson layout with right rail ---- */
.lesson-rail{display:none}
@media(min-width:1280px){
  .course-layout{grid-template-columns:272px minmax(0,1fr)}
  .lesson-workspace{display:grid;grid-template-columns:minmax(0,1fr) 232px;gap:44px;max-width:1340px;width:100%;margin:0 auto;padding:0 36px 80px}
  .lesson-main{min-width:0}
  .lesson-top,.lesson-content{max-width:none}
  .lesson-rail{display:block}
  .rail-inner{position:sticky;top:64px;max-height:calc(100vh - 64px);overflow:auto;padding:30px 0 30px;scrollbar-width:thin}
  .rail-title{font-size:11px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
  .toc{display:grid;gap:1px;border-left:1px solid var(--line);margin-bottom:28px}
  .toc a{display:block;padding:6px 0 6px 14px;margin-left:-1px;border-left:2px solid transparent;color:var(--muted);text-decoration:none;font-size:13px;line-height:1.35}
  .toc a:hover{color:var(--text)}
  .toc a.active{color:var(--accent);border-left-color:var(--accent);font-weight:600}
  .rail-status{display:grid;gap:6px}
  .rail-row{display:flex;align-items:center;gap:9px;font-size:13px;color:var(--text);text-decoration:none}
  .rail-row i{width:18px;height:18px;border-radius:50%;border:1.5px solid var(--line-strong);display:grid;place-items:center;font-style:normal;font-size:11px;color:#fff;flex:none}
  .rail-row.ok i{background:var(--green);border-color:var(--green)}
  .rail-row.ok{color:var(--muted)}
}
@media(min-width:1700px){.lesson-workspace{grid-template-columns:minmax(0,1fr) 260px;gap:56px}}
@media(min-width:1700px){
  .lesson-workspace{max-width:1500px;grid-template-columns:minmax(0,1fr) 280px;gap:64px}
  .prose,.prose p{font-size:17px!important}
  .goals-card li,.recap-card li,.drill-list li,.mistake p{font-size:16px}
  .code-block,.terminal{font-size:14px!important}
  .ide-editor .cm-editor{font-size:15px}
}