:root{--bg:#f5f6f3;--ink:#202a25;--muted:#6d776f;--green:#255940;--lime:#d6ef87;--border:#dce1d9;--white:#fff;--orange:#f0a66a}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 'Segoe UI',Arial,sans-serif}a{color:inherit;text-decoration:none}button,input,select,textarea{font:inherit}button,a,input,select,summary{touch-action:manipulation}button{cursor:pointer;border:1px solid var(--border);border-radius:9px;padding:10px 17px;background:white;color:var(--ink)}button:hover{border-color:var(--green);background:#eef3e8}button:disabled{opacity:.45;cursor:default}.primary{background:var(--green);color:white;border-color:var(--green)}.primary:hover{background:#18422d;color:white}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid var(--orange);outline-offset:3px}aside{width:246px;position:fixed;inset:0 auto 0 0;background:#fff;border-right:1px solid var(--border);padding:35px 24px;display:flex;flex-direction:column}.brand{display:flex;align-items:center;gap:8px;font-size:24px;font-weight:750;letter-spacing:-1px}.mark{background:var(--green);color:var(--lime);width:37px;height:37px;border-radius:10px;display:inline-flex;align-items:center;justify-content:center;font-size:22px}.mark span{font-size:16px}.dot{color:var(--green);margin-left:-7px}.caption{font-size:9px;letter-spacing:2px;color:var(--muted);margin:18px 0 40px}nav a{display:flex;align-items:center;gap:15px;padding:13px;border-radius:9px;margin:5px 0;color:#626e65}nav a.active{background:#eaf1e3;color:var(--green);font-weight:650}nav small{margin-left:auto;background:#fff;padding:0 6px;border-radius:4px}.side-bottom{margin-top:auto;font-size:13px}.side-bottom p{font-size:18px;line-height:1.4;font-weight:600}.side-bottom a{color:var(--green)}.side-bottom small{display:block;margin-top:24px;color:var(--muted)}main{margin-left:246px;padding:0 42px;max-width:1600px}header{height:85px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--border);font-size:13px;color:var(--muted)}.pill{padding:5px 12px;background:#eaf0e5;border-radius:20px;font-size:12px;color:var(--green)}#app{min-height:75vh;padding:32px 0 48px}h1,h2,h3,p{margin-top:0}h1{font-size:40px;line-height:1.18;letter-spacing:-1.5px;margin-bottom:18px}h2{font-size:24px;line-height:1.3;letter-spacing:-.5px}h3{font-size:18px;line-height:1.4}.muted{color:var(--muted)}.eyebrow{font-size:11px;letter-spacing:2px;text-transform:uppercase;color:var(--green);font-weight:700;margin-bottom:18px}.hero{display:grid;grid-template-columns:1.2fr 1fr;background:#e8eee1;border-radius:20px;overflow:hidden;min-height:310px;margin-bottom:24px}.hero-copy{padding:38px}.hero p{max-width:430px;color:#5d6a60}.hero-art{background:var(--green);color:var(--lime);position:relative;display:flex;align-items:center;justify-content:center;flex-direction:column;padding:30px;overflow:hidden}.hero-art:before{content:'';position:absolute;width:300px;height:300px;border:1px solid #62825e;border-radius:50%;transform:translate(100px,80px)}.array{display:flex;gap:8px;position:relative;margin:15px 0}.cell{width:50px;height:54px;border:1px solid #78966d;border-radius:8px;display:flex;align-items:center;justify-content:center;font:21px Consolas,monospace}.cell.on{background:var(--lime);color:var(--green);border-color:var(--lime)}.code-label{font:12px Consolas,monospace;position:relative}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.grid.two{grid-template-columns:repeat(2,1fr)}.card{background:white;border:1px solid var(--border);border-radius:14px;padding:24px}.stat{font-size:32px;font-weight:650;line-height:1.2}.stat small{font-size:16px;font-weight:400;color:var(--muted)}.label{font-size:12px;color:var(--muted);margin-bottom:9px}.section-title{display:flex;justify-content:space-between;align-items:center;margin:34px 0 18px;gap:15px}.section-title h2{margin:0}.section-title a{font-size:13px;color:var(--green)}.module{padding:22px;display:flex;flex-direction:column;gap:10px;min-height:190px}.module .num{font:13px Consolas,monospace;color:var(--green)}.module h3{margin:0}.module p{font-size:13px;margin:0}.module a{margin-top:auto;font-size:13px;color:var(--green)}progress{width:100%;height:7px;border:0;accent-color:var(--green)}.toolbar{display:flex;gap:12px;flex-wrap:wrap;margin:22px 0}.toolbar input{flex:1;min-width:160px}input,select,textarea{background:white;border:1px solid var(--border);padding:10px 12px;border-radius:8px;color:var(--ink)}.road-row{display:grid;grid-template-columns:35px 1fr auto;gap:15px;align-items:start;border-bottom:1px solid var(--border);padding:18px 4px}.road-row:last-child{border:0}.road-row input{width:21px;height:21px;accent-color:var(--green);margin-top:6px}.road-row h3{margin:0;font-size:16px}.road-row p{margin:5px 0;font-size:13px}.badge{font-size:11px;background:#eef2e9;color:var(--green);padding:3px 8px;border-radius:5px;white-space:nowrap}.badge.plan{background:#f3f1ed;color:#827565}details{margin:8px 0}summary{cursor:pointer;color:var(--green);font-size:13px}.lesson p{max-width:850px}.lesson h2{font-size:20px;margin-top:28px}pre{background:#1d2b23;color:#d9e9c7;padding:22px;border-radius:12px;overflow:auto;font:14px/1.65 Consolas,monospace;white-space:pre}code{font-family:Consolas,monospace}.note{border-left:3px solid var(--orange);background:#fff7ed;padding:16px 20px;border-radius:0 8px 8px 0}.lab-stage{background:#1d3327;color:#e1ebd7;border-radius:14px;padding:35px;min-height:260px}.lab-stage .array{flex-wrap:wrap}.lab-stage .cell{width:58px}.step-text{margin-top:22px;font-size:17px}.feedback{min-height:28px;margin:12px 0;color:var(--green);font-weight:600}.task pre{font-size:13px}.inline{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.small{font-size:13px}.spacer{margin-top:24px}footer{padding:20px 0 30px;color:var(--muted);font-size:12px;border-top:1px solid var(--border);display:flex;justify-content:space-between;gap:15px}#toast{position:fixed;right:25px;bottom:25px;background:var(--green);color:white;padding:12px 20px;border-radius:10px;display:none;z-index:5}.empty{padding:35px;text-align:center;color:var(--muted)}.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}.mini-chart{display:flex;align-items:end;gap:9px;height:75px;margin-top:20px}.mini-chart span{background:#b8d28d;width:26px;border-radius:5px 5px 0 0}.quiz-card{margin-top:20px}textarea{width:100%;min-height:90px}a.textlink{color:var(--green);text-decoration:underline}.number-big{font-size:70px;color:var(--lime);line-height:1.2} @media(min-width:1500px){main{padding:0 65px}}@media(max-width:1000px){aside{width:205px;padding:25px 16px}main{margin-left:205px;padding:0 25px}.grid{grid-template-columns:repeat(2,1fr)}.hero{grid-template-columns:1fr}.hero-art{min-height:190px}.hero h1{font-size:35px}}@media(max-width:650px){aside{position:static;width:auto;padding:16px;border-right:0;border-bottom:1px solid var(--border)}.brand{font-size:22px}.caption,.side-bottom{display:none}nav{display:flex;overflow:auto;margin-top:10px}nav a{white-space:nowrap;font-size:12px;padding:9px;gap:5px}nav small{display:none}main{margin:0;padding:0 18px}header{height:60px;font-size:11px}.pill{font-size:10px;padding:4px 7px}.grid,.grid.two{grid-template-columns:1fr}.hero-copy{padding:26px}.hero h1,h1{font-size:32px}.hero-art{min-height:180px}.road-row{grid-template-columns:28px 1fr;gap:9px}.road-row>.badge{grid-column:2}.card{padding:20px}.lab-stage{padding:22px}.lab-stage .cell{width:38px;height:44px;font-size:16px}footer{flex-direction:column}.section-title{align-items:start}}

/* Long-form C++20 lessons */
.reader-link{display:inline-block;padding:10px 17px;border-radius:9px}.long-lesson{max-width:940px;margin:0 auto}.long-lesson h1{max-width:860px;font-size:38px}.lecture-intro{font-size:19px;line-height:1.65;color:#4c5e51}.reading-meta{color:#657367;font-size:13px}.lecture-toc summary{font-size:18px;font-weight:650}.lecture-toc ol{list-style:none;margin:16px 0 0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:4px 20px}.lecture-toc button{display:block;width:100%;text-align:left;border:0;padding:8px 10px;font-size:14px;line-height:1.5;background:transparent}.lecture-toc button:hover{background:#edf3e6}.lecture-body{background:#fff;border:1px solid var(--border);border-radius:14px;margin-top:24px;padding:12px 42px 32px;font-size:17px;line-height:1.85;overflow-wrap:anywhere}.lecture-body p{margin:18px 0}.lecture-body h2{font-size:25px;line-height:1.35;margin:44px 0 20px;padding-top:24px;border-top:1px solid var(--border);scroll-margin-top:24px;letter-spacing:-.4px}.lecture-body h2:first-child{border:0;margin-top:12px}.lecture-body h3{margin-top:28px}.lecture-body li{margin:10px 0}.lecture-body :not(pre)>code{font-size:.88em;background:#eef2e9;padding:2px 5px;border-radius:4px;overflow-wrap:anywhere}.lecture-body pre{margin:0;border-radius:0 0 10px 10px;overflow:auto;max-width:100%;font-size:14px;line-height:1.7;overflow-wrap:normal}.code-block{min-width:0;margin:24px 0}.code-caption{background:#2c4032;color:#bdd6ac;border-radius:10px 10px 0 0;padding:9px 20px;font:12px 'Segoe UI',sans-serif;letter-spacing:.5px}.table-scroll{overflow-x:auto;margin:24px 0}.lecture-body table{border-collapse:collapse;width:100%;font-size:14px;line-height:1.6}.lecture-body th,.lecture-body td{border:1px solid #dce1d9;padding:10px 12px;text-align:left;min-width:60px}.lecture-body th{background:#edf2e7;color:#254b34}.lecture-body a{color:var(--green);text-decoration:underline;text-underline-offset:3px}.solution{border:1px solid #cedcc2;background:#f7faf3;border-radius:10px;margin:18px 0 30px;overflow:hidden}.solution summary{font-size:15px;font-weight:650;padding:15px 18px}.solution-body{padding:0 20px 12px}.solution-body p{margin-top:8px}.reader-navigation{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:26px 0}.reader-navigation strong{display:block;margin-top:8px;font-size:17px}.long-lesson #quiz{display:flex;gap:10px;flex-wrap:wrap}.long-lesson #answer{flex:1;min-width:150px}.long-lesson .quiz-card h2{margin-top:0}.long-lesson .actions{align-items:center;gap:12px 24px}
@media(max-width:950px){.lecture-body{padding:10px 24px 26px}.lecture-toc ol{grid-template-columns:1fr}.long-lesson h1{font-size:33px}}
@media(max-width:650px){.lecture-body{font-size:16px;padding:8px 18px 24px}.lecture-body h2{font-size:22px;margin-top:30px}.long-lesson h1{font-size:30px}.lecture-intro{font-size:17px}.reader-navigation{grid-template-columns:1fr}.lecture-body pre{padding:16px;font-size:12px}.solution-body{padding:0 12px 10px}.lecture-body table{font-size:13px}.lecture-toc{padding:16px}.reader-navigation>span{display:none}}