:root{--bg:#f6f5ef;--paper:#fffefa;--ink:#173c35;--muted:#526960;--line:#dce5dc;--accent:#137961;--accent-dark:#0d5f4d;--mint:#e8f5ef;--sand:#fff2db;--blue:#e8f0fb;--shadow:0 18px 55px rgba(22,57,47,.08);font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Tahoma,sans-serif;color:var(--ink);background:var(--bg);scroll-behavior:smooth}
*{box-sizing:border-box}body{margin:0;line-height:1.72;font-size:16px}a{color:var(--accent-dark);text-underline-offset:3px}a:hover{text-decoration-thickness:2px}button{font:inherit;cursor:pointer}img{max-width:100%;height:auto}code,kbd,pre{font-family:ui-monospace,SFMono-Regular,Consolas,monospace}code{font-size:.9em;background:#eaf1ea;padding:.12em .32em;border-radius:5px;overflow-wrap:anywhere}kbd{font-size:.86em;background:#fff;border:1px solid #b9c9c0;box-shadow:0 2px 0 #b9c9c0;border-radius:5px;padding:.1em .4em;white-space:nowrap}pre{margin:0;overflow-x:auto;white-space:pre;line-height:1.6}pre code{display:block;background:none;color:#f4fff8;padding:0;font-size:.9rem;overflow-wrap:normal}.skip{position:absolute;top:-80px;left:12px;z-index:100;background:#fff;padding:10px}.skip:focus{top:12px}
.topbar{position:sticky;top:0;z-index:20;background:rgba(255,254,250,.96);border-bottom:1px solid var(--line);backdrop-filter:blur(14px)}.topinner{max-width:1440px;margin:auto;padding:10px 28px;display:flex;align-items:center;gap:20px;justify-content:space-between}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:800;letter-spacing:.04em;color:var(--ink)}.brandmark{display:grid;place-items:center;width:36px;height:36px;border-radius:10px;background:var(--ink);color:white;font-size:21px}.brand small{display:block;font-size:.66rem;font-weight:600;color:var(--muted);letter-spacing:0}.toplinks{display:flex;gap:8px;flex-wrap:wrap}.toplinks a{text-decoration:none;color:var(--muted);padding:7px 11px;border-radius:8px;font-size:.92rem;font-weight:600}.toplinks a[aria-current=page],.toplinks a:hover{background:var(--mint);color:var(--accent-dark)}
.home{max-width:1160px;margin:0 auto;padding:42px 28px 80px}.hero{background:linear-gradient(125deg,#143e35 0%,#206c58 100%);color:white;border-radius:26px;padding:54px clamp(25px,5vw,70px);position:relative;overflow:hidden;box-shadow:var(--shadow)}.hero:after{content:"";position:absolute;right:-85px;top:-115px;width:360px;height:360px;border:1px solid rgba(255,255,255,.25);border-radius:50%;box-shadow:0 0 0 62px rgba(255,255,255,.04),0 0 0 124px rgba(255,255,255,.04);pointer-events:none}.eyebrow{text-transform:uppercase;letter-spacing:.16em;font-size:.75rem;font-weight:800;color:var(--accent)}.hero .eyebrow{color:#a5e8c9}.hero h1{font-size:clamp(2rem,4vw,3.7rem);line-height:1.23;max-width:750px;margin:.3em 0}.hero p{font-size:1.1rem;max-width:690px;color:#e1f0e9}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:25px}.button,.button-ghost{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:43px;border:1px solid var(--accent);border-radius:10px;padding:9px 16px;text-decoration:none;font-weight:700;background:var(--accent);color:#fff}.button:hover{background:var(--accent-dark);color:#fff}.button-ghost{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.55);color:#fff}.button-ghost:hover{background:rgba(255,255,255,.2);color:#fff}.statrow{display:flex;flex-wrap:wrap;gap:26px;margin-top:32px;color:#dbf1e6;font-size:.9rem}.statrow strong{display:block;color:#fff;font-size:1.3rem}
.home h2{font-size:1.55rem;margin:40px 0 15px}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.lesson-card{display:flex;flex-direction:column;gap:10px;background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:25px;box-shadow:var(--shadow);text-decoration:none;color:var(--ink);min-height:230px}.lesson-card:hover{border-color:#71b6a0;transform:translateY(-2px)}.lesson-card h3{font-size:1.28rem;line-height:1.35;margin:0}.lesson-card p{color:var(--muted);margin:0;flex:1}.lesson-card .arrow{color:var(--accent);font-weight:800}.lesson-card .chapter{font-weight:800;color:var(--accent);font-size:.8rem;letter-spacing:.08em}.note{border-radius:13px;padding:16px 18px;margin:20px 0;background:var(--mint);border-left:4px solid var(--accent)}.note.warn{background:var(--sand);border-color:#bc7827}.note.info{background:var(--blue);border-color:#577eae}.note strong{display:block;margin-bottom:2px}.note p{margin:.2em 0}.home .note{max-width:none}
.layout{max-width:1480px;margin:0 auto;display:grid;grid-template-columns:240px minmax(0,760px) 210px;gap:28px;padding:30px 28px 80px;justify-content:center}.rail,.toc{align-self:start;position:sticky;top:86px;max-height:calc(100vh - 106px);overflow-y:auto}.railbox,.tocbox{background:var(--paper);border:1px solid var(--line);border-radius:16px;padding:18px;box-shadow:var(--shadow)}.rail h2,.toc h2{font-size:.85rem;color:var(--muted);text-transform:uppercase;letter-spacing:.09em;margin:0 0 12px}.rail a,.toc a{display:block;text-decoration:none;border-radius:8px;padding:8px 10px;color:var(--muted);line-height:1.4;font-size:.91rem}.rail a:hover,.toc a:hover,.rail a[aria-current=page]{background:var(--mint);color:var(--accent-dark)}.rail .smallhead{margin:16px 9px 6px;font-size:.73rem;font-weight:800;color:var(--accent);letter-spacing:.08em}.toc a{font-size:.82rem;padding:6px 9px}.article{min-width:0}.article-head{border-radius:22px;background:var(--paper);padding:34px clamp(20px,4vw,42px);border:1px solid var(--line);box-shadow:var(--shadow);margin-bottom:20px}.article-head h1{font-size:clamp(1.85rem,3vw,2.7rem);line-height:1.28;margin:7px 0 12px}.article-head p{margin:0;color:var(--muted);font-size:1.05rem}.article-head .meta{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px}.pill{background:var(--mint);color:var(--accent-dark);border-radius:999px;font-size:.8rem;font-weight:700;padding:5px 11px}.article-section{background:var(--paper);border:1px solid var(--line);border-radius:18px;padding:30px clamp(18px,3vw,36px);margin-bottom:18px;box-shadow:var(--shadow);scroll-margin-top:88px}.article-section h2{font-size:1.55rem;line-height:1.3;margin:0 0 12px}.article-section h3{font-size:1.13rem;margin:18px 0 7px;line-height:1.4}.article-section p{margin:.65em 0;color:#314b42}.article-section ul,.article-section ol{padding-left:1.5em}.article-section li{margin:.45em 0}.step{padding:20px 0;border-top:1px solid var(--line);scroll-margin-top:88px}.step:first-of-type{border-top:0}.stephead{display:flex;align-items:flex-start;gap:12px;margin-bottom:10px}.stepnum{flex:none;display:grid;place-items:center;width:34px;height:34px;border-radius:9px;background:var(--accent);color:#fff;font-size:.83rem;font-weight:800}.stephead h3{margin:2px 0 0}.platforms{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:15px 0}.platform{background:#f5f8f4;border:1px solid var(--line);border-radius:12px;padding:15px}.platform h4{margin:0 0 7px;font-size:.88rem}.platform p,.platform ol{margin:5px 0}.platform ul,.platform ol{padding-left:1.3em}.os-picker{display:flex;gap:5px;padding:5px;background:var(--mint);width:max-content;max-width:100%;border-radius:10px;margin:16px 0}.os-picker button{border:0;border-radius:7px;padding:7px 12px;background:transparent;color:var(--accent-dark);font-weight:700}.os-picker button[aria-pressed=true]{background:#fff;box-shadow:0 2px 7px rgba(0,0,0,.1)}.os-hidden{display:none!important}
.codeblock{margin:15px 0;border-radius:12px;overflow:hidden;background:#142d29;color:white}.codehead{display:flex;justify-content:space-between;align-items:center;gap:12px;background:#21413a;padding:7px 11px 7px 16px;color:#c4e4d2;font-size:.75rem;letter-spacing:.03em}.codehead button{border:1px solid #628578;color:#fff;background:transparent;padding:5px 11px;border-radius:6px;font-weight:700;font-size:.77rem}.codehead button:hover{background:#2d5f50}.codeblock pre{padding:16px;max-height:500px}.path{font-family:ui-monospace,monospace;font-size:.86em;word-break:break-word}.check{display:flex;gap:11px;align-items:flex-start;padding:12px 14px;border-radius:10px;background:#f2f7f3;margin:13px 0;color:#254d3d}.check .tick{display:grid;place-items:center;flex:none;width:20px;height:20px;border-radius:50%;background:var(--accent);color:#fff;font-size:.72rem;font-weight:900;margin-top:2px}.figure{margin:18px 0;background:#f6f7f3;border:1px solid var(--line);border-radius:12px;overflow:hidden}.figure img{display:block;width:100%;max-height:580px;object-fit:contain;object-position:left top}.figure figcaption{font-size:.82rem;color:var(--muted);padding:10px 14px}.tablewrap{overflow-x:auto;margin:15px 0}table{border-collapse:collapse;width:100%;font-size:.9rem}th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line);vertical-align:top}th{background:var(--mint);color:var(--accent-dark)}td code{white-space:nowrap}.nextnav{display:flex;justify-content:space-between;gap:12px;margin:26px 0}.nextnav a{flex:1;text-decoration:none;background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:15px;font-weight:700}.nextnav a:last-child{text-align:right}.nextnav a:hover{border-color:var(--accent)}.foot{max-width:1160px;margin:0 auto;padding:25px 28px 50px;border-top:1px solid var(--line);color:var(--muted);font-size:.83rem}.foot p{margin:4px 0}.source-list{font-size:.85rem}.source-list li{margin:7px 0}.printbutton{border:1px solid var(--line);border-radius:8px;background:var(--paper);color:var(--muted);padding:5px 10px}.printbutton:hover{color:var(--accent-dark)}
@media(max-width:1080px){.layout{grid-template-columns:200px minmax(0,760px)}.toc{display:none}}@media(max-width:760px){.topinner{padding:8px 15px;align-items:flex-start}.toplinks{justify-content:flex-end}.toplinks a{padding:5px 7px;font-size:.78rem}.brand small{display:none}.home{padding:20px 14px 55px}.hero{padding:32px 24px}.lesson-grid{grid-template-columns:1fr}.lesson-card{min-height:0}.layout{display:block;padding:15px 12px 50px}.rail{position:static;max-height:none;margin-bottom:16px}.railbox{padding:11px}.rail h2,.rail .smallhead{display:none}.railbox nav{display:flex;overflow-x:auto;gap:4px}.rail a{white-space:nowrap}.article-head{padding:25px 20px}.article-section{padding:22px 18px}.platforms{grid-template-columns:1fr}.foot{padding:20px 16px}}@media print{.topbar,.rail,.toc,.os-picker,.codehead button,.nextnav,.printbutton{display:none!important}.layout{display:block;padding:0}.article-head,.article-section{border:0;box-shadow:none;break-inside:auto;padding:0;margin:0 0 18px}.article-section{page-break-before:auto}.step,.codeblock,.note,.figure{break-inside:avoid}body{font-size:11pt;background:#fff;color:#000}.article-head h1{font-size:24pt}.article-section h2{font-size:17pt}a{color:#000;text-decoration:underline}.codeblock{background:#eee;color:#111;border:1px solid #aaa}.codeblock pre code{color:#111}.codehead{background:#ddd;color:#111}.os-hidden{display:block!important}.foot{max-width:none}figure img{max-height:12cm}}
.builder{display:grid;gap:8px;padding:20px;border:1px solid var(--line);border-radius:13px;background:#f4f8f4;margin:17px 0}.builder label{font-size:.9rem}.builder input{width:100%;min-height:44px;border:1px solid #b9c9be;border-radius:8px;background:#fff;padding:9px 12px;font:inherit;color:var(--ink)}.builder input:focus{outline:3px solid #8bceb1}.builder-actions{display:flex;align-items:center;gap:13px;flex-wrap:wrap;margin-top:7px}.builder-actions .button{border:0}.builder-status{color:var(--accent-dark);font-size:.9rem}.article-section .codeblock pre{white-space:pre-wrap;overflow-wrap:anywhere}.article-section .codeblock code{white-space:pre-wrap}
.codehead button:disabled{opacity:.55;cursor:not-allowed}
@media(max-width:760px){.topinner{display:block}.toplinks{justify-content:flex-start;margin-top:6px}}
@media print{.codeblock pre{max-height:none;overflow:visible}.codeblock{break-inside:auto}.codehead{break-after:avoid}}