:root{--ink-bg:#11151c;--panel-bg:#19202b;--paper-fg:#dfe6ee;--dim-fg:#8d9aab;--string-green:#8fd694;--keyword-amber:#f2b84b;--error-rose:#ef7f8a;--rule-line:#2a3444}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--ink-bg);color:var(--paper-fg);font:16.5px/1.72 Georgia,"Iowan Old Style","Times New Roman",serif}
a{color:var(--string-green);text-underline-offset:3px}a:hover{color:var(--keyword-amber)}
.syntax-frame{display:grid;grid-template-columns:250px minmax(0,1fr);min-height:100vh}
.terminal-sidebar{background:var(--panel-bg);border-right:1px solid var(--rule-line);padding:28px 22px;position:sticky;top:0;align-self:start;min-height:100vh}
.prompt-wordmark{display:block;font:700 19px/1.3 ui-monospace,"SF Mono",Menlo,Consolas,monospace;color:var(--keyword-amber);text-decoration:none;margin-bottom:6px}
.prompt-wordmark::before{content:"$ ";color:var(--dim-fg)}
.shebang-tagline{font:12.5px/1.5 ui-monospace,Menlo,Consolas,monospace;color:var(--dim-fg);margin:0 0 26px}
.repl-menu{display:flex;flex-direction:column;gap:9px;font:14px/1.4 ui-monospace,Menlo,Consolas,monospace}
.repl-menu a{color:var(--paper-fg);text-decoration:none}.repl-menu a::before{content:"> ";color:var(--dim-fg)}.repl-menu a:hover{color:var(--string-green)}
.compiler-main{padding:44px clamp(18px,5vw,64px) 30px;min-width:0}
.compile-opening h1{font:700 clamp(28px,4.6vw,46px)/1.12 ui-monospace,Menlo,Consolas,monospace;margin:0 0 14px;color:#fff;max-width:20ch}
.compile-opening p{max-width:56ch;color:var(--dim-fg);font-size:18px;margin:0 0 34px}
.lesson-stack{list-style:none;margin:0;padding:0;border-top:1px solid var(--rule-line);max-width:820px}
.lesson-stack li{border-bottom:1px solid var(--rule-line)}
.lesson-line{display:grid;grid-template-columns:44px 1fr;gap:4px 14px;padding:20px 0;text-decoration:none;color:var(--paper-fg)}
.lesson-line:hover .lesson-heading{color:var(--string-green)}
.linenumber-gutter{font:13px/2 ui-monospace,Menlo,Consolas,monospace;color:var(--dim-fg);grid-row:span 3;text-align:right}
.commit-tag{font:11.5px/1.6 ui-monospace,Menlo,Consolas,monospace;letter-spacing:.09em;text-transform:uppercase;color:var(--keyword-amber)}
.lesson-heading{font:700 20px/1.3 ui-monospace,Menlo,Consolas,monospace;margin:0;color:#fff}
.lesson-blurb{margin:0;color:var(--dim-fg);font-size:15.5px;line-height:1.55}
.sourcefile-sheet{max-width:720px}
.sourcefile-sheet h1{font:700 clamp(25px,4.2vw,38px)/1.16 ui-monospace,Menlo,Consolas,monospace;color:#fff;margin:8px 0 14px}
.docstring-lead{font-size:18px;color:var(--dim-fg);border-left:3px solid var(--keyword-amber);padding-left:16px;margin:0 0 30px}
.sourcefile-sheet h2{font:700 18px/1.35 ui-monospace,Menlo,Consolas,monospace;color:var(--string-green);margin:34px 0 8px}
.sourcefile-sheet h2::before{content:"## ";color:var(--dim-fg)}
.sourcefile-sheet ul,.sourcefile-sheet ol{padding-left:22px}.sourcefile-sheet li{margin:7px 0}
.sourcefile-sheet code{font:14.5px ui-monospace,Menlo,Consolas,monospace;background:var(--panel-bg);padding:2px 6px;border-radius:3px;color:var(--keyword-amber);overflow-wrap:anywhere}
.stdout-callout{background:var(--panel-bg);border:1px solid var(--rule-line);border-radius:6px;padding:14px 18px;font-size:15.5px}
.sandbox-caution{border:1px dashed var(--error-rose);border-radius:6px;padding:12px 16px;font-size:14.5px;color:var(--dim-fg);margin-top:26px}
.changelog-stamp{margin-top:36px;font:12.5px/1.5 ui-monospace,Menlo,Consolas,monospace;color:var(--dim-fg)}
.stacktrace-foot{max-width:820px;margin-top:60px;padding-top:18px;border-top:1px solid var(--rule-line);font:13px/1.7 ui-monospace,Menlo,Consolas,monospace;color:var(--dim-fg);display:flex;flex-wrap:wrap;gap:6px 22px;justify-content:space-between}
@media(max-width:680px){.syntax-frame{display:block}.terminal-sidebar{position:static;min-height:0;border-right:0;border-bottom:1px solid var(--rule-line);padding:18px}.shebang-tagline{margin-bottom:12px}.repl-menu{flex-direction:row;flex-wrap:wrap;gap:6px 16px}.compiler-main{padding:26px 18px}.lesson-line{grid-template-columns:30px 1fr}}