/* Lesson document renderer — one simple, colorful house style. Blocks are
   numbered "N of TOTAL"; each cycles through an accent color so the page
   reads as a sequence of distinct, interesting steps rather than one long
   grey scroll. Practice code always runs on the student's own computer —
   this page only holds the prompt, the expected result, and a timed
   solution reveal. */

:root{
  --ink:#2B211A; --paper:#FFFFFF; --card:#FAF6F1; --line:#E0D5C7; --muted:#82695A;
  --deep:#b45309;
  --code:#2B211A; --codetext:#F3ECE3;
  --amber:#C97A12; --amberbg:#FFF4E0; --amberline:#F0CE94;
  --green:#12805C; --greenbg:#E7F8F0; --greenline:#9FE0C4;
  --examplelabel:#0D5A6B;
  --ambertext:#7A4E0C; --amberhover:#FCE7C3;
  --greentext:#0E5C40;
  --redline:#F0B4B4; --redbg:#FDECEC; --redtext:#7A1E1E;
  --font-display:Georgia,"Times New Roman",serif;
  --font-body:"Segoe UI",-apple-system,BlinkMacSystemFont,Roboto,sans-serif;
  --font-mono:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,monospace;
  --base-size:16.5px; --base-line:1.65;
  --radius:16px;
  --shadow:0 1px 2px rgba(102,73,48,.05),0 10px 26px -14px rgba(102,73,48,.20);

  /* block accent cycle */
  --c1:#2D6FCF; --c1bg:#E7F0FD;
  --c2:#C97A12; --c2bg:#FFF4E0;
  --c3:#2E9B4F; --c3bg:#EAF8EE;
  --c4:#1C8FA6; --c4bg:#E7F6F9;
  --c5:#5B62D9; --c5bg:#ECEDFC;
  --c6:#A34AC9; --c6bg:#F6EAFB;
  --c7:#B5851C; --c7bg:#FBF3E0;
}

*{box-sizing:border-box}
html:has(body.lesson-doc){background:var(--paper)}
.lesson-doc{background:var(--paper); color:var(--ink); font:var(--base-size)/var(--base-line) var(--font-body); min-height:100vh;
  overflow-wrap:anywhere; word-break:break-word}
body.lesson-doc{margin:0}
.lesson-doc code, .lesson-doc .mono{ font-family:var(--font-mono) }
/* Baseline safety net: a long unbroken line (e.g. a numpy array literal)
   must scroll inside its own box, never push past the card border. Blocks
   below layer padding/background/etc. on top of this. */
.lesson-doc pre{overflow-x:auto;max-width:100%}
.lesson-doc .wrap{max-width:880px;margin:0 auto;padding:0 24px 90px}
@media(max-width:700px){.lesson-doc .wrap{padding:0 16px 60px}}

/* ---------- header ---------- */
.lesson-doc header.lhead{background:linear-gradient(135deg,#0b2239,#123a5a 55%,#0e4f5c);color:#fff;padding:46px 0 38px;margin-bottom:30px}
.lesson-doc header.lhead .wrap{padding-bottom:0}
.lesson-doc .eyebrow{color:#E8D9C8;font-family:var(--font-mono);font-size:12px;
  letter-spacing:.6px;text-transform:uppercase;margin:0 0 10px}
.lesson-doc h1.ltitle{font-family:var(--font-display);font-size:clamp(28px,5vw,42px);
  margin:0 0 8px;letter-spacing:-.5px;font-weight:700}
.lesson-doc .lsub{color:#F3E7DA;font-size:17px;margin:0 0 12px}
.lesson-doc .lmeta-line{color:#E8D9C8;font-size:13.5px;margin:0 0 14px}
.lesson-doc ul.topics{list-style:none;display:flex;flex-wrap:wrap;gap:8px;margin:0 0 18px;padding:0}
.lesson-doc ul.topics li{background:rgba(255,255,255,.12);border-radius:999px;padding:6px 14px;font-size:13px}
.lesson-doc .meta{display:flex;flex-wrap:wrap;gap:10px}
.lesson-doc .pill{background:rgba(255,255,255,.14);border-radius:999px;padding:7px 15px;font-size:13px;font-weight:600}
@media(max-width:700px){.lesson-doc header.lhead{padding:32px 0 26px;margin-bottom:22px}}

/* ---------- progress bar ---------- */
.lesson-doc .bar{position:sticky;top:0;z-index:20;background:color-mix(in srgb, var(--paper) 92%, transparent);
  -webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);border-bottom:1px solid var(--line);padding:11px 0;margin-bottom:26px}
.lesson-doc .bar .wrap{padding-bottom:0;display:flex;align-items:center;gap:14px}
.lesson-doc .track{flex:1;height:8px;background:var(--line);border-radius:99px;overflow:hidden}
.lesson-doc .fill{height:100%;width:0;background:linear-gradient(90deg,var(--c4),var(--c3));
  border-radius:99px;transition:width .45s cubic-bezier(.4,0,.2,1)}
.lesson-doc .count{font-size:13px;font-weight:700;color:var(--deep);white-space:nowrap}

/* ---------- prose ---------- */
.lesson-doc .prose{margin-bottom:18px}
.lesson-doc .prose p{margin:0 0 12px}
.lesson-doc .prose pre{background:var(--code);color:var(--codetext);border-radius:10px;padding:15px 17px;
  overflow-x:auto;font-size:13.5px;line-height:1.55}
.lesson-doc .prose pre code,.lesson-doc .example-body pre code,.lesson-doc .hint pre code{color:inherit;background:none}
.lesson-doc .prose table{border-collapse:collapse;width:100%;margin:0 0 12px}
.lesson-doc .prose th,.lesson-doc .prose td{border:1px solid var(--line);padding:8px 10px;text-align:left;font-size:14px}
.lesson-doc .prose th{background:var(--paper);font-weight:600}

/* ---------- blocks: "N of TOTAL", cycling accent colors ---------- */
.lesson-doc .block{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:30px 32px 34px;margin-bottom:26px;
  border-top:5px solid var(--block-accent, var(--c4))}
.lesson-doc .block:nth-of-type(7n+1){--block-accent:var(--c1)}
.lesson-doc .block:nth-of-type(7n+2){--block-accent:var(--c2)}
.lesson-doc .block:nth-of-type(7n+3){--block-accent:var(--c3)}
.lesson-doc .block:nth-of-type(7n+4){--block-accent:var(--c4)}
.lesson-doc .block:nth-of-type(7n+5){--block-accent:var(--c5)}
.lesson-doc .block:nth-of-type(7n+6){--block-accent:var(--c6)}
.lesson-doc .block:nth-of-type(7n){--block-accent:var(--c7)}
.lesson-doc .block-head{display:flex;align-items:baseline;gap:14px;margin-bottom:18px}
.lesson-doc .block-head-intro{margin-bottom:14px}
.lesson-doc .block-count{flex:none;font-family:var(--font-mono);font-size:12.5px;font-weight:700;
  letter-spacing:.5px;color:#fff;background:var(--block-accent,var(--c4));border-radius:999px;padding:5px 13px}
.lesson-doc .block-title{font-family:var(--font-display);font-size:26px;margin:0;font-weight:700;color:var(--ink)}
@media(max-width:700px){
  .lesson-doc .block{padding:22px 20px 26px}
  .lesson-doc .block-head{flex-direction:column;align-items:flex-start;gap:8px}
  .lesson-doc .block-title{font-size:21px}
}

/* ---------- example ---------- */
.lesson-doc .example{background:var(--c4bg);border:1px solid var(--c4);border-left:5px solid var(--c4);
  border-radius:12px;padding:18px 20px;margin-bottom:20px}
.lesson-doc .example-label{display:block;font-family:var(--font-mono);font-size:11.5px;font-weight:700;
  letter-spacing:.7px;text-transform:uppercase;color:var(--examplelabel);margin-bottom:10px}
.lesson-doc .example-body .prose{margin-bottom:0}
.lesson-doc .example-body pre{background:var(--code);color:var(--codetext);border-radius:10px;
  padding:15px 17px;overflow-x:auto;font-size:13.5px;line-height:1.55}

.lesson-doc .example-protect pre{-webkit-user-select:none;user-select:none}

/* ---------- solution (a plain code panel) ---------- */
.lesson-doc .solution{background:var(--c4bg);border:1px solid var(--c4);border-left:5px solid var(--c4);
  border-radius:12px;padding:18px 20px;margin-bottom:20px}
.lesson-doc .solution-label{display:block;font-family:var(--font-mono);font-size:11.5px;font-weight:700;
  letter-spacing:.7px;text-transform:uppercase;color:var(--examplelabel);margin-bottom:10px}
.lesson-doc .solution-body .prose{margin-bottom:0}
.lesson-doc .solution-body pre{background:var(--code);color:var(--codetext);border-radius:10px;
  padding:15px 17px;overflow-x:auto;font-size:13.5px;line-height:1.55}

/* ---------- standalone resource links (Drive doc / notebook / etc) ---------- */
.lesson-doc .resource-link-wrap{margin-bottom:20px}
.lesson-doc a.resource-link{display:inline-flex;align-items:center;gap:10px;font-family:var(--font-mono);
  font-size:14px;font-weight:700;color:#fff;background:var(--c2,#2B6CB0);border-radius:10px;
  padding:12px 20px;text-decoration:none;box-shadow:0 2px 0 rgba(0,0,0,.08)}
.lesson-doc a.resource-link:hover{filter:brightness(1.08)}
.lesson-doc a.resource-link:before{content:"\1F4C4";font-size:16px}
.lesson-doc a.resource-link:after{content:"\2197";font-size:14px;opacity:.85}

/* ---------- tip ---------- */
.lesson-doc .tip{background:var(--amberbg);border:1px solid var(--amberline);border-left:5px solid var(--amber);
  border-radius:12px;padding:15px 18px;margin-bottom:20px;font-size:14.5px;color:var(--ambertext,#7A4E0C)}
.lesson-doc .tip p{margin:0 0 8px}
.lesson-doc .tip p:last-child{margin-bottom:0}

/* ---------- code blocks: copy button ---------- */
.lesson-doc .code-block{position:relative}
.lesson-doc .code-block pre{padding-right:76px}
.lesson-doc .copy-btn{position:absolute;top:10px;right:10px;background:#F3ECE3;
  color:#2B211A;border:1px solid rgba(255,255,255,.3);border-radius:6px;
  font-family:var(--font-mono);font-size:12px;font-weight:700;padding:5px 10px;
  cursor:pointer;transition:.15s;opacity:0;line-height:1;box-shadow:0 1px 3px rgba(0,0,0,.25)}
.lesson-doc .code-block:hover .copy-btn,
.lesson-doc .copy-btn:focus-visible{opacity:1}
.lesson-doc .copy-btn:hover{background:#fff}
.lesson-doc .copy-btn.copied{background:var(--green);color:#fff;border-color:var(--green);opacity:1}
@media(max-width:620px){.lesson-doc .copy-btn{opacity:1}}

/* ---------- practice ---------- */
.lesson-doc .practice{background:var(--paper);border:1.5px solid var(--line);border-radius:14px;
  padding:20px 22px;margin-bottom:16px}
.lesson-doc .practice.done{border-color:var(--green);background:var(--greenbg)}
.lesson-doc .practice-top{display:flex;gap:13px;align-items:flex-start}
.lesson-doc .practice-num{flex:0 0 28px;height:28px;border-radius:50%;background:var(--block-accent,var(--c4));
  color:#fff;font-size:12.5px;font-weight:700;display:grid;place-items:center;margin-top:1px}
.lesson-doc .practice.done .practice-num{background:var(--green)}
.lesson-doc .practice.done .practice-num{font-size:0}
.lesson-doc .practice.done .practice-num::after{content:"✓";font-size:14px}
.lesson-doc .practice-body{flex:1;min-width:0}
.lesson-doc .practice-label{display:block;font-family:var(--font-mono);font-size:11px;font-weight:700;
  letter-spacing:.6px;text-transform:uppercase;color:var(--muted);margin-bottom:8px}
.lesson-doc .practice-question{font-weight:500}
.lesson-doc .practice-question .prose:last-child{margin-bottom:0}
.lesson-doc .expect{background:var(--greenbg);border:1px solid var(--greenline);border-radius:8px;
  padding:9px 13px;margin-top:12px;font-size:13px}
.lesson-doc .expect b{color:var(--green);font-size:11px;letter-spacing:.6px;display:block;margin-bottom:3px}
.lesson-doc .expect .mono{color:var(--greentext,#0E5C40);display:block;white-space:pre-wrap;line-height:1.65;margin:0;font-family:var(--font-mono)}
.lesson-doc .expect pre.mono{overflow-x:auto}

/* ---------- hint / timer / mark done ---------- */
.lesson-doc .practice-actions{margin-top:14px;display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.lesson-doc button{font:inherit;cursor:pointer;border-radius:8px;border:1px solid transparent}
.lesson-doc .hbtn{background:var(--amberbg);border-color:var(--amberline);color:var(--amber);
  font-size:13.5px;font-weight:600;padding:9px 15px;transition:.15s}
.lesson-doc .hbtn:hover{background:var(--amberhover,#FCE7C3)}
.lesson-doc .hbtn:disabled{cursor:default;opacity:.95}
.lesson-doc .dbtn{background:var(--deep);color:#fff;font-size:13.5px;font-weight:600;padding:9px 17px}
.lesson-doc .dbtn:hover{background:#4d3722}
.lesson-doc .practice.done .dbtn{background:var(--green)}
.lesson-doc .timer{display:flex;align-items:center;gap:9px;font-size:13.5px;color:var(--amber);font-weight:600}
.lesson-doc .ring{width:26px;height:26px;border-radius:50%;flex:0 0 26px;
  background:conic-gradient(var(--amber) 0deg,var(--amberbg) 0deg)}
.lesson-doc .hint{margin-top:13px;background:var(--amberbg);border:1px solid var(--amberline);
  border-radius:10px;padding:15px 17px;display:none}
.lesson-doc .hint.show{display:block;animation:lesson-drop .3s ease}
@keyframes lesson-drop{from{opacity:0;transform:translateY(-7px)}to{opacity:1;transform:none}}
.lesson-doc .hint h4{margin:0 0 8px;font-size:11px;letter-spacing:.8px;color:var(--amber);text-transform:uppercase}
.lesson-doc .hint pre{margin:0;overflow-x:auto}
.lesson-doc .hint p{margin:9px 0 0;font-size:13.5px;color:var(--ambertext,#7A4E0C)}

/* ---------- preview-only chrome ---------- */
.lesson-doc .preview-warnings{border-color:var(--redline,#F0B4B4);background:var(--redbg,#FDECEC);color:var(--redtext,#7A1E1E);border-left-color:var(--c1)}
.lesson-doc .preview-warnings ul{margin:8px 0 0;padding-left:18px}
.lesson-doc .back-to-editor{margin:0 0 20px}
.lesson-doc .back-to-editor a{display:inline-flex;align-items:center;gap:7px;
  font-family:var(--font-mono);font-size:12.5px;font-weight:600;letter-spacing:.2px;
  color:var(--muted);background:var(--card);border:1px solid var(--line);
  border-radius:999px;padding:7px 14px 7px 12px;text-decoration:none;
  box-shadow:var(--shadow);transition:.15s}
.lesson-doc .back-to-editor a:hover{color:var(--deep);border-color:var(--c4);background:var(--c4bg)}

/* ---------- student mini nav ---------- */
.lesson-doc .lnav{background:var(--paper);border-bottom:1px solid var(--line)}
.lesson-doc .lnav .wrap{display:flex;align-items:center;justify-content:space-between;
  padding-top:12px;padding-bottom:12px}
.lesson-doc .lnav-brand{display:flex;align-items:center;gap:9px;text-decoration:none;color:var(--ink)}
.lesson-doc .lnav-mark{display:grid;place-items:center;width:30px;height:30px;border-radius:9px;
  background:var(--deep);color:#fff;font-family:var(--font-display);font-weight:700;font-size:14px}
.lesson-doc .lnav-name{font-family:var(--font-display);font-size:16px;font-weight:600}
.lesson-doc .lnav-back{display:inline-flex;align-items:center;gap:7px;
  font-family:var(--font-mono);font-size:12.5px;font-weight:700;letter-spacing:.2px;
  color:var(--deep);background:var(--card);border:1px solid var(--line);
  border-radius:999px;padding:8px 16px 8px 13px;text-decoration:none;transition:.15s}
.lesson-doc .lnav-back:hover{color:#fff;border-color:var(--deep);background:var(--deep)}
.lesson-doc .lnav-links{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.lesson-doc .lnav-icon{position:relative;padding:8px 12px}
.lesson-doc .lnav-badge{position:absolute;top:-6px;right:-6px;background:#DC2626;color:#fff;
  border-radius:999px;font-size:10px;font-weight:700;line-height:1;padding:3px 5px;min-width:16px;text-align:center}
.lesson-doc .lnav-logout-form{display:inline-flex}
.lesson-doc .lnav-logout-form .lnav-back{cursor:pointer;font:inherit}
@media(max-width:700px){
  .lesson-doc .lnav .wrap{flex-wrap:wrap;gap:10px;padding-bottom:12px}
  .lesson-doc .lnav-links{gap:6px}
  .lesson-doc .lnav-back{padding:7px 12px;font-size:12px}
}

/* ---------- gentle nudge toast ---------- */
.lesson-doc .nudge-stack{position:fixed;top:90px;right:18px;z-index:50;
  display:flex;flex-direction:column;gap:10px;width:250px;pointer-events:none}
.lesson-doc .nudge{pointer-events:auto;background:var(--paper);border:1.5px solid var(--line);
  border-left:4px solid var(--c4);border-radius:12px;padding:13px 15px;box-shadow:var(--shadow);
  opacity:0;transform:translateX(16px);transition:opacity .2s,transform .2s}
.lesson-doc .nudge.show{opacity:1;transform:none}
.lesson-doc .nudge-text{margin:0 0 10px;font-size:13.5px;color:var(--ink);line-height:1.4}
.lesson-doc .nudge-actions{display:flex;gap:8px;flex-wrap:wrap}
.lesson-doc .nudge-yes{background:var(--c4);color:#fff;border:none;border-radius:7px;
  font-size:12.5px;font-weight:600;padding:6px 11px}
.lesson-doc .nudge-yes:hover{background:#177789}
.lesson-doc .nudge-no{background:transparent;color:var(--muted);border:1px solid var(--line);
  border-radius:7px;font-size:12.5px;font-weight:600;padding:6px 11px}
.lesson-doc .nudge-no:hover{background:var(--card)}
@media(max-width:620px){.lesson-doc .nudge-stack{left:14px;right:14px;width:auto}}

/* ---------- finish ---------- */
.lesson-doc .done-msg{margin-top:26px;padding:22px 26px;background:var(--deep);color:#fff;
  border-radius:var(--radius);display:none}
.lesson-doc .done-msg.show{display:block;animation:lesson-drop .4s ease}
.lesson-doc .done-msg h3{margin:0 0 6px;font-family:var(--font-display);font-size:20px}
.lesson-doc .done-msg p{margin:0;color:#C7D5FA;font-size:14px}

.lesson-doc .lesson-complete-form{margin-top:18px;text-align:center}
.lesson-doc .lesson-complete-btn{background:var(--green);color:#fff;font-size:14.5px;font-weight:700;
  padding:13px 26px;border-radius:999px;border:none;box-shadow:0 2px 0 rgba(0,0,0,.08);cursor:pointer}
.lesson-doc .lesson-complete-btn:hover{filter:brightness(1.06)}

/* ---------- attached files ---------- */
.lesson-doc .lesson-files{list-style:none;margin:12px 0 0;padding:0;border:1px solid var(--line);
  border-radius:var(--radius);overflow:hidden;background:var(--card)}
.lesson-doc .lesson-file{display:flex;align-items:center;justify-content:space-between;gap:14px;
  padding:14px 18px;border-top:1px solid var(--line)}
.lesson-doc .lesson-file:first-child{border-top:none}
.lesson-doc .lesson-file-label{margin:0;font-weight:600}
.lesson-doc .lesson-file-meta{margin:2px 0 0;font-family:var(--font-mono);font-size:12px;color:var(--muted)}
.lesson-doc .lesson-file-download{flex:none;font-family:var(--font-mono);font-size:12.5px;font-weight:700;
  color:var(--deep);background:var(--paper);border:1px solid var(--line);border-radius:999px;
  padding:8px 16px;text-decoration:none;transition:.15s}
.lesson-doc .lesson-file-download:hover{color:#fff;background:var(--deep)}

@media(max-width:480px){
  .lesson-doc .meta{gap:8px}
  .lesson-doc .pill{padding:6px 12px;font-size:12px}
  .lesson-doc .practice{padding:16px 17px}
}
@media not all{
  .lesson-doc *,.lesson-doc *::before,.lesson-doc *::after{animation:none!important;transition:none!important}
}
.lesson-doc :focus-visible{outline:2px solid var(--c4);outline-offset:2px}
.lesson-doc .prose pre::selection,.lesson-doc .prose pre ::selection{background:#3B5BA5;color:#fff}

/* ---------- journey ---------- */
.lesson-doc .journey{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:20px}
.lesson-doc .journey-step{flex:1 1 160px;background:var(--paper);border:1px solid var(--line);
  border-left:4px solid var(--c4);border-radius:10px;padding:12px 14px}
.lesson-doc .journey-step.current{border-left-color:var(--green);background:var(--greenbg)}
.lesson-doc .journey-time{display:block;font-family:var(--font-mono);font-size:11px;
  font-weight:700;letter-spacing:.4px;color:var(--muted);margin-bottom:4px}
.lesson-doc .journey-title{display:block;font-weight:700}
.lesson-doc .journey-detail{display:block;font-size:13px;color:var(--muted);margin-top:2px}

/* ---------- figure ---------- */
.lesson-doc .lfigure{margin:0 0 20px;padding:0}
.lesson-doc .lfigure pre{background:var(--code);color:var(--codetext);border-radius:10px;
  padding:15px 17px;overflow-x:auto;font-size:13px;line-height:1.5;margin:0}
.lesson-doc .lfigure figcaption{margin-top:8px;font-size:13px;color:var(--muted);
  text-align:center;font-style:italic}

/* ---------- student color picker ---------- */
.theme-toggle-btn{position:fixed;left:18px;top:50%;transform:translateY(-50%);z-index:60;width:46px;height:46px;
  border-radius:50%;border:1px solid var(--line);background:var(--paper);font-size:20px;
  box-shadow:var(--shadow);cursor:pointer;display:grid;place-items:center}
.theme-toggle-btn:hover{filter:brightness(1.05)}
.theme-picker{position:fixed;left:72px;top:50%;transform:translateY(-50%);z-index:60;width:min(330px,calc(100vw - 36px));max-height:70vh;overflow-y:auto;background:var(--paper);
  border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);padding:16px;display:none}
.theme-picker.is-open{display:block}
.theme-picker-title{margin:0 0 12px;font-family:var(--font-display);font-size:15px;font-weight:700;color:var(--ink)}
.theme-row{display:flex;align-items:center;justify-content:space-between;gap:10px;
  font-size:13.5px;color:var(--ink);padding:6px 0}
.theme-row input[type=color]{width:38px;height:28px;border:1px solid var(--line);border-radius:6px;
  padding:0;background:none;cursor:pointer}
.theme-reset-btn{margin-top:10px;width:100%;background:var(--card);border:1px solid var(--line);
  color:var(--muted);font-size:12.5px;font-weight:600;padding:8px;border-radius:8px;cursor:pointer}
.theme-reset-btn:hover{background:var(--paper)}
@media(max-width:480px){
  .theme-toggle-btn{left:12px}
  .theme-picker{left:12px;top:auto;bottom:12px;transform:none;width:calc(100vw - 24px)}
}

/* ---------- mermaid diagrams ---------- */
.lesson-doc .mermaid-figure{background:var(--card);border:1.5px solid var(--line);
  border-radius:14px;padding:18px;overflow-x:auto}
.lesson-doc .mermaid-figure .mermaid{display:flex;justify-content:center}
.lesson-doc .mermaid-figure svg{max-width:100%}

/* ---------- objectives ---------- */
.lesson-doc .objectives{margin:0 0 20px;padding:0;list-style:none;counter-reset:obj}
.lesson-doc .objectives li{counter-increment:obj;position:relative;padding:2px 0 14px 38px;
  border-left:2px solid var(--line);margin-left:13px}
.lesson-doc .objectives li:last-child{border-left-color:transparent;padding-bottom:0}
.lesson-doc .objectives li::before{content:counter(obj);position:absolute;left:-13px;top:0;
  width:26px;height:26px;border-radius:50%;background:var(--c4);color:#fff;
  font-size:12.5px;font-weight:700;display:grid;place-items:center}
.lesson-doc .obj-text{font-weight:500}
.lesson-doc .obj-check{margin-top:6px;font-size:13px;color:var(--muted)}
.lesson-doc .obj-check b{color:var(--green);letter-spacing:.4px;text-transform:uppercase;font-size:11px;margin-right:4px}

/* ---------- steps (plain numbered recap) ---------- */
.lesson-doc .steps{margin:0 0 20px;padding:0;list-style:none;counter-reset:steps}
.lesson-doc .steps li{counter-increment:steps;position:relative;padding:4px 0 4px 38px;
  font-size:14.5px}
.lesson-doc .steps li::before{content:counter(steps);position:absolute;left:0;top:2px;
  width:22px;height:22px;border-radius:50%;background:var(--c3);color:#fff;
  font-size:11.5px;font-weight:700;display:grid;place-items:center}

/* ---------- grid ---------- */
.lesson-doc .lgrid{display:flex;flex-wrap:wrap;gap:14px;margin-bottom:20px}
.lesson-doc .lgrid-col{flex:1 1 200px;background:var(--card);border:1px solid var(--line);
  border-radius:12px;padding:16px 18px}
.lesson-doc .lgrid-heading{font-weight:700;margin:0 0 10px}
.lesson-doc .lgrid-col ul{margin:0;padding:0;list-style:none}
.lesson-doc .lgrid-col li{padding:4px 0;font-size:14px}

/* ---------- push ---------- */
.lesson-doc .push{background:var(--c5bg);border:1px solid var(--c5);border-radius:14px;
  padding:20px 22px;margin-bottom:20px}
.lesson-doc .push-title{font-family:var(--font-display);font-size:20px;font-weight:700;
  margin:0 0 8px;color:var(--c5)}
.lesson-doc .push-body p{margin:0 0 8px}
.lesson-doc .push-body p:last-child{margin-bottom:0}

/* ---------- checklist ---------- */
.lesson-doc .checklist{margin:0 0 20px;padding:0;list-style:none}
.lesson-doc .checklist-item{display:flex;align-items:center;gap:11px;padding:8px 0}
.lesson-doc .checklist-check{flex:0 0 22px;width:22px;height:22px;border-radius:6px;
  border:1.5px solid var(--line);background:var(--card);padding:0;position:relative}
.lesson-doc .checklist-item.done .checklist-check{background:var(--green);border-color:var(--green)}
.lesson-doc .checklist-item.done .checklist-check::after{content:"✓";position:absolute;inset:0;
  display:grid;place-items:center;color:#fff;font-size:13px}
.lesson-doc .checklist-item.done span{color:var(--muted);text-decoration:line-through}

/* ---------- quiz (ungraded warm-up) ---------- */
.lesson-doc .quiz{background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:18px 20px;margin-bottom:20px}
.lesson-doc .quiz-question{font-weight:500;margin:0 0 14px}
.lesson-doc .quiz-options{display:flex;flex-direction:column;gap:9px}
.lesson-doc .quiz-option{display:block;width:100%;text-align:left;background:var(--paper);
  border:1.5px solid var(--line);border-radius:10px;padding:10px 14px;font-size:14.5px;
  color:var(--ink);transition:.15s}
.lesson-doc .quiz-option:hover{border-color:var(--c4)}
.lesson-doc .quiz-option.picked.correct{border-color:var(--green);background:var(--greenbg)}
.lesson-doc .quiz-option.picked.incorrect{border-color:var(--redline);background:var(--redbg)}
.lesson-doc .quiz-option.revealed-correct{border-color:var(--green);background:var(--greenbg)}
.lesson-doc .quiz-option:disabled{cursor:not-allowed;opacity:.7}
.lesson-doc .quiz-option:disabled:not(.picked):hover{border-color:var(--line)}
.lesson-doc .quiz-feedback{max-height:0;overflow:hidden;opacity:0;font-size:13.5px;
  color:var(--muted);padding:0 14px;transition:.2s}
.lesson-doc .quiz-feedback.show{max-height:400px;opacity:1;padding:6px 14px 0}

/* ---------- card (quiet titled panel) ---------- */
.lesson-doc .card{background:var(--card);border:1px solid var(--line);border-radius:14px;
  padding:18px 20px;margin-bottom:20px}
.lesson-doc .card-title{font-weight:700;margin:0 0 10px;color:var(--ink)}
.lesson-doc .card-body p{margin:0 0 8px}
.lesson-doc .card-body p:last-child{margin-bottom:0}

/* ---------- aside (titled side-note) ---------- */
.lesson-doc .aside{background:var(--paper);border:1px dashed var(--line);border-left:4px solid var(--c6);
  border-radius:10px;padding:16px 18px;margin-bottom:20px}
.lesson-doc .aside-title{font-weight:700;margin:0 0 8px;color:var(--c6)}
.lesson-doc .aside-body p{margin:0 0 8px}
.lesson-doc .aside-body p:last-child{margin-bottom:0}
.lesson-doc .aside-purple{border-left-color:var(--c6);background:var(--c6bg)}
.lesson-doc .aside-purple .aside-title{color:var(--c6)}
.lesson-doc .aside-blue{border-left-color:var(--c1);background:var(--c1bg)}
.lesson-doc .aside-blue .aside-title{color:var(--c1)}
.lesson-doc .aside-amber{border-left-color:var(--c2);background:var(--c2bg)}
.lesson-doc .aside-amber .aside-title{color:var(--c2)}
.lesson-doc .aside-green{border-left-color:var(--c3);background:var(--c3bg)}
.lesson-doc .aside-green .aside-title{color:var(--c3)}
.lesson-doc .aside-teal{border-left-color:var(--c4);background:var(--c4bg)}
.lesson-doc .aside-teal .aside-title{color:var(--c4)}
.lesson-doc .aside-indigo{border-left-color:var(--c5);background:var(--c5bg)}
.lesson-doc .aside-indigo .aside-title{color:var(--c5)}
.lesson-doc .aside-gold{border-left-color:var(--c7);background:var(--c7bg)}
.lesson-doc .aside-gold .aside-title{color:var(--c7)}

/* ---------- rule (worked checks) ---------- */
.lesson-doc .rule{background:var(--greenbg);border:1px solid var(--greenline);border-radius:14px;
  padding:18px 20px;margin-bottom:20px}
.lesson-doc .rule-title{font-weight:700;margin:0 0 12px;color:var(--green)}
.lesson-doc .rule-check{padding:8px 0;border-top:1px solid var(--greenline)}
.lesson-doc .rule-check:first-of-type{border-top:none;padding-top:0}
.lesson-doc .rule-check-heading{font-family:var(--font-mono);font-size:11.5px;font-weight:700;
  letter-spacing:.4px;text-transform:uppercase;color:var(--green);margin:0 0 4px}
.lesson-doc .rule-check-body p{margin:0 0 6px;font-size:13.5px;color:var(--greentext,#0E5C40)}
.lesson-doc .rule-check-body p:last-child{margin-bottom:0}

/* ---------- task-block (:::task type=step|code|answer) ---------- */
.lesson-doc .task-note{margin-top:10px;font-size:14px}
.lesson-doc .task-note p{margin:0 0 8px}
.lesson-doc .task-note p:last-child{margin-bottom:0}
.lesson-doc .task-note .tip.mini-tip{margin:10px 0}
.lesson-doc .task-done-when{margin-top:12px;background:var(--greenbg);border:1px solid var(--greenline);
  border-radius:8px;padding:9px 14px;font-size:13.5px;color:var(--greentext,#0E5C40)}
.lesson-doc .task-done-when b{color:var(--green);font-size:11px;letter-spacing:.6px;
  text-transform:uppercase;display:block;margin-bottom:3px}
.lesson-doc .blank-input{font-family:var(--font-mono);font-size:13.5px;border:none;
  border-bottom:2px solid var(--c4);background:transparent;color:var(--ink);
  padding:2px 4px;min-width:110px}
.lesson-doc .blank-input:focus{outline:none;border-bottom-color:var(--c3)}

.theme-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
.theme-swatch{display:flex;flex-direction:column;gap:6px;padding:8px;border:2px solid;border-radius:12px;cursor:pointer;text-align:left;font:inherit}
.theme-swatch.is-on{box-shadow:0 0 0 2px currentColor}
.theme-swatch-bar{display:block;padding:4px 8px;border-radius:6px;font-weight:700;font-size:14px}
.theme-swatch-name{font-size:12px;font-weight:600}

.theme-sub{margin-top:14px !important;font-size:13px !important}
.theme-note{margin:8px 0 0;padding:6px 8px;border-radius:8px;background:#fef3c7;color:#78350f;font-size:12px}
.fnav-theme{background:none;border:0;cursor:pointer;font:inherit}

/* after answering: every option explains itself */
.lesson-doc .quiz-option-wrap.is-right .quiz-feedback.show::before{content:"✓ Correct – ";font-weight:700;color:var(--green)}
.lesson-doc .quiz-option-wrap.is-wrong .quiz-feedback.show::before{content:"✗ Not this one – ";font-weight:700;color:#b91c1c}
.lesson-doc .quiz.is-answered .quiz-option:disabled{opacity:1}
.lesson-doc .quiz.is-answered .quiz-option-wrap.is-wrong .quiz-option:not(.picked){opacity:.75}

/* tutor view */
.lesson-doc .hint.tutor-open{border-left:4px solid var(--green)}
.lesson-doc .quiz-student-pick{margin-left:6px;padding:1px 8px;border-radius:999px;background:#1e293b;color:#fff;font-size:12px;font-weight:600;white-space:nowrap}
.lesson-doc .quiz-not-answered{margin:8px 0 0;font-size:12.5px;color:var(--muted);font-style:italic}

.lesson-doc .hint pre{background:#1f1a17;color:#f5efe8;padding:12px 14px;border-radius:10px;overflow-x:auto}