/* ============================================================================
   LEARN — the gated learning area.

   Extends the site's existing brand rather than replacing it: the blue scale,
   Space Grotesk / Inter / IBM Plex Mono and the 14px radius all come straight
   from site.css. What is added here is a *surface scale* — the
   marketing site is one flat blue, but a documentation reader needs layered
   depth to separate a code block from a callout from the page beneath them.

   There is exactly one theme. The reader always renders in the brand's deep
   blue — no toggle, no prefers-color-scheme branch, no data-theme attribute.
   One appearance means one set of contrast decisions to get right, and it is
   the same on every Playbook page.
   ========================================================================= */

:root{
  /* Inherited brand */
  --l-brand:#3b82f6;
  --l-brand-deep:#1d56c4;

  /* The single accent. Every rule, badge, list marker, progress fill, timeline
     line and highlight box resolves here, so changing the accent is a one-line
     change rather than a hunt through the stylesheet. */
  --l-accent:#2f74e6;
  --l-accent-soft:rgba(47,116,230,0.18);
  --l-accent-line:rgba(47,116,230,0.42);

  /* Surfaces, dark theme (default) */
  --l-bg:#0f2f6b;
  --l-surface-1:#163a7d;
  --l-surface-2:#1d4590;
  --l-surface-3:#2453a6;
  --l-code-bg:#0a2350;

  --l-text-0:#ffffff;
  --l-text-1:rgba(255,255,255,0.84);
  --l-text-2:rgba(255,255,255,0.62);
  --l-text-3:rgba(255,255,255,0.42);

  --l-line:rgba(255,255,255,0.14);
  --l-line-strong:rgba(255,255,255,0.26);

  --l-ok:#4ade80;
  --l-warn:#2f74e6;   /* was amber; the brief replaces every yellow element with the accent, so warning callouts are distinguished by their glyph and title rather than by hue */
  --l-danger:#f87171;
  --l-info:#60a5fa;
  --l-tip:#5eead4;

  --l-radius:14px;
  --l-radius-sm:10px;
  --l-shadow:0 18px 44px rgba(4,20,54,0.34);
  --l-shadow-sm:0 6px 18px rgba(4,20,54,0.24);

  --l-rail-w:290px;
  --l-toc-w:230px;
  --l-topbar-h:64px;
  --l-measure:none;

  --l-disp:'Space Grotesk', sans-serif;
  --l-body:'Inter', sans-serif;
  --l-mono:'IBM Plex Mono', monospace;
}

/* ---------- shell ---------- */

body.learn{
  background:var(--l-bg);
  color:var(--l-text-0);
  font-family:var(--l-body);
  line-height:1.65;
  min-height:100vh;
  /* site.css sets Changa One on the universal selector; the reader needs Inter
     for body copy and Space Grotesk for headings, so both are reasserted. */
  -webkit-font-smoothing:antialiased;
}
/* The global box-sizing reset lives in site.css, which the learning pages do not
   load. Without this, any control with width:100% and padding overflows its
   container by exactly the padding plus border — which is what made form fields
   sit outside their card. Reset it here rather than patching each control. */
body.learn *, body.learn *::before, body.learn *::after{box-sizing:border-box;}

body.learn *{font-family:inherit;}
body.learn a{color:inherit; text-decoration:none;}
body.learn ul, body.learn ol{list-style:none;}

/* Form controls inherit the reader's type and never exceed their container. */
body.learn input, body.learn textarea, body.learn select{
  max-width:100%;
  font-family:var(--l-body);
}
body.learn input[type=checkbox], body.learn input[type=radio]{width:auto;}

.l-wrap{max-width:1440px; margin:0 auto; padding:0 28px;}

/* ---------- top bar ---------- */

.l-topbar{
  position:sticky; top:0; z-index:60;
  height:var(--l-topbar-h);
  display:flex; align-items:center; gap:20px;
  padding:0 28px;
  background:color-mix(in srgb, var(--l-bg) 82%, transparent);
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--l-line);
}
.l-topbar .brand{
  display:flex; align-items:center; gap:10px;
  font-family:var(--l-mono); font-size:14px; letter-spacing:-0.01em;
  color:var(--l-text-0); flex-shrink:0;
}
.l-topbar .brand .dot{
  width:8px; height:8px; border-radius:50%;
  background:var(--l-accent); box-shadow:0 0 12px var(--l-accent);
}
.l-topbar nav{display:flex; gap:26px; margin-left:14px;}
.l-topbar nav a{
  font-size:14px; color:var(--l-text-2); padding:6px 0;
  border-bottom:2px solid transparent; transition:color .2s, border-color .2s;
}
.l-topbar nav a:hover{color:var(--l-text-0);}
.l-topbar nav a.active{color:var(--l-text-0); border-bottom-color:var(--l-accent);}
.l-topbar .spacer{flex:1;}
.l-topbar .who{
  font-size:13px; color:var(--l-text-2);
  display:flex; align-items:center; gap:10px;
}
.l-avatar{
  width:32px; height:32px; border-radius:50%;
  background:linear-gradient(135deg, var(--l-brand), var(--l-brand-deep));
  color:#fff; display:grid; place-items:center;
  font-family:var(--l-disp); font-size:13px; font-weight:600;
  border:1px solid var(--l-line-strong);
}

.l-iconbtn{
  width:34px; height:34px; border-radius:9px;
  border:1px solid var(--l-line); background:var(--l-surface-2);
  color:var(--l-text-1); display:grid; place-items:center; cursor:pointer;
  transition:background .2s, color .2s, transform .15s;
}
.l-iconbtn:hover{background:var(--l-surface-3); color:var(--l-text-0); transform:translateY(-1px);}

/* ---------- buttons ---------- */

.l-btn{
  display:inline-flex; align-items:center; justify-content:center; gap:9px;
  padding:11px 20px; border-radius:10px; border:1px solid transparent;
  font-family:var(--l-body); font-size:14px; font-weight:600;
  cursor:pointer; transition:transform .18s, box-shadow .18s, background .18s;
  white-space:nowrap;
}
.l-btn:hover{transform:translateY(-2px);}
.l-btn-primary{
  background:linear-gradient(135deg, var(--l-brand), var(--l-brand-deep));
  color:#fff; box-shadow:var(--l-shadow-sm);
}
.l-btn-primary:hover{box-shadow:0 12px 28px rgba(59,130,246,0.36);}
.l-btn-accent{background:var(--l-accent); color:#fff;}
.l-btn-ghost{border-color:var(--l-line-strong); color:var(--l-text-1); background:transparent;}
.l-btn-ghost:hover{background:var(--l-surface-2); color:var(--l-text-0);}
.l-btn-sm{padding:7px 14px; font-size:13px;}
.l-btn:disabled{opacity:.5; cursor:not-allowed; transform:none;}

/* ---------- cards ---------- */

.l-card{
  /* Fills the content area it sits in. Nothing here reserves space for a second
     card alongside — where a page shows one card, it spans the full width, and
     grid containers below are what create multi-column arrangements when a page
     genuinely has several. */
  display:block;
  width:100%;
  max-width:none;
  box-sizing:border-box;

  background:var(--l-surface-1);
  border:1px solid var(--l-line);
  border-radius:var(--l-radius);
  padding:24px;
  box-shadow:var(--l-shadow-sm);
  transition:transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}
.l-card-hover:hover{
  transform:translateY(-3px);
  box-shadow:var(--l-shadow);
  border-color:var(--l-line-strong);
}

.l-eyebrow{
  font-family:var(--l-mono); font-size:11.5px; letter-spacing:.09em;
  text-transform:uppercase; color:var(--l-text-3);
  display:flex; align-items:center; gap:9px;
}
.l-eyebrow .bar{width:22px; height:1px; background:var(--l-accent);}

.l-h1{font-family:var(--l-disp); font-size:clamp(28px,3.4vw,40px); font-weight:700; letter-spacing:-0.02em; line-height:1.12;}
.l-h2{font-family:var(--l-disp); font-size:22px; font-weight:600; letter-spacing:-0.01em;}
.l-h3{font-family:var(--l-disp); font-size:17px; font-weight:600;}
.l-muted{color:var(--l-text-2); font-size:14px;}
.l-dim{color:var(--l-text-3); font-size:13px;}

.l-chip{
  display:inline-flex; align-items:center; gap:6px;
  font-family:var(--l-mono); font-size:11px; letter-spacing:.03em;
  padding:5px 11px; border-radius:20px;
  background:var(--l-surface-3); color:var(--l-text-1);
  border:1px solid var(--l-line);
}
.l-chip-accent{background:color-mix(in srgb, var(--l-accent) 18%, transparent); color:var(--l-accent); border-color:color-mix(in srgb, var(--l-accent) 34%, transparent);}
.l-chip-ok{background:color-mix(in srgb, var(--l-ok) 16%, transparent); color:var(--l-ok); border-color:color-mix(in srgb, var(--l-ok) 32%, transparent);}
.l-chip-danger{background:color-mix(in srgb, var(--l-danger) 16%, transparent); color:var(--l-danger); border-color:color-mix(in srgb, var(--l-danger) 32%, transparent);}

/* ---------- progress ----------

   One indicator, used everywhere: a straight horizontal white line with a light
   blue fill and the percentage above it. The circular rings this replaced are
   gone entirely — a single form means a student reads every progress figure in
   the Playbook the same way, whether it is a lesson, a level or a whole course.
*/

.l-progress{display:block; width:100%;}
.l-progress-head{
  display:flex; align-items:baseline; justify-content:space-between; gap:12px;
  margin-bottom:8px;
}
.l-progress-value{
  font-family:var(--l-disp); font-size:15px; font-weight:700; color:var(--l-text-0);
  line-height:1;
}
.l-progress-label{
  font-family:var(--l-mono); font-size:11px; letter-spacing:.07em;
  text-transform:uppercase; color:var(--l-text-3);
}

/* The track is a true straight line: square ends, full width, no rounding, so
   it reads as a rule rather than as a pill. */
.l-progress-track{
  position:relative;
  width:100%; height:3px;
  background:#ffffff;
  overflow:visible;
}
.l-progress-fill{
  display:block; height:100%;
  background:var(--l-progress-thumb, #7cb2f5);
  width:0;
  transition:width .9s cubic-bezier(.2,.8,.2,1);
}

/* The thumb sits on the line at the current position, so the exact value is
   readable at a glance even when the fill is short. */
.l-progress-thumb{
  position:absolute; top:50%; left:0;
  width:12px; height:12px; border-radius:50%;
  background:#7cb2f5;
  border:2px solid var(--l-bg);
  transform:translate(-50%,-50%);
  transition:left .9s cubic-bezier(.2,.8,.2,1);
}

.l-progress-sm .l-progress-value{font-size:13px;}
.l-progress-sm .l-progress-track{height:2px;}
.l-progress-sm .l-progress-thumb{width:9px; height:9px;}

/* Kept for the thin inline bars inside cards, now matching the same palette. */
.l-bar{height:3px; background:#ffffff; overflow:hidden;}
.l-bar span{
  display:block; height:100%;
  background:#7cb2f5;
  transition:width .9s cubic-bezier(.2,.8,.2,1);
}

/* ---------- reader layout ---------- */

.l-reader{
  display:grid;
  grid-template-columns:var(--l-rail-w) minmax(0,1fr) var(--l-toc-w);
  gap:36px;
  align-items:start;
  padding:32px 28px 96px;
  max-width:1600px; margin:0 auto;
}

.l-rail, .l-toc{
  position:sticky; top:calc(var(--l-topbar-h) + 24px);
  max-height:calc(100vh - var(--l-topbar-h) - 48px);
  overflow-y:auto;
  scrollbar-width:thin;
}
.l-rail::-webkit-scrollbar, .l-toc::-webkit-scrollbar{width:6px;}
.l-rail::-webkit-scrollbar-thumb, .l-toc::-webkit-scrollbar-thumb{background:var(--l-line-strong); border-radius:99px;}

/* level rail */
.l-level{
  border:1px solid var(--l-line); border-radius:12px;
  background:var(--l-surface-1); margin-bottom:12px; overflow:hidden;
}
.l-level-head{
  display:flex; align-items:center; gap:12px; padding:14px 16px;
  cursor:pointer; user-select:none;
}
.l-level-num{
  width:28px; height:28px; border-radius:8px; flex-shrink:0;
  display:grid; place-items:center;
  font-family:var(--l-mono); font-size:12px;
  background:var(--l-surface-3); color:var(--l-text-1);
}
.l-level.is-current .l-level-num{background:var(--l-accent); color:#fff;}
.l-level.is-locked{opacity:.72;}
.l-level.is-locked .l-level-num{background:transparent; border:1px dashed var(--l-line-strong); color:var(--l-text-3);}
.l-level-head h4{font-family:var(--l-disp); font-size:14px; font-weight:600; flex:1; min-width:0;}
.l-level-head .meta{font-family:var(--l-mono); font-size:11px; color:var(--l-text-3);}

.l-level-lessons{padding:0 10px 10px;}
.l-lesson-link{
  display:flex; align-items:center; gap:10px;
  padding:9px 10px; border-radius:8px;
  font-size:13.5px; color:var(--l-text-2);
  transition:background .18s, color .18s;
}
.l-lesson-link:hover{background:var(--l-surface-2); color:var(--l-text-0);}
.l-lesson-link.active{background:var(--l-surface-3); color:var(--l-text-0); font-weight:600;}
.l-lesson-link .tick{
  width:16px; height:16px; border-radius:50%; flex-shrink:0;
  border:1.5px solid var(--l-line-strong);
  display:grid; place-items:center; font-size:10px;
}
.l-lesson-link.done .tick{background:var(--l-ok); border-color:var(--l-ok); color:#04220f;}

/* ---------- article ---------- */

.l-article{min-width:0;}
.l-article-head{margin-bottom:34px; padding-bottom:26px; border-bottom:1px solid var(--l-line);}
.l-article-head h1{font-family:var(--l-disp); font-size:clamp(26px,3vw,36px); font-weight:700; letter-spacing:-0.02em; line-height:1.15; margin:12px 0 10px;}
.l-article-head .sub{color:var(--l-text-2); font-size:16px;}
.l-article-meta{display:flex; flex-wrap:wrap; gap:10px; margin-top:18px;}

/* Block rhythm. A documentation reader lives or dies on vertical spacing, so
   every block type gets its own margin rather than a blanket value. */
.l-blocks > * + *{margin-top:22px;}
.l-blocks h2{font-family:var(--l-disp); font-size:24px; font-weight:600; letter-spacing:-0.01em; margin-top:44px; scroll-margin-top:calc(var(--l-topbar-h) + 24px);}
.l-blocks h3{font-family:var(--l-disp); font-size:19px; font-weight:600; margin-top:34px; scroll-margin-top:calc(var(--l-topbar-h) + 24px);}
.l-blocks h4{font-family:var(--l-disp); font-size:16px; font-weight:600; margin-top:28px; scroll-margin-top:calc(var(--l-topbar-h) + 24px);}
.l-blocks p{color:var(--l-text-1); font-size:15.5px; line-height:1.78;}
.l-blocks strong{font-weight:650; color:var(--l-text-0);}
.l-blocks em{font-style:italic;}
.l-blocks a{color:var(--l-accent); border-bottom:1px solid color-mix(in srgb, var(--l-accent) 40%, transparent);}
.l-blocks a:hover{border-bottom-color:var(--l-accent);}
.l-blocks code.inline{
  font-family:var(--l-mono); font-size:13px;
  background:var(--l-surface-3); padding:2px 6px; border-radius:5px;
  border:1px solid var(--l-line);
}
.l-blocks ul, .l-blocks ol{padding-left:4px; display:flex; flex-direction:column; gap:9px;}
.l-blocks li{
  color:var(--l-text-1); font-size:15.5px; line-height:1.7;
  padding-left:26px; position:relative;
}
.l-blocks ul li::before{
  content:""; position:absolute; left:8px; top:11px;
  width:6px; height:6px; border-radius:50%; background:var(--l-accent);
}
.l-blocks ol{counter-reset:l-ol;}
.l-blocks ol li{counter-increment:l-ol;}
.l-blocks ol li::before{
  content:counter(l-ol); position:absolute; left:0; top:0;
  font-family:var(--l-mono); font-size:12px; color:var(--l-accent);
  width:18px; text-align:right;
}
.l-blocks hr{border:none; border-top:1px solid var(--l-line); margin:36px 0;}

/* table */
.l-table-wrap{overflow-x:auto; border:1px solid var(--l-line); border-radius:var(--l-radius-sm);}
.l-blocks table{width:100%; border-collapse:collapse; font-size:14px; min-width:440px;}
.l-blocks thead th{
  text-align:left; padding:13px 16px;
  background:var(--l-surface-2); color:var(--l-text-0);
  font-family:var(--l-disp); font-weight:600; font-size:13px;
  border-bottom:1px solid var(--l-line);
  white-space:nowrap;
}
.l-blocks tbody td{padding:12px 16px; color:var(--l-text-1); border-bottom:1px solid var(--l-line);}
.l-blocks tbody tr:last-child td{border-bottom:none;}
.l-blocks tbody tr:hover td{background:var(--l-surface-2);}
.l-table-caption{font-size:12.5px; color:var(--l-text-3); margin-top:9px; text-align:center;}

/* quote */
.l-quote{
  border-left:3px solid var(--l-accent);
  padding:6px 0 6px 22px;
}
.l-quote p{font-size:17px; font-style:italic; color:var(--l-text-0); line-height:1.6;}
.l-quote cite{display:block; margin-top:10px; font-style:normal; font-family:var(--l-mono); font-size:12.5px; color:var(--l-text-3);}

/* callout */
.l-callout{
  border-radius:var(--l-radius-sm);
  border:1px solid var(--c, var(--l-info));
  background:color-mix(in srgb, var(--c, var(--l-info)) 10%, transparent);
  padding:16px 18px 16px 48px;
  position:relative;
}
.l-callout::before{
  content:attr(data-glyph);
  position:absolute; left:16px; top:15px;
  width:20px; height:20px; border-radius:50%;
  background:var(--c, var(--l-info)); color:var(--l-bg);
  display:grid; place-items:center;
  font-size:12px; font-weight:700; font-family:var(--l-disp);
}
.l-callout h5{font-family:var(--l-disp); font-size:14px; font-weight:600; color:var(--c, var(--l-info)); margin-bottom:5px;}
.l-callout p{font-size:14.5px; color:var(--l-text-1); line-height:1.7;}
.l-callout.info{--c:var(--l-info);}
.l-callout.tip{--c:var(--l-tip);}
.l-callout.warning{--c:var(--l-warn);}
.l-callout.danger{--c:var(--l-danger);}
.l-callout.success{--c:var(--l-ok);}

/* figure */
.l-figure img{border-radius:var(--l-radius-sm); border:1px solid var(--l-line); width:100%;}
.l-figure figcaption{font-size:12.5px; color:var(--l-text-3); margin-top:9px; text-align:center;}

/* link card */
.l-linkcard{
  display:flex; align-items:center; gap:14px;
  padding:16px 18px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-2);
  transition:border-color .2s, transform .2s;
}
.l-linkcard:hover{border-color:var(--l-accent); transform:translateX(3px);}
.l-linkcard .body{flex:1; min-width:0;}
.l-linkcard h5{font-family:var(--l-disp); font-size:15px; font-weight:600;}
.l-linkcard p{font-size:13px; color:var(--l-text-2); margin-top:2px;}

/* ---------- code block ---------- */

.l-code{
  border:1px solid var(--l-line-strong);
  border-radius:var(--l-radius-sm);
  background:var(--l-code-bg);
  overflow:hidden;
  /* Code renders on its own dark surface in both themes: a snippet is a quoted
     artefact from an editor, and editors are dark. Keeping it constant also
     means the highlight palette only has to be tuned once. */
  color:#e6edf7;
}
.l-code-head{
  display:flex; align-items:center; gap:10px;
  padding:9px 12px; border-bottom:1px solid rgba(255,255,255,0.1);
  background:rgba(255,255,255,0.04);
}
.l-code-title{font-family:var(--l-disp); font-size:13.5px; font-weight:600; color:#fff;}
.l-code-spacer{flex:1;}
.l-code-tabs{display:flex; gap:4px; padding:8px 10px 0; background:rgba(255,255,255,0.02);}
.l-code-tab{
  font-family:var(--l-mono); font-size:12px;
  padding:7px 13px; border-radius:7px 7px 0 0;
  color:rgba(230,237,247,0.6); cursor:pointer;
  border:1px solid transparent; border-bottom:none;
  background:transparent; transition:background .18s, color .18s;
}
.l-code-tab:hover{color:#fff; background:rgba(255,255,255,0.05);}
.l-code-tab.active{background:var(--l-code-bg); color:#fff; border-color:rgba(255,255,255,0.12);}

.l-code-action{
  display:inline-flex; align-items:center; gap:6px;
  font-family:var(--l-mono); font-size:11.5px;
  padding:6px 11px; border-radius:7px; cursor:pointer;
  background:rgba(255,255,255,0.08); color:rgba(230,237,247,0.86);
  border:1px solid rgba(255,255,255,0.12);
  transition:background .18s, color .18s;
}
.l-code-action:hover{background:rgba(255,255,255,0.16); color:#fff;}
.l-code-action.copied{background:var(--l-ok); border-color:var(--l-ok); color:#04220f;}

.l-code-body{position:relative;}
.l-code-pane{display:none;}
.l-code-pane.active{display:block;}
.l-code pre{
  margin:0; padding:16px 16px 16px 0;
  overflow-x:auto; font-family:var(--l-mono); font-size:13px; line-height:1.65;
}
.l-code code{font-family:var(--l-mono); display:block;}

/* Line numbers are generated as a sibling column rather than ::before content
   on each line, so selecting the code and copying it does not drag the numbers
   along — the single most annoying thing a "premium" code block can do. */
.l-code-lines{
  display:grid; grid-template-columns:auto 1fr;
}
.l-code-gutter{
  padding:16px 12px 16px 16px; text-align:right;
  font-family:var(--l-mono); font-size:13px; line-height:1.65;
  color:rgba(230,237,247,0.3);
  border-right:1px solid rgba(255,255,255,0.08);
  user-select:none; -webkit-user-select:none;
  background:rgba(0,0,0,0.14);
}
.l-code-gutter span{display:block;}
.l-code-gutter span.hl{color:var(--l-accent);}

/* Collapsed state fades out rather than cutting, so it reads as "there is more"
   instead of "this is broken". */
.l-code-body.collapsed{max-height:var(--l-code-max, 420px); overflow:hidden;}
.l-code-body.collapsed::after{
  content:""; position:absolute; inset:auto 0 0 0; height:110px;
  background:linear-gradient(transparent, var(--l-code-bg));
  pointer-events:none;
}
.l-code-expand{
  width:100%; padding:10px; border:none; border-top:1px solid rgba(255,255,255,0.1);
  background:rgba(255,255,255,0.05); color:rgba(230,237,247,0.8);
  font-family:var(--l-mono); font-size:12px; cursor:pointer;
  transition:background .18s;
}
.l-code-expand:hover{background:rgba(255,255,255,0.1); color:#fff;}

.l-code-note{padding:14px 16px; border-top:1px solid rgba(255,255,255,0.1); font-size:13.5px;}
.l-code-note .k{font-family:var(--l-mono); font-size:11px; text-transform:uppercase; letter-spacing:.07em; color:rgba(230,237,247,0.5); display:block; margin-bottom:5px;}
.l-code-note p{color:rgba(230,237,247,0.82); line-height:1.7;}
.l-code-note pre{padding:10px 12px; background:rgba(0,0,0,0.28); border-radius:7px; font-size:12.5px; color:#c7f9d8;}

/* Minimal, self-hosted highlight palette. Deliberately restrained — six hues,
   all tested against the code surface for contrast. */
.hljs-keyword{color:#ff9ec7;}
.hljs-built_in,.hljs-type{color:#7dd3fc;}
.hljs-string,.hljs-attr{color:#a7f3d0;}
.hljs-number,.hljs-literal{color:#a5b4fc;}
.hljs-comment{color:rgba(230,237,247,0.42); font-style:italic;}
.hljs-title,.hljs-function{color:#c4b5fd;}
.hljs-meta{color:#94a3b8;}

/* ---------- video ---------- */

.l-video{border-radius:var(--l-radius-sm); overflow:hidden; border:1px solid var(--l-line); background:#000;}
.l-video video, .l-video iframe{width:100%; display:block; aspect-ratio:16/9; border:none;}
.l-video-bar{
  display:flex; align-items:center; gap:14px; flex-wrap:wrap;
  padding:11px 14px; background:var(--l-surface-2); border-top:1px solid var(--l-line);
}
.l-video-bar select{
  font-family:var(--l-mono); font-size:12px; padding:5px 9px;
  border-radius:7px; border:1px solid var(--l-line);
  background:var(--l-surface-3); color:var(--l-text-1); cursor:pointer;
}
.l-video-bar .grow{flex:1;}

/* ---------- attachments ---------- */

.l-files{display:grid; gap:10px;}
.l-file{
  display:flex; align-items:center; gap:14px;
  padding:14px 16px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-2);
  transition:border-color .2s, transform .2s;
}
.l-file:hover{border-color:var(--l-line-strong); transform:translateX(3px);}
.l-file.locked{opacity:.6;}
.l-file-icon{
  width:38px; height:38px; border-radius:9px; flex-shrink:0;
  display:grid; place-items:center;
  font-family:var(--l-mono); font-size:10px; font-weight:600;
  background:var(--l-surface-3); color:var(--l-accent);
  border:1px solid var(--l-line);
}
.l-file .body{flex:1; min-width:0;}
.l-file h5{font-family:var(--l-disp); font-size:14.5px; font-weight:600;}
.l-file p{font-size:12.5px; color:var(--l-text-2); margin-top:2px;}
.l-file .size{font-family:var(--l-mono); font-size:11px; color:var(--l-text-3);}

/* ---------- practice task ---------- */

.l-task{
  border:1px solid var(--l-line-strong); border-radius:var(--l-radius);
  background:var(--l-surface-1); overflow:hidden;
}
.l-task-head{
  display:flex; align-items:flex-start; gap:14px;
  padding:20px 22px; border-bottom:1px solid var(--l-line);
  background:linear-gradient(135deg, color-mix(in srgb, var(--l-accent) 8%, transparent), transparent);
}
.l-task-head .num{
  width:34px; height:34px; border-radius:10px; flex-shrink:0;
  display:grid; place-items:center;
  background:var(--l-accent); color:#fff;
  font-family:var(--l-disp); font-weight:700; font-size:15px;
}
.l-task-head .body{flex:1; min-width:0;}
.l-task-head h4{font-family:var(--l-disp); font-size:17px; font-weight:600;}
.l-task-head p{font-size:14px; color:var(--l-text-2); margin-top:4px;}
.l-task-section{padding:18px 22px; border-bottom:1px solid var(--l-line);}
.l-task-section:last-child{border-bottom:none;}
.l-task-section > .k{
  font-family:var(--l-mono); font-size:11px; text-transform:uppercase;
  letter-spacing:.07em; color:var(--l-text-3); display:block; margin-bottom:11px;
}
.l-req{display:flex; flex-direction:column; gap:9px;}
.l-req li{display:flex; gap:11px; font-size:14.5px; color:var(--l-text-1); line-height:1.65;}
.l-req li::before{content:"□"; color:var(--l-accent); flex-shrink:0; font-size:15px; line-height:1.5;}
.l-hints{display:flex; flex-direction:column; gap:9px;}
.l-hint{
  padding:12px 15px; border-radius:var(--l-radius-sm);
  background:color-mix(in srgb, var(--l-tip) 9%, transparent);
  border:1px solid color-mix(in srgb, var(--l-tip) 26%, transparent);
  font-size:14px; color:var(--l-text-1); line-height:1.65;
}
.l-hint .n{font-family:var(--l-mono); font-size:11px; color:var(--l-tip); display:block; margin-bottom:4px;}
.l-task-actions{display:flex; flex-wrap:wrap; gap:10px; padding:18px 22px; background:var(--l-surface-2);}
.l-task.is-complete{border-color:color-mix(in srgb, var(--l-ok) 46%, transparent);}
.l-task.is-complete .l-task-head{background:linear-gradient(135deg, color-mix(in srgb, var(--l-ok) 12%, transparent), transparent);}
.l-task.is-complete .l-task-head .num{background:var(--l-ok); color:#04220f;}

/* ---------- table of contents ---------- */

.l-toc h5{
  font-family:var(--l-mono); font-size:11px; text-transform:uppercase;
  letter-spacing:.08em; color:var(--l-text-3); margin-bottom:14px;
}
.l-toc a{
  display:block; padding:6px 0 6px 13px;
  font-size:13px; color:var(--l-text-2);
  border-left:2px solid var(--l-line);
  transition:color .2s, border-color .2s;
}
.l-toc a:hover{color:var(--l-text-0);}
.l-toc a.active{color:var(--l-accent); border-left-color:var(--l-accent); font-weight:600;}
.l-toc a.lvl-3{padding-left:26px; font-size:12.5px;}
.l-toc a.lvl-4{padding-left:38px; font-size:12px;}

.l-side-card{
  background:var(--l-surface-1); border:1px solid var(--l-line);
  border-radius:12px; padding:16px; margin-bottom:16px;
}

/* ---------- locked state ---------- */

.l-locked{
  text-align:center; padding:70px 32px;
  border:1px dashed var(--l-line-strong); border-radius:var(--l-radius);
  background:
    radial-gradient(circle at 50% 0%, color-mix(in srgb, var(--l-accent) 8%, transparent), transparent 62%),
    var(--l-surface-1);
}
.l-locked .lock{
  width:64px; height:64px; margin:0 auto 22px; border-radius:18px;
  display:grid; place-items:center;
  background:var(--l-surface-3); color:var(--l-accent);
  border:1px solid var(--l-line-strong);
}
.l-locked h2{font-family:var(--l-disp); font-size:24px; font-weight:700; margin-bottom:10px;}
.l-locked p{color:var(--l-text-2); max-width:460px; margin:0 auto 24px; font-size:15px;}

/* ---------- empty & skeleton ---------- */

.l-empty{
  text-align:center; padding:56px 28px;
  border:1px dashed var(--l-line); border-radius:var(--l-radius);
  color:var(--l-text-2);
}
.l-empty h3{font-family:var(--l-disp); font-size:18px; color:var(--l-text-0); margin-bottom:8px;}

.l-skel{
  background:linear-gradient(90deg, var(--l-surface-2) 25%, var(--l-surface-3) 50%, var(--l-surface-2) 75%);
  background-size:200% 100%;
  animation:l-shimmer 1.4s infinite;
  border-radius:8px;
}
@keyframes l-shimmer{to{background-position:-200% 0;}}

/* ---------- toast ---------- */

.l-toasts{position:fixed; right:22px; bottom:22px; z-index:200; display:flex; flex-direction:column; gap:10px;}
.l-toast{
  display:flex; align-items:center; gap:11px;
  padding:13px 18px; border-radius:11px;
  background:var(--l-surface-1); border:1px solid var(--l-line-strong);
  box-shadow:var(--l-shadow); font-size:14px; color:var(--l-text-0);
  animation:l-toast-in .3s cubic-bezier(.2,.9,.3,1.2);
}
.l-toast.ok{border-left:3px solid var(--l-ok);}
.l-toast.err{border-left:3px solid var(--l-danger);}
@keyframes l-toast-in{from{opacity:0; transform:translateY(14px) scale(.96);} to{opacity:1; transform:none;}}

/* ---------- reveal on scroll ---------- */

.l-reveal{opacity:0; transform:translateY(14px);}
.l-reveal.in{opacity:1; transform:none; transition:opacity .55s ease, transform .55s cubic-bezier(.2,.8,.2,1);}

/* Reading progress, pinned above the top bar. */
.l-readbar{position:fixed; top:0; left:0; right:0; height:2px; z-index:70; background:transparent;}
.l-readbar span{display:block; height:100%; width:0; background:linear-gradient(90deg, var(--l-brand), var(--l-accent));}

/* ---------- responsive ---------- */

@media (max-width:1280px){
  .l-reader{grid-template-columns:var(--l-rail-w) minmax(0,1fr); }
  .l-toc{display:none;}
}

@media (max-width:1000px){
  .l-reader{grid-template-columns:1fr; gap:24px; padding:22px 20px 80px;}
  /* The rail becomes an off-canvas drawer rather than disappearing — on a phone
     it is the only way to move between lessons. */
  .l-rail{
    position:fixed; inset:var(--l-topbar-h) auto 0 0; width:min(320px, 86vw);
    max-height:none; z-index:80; padding:20px;
    background:var(--l-surface-1); border-right:1px solid var(--l-line);
    transform:translateX(-102%); transition:transform .3s cubic-bezier(.2,.8,.2,1);
    overflow-y:auto;
  }
  .l-rail.open{transform:none; box-shadow:var(--l-shadow);}
  .l-rail-scrim{
    position:fixed; inset:0; z-index:79; background:rgba(4,20,54,0.5);
    opacity:0; pointer-events:none; transition:opacity .3s;
  }
  .l-rail-scrim.open{opacity:1; pointer-events:auto;}
  .l-topbar nav{display:none;}
}

@media (max-width:640px){
  .l-wrap{padding:0 18px;}
  .l-card{padding:18px;}
  .l-btn{width:100%;}
  .l-task-actions .l-btn{width:auto; flex:1;}
  .l-code pre{font-size:12px;}
}

@media (prefers-reduced-motion: reduce){
  .l-reveal, .l-reveal.in{opacity:1; transform:none; transition:none;}
  .l-bar span, .l-ring .fill{transition:none;}
  .l-card-hover:hover, .l-btn:hover, .l-file:hover, .l-linkcard:hover{transform:none;}
  .l-skel{animation:none;}
  .l-toast{animation:none;}
}

/* ---------- teaching blocks ---------- */

/* Expandable aside. <details>/<summary> rather than a JS toggle: it is keyboard
   accessible, findable by in-page search when open, and works with no script. */
.l-expand{
  border:1px solid var(--l-line); border-radius:var(--l-radius-sm);
  background:var(--l-surface-2); overflow:hidden;
}
.l-expand > summary{
  list-style:none; cursor:pointer;
  padding:14px 18px; display:flex; align-items:center; gap:11px;
  font-family:var(--l-disp); font-size:15px; font-weight:600; color:var(--l-text-0);
}
.l-expand > summary::-webkit-details-marker{display:none;}
.l-expand > summary::before{
  content:"›"; display:inline-block; color:var(--l-accent);
  font-size:19px; line-height:1; transition:transform .2s;
}
.l-expand[open] > summary::before{transform:rotate(90deg);}
.l-expand > summary:hover{background:var(--l-surface-3);}
.l-expand-body{padding:2px 18px 16px 40px; display:flex; flex-direction:column; gap:9px;}
.l-expand-body li{color:var(--l-text-1); font-size:14.5px; line-height:1.7;}

/* Best practices / common mistakes. Same structure, opposite marker and edge. */
.l-practice{
  border:1px solid var(--l-line); border-left:3px solid var(--c, var(--l-accent));
  border-radius:var(--l-radius-sm); background:var(--l-surface-2);
  padding:18px 20px;
}
.l-practice h5{
  font-family:var(--l-disp); font-size:14px; font-weight:600;
  color:var(--c, var(--l-accent)); margin-bottom:13px;
  display:flex; align-items:center; gap:8px;
}
.l-practice ul{display:flex; flex-direction:column; gap:12px;}
.l-practice li{display:flex; gap:11px; font-size:14.5px; color:var(--l-text-1); line-height:1.7;}
.l-practice li .mark{flex-shrink:0; font-weight:700; color:var(--c, var(--l-accent));}
.l-practice li .detail{display:block; color:var(--l-text-2); font-size:13.5px; margin-top:3px;}
.l-practice.good{--c:var(--l-ok);}
.l-practice.bad{--c:var(--l-danger);}

/* Additional resources */
.l-resources{
  border:1px solid var(--l-line); border-radius:var(--l-radius-sm);
  background:var(--l-surface-2); padding:18px 20px;
}
.l-resources h5{
  font-family:var(--l-disp); font-size:14px; font-weight:600;
  color:var(--l-accent); margin-bottom:13px;
}
.l-resources a{
  display:flex; align-items:baseline; gap:10px; padding:8px 0;
  border-top:1px solid var(--l-line); color:var(--l-text-1); font-size:14.5px;
}
.l-resources a:first-of-type{border-top:none;}
.l-resources a:hover{color:var(--l-accent);}
.l-resources a .desc{color:var(--l-text-3); font-size:13px;}

/* ---------- free / paid curriculum marks ---------- */

.l-free{
  font-family:var(--l-mono); font-size:10.5px; letter-spacing:.05em;
  text-transform:uppercase; padding:3px 8px; border-radius:20px;
  background:color-mix(in srgb, var(--l-ok) 16%, transparent);
  color:var(--l-ok); border:1px solid color-mix(in srgb, var(--l-ok) 34%, transparent);
}
.l-paid{
  font-family:var(--l-mono); font-size:10.5px; letter-spacing:.05em;
  text-transform:uppercase; padding:3px 8px; border-radius:20px;
  background:var(--l-surface-3); color:var(--l-text-3); border:1px solid var(--l-line);
}

/* ---------- premium lock (unpurchased playbook) ---------- */

/* Distinct from .l-paid on purpose. "Paid" describes what a session *is*;
   "Premium" with a lock describes what this student currently cannot open.
   A purchaser sees the first and never the second. */
.l-badge-premium{
  display:inline-flex; align-items:center; gap:5px;
  font-family:var(--l-mono); font-size:10.5px; letter-spacing:.05em;
  text-transform:uppercase; padding:3px 9px; border-radius:20px;
  background:color-mix(in srgb, var(--l-warn, #e0a458) 16%, transparent);
  color:var(--l-warn, #e0a458);
  border:1px solid color-mix(in srgb, var(--l-warn, #e0a458) 38%, transparent);
}

/* Dimmed and un-hoverable, so the row reads as unavailable before it is clicked.
   Opacity only — the title stays legible, because the point is to show what is
   being offered, not to hide it. */
.l-file-locked{
  opacity:.58;
  border-style:dashed;
}
.l-file-locked:hover{
  transform:none;
  border-color:color-mix(in srgb, var(--l-warn, #e0a458) 45%, transparent);
  opacity:.78;
}
.l-file-locked .l-file-icon{
  color:var(--l-warn, #e0a458);
}

/* A card that tells the reader something useful rather than something wrong.
   Blue-accented, so it is clearly not the red validation strip and clearly not an error: nothing
   has failed, there is just a better next step than the form underneath it. */
.l-notice{
  padding:22px 24px;
  border-color:color-mix(in srgb, var(--l-info) 34%, transparent);
  background:linear-gradient(180deg, color-mix(in srgb, var(--l-info) 8%, transparent), transparent);
}
.l-notice .l-btn{width:100%; text-align:center;}

/* The one-time credentials banner, shown on the playbook a self-registered student has just been
   let into. Green rather than the preview banner's accent: this one is a success, and it must not
   be mistaken at a glance for the "you are missing something" notice sitting under it. */
.l-new-account{
  border-color:color-mix(in srgb, var(--l-ok) 40%, transparent);
  background:linear-gradient(180deg, color-mix(in srgb, var(--l-ok) 8%, transparent), transparent);
}
/* Label above value rather than a two-column grid: the password is monospace and long, and a
   fixed label column squeezes it into a wrap on a phone. */
.l-credentials{display:grid; gap:12px;}
.l-credentials dt{
  font-family:var(--l-mono); font-size:11.5px; letter-spacing:.06em;
  text-transform:uppercase; color:var(--l-text-3);
}
.l-credentials dd{
  font-family:var(--l-mono); font-size:15px; color:var(--l-text-0);
  /* Selectable in one gesture and wrapping mid-token, because a generated password has no spaces
     to break at and must never be clipped out of sight. */
  user-select:all; word-break:break-all; margin-top:3px;
}

.l-preview-banner{
  border-color:color-mix(in srgb, var(--l-warn, #e0a458) 34%, transparent);
  background:linear-gradient(180deg,
    color-mix(in srgb, var(--l-warn, #e0a458) 7%, transparent), transparent);
}

.l-lock-premium{
  /* No fill: the amber icon and its ring carry the premium mark on their own. Transparent rather
     than an omitted declaration, because leaving it out falls back to the grey .lock tile. */
  background:transparent !important;
  color:var(--l-warn, #e0a458) !important;
  border-color:color-mix(in srgb, var(--l-warn, #e0a458) 38%, transparent) !important;
}

/* ---------- purchase dialog ---------- */

/* A native <dialog>: the browser handles focus trapping, Escape and inertness of
   the page behind it, all of which a hand-rolled modal gets wrong first. */
.l-dialog{
  border:1px solid var(--l-line-strong); border-radius:16px;
  background:var(--l-surface-2); color:var(--l-text-1);
  padding:0; max-width:460px; width:calc(100% - 32px);
  box-shadow:0 24px 70px rgba(0,0,0,.5);
}
.l-dialog::backdrop{
  background:rgba(6,10,20,.72);
  backdrop-filter:blur(3px);
}
.l-dialog-body{
  padding:30px 28px 26px;
  text-align:center;
}
.l-dialog-body p{max-width:none;}

/* ---------- auto-graded self-check ----------

   This block replaced the submission and instructor-feedback styles. Nothing here
   is decorative: the right/wrong colouring is the entire feedback channel now that
   no person reads a student's work, so it has to be unambiguous at a glance and
   still readable to someone who cannot distinguish the two hues — hence the ✓/✗
   glyphs and the left border weight carrying the same signal as the colour.
*/

.l-checks{
  border-top:1px solid var(--l-line);
  padding:20px 22px 22px; background:var(--l-surface-2);
}
.l-checks-head{
  display:flex; align-items:center; gap:12px; flex-wrap:wrap; margin-bottom:8px;
}
.l-checks-head h5{
  font-family:var(--l-mono); font-size:11px; text-transform:uppercase;
  letter-spacing:.07em; color:var(--l-text-3); margin:0;
}
.l-checks-score{
  font-family:var(--l-mono); font-size:11px; letter-spacing:.04em;
  padding:3px 10px; border-radius:20px;
  border:1px solid var(--l-line); color:var(--l-text-3); background:var(--l-surface-3);
}
.l-checks-score.ok{
  --sc:var(--l-ok);
  color:var(--sc); border-color:color-mix(in srgb, var(--sc) 40%, transparent);
  background:color-mix(in srgb, var(--sc) 14%, transparent);
}
.l-checks-score.warn{
  --sc:var(--l-danger);
  color:var(--sc); border-color:color-mix(in srgb, var(--sc) 40%, transparent);
  background:color-mix(in srgb, var(--sc) 14%, transparent);
}

.l-check{
  border:1px solid var(--l-line); border-left:3px solid var(--l-line);
  border-radius:var(--l-radius-sm);
  background:var(--l-surface-1); padding:16px 18px; margin-bottom:12px;
}
.l-check.is-right{border-left-color:var(--l-ok);}
.l-check.is-wrong{border-left-color:var(--l-danger);}

/* Pressed "check" with this one still blank. Deliberately a different treatment
   from is-wrong: nothing has been marked, and colouring an unanswered question the
   same as a failed one would tell the student they got it wrong when they have not
   yet answered it. */
.l-check.is-unanswered{
  border-color:color-mix(in srgb, var(--l-warn, #e0a458) 50%, transparent);
  border-left-color:var(--l-warn, #e0a458);
  background:color-mix(in srgb, var(--l-warn, #e0a458) 6%, transparent);
}
.l-check.is-unanswered .l-check-q::after{
  content:"answer required";
  font-family:var(--l-mono); font-size:10.5px; letter-spacing:.05em;
  text-transform:uppercase; color:var(--l-warn, #e0a458);
  margin-left:auto; padding-left:12px; white-space:nowrap; flex:none;
}

.l-check-q{
  font-size:14.5px; color:var(--l-text-0); line-height:1.65;
  margin-bottom:12px; display:flex; gap:10px; align-items:baseline;
}
.l-check-q .n{
  flex:none; font-family:var(--l-mono); font-size:11px; color:var(--l-text-3);
  min-width:18px;
}

.l-check-text{
  width:100%; box-sizing:border-box;
  padding:10px 13px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line-strong); background:var(--l-surface-2);
  color:var(--l-text-0); font-family:var(--l-body); font-size:14px;
}

.l-check-options{list-style:none; margin:0; padding:0; display:flex; flex-direction:column; gap:8px;}

.l-check-option{
  display:grid; grid-template-columns:auto 1fr; gap:4px 11px; align-items:start;
  padding:11px 13px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-2);
  cursor:pointer; transition:border-color .12s ease, background .12s ease;
}
.l-check-option:hover{border-color:var(--l-line-strong);}
.l-check-option input{margin:3px 0 0; accent-color:var(--l-accent); cursor:pointer;}
.l-check-option .t{font-size:14px; color:var(--l-text-1); line-height:1.6;}

/* The correction, per option. Only ever rendered for the one the student picked
   and the one they should have — annotating all four turns the question into a
   list of answers to memorise. */
.l-check-option .f{
  grid-column:2;
  font-size:13px; line-height:1.65; color:var(--l-text-2);
  padding-top:6px; margin-top:5px; border-top:1px dashed var(--l-line);
}
.l-check-option.right{
  border-color:color-mix(in srgb, var(--l-ok) 45%, transparent);
  background:color-mix(in srgb, var(--l-ok) 9%, transparent);
}
.l-check-option.right .f{color:var(--l-ok);}
.l-check-option.wrong{
  border-color:color-mix(in srgb, var(--l-danger) 45%, transparent);
  background:color-mix(in srgb, var(--l-danger) 9%, transparent);
}
.l-check-option.wrong .f{color:var(--l-danger);}

.l-check-verdict{margin-top:13px;}
.l-check-verdict .v{
  font-family:var(--l-mono); font-size:11px; letter-spacing:.05em;
  text-transform:uppercase; display:block; margin-bottom:6px;
}
.l-check.is-right .l-check-verdict .v{color:var(--l-ok);}
.l-check.is-wrong .l-check-verdict .v{color:var(--l-danger);}
.l-check-verdict .why{font-size:13.5px; color:var(--l-text-2); line-height:1.7;}
.l-check-verdict .model{
  font-family:var(--l-mono); font-size:12.5px; color:var(--l-text-1);
  margin-top:8px; padding:8px 11px; border-radius:var(--l-radius-sm);
  background:var(--l-surface-3); border:1px solid var(--l-line);
}

.l-checks-actions{display:flex; gap:11px; flex-wrap:wrap; margin-top:16px;}

/* ---------- sign-in ----------

   The Playbook's own auth screen. Rules live here rather than inline on the view
   so the narrow-viewport behaviour is defined once — this is the page most likely
   to be opened on a phone, from a link an instructor sent.
*/

.l-auth-shell{
  min-height:100vh;
  display:flex; align-items:center; justify-content:center;
  /* Padding rather than a fixed viewport height: on a short screen the card
     scrolls instead of being clipped. */
  padding:40px 20px;
  background:
    radial-gradient(circle at 20% 10%, rgba(59,130,246,.22), transparent 55%),
    radial-gradient(circle at 85% 80%, rgba(47,116,230,.16), transparent 50%);
}

/* min() rather than a flat max-width, so the card shrinks with the viewport
   instead of forcing the page to scroll sideways. */
.l-auth{width:min(420px, 100%);}

.l-field{margin-bottom:16px;}
.l-field label{
  display:block; margin-bottom:7px;
  color:var(--l-text-3); font-size:13px;
}
.l-field input{
  width:100%;
  padding:12px 14px; border-radius:10px;
  border:1px solid var(--l-line-strong);
  background:var(--l-surface-2); color:var(--l-text-0);
  font-family:var(--l-body); font-size:14.5px;
  transition:border-color .2s;
}
.l-field input:focus{border-color:var(--l-accent); outline:none;}
.l-field input::placeholder{color:var(--l-text-3);}

.l-field-error{color:var(--l-danger); font-size:12.5px; display:block; margin-top:6px;}

.l-auth-errors{color:var(--l-danger); font-size:13.5px; margin-bottom:18px;}
.l-auth-errors ul{display:flex; flex-direction:column; gap:6px;}
/* The tag helper still emits the element when there is nothing wrong — without
   this it renders as an empty gap above the first field. */
.l-auth-errors.validation-summary-valid{display:none;}

.l-remember{
  display:flex; align-items:center; gap:9px; margin-bottom:22px;
  font-size:13.5px; color:var(--l-text-2); cursor:pointer;
}
.l-remember input{accent-color:var(--l-accent);}

@media (max-width:420px){
  .l-auth-shell{padding:28px 16px;}
  .l-auth .l-card{padding:22px 18px;}
}

/* ══════════════════════════════════════════════════════════════════════════
   Architecture Simulator

   Reuses the reader's surfaces, chips and callouts wherever they fit — only
   the things with no existing equivalent are defined here: the questionnaire
   grid, the score bars, the reason lists and the evolution timeline.
   ══════════════════════════════════════════════════════════════════════════ */

.l-sim-form{display:flex; flex-direction:column; gap:18px;}

.l-sim-section h2{margin-bottom:18px;}

.l-sim-grid{
  display:grid; gap:18px;
  grid-template-columns:repeat(auto-fit, minmax(230px, 1fr));
}

.l-sim-field{display:flex; flex-direction:column; gap:7px;}
.l-sim-field > span{
  font-family:var(--l-disp); font-size:13px; font-weight:600;
  color:var(--l-text-1); letter-spacing:.01em;
}
.l-sim-field input, .l-sim-field select{
  width:100%; padding:10px 12px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-1);
  color:var(--l-text-0); font-family:var(--l-body); font-size:14px;
}
.l-sim-field select{cursor:pointer;}
/* The dropdown panel is painted by the OS, which does not inherit the page's
   colours — without this the options render as dark text on dark. */
.l-sim-field select option{background:var(--l-surface-2); color:var(--l-text-0);}
.l-sim-field input:focus, .l-sim-field select:focus{
  border-color:var(--l-accent); outline:none;
  box-shadow:0 0 0 3px var(--l-accent-soft);
}
.l-sim-field small{font-size:12.5px; color:var(--l-text-3); line-height:1.55;}

.l-sim-checks{display:grid; gap:12px; grid-template-columns:repeat(auto-fit, minmax(290px, 1fr));}

.l-sim-check{
  display:flex; align-items:flex-start; gap:11px; cursor:pointer;
  padding:13px 15px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-1);
  transition:border-color .15s ease, background .15s ease;
}
.l-sim-check:hover{border-color:var(--l-accent-line);}
.l-sim-check input{margin-top:2px; accent-color:var(--l-accent); flex-shrink:0;}
.l-sim-check > span{display:flex; flex-direction:column; gap:4px;}
.l-sim-check strong{font-size:13.5px; font-weight:600; color:var(--l-text-0);}
.l-sim-check small{font-size:12.5px; color:var(--l-text-3); line-height:1.6;}

/* ---- Verdict ---- */

.l-sim-verdict{
  border-color:var(--l-accent-line);
  background:linear-gradient(135deg, color-mix(in srgb, var(--l-accent) 12%, transparent), transparent);
}
.l-sim-verdict-head{
  display:flex; align-items:flex-start; justify-content:space-between;
  gap:24px; flex-wrap:wrap;
}
.l-sim-score{display:flex; align-items:baseline; gap:5px; flex-shrink:0;}
.l-sim-score .n{
  font-family:var(--l-disp); font-size:56px; font-weight:700; line-height:1;
  color:var(--l-accent);
}
.l-sim-score .d{font-size:15px; color:var(--l-text-3);}

.l-sim-sub{font-family:var(--l-disp); font-size:13px; font-weight:600; margin-bottom:12px;}

/* ---- Reason lists ---- */

.l-sim-reasons{display:flex; flex-direction:column; gap:11px;}
.l-sim-reasons li{
  display:flex; gap:12px; align-items:flex-start;
  font-size:14px; color:var(--l-text-1); line-height:1.7;
}
.l-sim-reasons .delta{
  flex-shrink:0; min-width:42px; text-align:center;
  font-family:var(--l-mono); font-size:12.5px; font-weight:500;
  padding:2px 7px; border-radius:6px;
}
.l-sim-reasons .delta.up{
  background:color-mix(in srgb, var(--l-ok) 16%, transparent); color:var(--l-ok);
}
.l-sim-reasons .delta.down{
  background:color-mix(in srgb, var(--l-danger) 16%, transparent); color:var(--l-danger);
}

/* ---- Score bars ---- */

.l-sim-bars{display:flex; flex-direction:column; gap:9px;}
.l-sim-bar{
  display:grid; grid-template-columns:210px 1fr 44px; gap:14px; align-items:center;
  padding:11px 15px; border-radius:var(--l-radius-sm);
  border:1px solid var(--l-line); background:var(--l-surface-1);
}
.l-sim-bar .name{
  font-size:13.5px; color:var(--l-text-1);
  display:flex; align-items:center; gap:8px; flex-wrap:wrap;
}
.l-sim-bar .track{height:8px; border-radius:99px; background:var(--l-surface-3); overflow:hidden;}
.l-sim-bar .track span{
  display:block; height:100%; border-radius:99px;
  background:var(--l-text-3); transition:width .4s ease;
}
.l-sim-bar .score{
  font-family:var(--l-mono); font-size:13px; color:var(--l-text-2); text-align:right;
}
/* The student's own decision, not the top scorer — the bar chart highlights what they chose so
   the eye lands on their row rather than on the winner. */
.l-sim-bar.is-chosen{border-color:var(--l-accent-line);}
.l-sim-bar.is-chosen .track span{background:var(--l-accent);}
.l-sim-bar.is-chosen .name, .l-sim-bar.is-chosen .score{color:var(--l-text-0); font-weight:600;}
.l-sim-bar.is-rejected{opacity:.55; border-style:dashed;}

@media (max-width:640px){
  .l-sim-bar{grid-template-columns:1fr 44px; }
  .l-sim-bar .track{grid-column:1/-1;}
}

/* ---- Suggestions ---- */

.l-sim-cols{display:grid; gap:16px; grid-template-columns:repeat(auto-fit, minmax(300px, 1fr));}

.l-sim-suggestions{display:flex; flex-direction:column; gap:14px;}
.l-sim-suggestions li{display:flex; flex-direction:column; gap:4px;}
.l-sim-suggestions strong{
  font-family:var(--l-disp); font-size:14px; font-weight:600; color:var(--l-accent);
}
.l-sim-suggestions span{font-size:13.5px; color:var(--l-text-2); line-height:1.7;}
.l-sim-suggestions.muted strong{color:var(--l-text-2);}

/* ---- Grouped suggestions and risks ----

   The rule set produces around thirty suggestions for a busy brief, and every one of them is
   worth saying — so the answer is reading order, not a shorter list. Each group is a plain
   <details>: no JavaScript, works before the stylesheet loads, and prints expanded when the
   browser prints. Groups holding something essential are rendered open by the view. */

.l-sim-group{border-top:1px solid var(--l-line); padding:14px 0;}
.l-sim-group:first-of-type{border-top:0; padding-top:0;}
.l-sim-group > summary{
  display:flex; align-items:center; gap:10px; cursor:pointer;
  list-style:none; padding:2px 0;
}
.l-sim-group > summary::-webkit-details-marker{display:none;}
/* The marker is drawn rather than inherited so it can rotate — a caret that turns is the clearest
   available signal that the section is a container and not a heading. */
.l-sim-group > summary::before{
  content:"›"; font-size:17px; line-height:1; color:var(--l-text-3);
  transition:transform .18s ease; transform:rotate(0deg);
}
.l-sim-group[open] > summary::before{transform:rotate(90deg);}
.l-sim-group > summary:hover .l-sim-group-title{color:var(--l-text-0);}
.l-sim-group-title{
  font-family:var(--l-disp); font-size:13px; font-weight:600; letter-spacing:.01em;
  color:var(--l-text-1); flex:1;
}
.l-sim-group-count{
  font-family:var(--l-mono); font-size:11.5px; color:var(--l-text-2);
  background:var(--l-surface-2); border:1px solid var(--l-line);
  border-radius:99px; padding:1px 8px; min-width:24px; text-align:center;
}

.l-sim-priority{
  font-family:var(--l-mono); font-size:10px; font-weight:600; letter-spacing:.06em;
  text-transform:uppercase; border-radius:99px; padding:2px 7px; margin-left:7px;
  vertical-align:middle; white-space:nowrap;
}
.l-sim-priority.essential{
  color:#fecaca; background:rgba(239,68,68,0.16); border:1px solid rgba(239,68,68,0.4);
}
.l-sim-priority.optional{
  color:var(--l-text-2); background:var(--l-surface-2); border:1px solid var(--l-line);
}

/* A collapsed section is a section somebody cannot read, and the printed report is the one that
   gets taken into a review meeting. Best effort only: browsers disagree on whether the contents of
   a closed <details> can be revealed from CSS at all, which is the price of using the element that
   needs no JavaScript. */
@media print{
  .l-sim-group > summary::before{display:none;}
  .l-sim-group > *{display:block !important;}
}

/* ---- Evolution timeline ---- */

.l-sim-timeline{display:flex; flex-direction:column;}
.l-sim-timeline li{
  display:grid; grid-template-columns:110px 1fr; gap:20px;
  padding:0 0 26px 0; position:relative;
}
/* The connecting line is drawn from each item except the last, so the timeline
   ends at the final marker instead of trailing past it. */
.l-sim-timeline li:not(:last-child)::before{
  content:""; position:absolute; left:127px; top:16px; bottom:-4px;
  width:1px; background:var(--l-line-strong);
}
.l-sim-timeline li::after{
  content:""; position:absolute; left:123px; top:10px;
  width:9px; height:9px; border-radius:50%;
  background:var(--l-accent); box-shadow:0 0 0 4px var(--l-bg);
}
.l-sim-timeline .when{
  font-family:var(--l-mono); font-size:12.5px; color:var(--l-accent);
  text-align:right; padding-top:2px;
}
.l-sim-timeline .body h4{
  font-family:var(--l-disp); font-size:15px; font-weight:600;
  color:var(--l-text-0); margin-bottom:6px;
}
.l-sim-timeline .body p{font-size:13.5px; color:var(--l-text-2); line-height:1.75;}

@media (max-width:560px){
  .l-sim-timeline li{grid-template-columns:1fr; gap:6px; padding-left:22px;}
  .l-sim-timeline li:not(:last-child)::before{left:4px;}
  .l-sim-timeline li::after{left:0;}
  .l-sim-timeline .when{text-align:left;}
}

/* ---- Tables ---- */

.l-sim-inputs{width:100%; border-collapse:collapse;}
.l-sim-inputs th, .l-sim-inputs td{
  padding:9px 0; text-align:left; font-size:13.5px;
  border-bottom:1px solid var(--l-line);
}
.l-sim-inputs tr:last-child th, .l-sim-inputs tr:last-child td{border-bottom:none;}
.l-sim-inputs th{color:var(--l-text-2); font-weight:500; width:45%;}
.l-sim-inputs td{color:var(--l-text-0);}

.l-sim-history{width:100%; border-collapse:collapse; min-width:640px;}
.l-sim-history th, .l-sim-history td{
  padding:12px 16px; text-align:left; font-size:13.5px;
  border-bottom:1px solid var(--l-line); white-space:nowrap;
}
.l-sim-history th{
  font-family:var(--l-disp); font-size:12px; font-weight:600;
  color:var(--l-text-3); text-transform:uppercase; letter-spacing:.05em;
}
.l-sim-history tbody tr:last-child td{border-bottom:none;}
.l-sim-history tbody tr:hover{background:var(--l-surface-1);}
.l-sim-history a{color:var(--l-text-0); font-weight:600;}
.l-sim-history a:hover{color:var(--l-accent);}

/* ══════════════════════════════════════════════════════════════════════════
   Simulator — the decision review

   Everything below serves one idea: the student made a choice and the page is
   arguing with it. The chooser, the consequence meters, the value/cost ledger,
   the rollback breakdown and the alternative cards all exist because a number
   on its own teaches the wrong lesson.
   ══════════════════════════════════════════════════════════════════════════ */

/* ---- Choosing an architecture ---- */

.l-sim-decision{border-color:var(--l-accent-line);}

.l-sim-choices{display:grid; gap:11px; grid-template-columns:repeat(auto-fit, minmax(310px, 1fr));}

.l-sim-choice{
  display:flex; gap:11px; align-items:flex-start; cursor:pointer;
  padding:13px 15px; border-radius:11px;
  border:1px solid var(--l-line); background:var(--l-surface-1);
  transition:border-color .15s ease, background .15s ease;
}
.l-sim-choice:hover{border-color:var(--l-accent-line);}
.l-sim-choice input{margin-top:3px; accent-color:var(--l-accent); flex-shrink:0;}
.l-sim-choice > span{display:flex; flex-direction:column; gap:5px;}
.l-sim-choice strong{font-size:14px; font-weight:600; color:var(--l-text-0);}
.l-sim-choice small{font-size:12.5px; color:var(--l-text-3); line-height:1.6;}
.l-sim-choice:has(input:checked){
  border-color:var(--l-accent); background:color-mix(in srgb, var(--l-accent) 9%, transparent);
}
.l-sim-choice:has(input:checked) strong{color:var(--l-accent);}

/* ---- Consequence dimensions ---- */

.l-sim-dims{display:flex; flex-direction:column; gap:10px;}

.l-sim-dim{
  border:1px solid var(--l-line); border-radius:12px;
  background:var(--l-surface-1); overflow:hidden;
}
.l-sim-dim summary{
  display:grid; grid-template-columns:minmax(170px, 1fr) minmax(120px, 2fr) 52px;
  gap:16px; align-items:center; padding:15px 18px; cursor:pointer; list-style:none;
}
.l-sim-dim summary::-webkit-details-marker{display:none;}
.l-sim-dim summary:hover{background:var(--l-surface-2);}
.l-sim-dim .head{display:flex; flex-direction:column; gap:3px; min-width:0;}
.l-sim-dim .title{
  font-family:var(--l-disp); font-size:14px; font-weight:600; color:var(--l-text-0);
}
.l-sim-dim .band{font-size:12px; color:var(--l-text-3);}
.l-sim-dim .meter{height:8px; border-radius:99px; background:var(--l-surface-3); overflow:hidden;}
.l-sim-dim .meter span{display:block; height:100%; border-radius:99px; background:var(--l-text-3);}
.l-sim-dim .num{
  font-family:var(--l-mono); font-size:15px; text-align:right; color:var(--l-text-1);
}

/* Tone comes from the dimension's Goodness, so a cost row and a capability row are coloured on the
   same axis and neither the view nor the stylesheet has to know which way round a number runs. */
.l-sim-dim[data-tone="good"] .meter span{background:var(--l-ok);}
.l-sim-dim[data-tone="good"] .num{color:var(--l-ok);}
.l-sim-dim[data-tone="warn"] .meter span{background:var(--l-accent);}
.l-sim-dim[data-tone="warn"] .num{color:var(--l-accent);}
.l-sim-dim[data-tone="bad"] .meter span{background:var(--l-danger);}
.l-sim-dim[data-tone="bad"] .num{color:var(--l-danger);}

.l-sim-dim .body{padding:2px 18px 20px; border-top:1px solid var(--l-line);}
.l-sim-dim .body .q{
  font-size:13px; color:var(--l-text-3); margin:14px 0 10px; font-style:italic;
}
.l-sim-dim .body .v{font-size:14px; color:var(--l-text-1); line-height:1.75;}

.l-sim-reasons .delta.base{
  background:var(--l-surface-3); color:var(--l-text-2); border-color:transparent;
}

@media (max-width:640px){
  .l-sim-dim summary{grid-template-columns:1fr 46px; gap:9px;}
  .l-sim-dim .meter{grid-column:1/-1;}
}

/* ---- ROI ---- */

.l-sim-roi-head{
  display:flex; gap:22px; align-items:center; justify-content:space-between; flex-wrap:wrap;
}
.l-sim-roi .scale{display:flex; flex-direction:column; gap:11px; flex:1; min-width:260px;}
.l-sim-roi .row{display:grid; grid-template-columns:110px 1fr 40px; gap:12px; align-items:center;}
.l-sim-roi .row .k{font-size:13px; color:var(--l-text-2);}
.l-sim-roi .row .n{font-family:var(--l-mono); font-size:14px; text-align:right; color:var(--l-text-0);}
.l-sim-roi .meter{height:9px; border-radius:99px; background:var(--l-surface-3); overflow:hidden;}
.l-sim-roi .meter span{display:block; height:100%; border-radius:99px;}
.l-sim-roi .meter[data-tone="good"] span{background:var(--l-ok);}
.l-sim-roi .meter[data-tone="bad"] span{background:var(--l-danger);}

.l-sim-roi-band{
  font-family:var(--l-disp); font-size:14px; font-weight:600; padding:9px 16px;
  border-radius:99px; border:1px solid var(--l-line); background:var(--l-surface-2);
  color:var(--l-text-1); white-space:nowrap;
}
.l-sim-roi-band[data-band="Justified"], .l-sim-roi-band[data-band="Reasonable"]{
  color:var(--l-ok); border-color:color-mix(in srgb, var(--l-ok) 34%, transparent);
  background:color-mix(in srgb, var(--l-ok) 12%, transparent);
}
.l-sim-roi-band[data-band="Marginal"]{
  color:var(--l-accent); border-color:var(--l-accent-line);
  background:color-mix(in srgb, var(--l-accent) 12%, transparent);
}
.l-sim-roi-band[data-band="Overbuilt"], .l-sim-roi-band[data-band="Underbuilt"]{
  color:var(--l-danger); border-color:color-mix(in srgb, var(--l-danger) 34%, transparent);
  background:color-mix(in srgb, var(--l-danger) 12%, transparent);
}

.l-sim-roi-headline{
  margin-top:22px; font-size:15px; line-height:1.85; color:var(--l-text-1);
}

.l-sim-ledger{width:100%; border-collapse:collapse; font-size:13.5px;}
.l-sim-ledger th, .l-sim-ledger td{
  text-align:left; padding:12px 10px; border-bottom:1px solid var(--l-line); vertical-align:top;
}
.l-sim-ledger thead th{
  font-family:var(--l-disp); font-size:12px; text-transform:uppercase;
  letter-spacing:.06em; color:var(--l-text-3); font-weight:600;
}
.l-sim-ledger td strong{display:block; color:var(--l-text-0); font-weight:600; margin-bottom:3px;}
.l-sim-ledger td small{display:block; color:var(--l-text-3); font-size:12.5px; line-height:1.6;}
.l-sim-ledger .num{font-family:var(--l-mono); text-align:center; width:78px; color:var(--l-text-1);}
.l-sim-ledger .verdict{color:var(--l-text-2); line-height:1.65; max-width:260px;}
.l-sim-ledger .tag{
  display:inline-block; margin-right:6px; padding:2px 8px; border-radius:99px;
  font-size:11.5px; font-weight:600;
}
.l-sim-ledger .tag.ok{background:color-mix(in srgb, var(--l-ok) 16%, transparent); color:var(--l-ok);}
.l-sim-ledger .tag.warn{background:color-mix(in srgb, var(--l-accent) 16%, transparent); color:var(--l-accent);}
.l-sim-ledger .tag.bad{background:color-mix(in srgb, var(--l-danger) 16%, transparent); color:var(--l-danger);}
.l-sim-ledger tr.is-unmet{background:color-mix(in srgb, var(--l-danger) 5%, transparent);}
.l-sim-ledger tr.is-wasted{background:color-mix(in srgb, var(--l-accent) 5%, transparent);}
.l-sim-ledger tbody tr:last-child td{border-bottom:none;}

/* ---- Rollback ---- */

.l-sim-rollback-head{
  display:flex; gap:20px; align-items:flex-start; justify-content:space-between; flex-wrap:wrap;
}
.l-sim-rollback .l-sim-score .n[data-tone="bad"]{color:var(--l-danger);}
.l-sim-rollback .l-sim-score .n[data-tone="warn"]{color:var(--l-accent);}
.l-sim-rollback .l-sim-score .n[data-tone="good"]{color:var(--l-ok);}

.l-sim-factors{width:100%; border-collapse:collapse; font-size:13.5px;}
.l-sim-factors th, .l-sim-factors td{
  text-align:left; padding:11px 10px; border-bottom:1px solid var(--l-line); vertical-align:top;
}
.l-sim-factors th{color:var(--l-text-0); font-weight:600; width:190px;}
.l-sim-factors td{color:var(--l-text-2); line-height:1.7;}
.l-sim-factors td.w{width:110px;}
.l-sim-factors tbody tr:last-child th, .l-sim-factors tbody tr:last-child td{border-bottom:none;}

.l-sim-worklist{display:flex; flex-direction:column; gap:10px;}
.l-sim-worklist li{
  position:relative; padding-left:20px; font-size:13.5px; line-height:1.75; color:var(--l-text-1);
}
.l-sim-worklist li::before{
  content:""; position:absolute; left:2px; top:9px; width:6px; height:6px;
  border-radius:50%; background:var(--l-accent);
}
.l-sim-worklist.muted li{color:var(--l-text-2);}
.l-sim-worklist.muted li::before{background:var(--l-text-3);}

/* ---- Trade-offs ---- */

.l-sim-tradeoffs{display:grid; gap:14px; grid-template-columns:repeat(auto-fit, minmax(320px, 1fr));}

.l-sim-tradeoff{display:flex; flex-direction:column; gap:12px;}
.l-sim-tradeoff .k{
  display:block; font-family:var(--l-disp); font-size:11.5px; font-weight:600;
  text-transform:uppercase; letter-spacing:.07em; margin-bottom:6px;
}
.l-sim-tradeoff .gain .k{color:var(--l-ok);}
.l-sim-tradeoff .cost .k{color:var(--l-danger);}
.l-sim-tradeoff p{font-size:14px; line-height:1.7; color:var(--l-text-1);}
.l-sim-tradeoff .arrow{
  font-size:12px; color:var(--l-text-3); text-transform:uppercase;
  letter-spacing:.08em; border-top:1px solid var(--l-line); padding-top:12px;
}

/* ---- Comparison ---- */

.l-sim-compare{width:100%; border-collapse:collapse; min-width:900px; font-size:13.5px;}
.l-sim-compare th, .l-sim-compare td{
  text-align:left; padding:12px 12px; border-bottom:1px solid var(--l-line); white-space:nowrap;
}
.l-sim-compare thead th{
  font-family:var(--l-disp); font-size:11.5px; text-transform:uppercase;
  letter-spacing:.06em; color:var(--l-text-3); font-weight:600;
}
.l-sim-compare td.num{font-family:var(--l-mono); color:var(--l-text-2); text-align:center;}
.l-sim-compare td strong{color:var(--l-text-0); margin-right:7px;}
.l-sim-compare tbody tr:hover{background:var(--l-surface-1);}
.l-sim-compare tr.is-yours{background:color-mix(in srgb, var(--l-accent) 8%, transparent);}
.l-sim-compare tr.is-yours td, .l-sim-compare tr.is-yours td.num{color:var(--l-text-0); font-weight:600;}
.l-sim-compare tr.is-rejected{opacity:.5;}
.l-sim-compare tbody tr:last-child td{border-bottom:none;}

.l-sim-alts{display:flex; flex-direction:column; gap:14px;}

.l-sim-alt.is-rejected{border-style:dashed; opacity:.75;}
.l-sim-alt-head{
  display:flex; gap:18px; align-items:flex-start; justify-content:space-between; flex-wrap:wrap;
}
.l-sim-alt-head .fit{display:flex; align-items:baseline; gap:5px; flex-shrink:0;}
.l-sim-alt-head .fit .n{font-family:var(--l-mono); font-size:26px; color:var(--l-text-0);}
.l-sim-alt-head .fit .d{font-size:12px; color:var(--l-text-3);}
.l-sim-alt-why{margin-top:14px; font-size:14px; line-height:1.85; color:var(--l-text-1);}

.l-sim-alt-deltas{
  display:grid; gap:11px; margin-top:16px;
  grid-template-columns:repeat(auto-fit, minmax(240px, 1fr));
}
.l-sim-alt-deltas .d{
  padding:12px 14px; border-radius:10px; background:var(--l-surface-1);
  border-left:3px solid var(--l-text-3);
}
.l-sim-alt-deltas .d.up{border-left-color:var(--l-ok);}
.l-sim-alt-deltas .d.down{border-left-color:var(--l-danger);}
.l-sim-alt-deltas .k{
  display:block; font-family:var(--l-disp); font-size:12.5px; font-weight:600; color:var(--l-text-0);
}
.l-sim-alt-deltas .v{
  display:block; font-family:var(--l-mono); font-size:13px; color:var(--l-text-1); margin:4px 0 7px;
}
.l-sim-alt-deltas .v em{font-family:inherit; font-style:normal; color:var(--l-text-3); font-size:12px;}
.l-sim-alt-deltas p{font-size:12.5px; line-height:1.65; color:var(--l-text-2);}

/* ---- Re-running the same brief ---- */

.l-sim-rerun{display:flex; gap:16px; align-items:flex-end; flex-wrap:wrap;}
.l-sim-rerun .l-sim-field{flex:1; min-width:260px;}