/* VCN Glass Box -- shared lab shell.
   DNA: persona Rams (restrained, functional, honest), force ILLUMINATE /
   make-the-invisible-visible, mood glass-luminous / trace-waterfall. Instrument-
   panel dark ground + span-blue accent reads "observability console". ASCII-only
   (no glyphs). Class contract matches the proven vcn-40 lab shell so lab pages
   drop in unchanged; tokens align to the deck SLIDE-GUIDE glass-luminous set. */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0b0f14;            /* instrument-panel ground */
  --fg: #e8eef5;
  --accent: #4da3ff;        /* span-blue: the trace */
  --muted: rgba(232, 238, 245, 0.55);
  --subtle: rgba(232, 238, 245, 0.08);
  --surface: rgba(232, 238, 245, 0.04);
  --border: rgba(232, 238, 245, 0.16);
  --alarm: #ffb84d;         /* slow span (amber) */
  --refuse: #ff5470;        /* errored span (red) */
  --ok: #4fe0b0;
  --font-body: 'Space Grotesk', ui-sans-serif, system-ui, sans-serif;
  --font-mono: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, monospace;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.5;
}

html { scrollbar-width: thin; scrollbar-color: var(--border) var(--bg); }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid transparent; transition: border-color 150ms; }
a:hover { border-bottom-color: var(--accent); }

button, input, textarea { font-family: inherit; color: inherit; }
::selection { background: var(--accent); color: var(--bg); }

/* Top-left chrome. */
.chrome {
  position: fixed; left: 1.5rem; top: 1.25rem; z-index: 50;
  font-family: var(--font-mono); font-size: 0.6875rem;
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted);
}
.chrome a { color: var(--muted); border-bottom: 1px solid var(--subtle); }
.chrome a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.chrome .sep { margin: 0 0.6rem; opacity: 0.5; }
.chrome .name { color: var(--fg); }

/* Page shell. */
.lab-frame { max-width: 1080px; margin: 0 auto; padding: 5rem 1.75rem 4rem; }

.lab-head { margin-bottom: 2.5rem; padding-bottom: 1.75rem; border-bottom: 1px solid var(--border); }
.lab-head .eyebrow {
  font-family: var(--font-mono); font-size: 0.6875rem;
  letter-spacing: 0.16em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.85rem;
}
.lab-head .eyebrow .dot { color: var(--accent); margin-right: 0.5rem; }
.lab-head h1 {
  font-weight: 500; font-size: clamp(2rem, 5.5vw, 3.4rem);
  letter-spacing: -0.02em; line-height: 1.03; margin-bottom: 1rem;
}
.lab-head .lede { font-size: clamp(1rem, 1.4vw, 1.15rem); color: var(--muted); max-width: 62ch; line-height: 1.55; }

.muted { color: var(--muted); }
.mono { font-family: var(--font-mono); }
.accent { color: var(--accent); }
.ok-c { color: var(--ok); }
.alarm-c { color: var(--alarm); }

/* Card grid (lab index). */
.grid-cards {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1px; background: var(--border); border: 1px solid var(--border);
}
.lab-card {
  background: var(--bg); padding: 1.75rem 1.5rem 1.6rem;
  display: flex; flex-direction: column; text-decoration: none; color: inherit;
  border-bottom: 1px solid transparent; transition: background 180ms;
}
.lab-card:hover { background: rgba(77,163,255,0.06); }
.lab-card .num {
  font-family: var(--font-mono); font-size: 0.6875rem; letter-spacing: 0.16em;
  color: var(--accent); margin-bottom: 0.85rem; text-transform: uppercase;
}
.lab-card .badges { display: flex; gap: 0.5rem; margin-bottom: 0.8rem; }
.badge {
  font-family: var(--font-mono); font-size: 0.62rem; letter-spacing: 0.14em;
  text-transform: uppercase; padding: 0.2rem 0.5rem; border: 1px solid var(--border); color: var(--muted);
}
.badge.easy { color: var(--ok); border-color: rgba(79,224,176,0.4); }
.badge.core { color: var(--accent); border-color: rgba(77,163,255,0.45); }
.lab-card .name { font-weight: 500; font-size: 1.5rem; letter-spacing: -0.015em; margin-bottom: 0.5rem; line-height: 1.15; }
.lab-card .desc { color: var(--muted); line-height: 1.5; font-size: 0.95rem; margin-bottom: 1.4rem; flex-grow: 1; }
.lab-card .foot {
  display: flex; justify-content: space-between; align-items: baseline;
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted);
}
.lab-card .foot .arrow { color: var(--accent); font-size: 0.85rem; transition: transform 200ms; }
.lab-card:hover .foot .arrow { transform: translateX(4px); }

/* Step grid (lab page). */
.step-grid { display: grid; grid-template-columns: 64px 1fr; gap: 1rem 1.4rem; margin: 1.5rem 0 2rem; }
.step-num {
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--accent);
  letter-spacing: 0.1em; text-transform: uppercase; padding-top: 0.3rem;
}
.step-body { min-width: 0; }  /* let 1fr track shrink below <pre> -> overflow-x:auto contains scroll (no page overflow) */
.step-body h3 { font-size: 1.1rem; font-weight: 500; margin-bottom: 0.4rem; letter-spacing: -0.01em; }
.step-body p { color: var(--muted); font-size: 0.93rem; margin-bottom: 0.85rem; line-height: 1.55; }
.step-body p .mono { color: var(--fg); }

/* Code block with copy button. */
.code-wrap { position: relative; margin: 0.5rem 0 0; border: 1px solid var(--border); min-width: 0; overflow: hidden; }
.code-wrap .head {
  display: flex; justify-content: space-between; align-items: center;
  padding: 0.5rem 0.95rem; border-bottom: 1px solid var(--border);
  font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--muted); background: rgba(232,238,245,0.02);
}
.code-wrap pre {
  margin: 0; padding: 1rem 1.1rem; background: #05080c;
  font-family: var(--font-mono); font-size: 0.8rem; line-height: 1.55;
  color: var(--fg); overflow-x: auto; white-space: pre; max-height: 70vh;
}
.copy-btn {
  background: var(--bg); border: 1px solid var(--border); color: var(--muted);
  font-family: var(--font-mono); font-size: 0.62rem; letter-spacing: 0.14em;
  text-transform: uppercase; padding: 0.3rem 0.7rem; cursor: pointer;
}
.copy-btn:hover { color: var(--accent); border-color: var(--accent); }
.copy-btn.copied { color: var(--ok); border-color: var(--ok); }

/* Panels + callouts. */
.panel { border: 1px solid var(--border); background: var(--surface); padding: 1.2rem 1.3rem; margin: 1.5rem 0; }
.panel h3 {
  font-size: 0.78rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent); font-family: var(--font-mono); margin-bottom: 0.7rem; font-weight: 500;
}
.panel p { font-size: 0.92rem; line-height: 1.55; color: var(--fg); margin-bottom: 0.5rem; overflow-wrap: break-word; }
.panel p .mono, .callout .mono, .lede .mono { overflow-wrap: anywhere; }  /* long URLs / dotted attr keys must break, not widen the page */
.panel p:last-child { margin-bottom: 0; }
.panel strong { color: var(--accent); font-weight: 500; }

.verify-block {
  margin-top: 1rem; padding: 0.85rem 1.05rem; background: rgba(79,224,176,0.05);
  border-left: 2px solid var(--ok); font-family: var(--font-mono); font-size: 0.8rem; color: var(--fg);
}
.verify-block .label {
  color: var(--ok); font-size: 0.7rem; letter-spacing: 0.14em; text-transform: uppercase;
  display: block; margin-bottom: 0.4rem;
}
.verify-block pre { background: transparent; padding: 0; margin: 0; white-space: pre; overflow-x: auto; font: inherit; color: inherit; }

.callout {
  border-left: 2px solid var(--accent); padding: 0.85rem 1.1rem; background: rgba(77,163,255,0.06);
  font-size: 0.93rem; line-height: 1.55; color: var(--fg); margin: 1.5rem 0;
}
.callout strong { color: var(--accent); font-weight: 500; }

.next-link {
  display: flex; justify-content: space-between; align-items: baseline;
  margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--border);
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted);
}
.next-link a { color: var(--accent); }

@media (max-width: 640px) {
  .step-grid { grid-template-columns: 1fr; gap: 0.4rem; }
  .step-num { padding-top: 0; }
}