.failure-lab-page {
  --failure-trace-bg: #0a0a0f;
  --failure-trace-surface: #111118;
  --failure-trace-surface-deep: #0d0d13;
  --failure-trace-line: rgba(255, 255, 255, 0.11);
  --failure-trace-line-strong: rgba(255, 255, 255, 0.19);
  --failure-trace-ink: #f0eee7;
  --failure-trace-muted: #aaa9a0;
  --failure-trace-dim: #8a8992;
  --failure-trace-amber: #f5a623;
  --failure-trace-cyan: #89c6c9;
  --failure-trace-violet: #b0a1d5;
  color: var(--failure-trace-ink);
  background-color: var(--failure-trace-bg);
  background-image:
    radial-gradient(circle at 73% 8%, rgba(137, 198, 201, 0.07), transparent 31rem),
    linear-gradient(180deg, #0d0d13 0%, var(--failure-trace-bg) 42%, #0c0c11 100%);
}

.failure-lab-page main {
  width: min(calc(100% - 48px), 1180px);
  min-width: 0;
  margin: 0 auto;
  padding: 0 0 7rem;
}

.failure-lab-page :is(h1, h2, h3, h4, p, ul, ol, dl) { max-width: none; }
.failure-lab-page a { overflow-wrap: anywhere; }
.failure-lab-page :is(a, button, input, summary):focus-visible { outline: 2px solid var(--failure-trace-amber); outline-offset: 4px; }

.failure-trace-visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.failure-trace-label,
.failure-trace-eyebrow,
.failure-trace-stage-index,
.failure-trace-reading-type {
  margin: 0;
  color: var(--failure-trace-amber);
  font: 500 0.68rem/1.35 "IBM Plex Mono", monospace;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

/* Identity */
.failure-trace-hero {
  padding: clamp(3.25rem, 7vw, 6.5rem) 0 clamp(2.75rem, 5vw, 4.75rem);
  border-bottom: 1px solid var(--failure-trace-line);
}

.failure-trace-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(17rem, 0.65fr);
  gap: clamp(2rem, 7vw, 6rem);
  align-items: end;
  margin-top: 1.4rem;
}

.failure-trace-hero h1 {
  margin: 0;
  color: var(--failure-trace-ink);
  font: 400 clamp(4.2rem, 8vw, 6.6rem)/0.9 "DM Serif Display", Georgia, serif;
  letter-spacing: -0.055em;
}
.failure-trace-hero h1 span { color: var(--failure-trace-amber); }

.failure-trace-deck {
  max-width: 19ch !important;
  margin: 1.35rem 0 0;
  color: var(--failure-trace-ink);
  font: 400 clamp(1.4rem, 2.6vw, 2rem)/1.18 "DM Serif Display", Georgia, serif;
  letter-spacing: -0.025em;
}

.failure-trace-hero-context { align-self: end; padding: 0 0 0.35rem; }
.failure-trace-truth {
  display: inline-flex;
  min-height: 32px;
  align-items: center;
  padding: 0.3rem 0.65rem;
  border: 1px solid rgba(245, 166, 35, 0.52);
  color: var(--failure-trace-amber);
  background: rgba(245, 166, 35, 0.06);
  font: 500 0.65rem/1.2 "IBM Plex Mono", monospace;
  letter-spacing: 0.11em;
}
.failure-trace-hero-context p { max-width: 34rem; margin: 1rem 0 0; color: var(--failure-trace-muted); font-size: 0.96rem; line-height: 1.65; }

/* Investigation context */
.failure-trace-scenario {
  display: grid;
  grid-template-columns: minmax(18rem, 0.7fr) minmax(0, 1.3fr);
  gap: clamp(2rem, 6vw, 5rem);
  align-items: end;
  padding: clamp(2.75rem, 5vw, 4.5rem) 0;
  border-bottom: 1px solid var(--failure-trace-line);
  background-color: var(--failure-trace-bg);
}
.failure-trace-scenario > *,
.failure-trace-scenario-copy,
.failure-trace-scenario-options {
  min-width: 0;
  min-inline-size: 0;
  max-width: 100%;
}

.failure-trace-scenario-copy h2 {
  margin: 0.65rem 0 0;
  color: var(--failure-trace-ink);
  font: 400 clamp(2.3rem, 4.6vw, 3.7rem)/0.98 "DM Serif Display", Georgia, serif;
  letter-spacing: -0.04em;
}
.failure-trace-scenario-copy > p:not(.failure-trace-label) { margin: 0.9rem 0 0; color: var(--failure-trace-muted); line-height: 1.6; }
.failure-trace-scenario-copy .failure-trace-scenario-boundary { color: var(--failure-trace-cyan); font-size: 0.82rem; }
.failure-trace-context-details { margin-top: 1rem; }
.failure-trace-context-details summary,
.failure-trace-reading-details summary {
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--failure-trace-muted);
  cursor: pointer;
  font: 500 0.72rem/1.35 "IBM Plex Mono", monospace;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.failure-trace-context-details ul { margin: 0.45rem 0 0; padding-left: 1.25rem; color: var(--failure-trace-muted); font-size: 0.84rem; line-height: 1.65; }

.failure-trace-scenario-options { display: flex; flex-wrap: wrap; gap: 0.55rem; margin: 0; padding: 0; border: 0; }
.failure-trace-scenario-options label { position: relative; display: inline-flex; min-width: 0; min-height: 44px; cursor: pointer; }
.failure-trace-scenario-options input { position: absolute; width: 1px; height: 1px; opacity: 0; }
.failure-trace-scenario-options span {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.62rem 0.85rem;
  border: 1px solid var(--failure-trace-line);
  border-radius: 4px;
  color: var(--failure-trace-muted);
  background: var(--failure-trace-surface);
  font: 500 0.74rem/1.3 "IBM Plex Mono", monospace;
  transition: border-color 160ms ease, background-color 160ms ease, color 160ms ease;
}
.failure-trace-scenario-options label:hover span { border-color: var(--failure-trace-line-strong); color: var(--failure-trace-ink); }
.failure-trace-scenario-options input:checked + span { border-color: rgba(245, 166, 35, 0.78); color: #0a0a0f; background: var(--failure-trace-amber); }
.failure-trace-scenario-options input:focus-visible + span { outline: 2px solid var(--failure-trace-amber); outline-offset: 4px; }

/* Workspace */
.failure-trace-workspace { padding-top: clamp(3.5rem, 6vw, 5.5rem); }
.failure-trace-workspace-heading {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(16rem, 0.55fr);
  gap: 2rem;
  align-items: end;
}
.failure-trace-workspace-heading h2,
.failure-trace-optional h2,
.failure-trace-reference-heading h2 {
  margin: 0.6rem 0 0;
  color: var(--failure-trace-ink);
  font: 400 clamp(2rem, 4vw, 3.25rem)/1 "DM Serif Display", Georgia, serif;
  letter-spacing: -0.04em;
}
.failure-trace-workspace-heading > p { margin: 0; color: var(--failure-trace-muted); font-size: 0.9rem; line-height: 1.65; }

.failure-trace-stage-nav {
  position: sticky;
  z-index: 40;
  top: var(--lab-shell-stack-height, 112px);
  margin-top: 1.8rem;
  border: 1px solid var(--failure-trace-line);
  background: var(--failure-trace-bg);
  box-shadow: 0 16px 28px -18px rgba(10, 10, 15, 0.98);
}
.failure-trace-stage-nav::after {
  position: absolute;
  z-index: 0;
  right: -1px;
  bottom: -24px;
  left: -1px;
  height: 24px;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(10, 10, 15, 0.98), rgba(10, 10, 15, 0));
  content: "";
}
.failure-trace-stage-context {
  position: relative;
  z-index: 2;
  display: flex;
  min-height: 28px;
  align-items: center;
  gap: 0.55rem;
  padding: 0.34rem 0.7rem;
  border-bottom: 1px solid var(--failure-trace-line);
  color: var(--failure-trace-dim);
  background: #0a0a0f;
  font: 500 0.56rem/1.2 "IBM Plex Mono", monospace;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.failure-trace-stage-context strong { color: var(--failure-trace-cyan); font: inherit; letter-spacing: 0.08em; }
.failure-trace-stage-context span:last-child { margin-left: auto; }

.failure-trace-rail-key {
  position: relative;
  z-index: 2;
  display: flex;
  min-height: 34px;
  align-items: center;
  gap: 0.9rem;
  padding: 0.38rem 0.7rem;
  border-bottom: 1px solid var(--failure-trace-line);
  color: var(--failure-trace-muted);
  background: var(--failure-trace-surface-deep);
  font: 500 0.55rem/1.25 "IBM Plex Mono", monospace;
}
.failure-trace-rail-key-title { margin-right: 0.15rem; color: var(--failure-trace-dim); font: inherit; letter-spacing: 0.1em; }
.failure-trace-rail-key-item { display: inline-flex; align-items: center; gap: 0.38rem; white-space: nowrap; }
.failure-trace-rail-key-mark { display: inline-block; width: 0.72rem; height: 0.72rem; border: 1px solid var(--failure-trace-line-strong); border-radius: 50%; }
.failure-trace-rail-key-mark[data-rail-state="active"] { border-color: var(--failure-trace-amber); background: var(--failure-trace-amber); }
.failure-trace-rail-key-mark[data-rail-state="supported"] { border-color: var(--failure-trace-cyan); }
.failure-trace-rail-key-mark[data-rail-state="unmapped"] { border-color: var(--failure-trace-muted); border-style: dashed; }
.failure-trace-rail-key-mark[data-rail-state="gap"] { border-color: var(--failure-trace-violet); box-shadow: inset 0 0 0 2px rgba(176, 161, 213, 0.08); }

.failure-trace-stage-nav ol { position: relative; z-index: 1; display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); margin: 0; padding: 0; list-style: none; }
.failure-trace-stage-nav ol::before { position: absolute; top: 1.65rem; right: 8%; left: 8%; height: 1px; background: rgba(255, 255, 255, 0.15); content: ""; }
.failure-trace-stage-nav li { position: relative; min-width: 0; }
.failure-trace-stage-nav a {
  position: relative;
  z-index: 1;
  display: grid;
  min-height: 94px;
  place-items: center;
  align-content: center;
  gap: 0.16rem;
  padding: 0.65rem 0.35rem;
  color: var(--failure-trace-dim);
  text-decoration: none;
  transition: color 160ms ease, background-color 160ms ease;
}
.failure-trace-stage-nav a:hover { color: var(--failure-trace-ink); background: rgba(255, 255, 255, 0.025); }
.failure-trace-stage-nav svg { width: 24px; height: 24px; margin-bottom: 0.08rem; padding: 4px; border: 1px solid transparent; border-radius: 50%; background: var(--failure-trace-surface-deep); fill: none; stroke: currentColor; stroke-linecap: round; stroke-linejoin: round; stroke-width: 1.4; }
.failure-trace-stage-nav a > span { color: var(--failure-trace-amber); font: 500 0.58rem/1.2 "IBM Plex Mono", monospace; letter-spacing: 0.08em; }
.failure-trace-stage-nav a > strong { color: inherit; font: 500 0.67rem/1.2 "IBM Plex Mono", monospace; text-align: center; }
.failure-trace-stage-support-label { margin-top: 0.14rem; color: var(--failure-trace-dim); font: 500 0.5rem/1.15 "IBM Plex Mono", monospace; letter-spacing: 0.1em; text-transform: uppercase; }
.failure-trace-stage-nav li[data-stage-support="supported"] a { color: #aaa9b1; }
.failure-trace-stage-nav li[data-stage-support="supported"] svg { border-color: rgba(137, 198, 201, 0.42); color: var(--failure-trace-cyan); }
.failure-trace-stage-nav li[data-stage-support="supported"] .failure-trace-stage-support-label { color: rgba(137, 198, 201, 0.78); }
.failure-trace-stage-nav li[data-stage-support="unmapped"] a { color: #8a8992; }
.failure-trace-stage-nav li[data-stage-support="unmapped"] svg { border-color: rgba(170, 169, 160, 0.45); border-style: dashed; color: var(--failure-trace-muted); }
.failure-trace-stage-nav li[data-stage-support="unmapped"] a > span { color: #8a8992; }
.failure-trace-stage-nav li[data-stage-support="unmapped"] .failure-trace-stage-support-label { color: #8a8992; }
.failure-trace-stage-nav li[data-stage-support="gap"] a { color: var(--failure-trace-cyan); }
.failure-trace-stage-nav li[data-stage-support="gap"] svg { border-color: rgba(176, 161, 213, 0.62); color: var(--failure-trace-violet); }
.failure-trace-stage-nav li[data-stage-support="gap"] a > span { color: var(--failure-trace-cyan); }
.failure-trace-stage-nav li[data-stage-support="gap"] .failure-trace-stage-support-label { color: var(--failure-trace-violet); }
.failure-trace-stage-nav a[aria-current="step"] { color: var(--failure-trace-ink) !important; background: rgba(245, 166, 35, 0.055); }
.failure-trace-stage-nav a[aria-current="step"] svg { border-color: var(--failure-trace-amber) !important; color: #0a0a0f !important; background: var(--failure-trace-amber); }
.failure-trace-stage-nav a[aria-current="step"] > span,
.failure-trace-stage-nav a[aria-current="step"] .failure-trace-stage-support-label { color: var(--failure-trace-amber) !important; }

.failure-trace-stage-stack { position: relative; }
.failure-trace-stage { scroll-margin-top: calc(var(--lab-shell-stack-height, 112px) + 176px); padding: clamp(2.5rem, 5vw, 4.5rem) 0 0; }
#failure-laboratory-main[data-stage-enhanced="true"] .failure-trace-stage:not([data-active-stage]) { display: none; }
.failure-trace-stage-header { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 1.5rem; align-items: start; padding-bottom: clamp(1.75rem, 3vw, 2.5rem); border-bottom: 1px solid var(--failure-trace-line); }
.failure-trace-stage-header h3 {
  max-width: 18ch !important;
  margin: 0.7rem 0 0;
  color: var(--failure-trace-ink);
  font: 400 clamp(2.7rem, 5.8vw, 4.8rem)/0.98 "DM Serif Display", Georgia, serif;
  letter-spacing: -0.045em;
}
.failure-trace-stage-state { margin-top: 0.15rem; color: var(--failure-trace-amber); font: 500 0.62rem/1.35 "IBM Plex Mono", monospace; letter-spacing: 0.12em; text-transform: uppercase; }
.failure-trace-stage-state--open { color: var(--failure-trace-cyan); }
.failure-trace-stage-content { display: grid; gap: 1px; padding-top: 0; background: var(--failure-trace-line); }

.failure-trace-stage-purpose {
  display: grid;
  grid-template-columns: minmax(16rem, 0.8fr) minmax(0, 1.2fr);
  gap: clamp(1.5rem, 5vw, 4rem);
  align-items: center;
  padding: 1.15rem clamp(1.4rem, 3vw, 2.35rem);
  background: rgba(10, 10, 15, 0.92);
}
.failure-trace-stage-purpose-label { margin: 0; color: var(--failure-trace-cyan); font: 500 0.59rem/1.3 "IBM Plex Mono", monospace; letter-spacing: 0.12em; }
.failure-trace-stage-purpose-text { margin: 0.45rem 0 0; color: var(--failure-trace-muted); font-size: 0.84rem; line-height: 1.55; }
.failure-trace-stage-flow { display: flex; align-items: center; justify-content: flex-end; gap: 0.55rem; color: var(--failure-trace-muted); font: 500 0.68rem/1.35 "IBM Plex Mono", monospace; }
.failure-trace-stage-flow span { padding: 0.42rem 0.58rem; border: 1px solid var(--failure-trace-line); background: rgba(17, 17, 24, 0.56); text-align: center; }
.failure-trace-stage-flow b { color: var(--failure-trace-cyan); font-weight: 400; }

.failure-trace-reading,
.failure-trace-unmapped,
.failure-trace-recovery-gap,
.failure-trace-recovery-assessment { min-width: 0; padding: clamp(1.6rem, 3.5vw, 2.7rem); background: rgba(13, 13, 19, 0.96); }
.failure-trace-reading-heading { display: flex; justify-content: space-between; gap: 1rem; align-items: flex-start; }
.failure-trace-reading-heading h4,
.failure-trace-unmapped h4,
.failure-trace-recovery-gap h4,
.failure-trace-recovery-assessment h4 { margin: 0.45rem 0 0; color: var(--failure-trace-ink); font: 400 clamp(1.65rem, 3vw, 2.35rem)/1 "DM Serif Display", Georgia, serif; letter-spacing: -0.025em; }
.failure-trace-reading-type { color: var(--failure-trace-cyan); }
.failure-trace-evidence {
  display: inline-flex;
  min-height: 28px;
  align-items: center;
  padding: 0.24rem 0.55rem;
  border: 1px solid var(--failure-trace-line-strong);
  color: var(--failure-trace-muted);
  background: transparent;
  font: 500 0.6rem/1.25 "IBM Plex Mono", monospace;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}
.failure-trace-evidence-list { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 0.35rem; }
.failure-trace-evidence[data-evidence-mode="simulated"] { border-color: rgba(137, 198, 201, 0.55); color: var(--failure-trace-cyan); }
.failure-trace-evidence[data-evidence-mode="measured"] { border-color: rgba(245, 166, 35, 0.6); color: var(--failure-trace-amber); }
.failure-trace-evidence[data-evidence-mode="recorded-replay"],
.failure-trace-evidence[data-evidence-mode="stale-measured"] { border-color: rgba(176, 161, 213, 0.58); color: var(--failure-trace-violet); }
.failure-trace-evidence[data-evidence-mode="unknown"],
.failure-trace-evidence[data-evidence-mode="unavailable"],
.failure-trace-evidence[data-evidence-mode="not-applicable-unscored"] { border-style: dashed; color: var(--failure-trace-muted); }
.failure-trace-demonstrates { max-width: 48rem !important; margin: 1.35rem 0 0; color: var(--failure-trace-muted); font-size: 1rem; line-height: 1.65; }
.failure-trace-proof { max-width: 48rem; margin-top: 1.8rem; padding-left: 1rem; border-left: 2px solid var(--failure-trace-amber); }
.failure-trace-proof strong { display: block; color: var(--failure-trace-amber); font: 500 0.64rem/1.3 "IBM Plex Mono", monospace; letter-spacing: 0.11em; text-transform: uppercase; }
.failure-trace-proof p { margin: 0.55rem 0 0; color: var(--failure-trace-muted); line-height: 1.6; }
.failure-trace-reading-details { margin-top: 1rem; }
.failure-trace-reading-details p,
.failure-trace-reading-details li { color: var(--failure-trace-muted); font-size: 0.84rem; line-height: 1.6; }
.failure-trace-reading-details ul { margin: 0.5rem 0 0; padding-left: 1.15rem; }
.failure-trace-reading-facts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; max-width: 48rem; margin: 0 0 1rem; background: var(--failure-trace-line); }
.failure-trace-reading-facts > div { padding: 0.8rem 0.9rem; background: rgba(10, 10, 15, 0.78); }
.failure-trace-reading-facts dt { color: var(--failure-trace-dim); font: 500 0.58rem/1.3 "IBM Plex Mono", monospace; letter-spacing: 0.1em; text-transform: uppercase; }
.failure-trace-reading-facts dd { margin: 0.35rem 0 0; color: var(--failure-trace-muted); font-size: 0.78rem; line-height: 1.5; }
.failure-trace-detail-label { margin: 0.9rem 0 0; color: var(--failure-trace-cyan) !important; font: 500 0.6rem/1.3 "IBM Plex Mono", monospace !important; letter-spacing: 0.1em; text-transform: uppercase; }
.failure-trace-reading-link { display: inline-flex; min-height: 44px; align-items: center; gap: 0.65rem; margin-top: 1.75rem; color: var(--failure-trace-ink); font: 500 0.78rem/1.3 "IBM Plex Mono", monospace; text-decoration: none; }
.failure-trace-reading-link span { color: var(--failure-trace-amber); }
.failure-trace-reading-link:hover { color: var(--failure-trace-amber); }

.failure-trace-unmapped { min-height: 13rem; }
.failure-trace-open-status { display: inline-flex; min-height: 28px; align-items: center; padding: 0.24rem 0.55rem; border: 1px dashed rgba(170, 169, 160, 0.55); color: var(--failure-trace-muted); font: 500 0.6rem/1.25 "IBM Plex Mono", monospace; letter-spacing: 0.08em; }
.failure-trace-unmapped h4 { max-width: 28ch !important; margin-top: 1.15rem; }
.failure-trace-open-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; margin-top: 1.6rem; background: var(--failure-trace-line); }
.failure-trace-open-grid section { padding: 1rem 1.1rem; background: rgba(10, 10, 15, 0.72); }
.failure-trace-open-label { margin: 0; color: var(--failure-trace-cyan) !important; font: 500 0.59rem/1.3 "IBM Plex Mono", monospace !important; letter-spacing: 0.11em; }
.failure-trace-open-grid section > p:last-child { margin: 0.65rem 0 0; color: var(--failure-trace-muted); font-size: 0.84rem; line-height: 1.6; }

.failure-trace-recovery-gap { display: grid; grid-template-columns: 6rem minmax(0, 1fr); gap: clamp(1.25rem, 4vw, 3rem); align-items: center; min-height: 18rem; }
.failure-trace-gap-mark { position: relative; display: block; width: 5rem; height: 5rem; border: 1px solid var(--failure-trace-line-strong); border-right-color: transparent; border-radius: 50%; }
.failure-trace-gap-mark::after { position: absolute; right: -0.35rem; bottom: 0.55rem; width: 1rem; height: 1px; background: var(--failure-trace-cyan); content: ""; transform: rotate(-34deg); transform-origin: left center; }
.failure-trace-recovery-gap p:not(.failure-trace-reading-type) { max-width: 45rem !important; margin: 0.9rem 0 0; color: var(--failure-trace-muted); line-height: 1.65; }

.failure-trace-recovery-assessment { display: grid; gap: 1.5rem; }
.failure-trace-recovery-assessment-heading { display: grid; grid-template-columns: 6rem minmax(0, 1fr); gap: clamp(1.25rem, 4vw, 3rem); align-items: center; }
.failure-trace-recovery-assessment-heading p:not(.failure-trace-reading-type) { max-width: 48rem !important; margin: 0.9rem 0 0; color: var(--failure-trace-muted); line-height: 1.65; }
.failure-trace-recovery-sources { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--failure-trace-line); }
.failure-trace-recovery-source { min-height: 76px; display: flex; flex-direction: column; justify-content: center; padding: 0.9rem 1rem; background: rgba(10, 10, 15, 0.78); color: var(--failure-trace-ink); text-decoration: none; }
.failure-trace-recovery-source:hover { background: rgba(137, 198, 201, 0.055); }
.failure-trace-recovery-source strong { font: 500 0.78rem/1.35 "IBM Plex Mono", monospace; }
.failure-trace-recovery-source span { margin-top: 0.3rem; color: var(--failure-trace-cyan); font: 500 0.61rem/1.35 "IBM Plex Mono", monospace; letter-spacing: 0.06em; text-transform: uppercase; }
.failure-trace-recovery-conclusion { max-width: 52rem; padding-left: 1rem; border-left: 2px solid var(--failure-trace-violet); }
.failure-trace-recovery-conclusion strong { color: var(--failure-trace-violet); font: 500 0.6rem/1.3 "IBM Plex Mono", monospace; letter-spacing: 0.11em; }
.failure-trace-recovery-conclusion p { margin: 0.55rem 0 0; color: var(--failure-trace-muted); line-height: 1.6; }

.failure-trace-stage-actions { display: flex; justify-content: space-between; gap: 1rem; min-height: 72px; align-items: center; border-bottom: 1px solid var(--failure-trace-line); }
.failure-trace-stage-action { display: inline-flex; min-height: 44px; align-items: center; gap: 0.55rem; color: var(--failure-trace-muted); font: 500 0.72rem/1.35 "IBM Plex Mono", monospace; text-decoration: none; }
.failure-trace-stage-action:hover,
.failure-trace-stage-action--next { color: var(--failure-trace-ink); }
.failure-trace-stage-action--next span { color: var(--failure-trace-amber); }
.failure-trace-stage-end { color: var(--failure-trace-dim); font: 500 0.68rem/1.45 "IBM Plex Mono", monospace; text-align: right; }

/* Optional interpretation */
.failure-trace-optional { display: grid; grid-template-columns: minmax(0, 0.7fr) minmax(0, 1.3fr); gap: clamp(2rem, 6vw, 5rem); align-items: start; margin-top: clamp(4rem, 8vw, 7rem); padding-top: clamp(2.5rem, 4vw, 3.5rem); border-top: 1px solid var(--failure-trace-line); }
.failure-trace-optional > div:first-child > p:last-child { margin: 1rem 0 0; color: var(--failure-trace-muted); line-height: 1.65; }
.failure-trace-optional-links { border-top: 1px solid var(--failure-trace-line); }
.failure-trace-optional-links a { display: flex; min-height: 76px; align-items: center; justify-content: space-between; gap: 1rem; padding: 1rem 0; border-bottom: 1px solid var(--failure-trace-line); color: var(--failure-trace-ink); text-decoration: none; }
.failure-trace-optional-links a:hover { color: var(--failure-trace-amber); }
.failure-trace-optional-links strong,
.failure-trace-optional-links small { display: block; }
.failure-trace-optional-links strong { font: 500 0.95rem/1.3 "IBM Plex Mono", monospace; }
.failure-trace-optional-links small { margin-top: 0.35rem; color: var(--failure-trace-muted); font: 400 0.75rem/1.4 "IBM Plex Mono", monospace; }

/* Reference */
.failure-trace-reference { margin-top: clamp(4rem, 8vw, 7rem); padding-top: clamp(2.5rem, 4vw, 3.5rem); border-top: 1px solid var(--failure-trace-line); }
.failure-trace-reference-heading { margin-bottom: 2rem; }
.failure-trace-reference > details { border-top: 1px solid var(--failure-trace-line); }
.failure-trace-reference > details:last-child { border-bottom: 1px solid var(--failure-trace-line); }
.failure-trace-reference > details > summary { display: flex; min-height: 64px; align-items: center; justify-content: space-between; gap: 1rem; padding: 0.75rem 0; color: var(--failure-trace-ink); cursor: pointer; font: 500 0.8rem/1.35 "IBM Plex Mono", monospace; list-style: none; }
.failure-trace-reference > details > summary::-webkit-details-marker { display: none; }
.failure-trace-reference > details[open] > summary > span:last-child { transform: rotate(45deg); }
.failure-trace-reference-body { margin: 0; padding: 0.5rem 0 2rem; }
.failure-trace-reference-paths { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--failure-trace-line); }
.failure-trace-reference-paths article { padding: 1.25rem; background: var(--failure-trace-surface-deep); }
.failure-trace-reference-paths h3 { margin: 0; color: var(--failure-trace-ink); font: 500 0.95rem/1.4 "IBM Plex Mono", monospace; }
.failure-trace-reference-paths ol { margin: 1rem 0 0; padding-left: 1.25rem; color: var(--failure-trace-muted); font-size: 0.78rem; line-height: 1.65; }
.failure-trace-reference-paths p { margin: 1rem 0 0; color: var(--failure-trace-dim); font-size: 0.75rem; line-height: 1.55; }
.failure-trace-mode-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--failure-trace-line); }
.failure-trace-mode-list > div { padding: 1rem; background: var(--failure-trace-surface-deep); }
.failure-trace-mode-list dd { margin: 0.7rem 0 0; color: var(--failure-trace-muted); font-size: 0.8rem; line-height: 1.55; }
.failure-trace-destinations { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; padding-left: 0; background: var(--failure-trace-line); list-style: none; }
.failure-trace-destinations a { display: block; min-height: 72px; padding: 1rem; background: var(--failure-trace-surface-deep); color: var(--failure-trace-ink); text-decoration: none; }
.failure-trace-destinations strong,
.failure-trace-destinations span { display: block; }
.failure-trace-destinations strong { font: 500 0.85rem/1.35 "IBM Plex Mono", monospace; }
.failure-trace-destinations span { margin-top: 0.35rem; color: var(--failure-trace-muted); font-size: 0.76rem; }
.failure-trace-unsupported-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--failure-trace-line); }
.failure-trace-unsupported-item { padding: 1rem; background: var(--failure-trace-surface-deep); }
.failure-trace-unsupported-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; }
.failure-trace-unsupported-heading h3 { margin: 0; color: var(--failure-trace-ink); font: 500 0.88rem/1.4 "IBM Plex Mono", monospace; }
.failure-trace-unsupported-item > p { margin: 0.8rem 0 0; color: var(--failure-trace-muted); font-size: 0.8rem; line-height: 1.55; }
.failure-trace-unsupported-item .failure-trace-unsupported-proof { color: var(--failure-trace-dim); }
.failure-trace-reference-empty { grid-column: 1 / -1; margin: 0; padding: 1rem; color: var(--failure-trace-muted); background: var(--failure-trace-surface-deep); font-size: 0.8rem; line-height: 1.55; }
.failure-trace-rules { columns: 2; column-gap: 3rem; padding-left: 1.2rem; color: var(--failure-trace-muted); font-size: 0.84rem; line-height: 1.65; }
.failure-trace-rules li { break-inside: avoid; margin-bottom: 0.7rem; }
.failure-trace-noscript { margin: 2rem 0 0; padding: 1rem; border-left: 2px solid var(--failure-trace-amber); color: var(--failure-trace-muted); background: rgba(245, 166, 35, 0.045); font-size: 0.82rem; line-height: 1.6; }

@media (max-width: 900px) {
  .failure-trace-hero-grid,
  .failure-trace-scenario,
  .failure-trace-workspace-heading,
  .failure-trace-optional,
  .failure-trace-stage-purpose { grid-template-columns: 1fr; }
  .failure-trace-hero-context { max-width: 40rem; }
  .failure-trace-scenario { align-items: start; }
  .failure-trace-stage-flow { justify-content: flex-start; flex-wrap: wrap; }
  .failure-trace-stage-nav { overflow-x: auto; overscroll-behavior-inline: contain; scrollbar-width: thin; }
  .failure-trace-stage-nav::after { display: none; }
  .failure-trace-stage-nav ol { min-width: 720px; }
  .failure-trace-rail-key { position: sticky; left: 0; min-width: min(100vw, 720px); flex-wrap: wrap; }
  .failure-trace-recovery-sources { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .failure-trace-reference-paths,
  .failure-trace-mode-list,
  .failure-trace-destinations,
  .failure-trace-unsupported-list { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  .failure-lab-page main { width: min(calc(100% - 32px), 1180px); padding-bottom: 6rem; }
  .failure-trace-hero { padding-top: 2.75rem; }
  .failure-trace-hero h1 { font-size: clamp(3.5rem, 17vw, 5.1rem); }
  .failure-trace-deck { font-size: 1.45rem; }
  .failure-trace-scenario-options {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
    min-width: 0;
    min-inline-size: 0;
    overflow: visible;
    padding: 0.15rem 0 0.4rem;
  }
  .failure-trace-scenario-options label { min-width: 0; }
  .failure-trace-scenario-options span { width: 100%; justify-content: center; text-align: center; }
  .failure-trace-stage-nav { top: var(--lab-shell-stack-height, 104px); margin-right: -16px; margin-left: -16px; border-right: 0; border-left: 0; overflow: visible; }
  .failure-trace-stage-context { position: relative; left: auto; width: 100%; min-width: 0; }
  .failure-trace-stage-context span:last-child { display: none; }
  .failure-trace-rail-key { position: relative; left: auto; width: 100%; min-width: 0; gap: 0.55rem 0.8rem; }
  .failure-trace-rail-key-title { width: 100%; }
  .failure-trace-stage-nav ol { min-width: 0; grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .failure-trace-stage-nav ol::before { display: none; }
  .failure-trace-stage-nav a { min-height: 86px; }
  .failure-trace-stage-header { grid-template-columns: 1fr; }
  .failure-trace-stage-header h3 { font-size: clamp(2.45rem, 12vw, 3.5rem); }
  .failure-trace-reading-heading { display: block; }
  .failure-trace-reading-heading .failure-trace-evidence { margin-top: 1rem; }
  .failure-trace-evidence-list { justify-content: flex-start; margin-top: 1rem; }
  .failure-trace-reading-facts,
  .failure-trace-open-grid,
  .failure-trace-recovery-sources { grid-template-columns: 1fr; }
  .failure-trace-recovery-gap,
  .failure-trace-recovery-assessment-heading { grid-template-columns: 1fr; }
  .failure-trace-gap-mark { width: 3.5rem; height: 3.5rem; }
  .failure-trace-stage-actions { align-items: flex-start; padding: 0.85rem 0; }
  .failure-trace-stage-end { max-width: 15rem; }
  .failure-trace-rules { columns: 1; }
}

@media (max-width: 360px) {
  .failure-lab-page main { width: min(calc(100% - 24px), 1180px); }
  .failure-trace-stage-nav { margin-right: -12px; margin-left: -12px; }
  .failure-trace-hero h1 { font-size: 3.35rem; }
  .failure-trace-stage-actions { display: grid; grid-template-columns: 1fr; }
  .failure-trace-stage-action--next,
  .failure-trace-stage-end { justify-self: start; text-align: left; }
}

@media (prefers-reduced-motion: reduce) {
  .failure-lab-page *,
  .failure-lab-page *::before,
  .failure-lab-page *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}