/* ============================================================
   BRAG — landing page styles
   Built on tokens.css. Editorial Swiss-rooted layout.
   See planning/design/landing_spec.md for section blueprint.
   ============================================================ */

/* --- reset (minimal) ----------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale; text-rendering: optimizeLegibility; }
body { margin: 0; }
img, svg { display: block; max-width: 100%; height: auto; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer;
  padding: 0; }
a { color: inherit; text-decoration: none; }

/* --- base typography ----------------------------------------- */
body {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.55;
  color: var(--ink);
  background: var(--paper);
  font-feature-settings: "kern" 1, "liga" 1, "cv11" 1;
  letter-spacing: -0.005em;
}
p { letter-spacing: -0.005em; }

p { margin: 0 0 1em 0; max-width: var(--measure); }
p:last-child { margin-bottom: 0; }
strong { font-weight: 600; }
em { font-style: italic; }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  margin: 0;
  line-height: 1.08;
  letter-spacing: -0.01em;
  font-weight: 500;
  color: var(--ink);
}

.hero-text {
  font-size: var(--fs-hero);
  line-height: 1.05;
  letter-spacing: -0.022em;
  font-weight: 500;
  font-variation-settings: "opsz" 72;
  margin: 0;
  max-width: 22ch;
}
.h1 { font-size: var(--fs-h1); font-variation-settings: "opsz" 48; letter-spacing: -0.02em; }
.h2 { font-size: var(--fs-h2); font-variation-settings: "opsz" 36; letter-spacing: -0.018em; }
.h3 { font-size: var(--fs-h3); font-variation-settings: "opsz" 28; }
.h4 { font-size: var(--fs-h4); font-variation-settings: "opsz" 24; }
.h5 { font-size: var(--fs-h5); font-variation-settings: "opsz" 18; line-height: 1.2; }

.lead {
  font-size: var(--fs-lead);
  line-height: 1.4;
  font-weight: 400;
  letter-spacing: -0.012em;
  max-width: 32em;
  color: var(--ink);
}

.eyebrow {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin: 0;
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
}
.eyebrow::before, .eyebrow::after {
  content: "";
  display: inline-block;
  width: 1.2em;
  height: 1px;
  background: var(--rule-strong);
}
.eyebrow.no-rule::before, .eyebrow.no-rule::after { display: none; }

.mono { font-family: var(--font-mono); font-feature-settings: "tnum" 1, "zero" 1; }
.ui { font-family: var(--font-ui); }
.dim { color: var(--ink-mute); }

::selection { background: var(--ink); color: var(--paper); }

/* --- the page grid ------------------------------------------- */
/*
   12-column grid, padding-inline for side margins. Grid lines run 1..13.
     sidebar  col 1-2  -> lines 1/3
     argument col 3-8  -> lines 3/9
     display  col 3-11 -> lines 3/12
     sidenote col 10-12 -> lines 10/13
     full     col 1-12 -> lines 1/13
*/
.section {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  column-gap: var(--grid-gap);
  row-gap: var(--space-4);
  max-width: var(--grid-max);
  margin: 0 auto;
  padding-inline: var(--grid-margin);
  padding-block: var(--space-section);
  position: relative;
}
.section + .section { border-top: var(--hairline); }
.section--tight { padding-block: var(--space-section-tight); }
.section--flush-top { padding-top: var(--space-5); }

.sidebar  { grid-column: 1 / 3; }
.argument { grid-column: 3 / 9; }
.display  { grid-column: 3 / 12; }
.sidenote { grid-column: 10 / 13; }
.full     { grid-column: 1 / 13; }
.center   { grid-column: 3 / 11; }

@media (max-width: 1023px) {
  .section { row-gap: var(--space-3); column-gap: 0; }
  .sidebar, .argument, .display, .sidenote, .full, .center {
    grid-column: 1 / 13;
  }
}

/* --- section number (sidebar) --------------------------------- */
.section-num {
  font-family: var(--font-display);
  font-size: clamp(2rem, 3vw, 3rem);
  font-weight: 400;
  color: var(--rule-strong);
  line-height: 1;
  letter-spacing: -0.03em;
  font-feature-settings: "tnum" 1, "lnum" 1;
}
.section-num.small {
  font-size: clamp(1.25rem, 1.75vw, 1.625rem);
  color: var(--ink-soft);
}
@media (max-width: 1023px) {
  .section-num {
    font-size: 1.5rem;
    color: var(--ink-soft);
    display: inline-block;
    margin-right: var(--space-2);
  }
}

/* --- hairline rule ------------------------------------------- */
.hr {
  height: 1px;
  background: var(--rule);
  border: 0;
  margin: 0;
}
.hr--strong { background: var(--rule-strong); }
.hr--ink { background: var(--ink); }

/* --- header / nav -------------------------------------------- */
.site-header {
  border-bottom: var(--hairline);
}
.site-header .full {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
  padding-block: var(--space-3);
}
.wordmark {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1;
}
.wordmark sub {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  text-transform: uppercase;
  letter-spacing: 0.10em;
  font-weight: 600;
  color: var(--ink-mute);
  margin-left: 0.6em;
  vertical-align: middle;
  bottom: 0;
}
.nav {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
}
.nav a {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-mute);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: color var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
.nav a:hover, .nav a:focus-visible { color: var(--ink); border-bottom-color: var(--ink); }
.nav a:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; }

@media (max-width: 640px) {
  .site-header .full { flex-direction: column; align-items: flex-start; gap: var(--space-2); }
  .nav { gap: var(--space-3); }
  .nav a { font-size: 0.6875rem; }
}

/* --- HERO (section 02) --------------------------------------- */
.hero .sidebar { display: flex; flex-direction: column; gap: var(--space-3); }
.hero .display { display: flex; flex-direction: column; gap: var(--space-5); }
.hero-text { color: var(--ink); }
.hero-text .signal {
  color: var(--signal);
  display: block;
  margin-top: 0.35em;
  font-size: 0.7em;
  font-weight: 500;
  letter-spacing: -0.018em;
  font-variation-settings: "opsz" 48;
}
.hero-text .hero-expand {
  display: block;
  margin-top: 1.6em;
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  font-weight: 400;
  letter-spacing: 0;
  color: var(--ink-mute);
  text-transform: none;
  font-variation-settings: normal;
  line-height: 1.5;
}
@media (max-width: 1023px) {
  .hero-text .signal { font-size: 0.78em; margin-top: 0.4em; }
  .hero-text .hero-expand { margin-top: 1.4em; }
}

.hero .lead-block {
  padding-top: var(--space-5);
  border-top: var(--hairline);
}

/* --- diagnosis problems -------------------------------------- */
.problem-stack {
  display: grid;
  grid-template-columns: 1fr;
  margin-top: var(--space-4);
  border-top: var(--hairline-strong);
}
.problem-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  column-gap: var(--space-5);
  padding: var(--space-4) 0;
  border-bottom: var(--hairline);
}
.problem-row h4 {
  font-family: var(--font-display);
  font-size: var(--fs-h5);
  font-weight: 500;
  font-variation-settings: "opsz" 24;
  letter-spacing: -0.01em;
  line-height: 1.15;
  margin: 0;
}
.problem-row p {
  margin: 0;
  font-size: var(--fs-body);
  color: var(--ink-soft);
  max-width: 36em;
}
@media (max-width: 768px) {
  .problem-row { grid-template-columns: 1fr; row-gap: var(--space-2); }
}

/* --- the rule (section 04) ----------------------------------- */
.rule-statement {
  padding-block: var(--space-7);
}
.rule-statement h2 {
  font-size: var(--fs-h1);
  font-variation-settings: "opsz" 48;
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.1;
  max-width: 22ch;
  color: var(--ink);
}
.rule-statement .coda {
  margin-top: var(--space-5);
  font-size: var(--fs-lead);
  color: var(--ink-soft);
  font-style: italic;
  max-width: 32em;
}

/* --- pipeline stages (section 05) ---------------------------- */
.stage-intro { display: flex; flex-direction: column; gap: var(--space-3); }
.stage {
  display: grid;
  grid-template-columns: subgrid;
  grid-column: 1 / 13;
  padding-top: var(--space-5);
  margin-top: var(--space-5);
  border-top: var(--hairline);
  row-gap: var(--space-3);
}
.stage:first-of-type { border-top: var(--hairline-strong); }

.stage > .sidebar { display: flex; flex-direction: column; gap: var(--space-2); }
.stage > .argument { display: flex; flex-direction: column; gap: var(--space-3); }
.stage > .display { display: flex; flex-direction: column; gap: var(--space-3); }

.stage h3 {
  font-family: var(--font-display);
  font-size: var(--fs-h4);
  font-weight: 500;
  font-variation-settings: "opsz" 32;
  letter-spacing: -0.015em;
  line-height: 1.1;
}

.stage-model {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  font-weight: 500;
}

@media (max-width: 1023px) {
  .stage {
    grid-column: 1 / 13;
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
  }
}

/* --- artifact (code/data block) ------------------------------ */
.artifact {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  line-height: 1.55;
  background: var(--paper-raised);
  border: var(--hairline);
  padding: var(--space-3) var(--space-3);
  color: var(--ink-soft);
  white-space: pre-wrap;
  word-break: break-word;
  overflow-x: auto;
  position: relative;
}
.artifact-label {
  display: block;
  font-family: var(--font-ui);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin-bottom: var(--space-2);
  padding-bottom: var(--space-1);
  border-bottom: 1px solid var(--rule);
}
.artifact .k { color: var(--ink); font-weight: 500; }
.artifact .s { color: var(--ink-soft); }
.artifact .n { color: var(--signal); font-feature-settings: "tnum" 1; }
.artifact .c { color: var(--ink-mute); font-style: italic; }
.artifact .v { color: var(--verify); font-weight: 500; }
.artifact .w { color: var(--warn); font-weight: 500; }

/* --- strategy list (refutation) ------------------------------ */
.strategies {
  list-style: none;
  padding: 0;
  margin: var(--space-3) 0 0;
  border-top: var(--hairline);
}
.strategies li {
  display: grid;
  grid-template-columns: 2.5em minmax(0, 12em) minmax(0, 1fr);
  column-gap: var(--space-3);
  padding: var(--space-2) 0;
  border-bottom: var(--hairline);
  font-size: var(--fs-body);
  align-items: baseline;
}
.strategies .n {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  font-feature-settings: "tnum" 1;
}
.strategies .name {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--signal);
  font-weight: 500;
}
.strategies .gloss {
  font-family: var(--font-body);
  color: var(--ink-soft);
}
@media (max-width: 640px) {
  .strategies li {
    grid-template-columns: 2em 1fr;
    row-gap: 4px;
  }
  .strategies .gloss { grid-column: 2; }
}

/* --- comparison (section 06) THE SHOWPIECE ------------------- */
.compare-wrap {
  margin-top: var(--space-4);
  border-top: var(--hairline-strong);
}

.compare-query {
  display: grid;
  grid-template-columns: max-content 1fr;
  column-gap: var(--space-3);
  align-items: baseline;
  padding-block: var(--space-3);
  border-bottom: var(--hairline);
}
.compare-query .label {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.compare-query .q {
  font-family: var(--font-display);
  font-size: var(--fs-h5);
  font-variation-settings: "opsz" 24;
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-bottom: var(--hairline);
}
.compare-col {
  padding: var(--space-4) var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.compare-col + .compare-col {
  border-left: var(--hairline);
}
.compare-col header {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-bottom: var(--space-2);
  border-bottom: var(--hairline);
}
.compare-col h3 {
  font-family: var(--font-display);
  font-size: var(--fs-h4);
  font-weight: 500;
  font-variation-settings: "opsz" 32;
  letter-spacing: -0.015em;
}
.compare-col[data-system="brag"] h3 { color: var(--ink); }
.compare-col[data-system="normal"] h3 { color: var(--ink); }

.compare-stage {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}
.compare-stage[hidden] { display: none; }
.compare-stage.is-revealed {
  animation: revealStage var(--dur-slow) var(--ease-out) both;
}
@keyframes revealStage {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}
.compare-stage-label {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.compare-stage-body {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-soft);
  line-height: 1.5;
}
.compare-stage-body.prose {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  color: var(--ink);
  font-weight: 400;
  line-height: 1.5;
  padding-left: var(--space-2);
  border-left: 2px solid var(--rule-strong);
}
.compare-stage-body.prose::before { content: "\201C"; margin-right: 0.1em; color: var(--ink-mute); }
.compare-stage-body.prose::after  { content: "\201D"; margin-left: 0.1em; color: var(--ink-mute); }

.compare-outcome {
  margin-top: auto;
  padding-top: var(--space-3);
  border-top: var(--hairline);
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
}
.compare-outcome.fail { color: var(--signal); }
.compare-outcome.ok   { color: var(--verify); }
.compare-outcome::before {
  content: "";
  display: inline-block;
  width: 0.85em;
  height: 0.85em;
  margin-right: 0.6em;
  vertical-align: -0.05em;
  border-radius: 50%;
}
.compare-outcome.fail::before { background: var(--signal); }
.compare-outcome.ok::before   { background: var(--verify); }

.compare-controls {
  display: flex;
  gap: var(--space-3);
  justify-content: space-between;
  align-items: center;
  padding-block: var(--space-3);
  flex-wrap: wrap;
}
.btn-text {
  font-family: var(--font-ui);
  font-size: var(--fs-caption);
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--ink);
  border-bottom: 1px solid var(--ink);
  padding: 4px 0;
  transition: color var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
.btn-text:hover, .btn-text:focus-visible {
  color: var(--signal);
  border-bottom-color: var(--signal);
}
.btn-text:focus-visible { outline: 2px solid var(--signal); outline-offset: 4px; }
.btn-text[disabled] { color: var(--ink-mute); border-bottom-color: var(--ink-mute); cursor: default; }
.btn-text .arrow { display: inline-block; margin-left: 0.4em; transition: transform var(--dur) var(--ease-out); }
.btn-text:hover .arrow { transform: translateX(2px); }

.compare-note {
  font-family: var(--font-ui);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  max-width: 50em;
  margin-top: var(--space-3);
}

@media (max-width: 768px) {
  .compare-grid { grid-template-columns: 1fr; }
  .compare-col + .compare-col { border-left: 0; border-top: var(--hairline); }
}

/* --- gallery (section 07) ----------------------------------- */
.gallery {
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 0;
  row-gap: 0;
  margin-top: var(--space-4);
  border-top: var(--hairline-strong);
  border-left: var(--hairline);
}
.trace-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-4);
  border-right: var(--hairline);
  border-bottom: var(--hairline);
  background: var(--paper);
  text-decoration: none;
  color: inherit;
  transition: background var(--dur) var(--ease-out);
  min-height: 240px;
}
.trace-card:hover, .trace-card:focus-visible {
  background: var(--paper-raised);
}
.trace-card:focus-visible { outline: 2px solid var(--signal); outline-offset: -2px; }
.trace-card header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-2);
}
.trace-card .did {
  font-family: var(--font-display);
  font-size: var(--fs-h4);
  font-weight: 500;
  font-variation-settings: "opsz" 32;
  letter-spacing: -0.02em;
  color: var(--ink);
  line-height: 1;
}
.trace-card .kind {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.trace-card .q {
  font-family: var(--font-display);
  font-size: var(--fs-h5);
  font-weight: 500;
  font-variation-settings: "opsz" 24;
  letter-spacing: -0.01em;
  line-height: 1.18;
  color: var(--ink);
  flex-grow: 1;
}
.trace-card footer {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding-top: var(--space-2);
  border-top: var(--hairline);
}
.trace-card .open {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  margin-top: var(--space-2);
}
.trace-card .open .arrow { transition: transform var(--dur) var(--ease-out); }
.trace-card:hover .open .arrow { transform: translateX(3px); }

@media (max-width: 768px) {
  .gallery { grid-template-columns: 1fr; }
}

/* --- chips --------------------------------------------------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  padding: 2px 0;
  border-top: 1px solid currentColor;
  border-bottom: 1px solid currentColor;
  color: var(--ink-mute);
}
.chip--normal { color: var(--verify); }
.chip--partial { color: var(--warn); }
.chip--clarify { color: var(--warn); }
.chip--halt { color: var(--halt); }
.chip--refute-strong { color: var(--signal); }
.chip--refute-loop { color: var(--signal); }
.chip--refute-strengthened { color: var(--verify); }
.chip--bypass { color: var(--ink-mute); }
.chip-line {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  letter-spacing: 0;
  text-transform: none;
  font-weight: 400;
}

/* --- architecture (section 08) ------------------------------- */
.arch {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-top: var(--space-4);
  padding-block: var(--space-3);
  border-top: var(--hairline-strong);
}
.arch-step {
  display: grid;
  grid-template-columns: 4em 1fr 14em;
  column-gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: var(--hairline);
  align-items: baseline;
}
.arch-step .id {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  font-feature-settings: "tnum" 1;
}
.arch-step .label {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.arch-step .label .name {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink);
}
.arch-step .label .desc {
  font-family: var(--font-body);
  font-size: var(--fs-caption);
  color: var(--ink-soft);
  max-width: 50em;
}
.arch-step .meta {
  font-family: var(--font-mono);
  font-size: var(--fs-caption);
  color: var(--ink-mute);
  text-align: right;
}
.arch-arrow {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  color: var(--rule-strong);
  text-align: center;
  margin-block: -8px;
  line-height: 1;
}
@media (max-width: 768px) {
  .arch-step {
    grid-template-columns: 3em 1fr;
    row-gap: var(--space-1);
  }
  .arch-step .meta { grid-column: 2; text-align: left; }
}

.factstore {
  margin-top: var(--space-6);
  padding-top: var(--space-5);
  border-top: var(--hairline-strong);
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: var(--space-4);
  row-gap: var(--space-4);
}
.factstore h3 {
  grid-column: 1 / -1;
  font-family: var(--font-display);
  font-size: var(--fs-h4);
  font-weight: 500;
  font-variation-settings: "opsz" 32;
  letter-spacing: -0.015em;
}
.factstore p {
  grid-column: 1 / -1;
  max-width: var(--measure);
}
.factstore .path {
  padding: var(--space-3);
  border: var(--hairline);
  background: var(--paper-raised);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.factstore .path h4 {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--signal);
  margin: 0;
}
.factstore .path p {
  font-size: var(--fs-caption);
  color: var(--ink-soft);
  max-width: none;
  margin: 0;
}
@media (max-width: 768px) {
  .factstore { grid-template-columns: 1fr; }
}

/* --- principle row actions (section 08) ---------------------- */
#builders .problem-row {
  scroll-margin-top: var(--space-5);
  transition: background var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
#builders .problem-row:target {
  background: var(--paper-raised);
  border-left: 2px solid var(--signal);
  padding-left: var(--space-3);
  margin-left: calc(-1 * var(--space-3) - 2px);
}
.principle-actions {
  grid-column: 1 / -1;
  display: flex;
  gap: var(--space-4);
  align-items: baseline;
  margin-top: var(--space-2);
  padding-top: var(--space-1);
}
.principle-link {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
  border-bottom: 1px solid var(--rule-strong);
  padding-bottom: 2px;
  display: inline-flex;
  align-items: baseline;
  gap: 0.4em;
  transition: color var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
.principle-link:hover, .principle-link:focus-visible {
  color: var(--signal);
  border-bottom-color: var(--signal);
}
.principle-link:focus-visible { outline: 2px solid var(--signal); outline-offset: 4px; }
.principle-link .arrow { transition: transform var(--dur) var(--ease-out); }
.principle-link:hover .arrow { transform: translateX(2px); }

.principle-share {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-mute);
  background: none;
  border: 0;
  border-bottom: 1px dashed var(--rule);
  padding: 0 0 2px;
  cursor: pointer;
  transition: color var(--dur) var(--ease-out), border-color var(--dur) var(--ease-out);
}
.principle-share:hover { color: var(--ink); border-bottom-color: var(--ink); }
.principle-share:focus-visible { outline: 2px solid var(--signal); outline-offset: 4px; }
.principle-share.copied {
  color: var(--verify);
  border-bottom-color: var(--verify);
  border-bottom-style: solid;
}

@media (max-width: 768px) {
  .principle-actions { flex-wrap: wrap; gap: var(--space-2) var(--space-4); }
}

/* --- colophon (section 10) ----------------------------------- */
.colophon {
  display: grid;
  grid-template-columns: 1fr;
  row-gap: var(--space-2);
  margin-top: var(--space-4);
  padding-block: var(--space-4);
  border-top: var(--hairline-strong);
  border-bottom: var(--hairline-strong);
}
.colophon h3 {
  font-family: var(--font-display);
  font-size: var(--fs-h3);
  font-weight: 500;
  font-variation-settings: "opsz" 36;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-3);
}
.colophon h3 .sub {
  display: block;
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin-top: 0.4em;
}
.col-row {
  display: grid;
  grid-template-columns: 11em 1fr;
  column-gap: var(--space-3);
  padding: var(--space-1) 0;
  font-size: var(--fs-caption);
  align-items: baseline;
}
.col-row dt {
  font-family: var(--font-ui);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  font-size: var(--fs-eyebrow);
}
.col-row dd {
  font-family: var(--font-body);
  color: var(--ink);
  margin: 0;
}
.col-row dd a { border-bottom: 1px solid var(--rule-strong); }
.col-row dd a:hover { border-bottom-color: var(--ink); color: var(--signal); }
.col-row.mono dd { font-family: var(--font-mono); font-size: var(--fs-caption); }
@media (max-width: 640px) {
  .col-row { grid-template-columns: 1fr; row-gap: 2px; padding-block: var(--space-1); }
}

.copyright {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
  padding-block: var(--space-4);
}

/* --- proof teaser (bridge between diagnosis and rule) ------- */
.proof-teaser {
  padding-block: var(--space-5);
}
.proof-teaser .full {
  border-top: var(--hairline-strong);
  padding-top: var(--space-4);
}
.proof-teaser-header {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}
.proof-teaser-q {
  font-family: var(--font-display);
  font-size: var(--fs-h5);
  font-weight: 500;
  font-variation-settings: "opsz" 24;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 0;
}
.proof-teaser-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border-top: var(--hairline);
}
.proof-teaser-col {
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.proof-teaser-col + .proof-teaser-col {
  border-left: var(--hairline);
}
.proof-teaser-label {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.10em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.proof-teaser-answer {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  color: var(--ink-soft);
  margin: 0;
  padding-left: var(--space-2);
  border-left: 2px solid var(--rule-strong);
  max-width: 36em;
}
.proof-teaser-link {
  padding-top: var(--space-3);
}
@media (max-width: 768px) {
  .proof-teaser-grid { grid-template-columns: 1fr; }
  .proof-teaser-col + .proof-teaser-col { border-left: 0; border-top: var(--hairline); }
}

/* --- pipeline overview (compact at-a-glance) ---------------- */
.pipeline-overview {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  margin-top: var(--space-4);
  border-top: var(--hairline-strong);
  border-left: var(--hairline);
}
.pov-step {
  padding: var(--space-2);
  display: flex;
  flex-direction: column;
  gap: 4px;
  border-right: var(--hairline);
  border-bottom: var(--hairline);
}
.pov-id {
  font-family: var(--font-mono);
  font-size: var(--fs-eyebrow);
  color: var(--ink-mute);
  font-feature-settings: "tnum" 1;
}
.pov-name {
  font-family: var(--font-ui);
  font-size: var(--fs-eyebrow);
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
}
.pov-model {
  font-family: var(--font-mono);
  font-size: var(--fs-eyebrow);
  color: var(--ink-mute);
}
@media (max-width: 768px) {
  .pipeline-overview { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 480px) {
  .pipeline-overview { grid-template-columns: repeat(2, 1fr); }
}

/* --- utilities ----------------------------------------------- */
.stack-1 { display: flex; flex-direction: column; gap: var(--space-1); }
.stack-2 { display: flex; flex-direction: column; gap: var(--space-2); }
.stack-3 { display: flex; flex-direction: column; gap: var(--space-3); }
.stack-4 { display: flex; flex-direction: column; gap: var(--space-4); }
.stack-5 { display: flex; flex-direction: column; gap: var(--space-5); }
.center-text { text-align: center; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: var(--space-3); top: var(--space-3); padding: var(--space-2);
  background: var(--ink); color: var(--paper); z-index: 100; }