/* ============================================================
   case-study1.css - editorial single-column variant.
   Same content, quieter design. Inspired by the Autograph
   template's blog-post layout: one text column, generous
   whitespace, no persistent chrome, media allowed to breathe
   wider than the text.
============================================================ */

:root {
  --cs1-page-max:      1280px;   /* wide media / hero band */
  --cs1-text-max:       720px;   /* article text column */
  --cs1-side-pad:       24px;    /* mobile side padding */
  --cs1-ink:            #0d0d0d;
  --cs1-mute:           rgba(13, 13, 13, 0.58);
  --cs1-hair:           rgba(13, 13, 13, 0.12);
  --cs1-paper:          #fdfdfc;
}

.cs1-body {
  background: var(--cs1-paper);
  color: var(--cs1-ink);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: clip;     /* nothing should scroll the whole page sideways; clip (not hidden) preserves position:sticky */
}

.cs1-skip {
  position: absolute; left: -9999px;
}
.cs1-skip:focus {
  left: 20px; top: 20px; padding: 8px 12px;
  background: var(--cs1-ink); color: var(--cs1-paper);
  z-index: 1000;
}

/* ============================================================
   Top bar - minimal, non-sticky. Same weight as body meta.
============================================================ */

.cs1-topbar {
  max-width: var(--cs1-page-max);
  margin: 0 auto;
  padding: 28px var(--cs1-side-pad);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.cs1-topbar__close {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--cs1-ink);
  text-decoration: none;
  transition: opacity 160ms ease;
}
.cs1-topbar__close:hover { opacity: 0.55; }
.cs1-topbar__close svg { display: block; }
.cs1-topbar__spacer { display: block; }

/* ============================================================
   Hero band - spans the full page above the two-column layout
============================================================ */

.cs1-hero {
  max-width: var(--cs1-page-max);
  margin: 0 auto 40px;
  padding: 0 var(--cs1-side-pad) 48px;
  border-bottom: 1px solid var(--cs1-hair);
}
.cs1-hero__inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 3fr);
  gap: 48px;
  align-items: center;
}
.cs1-hero__text {
  min-width: 0;
}
.cs1-hero__media {
  min-width: 0;
}
.cs1-hero__media img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 6px;
}
@media (max-width: 900px) {
  .cs1-hero__inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}
.cs1-hero__kicker {
  margin: 0 0 24px;
  font-family: 'Inter', sans-serif;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs1-hero__title {
  margin: 0 0 20px;
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: clamp(48px, 6vw, 72px);
  line-height: 0.98;
  letter-spacing: -0.02em;
  color: var(--cs1-ink);
}
.cs1-hero__deck {
  margin: 0;
  font-size: 18px;
  line-height: 1.5;
  color: var(--cs1-ink);
  font-weight: 400;
  max-width: 100%;
}
.cs1-hero__meta {
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--cs1-mute);
}
.cs1-hero__meta span[aria-hidden="true"] {
  color: var(--cs1-hair);
}

/* ============================================================
   Two-column layout: sticky TOC on the left + article on right
============================================================ */

.cs1-layout {
  max-width: var(--cs1-page-max);
  margin: 0 auto;
  padding: 40px var(--cs1-side-pad) 160px;
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 80px;
  align-items: start;
}

.cs1-toc {
  position: sticky;
  top: 32px;
  align-self: start;
}
.cs1-toc__card {
  padding: 24px;
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  background: var(--cs1-paper);
  max-height: calc(100vh - 80px);
  display: flex;
  flex-direction: column;
}
.cs1-toc__toggle {
  all: unset;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  font-weight: 600;
  color: var(--cs1-ink);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--cs1-hair);
  margin-bottom: 4px;
}
.cs1-toc__toggle svg {
  transition: transform 200ms ease;
  color: var(--cs1-mute);
}
.cs1-toc__toggle[aria-expanded="false"] svg {
  transform: rotate(-90deg);
}
.cs1-toc__list {
  list-style: none;
  /* Pull outward by the anchor's horizontal padding so the text
     inside each anchor lines up with the 'On this page' header. */
  margin: 0 -12px;
  padding: 8px 0 4px;
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
}
.cs1-toc__toggle[aria-expanded="false"] + .cs1-toc__list {
  display: none;
}
.cs1-toc__list li {
  margin: 0;
}
/* Intro row - shown only on the mobile horizontal strip */
.cs1-toc__item--intro { display: none; }
.cs1-toc__list a {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: baseline;
  column-gap: 10px;
  padding: 10px 12px;
  border-radius: 6px;
  text-decoration: none;
  color: var(--cs1-mute);
  transition: color 160ms ease, background 160ms ease;
}
.cs1-toc__list a:hover {
  color: var(--cs1-ink);
  background: rgba(0,0,0,0.03);
}
.cs1-toc__list a.is-current {
  color: var(--cs1-ink);
  background: rgba(0,0,0,0.05);
}
.cs1-toc__num {
  font-family: 'Inter', sans-serif;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs1-toc__list a.is-current .cs1-toc__num { color: var(--cs1-ink); }
.cs1-toc__title {
  font-family: 'Inter', sans-serif;
  font-size: 13.5px;
  line-height: 1.35;
  font-weight: 500;
}

.cs1-article {
  min-width: 0;
}

/* ============================================================
   Body wrap - flowing article stack inside the right column
============================================================ */

.cs1-body-wrap {
  max-width: 100%;
  margin: 0;
}

/* Every direct child hugs the left edge and fills the article
   column - text sections, banner, hero image, closing card all
   share the same width. */
.cs1-body-wrap > * {
  max-width: 100%;
  margin-left: 0;
  margin-right: 0;
}

/* ============================================================
   Legacy chapter/section - .cs-sec is the source class we
   preserved from case-study.html. Restyle for single-column.
============================================================ */

.cs-sec {
  padding: 0;
  margin: 0 0 64px;
  border: 0;
  max-width: 100%;
}
.cs-sec:last-child { margin-bottom: 0; }

/* Thick separator between chapters. First section (intro) skips it
   because it isn't preceded by another chapter section. The closing
   ink card skips it too - the black card is its own hard break. */
.cs-sec + .cs-sec {
  padding-top: 64px;
  border-top: 2px solid var(--cs1-ink);
}
.cs-sec + .cs-sec--closing {
  border-top: 0;
  padding-top: 0;
}

.cs-sec__num {
  margin: 0 0 10px;
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs-sec__title {
  margin: 0 0 16px;
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: clamp(30px, 3.4vw, 40px);
  line-height: 1.08;
  letter-spacing: -0.012em;
  color: var(--cs1-ink);
  text-align: left;
  overflow-wrap: break-word;
  word-break: normal;
  hyphens: none;
}

.cs-sec__body {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* Body typography inside sections */
.cs-sec__body p,
.cs1-deep p,
.cs1-l3 p {
  margin: 0;
}
.type--body-l {
  font-size: 20px;
  line-height: 1.55;
  font-weight: 400;
}
.type--body-m {
  font-size: 17px;
  line-height: 1.7;
  font-weight: 400;
}
.cs-sec__body .type--label,
.cs1-deep .type--label {
  display: inline;
  font-family: 'Inter', sans-serif;
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cs1-mute);
  margin-right: 8px;
}

/* Pull quote - big, left-aligned display treatment inside the column */
.cs-pull {
  font-family: var(--font-display), 'Inter', sans-serif;
  font-size: clamp(22px, 2.6vw, 28px);
  line-height: 1.2;
  font-weight: 700;
  color: var(--cs1-ink);
  border: 0;
  padding: 12px 0 4px !important;
  margin: 8px 0 4px !important;
  text-align: left;
  max-width: 100%;
  letter-spacing: -0.005em;
  overflow-wrap: break-word;
  word-break: normal;
  hyphens: none;
}

/* Subheading inside a body block */
.cs-h3 {
  margin: 32px 0 8px 0 !important;
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -0.005em;
  color: var(--cs1-ink);
}
.type--display-xs {
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: 22px;
  line-height: 1.2;
}

.cs-note {
  font-size: 14px;
  color: var(--cs1-mute);
  font-style: italic;
  border-top: 1px solid var(--cs1-hair);
  padding-top: 20px;
  margin-top: 12px;
}

.cs-ul {
  margin: 8px 0;
  padding-left: 20px;
}
.cs-ul li {
  margin-bottom: 6px;
}

/* Two-column split - used for Fixed/Variable style paired lists */
.cs-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px 48px;
  margin: 12px 0;
}
.cs-split > div .type--label {
  display: block;
  margin: 0 0 12px;
  color: var(--cs1-mute);
}
@media (max-width: 640px) {
  .cs-split { grid-template-columns: 1fr; gap: 20px; }
}

.cs-ol {
  margin: 8px 0;
  padding-left: 24px;
  counter-reset: cs1-ol;
  list-style: none;
}
.cs-ol li {
  counter-increment: cs1-ol;
  position: relative;
  padding-left: 44px;
  margin-bottom: 20px;
}
.cs-ol li::before {
  content: counter(cs1-ol, decimal-leading-zero);
  position: absolute;
  left: 0;
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.16em;
  color: var(--cs1-mute);
  top: 6px;
}
.cs-ol--big li {
  font-size: 18px;
  line-height: 1.5;
}

/* Flow strip - stays as an accent line */
.cs-flow {
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  font-size: 14px;
  line-height: 1.5;
  padding: 20px 24px;
  background: rgba(0,0,0,0.03);
  border-left: 2px solid var(--cs1-ink);
  border-radius: 0 4px 4px 0;
  margin: 8px 0;
}

/* ============================================================
   Media - images and video. Allowed to escape the text column
   for full "1120px" width, but stays inside the padded article.
============================================================ */

.cs-media {
  margin: 8px 0 16px;
  max-width: var(--cs1-page-max);
  width: 100%;
}
.cs-media img,
.cs-media video {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 6px;
}
.cs-media__desc {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--cs1-mute);
  text-align: left;
}

/* Placeholder box (still used for a couple of unfilled media slots) */
.cs-media__box {
  border: 1px dashed var(--cs1-hair);
  border-radius: 6px;
  padding: 40px 32px;
  min-height: 160px;
  background: rgba(0,0,0,0.02);
  display: flex;
  flex-direction: column;
  gap: 12px;
  justify-content: center;
}

/* Hero image + banner (opening image slots at top of article) */
.cs-hero {
  padding: 0;
  margin: 0 0 64px;
  max-width: var(--cs1-page-max);
}
.cs-hero__banner {
  margin: 0;                       /* kill default <figure> browser margin */
}
.cs-hero__banner img {
  width: 100%;
  height: auto;
  border-radius: 6px;
  display: block;
}
.cs-hero-image {
  margin: 0 0 48px;
  max-width: var(--cs1-page-max);
}
.cs-hero-image__figure {
  margin: 0;                       /* kill default <figure> browser margin */
}
.cs-hero-image img {
  width: 100%;
  height: auto;
  border-radius: 6px;
  display: block;
}
.cs-hero__project {
  padding: 24px 0 0;
  max-width: var(--cs1-text-max);
  margin: 0;
}
.cs-hero__eyebrow {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cs1-mute);
  margin-bottom: 12px;
}
.cs-hero__title {
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: clamp(28px, 3.5vw, 38px);
  line-height: 1.05;
  letter-spacing: -0.005em;
  margin: 0;
  color: var(--cs1-ink);
}

/* ============================================================
   Deep-dive block - collapsible <details> under a chapter.
   Editorial expand strip: eyebrow + label + plus marker.
============================================================ */

.cs1-deep {
  max-width: 100%;
  margin: 12px 0 0;
  background: rgba(0,0,0,0.05);
  border-radius: 6px;
  overflow: hidden;
}
.cs1-deep + .cs1-deep {
  margin-top: 0;
  border-top: 0;
}

.cs1-deep__summary {
  list-style: none;
  cursor: pointer;
  padding: 22px 24px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  column-gap: 20px;
  align-items: center;
  transition: background 160ms ease;
}
.cs1-deep__summary::-webkit-details-marker,
.cs1-deep__summary::marker { display: none; }
.cs1-deep__summary:hover,
.cs1-deep[open] > .cs1-deep__summary {
  background: rgba(0,0,0,0.04);
}

.cs1-deep__eyebrow {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs1-deep__label {
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  font-weight: 500;
  color: var(--cs1-ink);
  letter-spacing: -0.002em;
}
.cs1-deep__marker {
  position: relative;
  width: 14px;
  height: 14px;
}
.cs1-deep__marker::before,
.cs1-deep__marker::after {
  content: "";
  position: absolute;
  top: 50%; left: 50%;
  background: var(--cs1-ink);
  transform-origin: center;
  transition: transform 220ms ease;
}
.cs1-deep__marker::before {
  width: 14px; height: 1.5px;
  transform: translate(-50%, -50%);
}
.cs1-deep__marker::after {
  width: 1.5px; height: 14px;
  transform: translate(-50%, -50%);
}
.cs1-deep[open] .cs1-deep__marker::after {
  transform: translate(-50%, -50%) rotate(90deg);
  opacity: 0;
}

.cs1-deep__body {
  padding: 8px 24px 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ============================================================
   Prompt block - collapsible <details> nested inside the
   deep-dive. Ink-surface interior when open.
============================================================ */

.cs1-l3 {
  margin: 8px 0 !important;
  border: 1px solid var(--cs1-ink);
  border-radius: 6px;
  overflow: hidden;
  background: var(--cs1-paper);
  max-width: 100%;
}
.cs1-l3__summary {
  list-style: none;
  cursor: pointer;
  padding: 18px 22px;
  background: var(--cs1-ink);
  color: var(--cs1-paper);
  display: grid;
  grid-template-columns: auto 1fr auto;
  column-gap: 20px;
  align-items: center;
  transition: opacity 160ms ease;
}
.cs1-l3__summary::-webkit-details-marker,
.cs1-l3__summary::marker { display: none; }
.cs1-l3__summary:hover { opacity: 0.88; }

.cs1-l3__eyebrow {
  font-family: 'Inter', sans-serif;
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.55);
}
.cs1-l3__label {
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  font-weight: 500;
  color: var(--cs1-paper);
  letter-spacing: -0.002em;
}
.cs1-l3__marker {
  position: relative;
  width: 12px; height: 12px;
}
.cs1-l3__marker::before,
.cs1-l3__marker::after {
  content: "";
  position: absolute;
  top: 50%; left: 50%;
  background: var(--cs1-paper);
  transition: transform 220ms ease, opacity 220ms ease;
}
.cs1-l3__marker::before {
  width: 12px; height: 1.5px;
  transform: translate(-50%, -50%);
}
.cs1-l3__marker::after {
  width: 1.5px; height: 12px;
  transform: translate(-50%, -50%);
}
.cs1-l3[open] .cs1-l3__marker::after {
  transform: translate(-50%, -50%) rotate(90deg);
  opacity: 0;
}

.cs1-l3__body {
  padding: 32px !important;
  background: var(--cs1-ink);
  color: var(--cs1-paper);
}
.cs1-l3 .cs-l3__label {
  color: rgba(255,255,255,0.5) !important;
  margin: 0 0 12px !important;
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.cs1-l3 .cs-l3__note {
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  line-height: 1.6;
  color: rgba(255,255,255,0.7);
  font-style: italic;
  margin: 0 0 24px;
  max-width: 640px;
}
.cs-prompt {
  font-family: 'SF Mono', ui-monospace, 'JetBrains Mono', Menlo, Consolas, monospace;
  font-size: 12.5px;
  line-height: 1.65;
  color: rgba(255,255,255,0.9);
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 4px;
  padding: 24px;
  white-space: pre-wrap;
  overflow-x: auto;
  margin: 0;
  max-width: 100%;
}

/* Nested media inside the prompt block (result videos) */
.cs1-l3 .cs-media {
  margin: 28px 0 0;
  max-width: 100%;
}

/* ============================================================
   Closing section - the "Start with the idea." card
============================================================ */

.cs-sec--closing {
  background: var(--cs1-ink);
  color: var(--cs1-paper);
  padding: 80px 48px !important;
  border-radius: 6px;
  max-width: 100% !important;
  margin: 80px 0 0 !important;
  text-align: left;
}
.cs-sec--closing .cs-sec__num,
.cs-sec--closing .cs-sec__title,
.cs-sec--closing .cs-sec__body {
  max-width: 100%;
  margin-left: 0;
  margin-right: 0;
}
.cs-sec--closing .cs-sec__num {
  color: rgba(255,255,255,0.5);
}
.cs-sec--closing .cs-sec__title {
  color: var(--cs1-paper);
  font-size: clamp(40px, 5vw, 56px);
  margin-bottom: 24px;
}
.cs-sec--closing .cs-sec__body p {
  color: rgba(255,255,255,0.85);
}
.cs-sec--closing .cs-pull {
  color: var(--cs1-paper);
}

/* Surface ink helper for legacy .cs elements that still ride the token */
.surface--ink .type--label { color: rgba(255,255,255,0.6); }
.surface--ink .cs-pull { color: var(--cs1-paper); }

/* ============================================================
   Tool tiles (Chapter 07) - keep the paired-card look
============================================================ */

.cs-tools {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 24px 0 32px;
}
.cs-tools__card {
  margin: 0;
  padding: 28px;
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  background: var(--cs1-paper);
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.cs-tools__logo-box {
  width: 100%;
  aspect-ratio: 2 / 1;
  min-height: 96px;
  border-radius: 4px;
  background: rgba(0,0,0,0.03);
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  padding: 16px 24px;
}
.cs-tools__logo-box img {
  max-width: 70%;
  max-height: 60%;
  width: auto; height: auto;
  object-fit: contain;
}
.cs-tools__logo--symbol {
  max-width: 44px !important;
  max-height: 44px !important;
}
.cs-tools__logo-name {
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: 22px;
  color: var(--cs1-ink);
}
.cs-tools__role {
  margin: 0;
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
@media (max-width: 640px) {
  .cs-tools { grid-template-columns: 1fr; }
}

/* ============================================================
   Engine cards (Chapter 31) - simplified spec sheet
============================================================ */

.cs-engines-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
  margin: 24px 0 40px;
}
.cs-engine {
  position: relative;
  padding: 32px 28px 32px;
  background: var(--cs1-paper);
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  display: flex;
  flex-direction: column;
}
.cs-engine::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: var(--cs1-ink);
  border-radius: 6px 6px 0 0;
}
.cs-engine__head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 20px;
  font-family: 'SF Mono', ui-monospace, Menlo, monospace;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs-engine__code { color: var(--cs1-ink); }
.cs-engine__title {
  margin: 0 0 24px;
  font-family: var(--font-display), 'Inter', sans-serif;
  font-weight: 700;
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: -0.005em;
  color: var(--cs1-ink);
}
.cs-engine__spec {
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}
.cs-engine__row {
  display: grid;
  grid-template-columns: 72px 1fr;
  column-gap: 20px;
  padding: 12px 0;
  border-top: 1px solid var(--cs1-hair);
}
.cs-engine__row:first-child {
  border-top: 0;
  padding-top: 0;
}
.cs-engine__row dt {
  margin: 0;
  padding-top: 3px;
  font-family: 'SF Mono', ui-monospace, Menlo, monospace;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs-engine__row dd {
  margin: 0;
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  line-height: 1.55;
  color: var(--cs1-ink);
}

/* ============================================================
   Project map (Chapter 30) - kept as tag-cloud style groups
============================================================ */

.cs-map {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
  margin: 24px 0;
}
.cs-map__group {
  padding: 24px;
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  display: grid;
  gap: 12px;
  background: var(--cs1-paper);
}

/* Map teaser and flowmap - if used */
.cs-map-teaser {
  margin: 32px 0;
  padding: 32px;
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  background: var(--cs1-paper);
}
.cs-flowmap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin: 24px 0;
}
.cs-flowmap__step {
  padding: 16px;
  border: 1px solid var(--cs1-hair);
  border-radius: 6px;
  min-width: 140px;
}
.cs-flowmap__num {
  font-family: 'SF Mono', ui-monospace, Menlo, monospace;
  font-size: 11px;
  color: var(--cs1-mute);
  letter-spacing: 0.16em;
}
.cs-flowmap__label {
  font-weight: 600;
  font-size: 14px;
  margin-top: 4px;
}
.cs-flowmap__desc {
  font-size: 12px;
  color: var(--cs1-mute);
  margin-top: 4px;
}
.cs-flowmap__arrow {
  color: var(--cs1-mute);
}

/* ============================================================
   Footer - simple end mark and back-link
============================================================ */

.cs1-footer {
  max-width: 100%;
  margin: 120px 0 0;
  padding: 48px 0 0;
  border-top: 1px solid var(--cs1-hair);
  display: flex;
  flex-direction: column;
  gap: 16px;
  text-align: left;
  align-items: flex-start;
}
.cs1-footer__eyebrow {
  margin: 0;
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cs1-mute);
}
.cs1-footer__note {
  margin: 0;
  max-width: 680px;
  font-family: 'Inter', sans-serif;
  font-size: 18px;
  line-height: 1.5;
  color: var(--cs1-ink);
}
.cs1-footer__email {
  font-weight: 700;
  color: var(--cs1-ink);
  border-bottom: 1px solid var(--cs1-ink);
  padding-bottom: 1px;
}

/* ============================================================
   Responsive tweaks
============================================================ */

/* Tablet and below - stack sidebar above article, hero to 1 col.
   The TOC turns into a sticky horizontal chip strip pinned to the
   top of the viewport (topbar scrolls out of the way first). */
@media (max-width: 960px) {
  .cs1-topbar { padding: 20px var(--cs1-side-pad); }
  .cs1-hero {
    margin: 0 auto 32px;
    padding: 0 var(--cs1-side-pad) 32px;
  }
  .cs1-layout {
    grid-template-columns: minmax(0, 1fr);   /* stop content from forcing the grid wider */
    gap: 0;
    padding: 0 0 120px;
  }
  .cs1-article {
    padding: 24px var(--cs1-side-pad) 0;
    min-width: 0;
  }

  .cs1-toc {
    position: sticky;
    top: 0;
    z-index: 90;
    max-width: none;
    margin: 0;
    background: var(--cs1-paper);
    border-top: 1px solid var(--cs1-hair);
    border-bottom: 1px solid var(--cs1-hair);
    min-width: 0;
    overflow: hidden;               /* clip so the internal chip row can scroll without pushing the page wide */
  }

  .cs1-toc__card {
    padding: 0;
    background: transparent;
    border: 0;
    border-radius: 0;
    max-height: none;
    display: block;
  }
  .cs1-toc__toggle { display: none; }

  .cs1-toc__list {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 6px;
    margin: 0;
    padding: 10px var(--cs1-side-pad);
    max-height: none;
    overflow-x: auto;
    overflow-y: hidden;
    scroll-behavior: smooth;
    scroll-snap-type: x proximity;
    scroll-padding-left: var(--cs1-side-pad);
    scrollbar-width: none;
    -ms-overflow-style: none;
  }
  .cs1-toc__list::-webkit-scrollbar { display: none; }

  .cs1-toc__list li { flex: 0 0 auto; }
  .cs1-toc__item--intro { display: block; }

  .cs1-toc__list a {
    display: inline-flex;
    grid-template-columns: none;
    align-items: baseline;
    gap: 6px;
    padding: 8px 14px;
    border: 1px solid var(--cs1-hair);
    border-radius: 999px;
    background: transparent;
    color: var(--cs1-mute);
    white-space: nowrap;
    scroll-snap-align: start;
    text-decoration: none;
    transition: background 160ms ease, color 160ms ease, border-color 160ms ease;
  }
  .cs1-toc__list a:hover { background: transparent; color: var(--cs1-ink); }
  .cs1-toc__list a.is-current {
    background: var(--cs1-ink);
    color: var(--cs1-paper);
    border-color: var(--cs1-ink);
  }
  .cs1-toc__num {
    font-size: 11px;
    letter-spacing: 0.12em;
    color: inherit;
  }
  .cs1-toc__list a.is-current .cs1-toc__num { color: var(--cs1-paper); }
  .cs1-toc__title {
    font-size: 13px;
    font-weight: 500;
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .cs-sec { margin: 0 0 48px; }
  .cs-sec + .cs-sec { padding-top: 48px; }
}

/* Very narrow phone - hide chapter title on the chips, keep just the number */
@media (max-width: 480px) {
  .cs1-toc__list a { padding: 7px 12px; }
  .cs1-toc__title { display: none; }
}

/* Phone */
@media (max-width: 640px) {
  :root { --cs1-side-pad: 16px; }
  .cs1-topbar { padding: 16px var(--cs1-side-pad); }
  .cs1-hero { padding-bottom: 24px; }
  .cs1-hero__inner { gap: 24px; }
  .cs1-hero__kicker { margin-bottom: 16px; }
  .cs1-hero__title { font-size: 44px; }
  .cs1-hero__deck { font-size: 16px; }
  .cs-sec { margin: 0 0 40px; }
  .cs-sec + .cs-sec { padding-top: 40px; }
  .cs-sec__num { margin: 0 0 8px; font-size: 10px; }
  .cs-sec__title { font-size: 26px; margin-bottom: 12px; }
  .type--body-l { font-size: 17px; }
  .type--body-m { font-size: 15px; line-height: 1.6; }
  .cs-pull { font-size: 19px; padding: 8px 0 4px !important; margin: 8px 0 4px !important; }
  .cs1-deep { margin-top: 8px; }
  .cs1-deep__summary { padding: 16px 16px; column-gap: 12px; }
  .cs1-deep__body { padding: 4px 16px 20px; }
  .cs1-deep__label { font-size: 14px; }
  .cs1-l3 { margin: 8px 0 !important; }
  .cs1-l3__summary { padding: 14px 16px; }
  .cs1-l3__label { font-size: 13px; }
  .cs1-l3__body { padding: 20px 16px !important; }
  .cs-prompt { font-size: 12px; padding: 16px; line-height: 1.55; }
  .cs-engine { padding: 22px 18px; }
  .cs-engine__row { grid-template-columns: 68px 1fr; column-gap: 16px; }
  .cs-tools__card { padding: 20px; }
  .cs1-footer {
    margin-top: 80px;
    padding: 32px 0 0;
  }
  .cs1-footer__note { font-size: 16px; }
}

/* Very narrow phone - keep the title from breaking the layout */
@media (max-width: 380px) {
  .cs1-hero__title { font-size: 40px; }
  .cs-sec__title { font-size: 24px; }
}

/* ── MOBILE FOOTER (case-study) ──────────────────────────────
   Mirrors About page's .hero__chrome so visitors get a persistent
   brand + WHO'S RIDING nav + sound / night / close row at the
   bottom, and never have to scroll back to the topbar to exit.
   Hidden on desktop. */
.cs1-mobile-chrome,
.cs1-mobile-close,
.cs1-sound-toggle,
.cs1-night-toggle { display: none; }

/* Night-mode palette flip — mirrors About's is-night-mode behaviour. */
body.is-night-mode {
  --cs1-ink:   #fdfdfc;
  --cs1-mute:  rgba(253, 253, 252, 0.58);
  --cs1-hair:  rgba(253, 253, 252, 0.18);
  --cs1-paper: #0d0d0d;
}

@media (max-width: 767px) {
  /* Hide topbar close since the mobile footer × now covers exit. */
  .cs1-topbar__close { display: none; }
  .cs1-topbar { min-height: 24px; }

  /* Give the article breathing room above the fixed 164 px footer. */
  .cs1-layout { padding-bottom: 200px; }

  .cs1-mobile-chrome {
    display: grid;
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    height: 164px;
    padding: 32px 20px 0;
    background: linear-gradient(to top, var(--cs1-paper) 55%, rgba(255,255,255,0));
    z-index: 1200;
    grid-template-columns: 45px 1fr auto;
    grid-template-rows: 33px 1px;
    column-gap: 16px;
    row-gap: 20px;
    align-items: center;
    align-content: start;
    pointer-events: none;
  }
  .cs1-mobile-chrome > * { pointer-events: auto; }

  .cs1-mobile-brand {
    grid-column: 1;
    grid-row: 1;
    width: 45px;
    height: 33px;
    display: block;
  }
  .cs1-mobile-brand img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
    filter: invert(1);            /* logo asset is white; invert for the paper background */
  }

  .cs1-mobile-rule {
    grid-column: 1 / -1;
    grid-row: 2;
    height: 1px;
    width: 100%;
    background: var(--cs1-ink);
    opacity: 0.2;
  }

  .cs1-mobile-nav {
    grid-column: 3;
    grid-row: 1;
    align-self: end;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 4px;
  }
  .cs1-mobile-nav a {
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.02em;
    color: var(--cs1-ink);
    text-decoration: none;
    display: inline-block;
    width: min-content;
    text-align: right;
    line-height: 1.2;
  }

  .cs1-mobile-close {
    display: grid;
    place-items: center;
    position: fixed;
    bottom: 32px;
    right: 20px;
    width: 26px;
    height: 26px;
    padding: 0;
    background: transparent;
    border: none;
    z-index: 1201;
  }
  .cs1-mobile-close img {
    display: block;
    width: 22px;
    height: 22px;
    object-fit: contain;
    filter: invert(1);            /* close.svg is white; invert for paper background */
  }
  body.is-night-mode .cs1-mobile-close img { filter: none; }
  body.is-night-mode .cs1-mobile-brand img { filter: none; }

  /* Sound toggle — bottom-left, mirrors About's .sound-toggle. */
  .cs1-sound-toggle {
    display: grid;
    place-items: center;
    position: fixed;
    bottom: 32px;
    left: 20px;
    width: 26px;
    height: 26px;
    padding: 0;
    background: transparent;
    border: none;
    color: var(--cs1-ink);
    z-index: 1201;
    cursor: pointer;
  }
  .cs1-sound-toggle__icon {
    grid-area: 1 / 1;
    width: 20px;
    height: 20px;
    transition: opacity 200ms ease;
  }
  .cs1-sound-toggle__icon--off { opacity: 0; }
  .cs1-sound-toggle.is-off .cs1-sound-toggle__icon--on  { opacity: 0; }
  .cs1-sound-toggle.is-off .cs1-sound-toggle__icon--off { opacity: 1; }

  /* Night toggle — bottom-center, mirrors About's .night-toggle. */
  .cs1-night-toggle {
    display: grid;
    place-items: center;
    position: fixed;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    width: 26px;
    height: 26px;
    padding: 0;
    background: transparent;
    border: none;
    color: var(--cs1-ink);
    z-index: 1201;
    cursor: pointer;
  }
  .cs1-night-toggle__icon {
    grid-area: 1 / 1;
    width: 20px;
    height: 20px;
    transition: opacity 200ms ease;
  }
  .cs1-night-toggle__icon--sun { opacity: 0; }
  body.is-night-mode .cs1-night-toggle__icon--moon { opacity: 0; }
  body.is-night-mode .cs1-night-toggle__icon--sun  { opacity: 1; }
}