/*
 * Product design case study (see case-study-template.html).
 * Layout: sticky vertical section nav on the left, content on the right.
 * Motion is driven by case-study.js and turned off for reduced-motion users.
 */

:root {
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --accent: #7457d6;
  --line: rgba(0, 0, 0, 0.12);
  --surface: rgba(0, 0, 0, 0.03);
  --shimmer: rgba(0, 0, 0, 0.06);
}

:root[data-theme="dark"] {
  --accent: #a891f5;
  --line: rgba(255, 255, 255, 0.14);
  --surface: rgba(255, 255, 255, 0.04);
  --shimmer: rgba(255, 255, 255, 0.08);
}

/* small capitalized labels */
.cs-caps {
  font-family: var(--mono);
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
}

.cs-muted {
  color: var(--muted);
}

/* ---------- loader ---------- */

.cs-loader {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

.cs-loader[hidden] {
  display: none;
}

.cs-loader.done {
  opacity: 0;
  visibility: hidden;
}

.cs-loader-inner {
  width: min(80vw, 32rem);
}

.cs-loader-count {
  font-size: 4rem;
  letter-spacing: -0.02em;
  color: var(--ink-strong);
}

.cs-loader-bar {
  height: 1px;
  margin: 1.2rem 0;
  background: var(--line);
}

.cs-loader-bar span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--accent);
}

.cs-loader-log {
  color: var(--muted);
}

.cs-loader-log::after {
  content: "_";
  animation: cs-blink 0.8s steps(1) infinite;
}

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

.case-study {
  display: grid;
  grid-template-columns: minmax(14rem, 2fr) 10fr;
  column-gap: var(--gap);
  padding: var(--pad) var(--pad) 0;
}

.case-study[hidden] {
  display: none;
}

.cs-body {
  min-width: 0;
  padding: 0;
}

/* ---------- vertical nav ---------- */

.cs-nav {
  position: sticky;
  top: var(--pad);
  align-self: start;
  display: flex;
  flex-direction: column;
  max-height: calc(100vh - var(--pad) * 2);
}

.cs-nav-title {
  margin-bottom: 2rem;
  color: var(--ink-strong);
}

.cs-nav ol {
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line);
}

.cs-nav a {
  position: relative;
  display: flex;
  gap: 1rem;
  padding: 0.55rem 0 0.55rem 1.2rem;
  font-size: 1.1rem;
  color: var(--muted);
}

.cs-nav a .cs-caps {
  font-size: 0.85rem;
  line-height: 1.9;
}

/* the active marker sits on the rail */
.cs-nav a::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: -1px;
  width: 2px;
  background: var(--accent);
  transform: scaleY(0);
  transition: transform 0.3s ease;
}

.cs-nav a:hover {
  color: var(--ink-strong);
}

.cs-nav a.active {
  color: var(--ink-strong);
}

.cs-nav a.active::before {
  transform: scaleY(1);
}

.cs-nav-progress {
  margin-top: 2.4rem;
  color: var(--muted);
}

.cs-nav-track {
  height: 1px;
  margin-bottom: 0.8rem;
  background: var(--line);
}

.cs-nav-track span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--ink-strong);
  transform: scaleX(0);
  transform-origin: left;
}

/* ---------- sections ---------- */

.cs-section {
  padding-bottom: 9rem;
  scroll-margin-top: var(--pad);
}

.cs-eyebrow {
  margin-bottom: 2.4rem;
  color: var(--muted);
}

.cs-label {
  margin-bottom: 1rem;
  color: var(--muted);
}

.cs-title {
  margin: 0;
  font-size: 7rem;
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--ink-strong);
}

.cs-lede {
  max-width: 48rem;
  margin-top: 2.4rem;
  font-size: 2rem;
  line-height: 1.35;
}

.cs-statement {
  max-width: 60rem;
  font-size: 3rem;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--ink-strong);
}

.cs-section h3 {
  margin: 0;
  font-size: 1.6rem;
  font-weight: 500;
  color: var(--ink-strong);
}

.cs-meta {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 2rem;
  margin: 4rem 0;
  padding: 1.6rem 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.cs-meta dt {
  margin-bottom: 0.4rem;
  color: var(--muted);
}

.cs-meta dd {
  margin: 0;
}

.cs-two {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--gap);
  margin-top: 4rem;
}

/* ---------- frames (image slots) ---------- */

.cs-frame {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 0.6rem;
  background: var(--surface);
}

.cs-frame img {
  display: block;
  width: 100%;
  margin: 0;
  opacity: 0;
  transition: opacity 0.6s ease;
}

.cs-frame img.loaded {
  opacity: 1;
}

/* stand-in for an image; swap for an <img> */
.cs-skeleton {
  aspect-ratio: 16 / 9;
  background: linear-gradient(100deg, transparent 30%, var(--shimmer) 50%, transparent 70%) 0 0 / 250% 100%;
  animation: cs-shimmer 1.8s linear infinite;
}

.cs-sources .cs-skeleton {
  aspect-ratio: 4 / 3;
}

/* ---------- metrics ---------- */

/* equal space between metrics, whatever each number's width */
/* even gaps between metrics, however wide each number is */
.cs-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 3rem 7rem;
}

.cs-metric-value {
  margin-bottom: 0.8rem;
  font-size: 5rem;
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--ink-strong);
}

.cs-metric .cs-caps {
  color: var(--muted);
}

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

.cs-sources,
.cs-decisions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.6rem;
}

.cs-card {
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  padding: 1.6rem;
  border: 1px solid var(--line);
  border-radius: 0.6rem;
  transition: border-color 0.3s ease, transform 0.3s ease;
}

.cs-card:hover {
  border-color: var(--accent);
}

.cs-card .cs-muted {
  display: block;
  margin-bottom: 0.2rem;
}

.cs-tag {
  color: var(--accent);
}

/* ---------- numbered lists ---------- */

.cs-insights {
  margin-top: 4rem;
}

.cs-insights ol,
.cs-log,
.cs-takeaways,
.cs-notes {
  margin: 0;
  padding: 0;
  list-style: none;
}

.cs-insights li,
.cs-log li,
.cs-takeaways li {
  display: grid;
  grid-template-columns: 6rem 1fr;
  padding: 1.2rem 0;
  border-top: 1px solid var(--line);
}

.cs-insights li .cs-caps,
.cs-log li .cs-caps,
.cs-takeaways li .cs-caps {
  color: var(--muted);
  line-height: 1.9;
}

.cs-log {
  margin-top: 2.4rem;
}

.cs-log li {
  grid-template-columns: 12rem 1fr;
}

.cs-takeaways li {
  font-size: 2rem;
  line-height: 1.3;
  color: var(--ink-strong);
}

.cs-takeaways li .cs-caps {
  line-height: 2.6;
}

/* ---------- process stages ---------- */

.cs-stage {
  display: grid;
  grid-template-columns: 7fr 3fr;
  gap: 1.6rem var(--gap);
  padding-left: 2.4rem;
  border-left: 1px solid var(--line);
  position: relative;
}

.cs-stage + .cs-stage {
  padding-top: 5rem;
}

/* node on the timeline */
.cs-stage::before {
  content: "";
  position: absolute;
  left: -0.45rem;
  width: 0.8rem;
  height: 0.8rem;
  border: 1px solid var(--accent);
  border-radius: 50%;
  background: var(--bg);
}

.cs-stage + .cs-stage::before {
  top: 5rem;
}

.cs-stage.in::before {
  background: var(--accent);
  transition: background 0.4s ease 0.3s;
}

.cs-stage-head {
  grid-column: 1 / -1;
  display: flex;
  align-items: baseline;
  gap: 1.2rem;
  flex-wrap: wrap;
  margin-top: -0.3rem;
}

/* prototype slot under each fidelity's design */
.cs-proto {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  margin-top: 1.6rem;
}

.cs-proto .cs-frame iframe,
.cs-proto .cs-frame video {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 0;
}

.cs-proto-note {
  margin-top: 1.6rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--line);
}

.cs-notes li {
  padding: 0.8rem 0;
  border-top: 1px solid var(--line);
}

/* ---------- AI layer ---------- */

.cs-ai {
  display: grid;
  grid-template-columns: 6fr 4fr;
  gap: var(--gap);
  margin-top: 4rem;
}

.cs-ai-demo {
  display: flex;
  flex-direction: column;
  gap: 1.6rem;
  padding: 1.6rem;
  border: 1px solid var(--line);
  border-radius: 0.6rem;
  background: var(--surface);
}

.cs-ai-head {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--muted);
}

.cs-dot {
  width: 0.6rem;
  height: 0.6rem;
  border-radius: 50%;
  background: var(--accent);
  animation: cs-pulse 1.6s ease-in-out infinite;
}

.cs-ai-prompt,
.cs-ai-reply {
  display: grid;
  grid-template-columns: 5rem 1fr;
}

.cs-ai-prompt {
  padding: 1rem 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.cs-ai-reply {
  min-height: 6rem;
  font-size: 1.4rem;
  color: var(--ink-strong);
}

.cs-ai-reply .cs-caret {
  grid-column: 2;
}

.cs-caret {
  display: inline-block;
  width: 0.5em;
  height: 1em;
  background: var(--accent);
  animation: cs-blink 0.8s steps(1) infinite;
}

.cs-ai-foot {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: var(--muted);
}

.cs-ai-meter,
.cs-bar-track {
  position: relative;
  flex: 1;
  height: 0.3rem;
  border-radius: 999px;
  background: var(--line);
  overflow: hidden;
}

.cs-ai-meter span,
.cs-bar-track span {
  position: absolute;
  inset: 0;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 1.2s cubic-bezier(0.2, 0.7, 0.2, 1) 0.2s;
}

.in .cs-ai-meter span,
.in .cs-bar-track span {
  transform: scaleX(var(--v));
}

.cs-states {
  margin: 0;
}

.cs-states div {
  padding: 1rem 0;
  border-top: 1px solid var(--line);
}

.cs-states dt {
  margin-bottom: 0.3rem;
  color: var(--accent);
}

.cs-states dd {
  margin: 0;
}

/* ---------- validation ---------- */

.cs-bars {
  display: flex;
  flex-direction: column;
  gap: 1.6rem;
}

.cs-bar p {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.6rem;
}

.cs-bar-track {
  display: block;
}

.cs-chart {
  display: block;
  width: 100%;
  height: 14rem;
  overflow: visible;
}

.cs-chart line {
  stroke: var(--line);
  stroke-width: 1;
  vector-effect: non-scaling-stroke;
}

.cs-chart .cs-chart-launch {
  stroke-dasharray: 3 3;
}

.cs-chart polyline {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
  vector-effect: non-scaling-stroke;
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  transition: stroke-dashoffset 1.8s cubic-bezier(0.4, 0, 0.2, 1) 0.2s;
}

.in .cs-chart polyline {
  stroke-dashoffset: 0;
}

.cs-chart-key {
  display: flex;
  justify-content: space-between;
  margin-top: 0.8rem;
}

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

.js-motion [data-reveal] {
  opacity: 0;
  transform: translateY(1.6rem);
  transition: opacity 0.8s ease, transform 0.8s cubic-bezier(0.2, 0.7, 0.2, 1);
  transition-delay: var(--delay, 0s);
}

.js-motion [data-reveal].in {
  opacity: 1;
  transform: none;
}

@keyframes cs-shimmer {
  to { background-position: -250% 0; }
}

@keyframes cs-blink {
  50% { opacity: 0; }
}

@keyframes cs-pulse {
  50% { opacity: 0.3; transform: scale(0.8); }
}

@media (prefers-reduced-motion: reduce) {
  .cs-skeleton,
  .cs-dot,
  .cs-caret,
  .cs-loader-log::after {
    animation: none;
  }
}

/* ---------- mobile: nav becomes a horizontal strip ---------- */

@media (max-width: 767px) {
  .case-study {
    display: block;
    padding: 0 var(--pad);
  }

  .cs-nav {
    position: sticky;
    top: 0;
    z-index: 10;
    max-height: none;
    margin: 0 calc(var(--pad) * -1) 3rem;
    padding: 0 var(--pad);
    background: var(--bg);
    border-bottom: 1px solid var(--line);
  }

  .cs-nav-title {
    display: none;
  }

  .cs-nav ol {
    display: flex;
    overflow-x: auto;
    scrollbar-width: none;
    border-left: 0;
  }

  .cs-nav ol::-webkit-scrollbar {
    display: none;
  }

  .cs-nav a {
    padding: 1.2rem 1.6rem 1.2rem 0;
    white-space: nowrap;
  }

  .cs-nav a::before {
    top: auto;
    bottom: 0;
    left: 0;
    right: 1.6rem;
    width: auto;
    height: 2px;
    transform: scaleX(0);
  }

  .cs-nav a.active::before {
    transform: scaleX(1);
  }

  /* progress becomes a hairline under the strip */
  .cs-nav-progress {
    position: absolute;
    left: 0;
    right: 0;
    bottom: -1px;
    margin: 0;
  }

  .cs-nav-progress p {
    display: none;
  }

  .cs-nav-track {
    margin: 0;
    background: transparent;
  }

  .cs-section {
    padding-bottom: 6rem;
    scroll-margin-top: 5rem;
  }

  .cs-title {
    font-size: 4.6rem;
  }

  .cs-statement {
    font-size: 2.4rem;
  }

  .cs-meta {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .cs-metrics {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 3rem 2rem;
  }

  .cs-metric-value {
    font-size: 4rem;
  }

  .cs-two,
  .cs-sources,
  .cs-decisions,
  .cs-ai,
  .cs-stage {
    grid-template-columns: minmax(0, 1fr);
  }

  .cs-stage {
    padding-left: 1.6rem;
  }

  .cs-log li {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }
}

/* ---------- product design overview (product-design.html) ---------- */

.pd-overview {
  padding: var(--pad) var(--pad) 0;
}

.pd-overview[hidden] {
  display: none;
}

.pd-meta {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-bottom: 6rem;
}

.pd-cases {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 6rem var(--gap);
}

.pd-case-featured {
  grid-column: 1 / -1;
}

.pd-case-link {
  display: block;
  color: var(--ink);
}

.pd-case-link:hover {
  color: var(--ink);
}

.pd-case-cover {
  transition: border-color 0.3s ease;
}

.pd-case-cover img,
.pd-case-cover .cs-skeleton {
  transition: transform 0.8s cubic-bezier(0.2, 0.7, 0.2, 1);
}

.pd-case-featured .pd-case-cover .cs-skeleton {
  aspect-ratio: 21 / 9;
}

.pd-case-link:hover .pd-case-cover {
  border-color: var(--accent);
}

.pd-case-link:hover .pd-case-cover img,
.pd-case-link:hover .pd-case-cover .cs-skeleton {
  transform: scale(1.02);
}

.pd-case-body {
  margin-top: 1.6rem;
}

.pd-case-title {
  margin: 0;
  font-size: 2.4rem;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--ink-strong);
  transition: color 0.3s ease;
}

.pd-case-link:hover .pd-case-title {
  color: var(--accent);
}

.pd-arrow {
  display: inline-block;
  margin-left: 0.4em;
  opacity: 0;
  transform: translateX(-0.4em);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.pd-case-link:hover .pd-arrow,
.pd-case-link:focus-visible .pd-arrow {
  opacity: 1;
  transform: none;
}

.pd-case-summary {
  max-width: 44rem;
  margin-top: 0.6rem;
}

.pd-case-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.6rem;
  margin-top: 1.2rem;
}

@media (max-width: 767px) {
  .pd-overview {
    padding: 0 var(--pad);
  }

  .pd-meta {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    margin-bottom: 4rem;
  }

  .pd-cases {
    grid-template-columns: minmax(0, 1fr);
    gap: 4rem;
  }

  .pd-case-featured .pd-case-cover .cs-skeleton {
    aspect-ratio: 16 / 9;
  }

  .pd-arrow {
    opacity: 1;
    transform: none;
  }
}

/* ---------- case study: back and next links ---------- */

.cs-back {
  display: block;
  width: fit-content;
  margin-bottom: 2.4rem;
  color: var(--muted);
}

.cs-back:hover {
  color: var(--ink-strong);
}

.cs-next {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 4rem 0;
  border-top: 1px solid var(--line);
  color: var(--ink-strong);
}

.cs-next:hover {
  color: var(--accent);
}

.cs-next-title {
  font-size: 4rem;
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.cs-next:hover .pd-arrow {
  opacity: 1;
  transform: none;
}

@media (max-width: 767px) {
  .cs-back {
    margin: 1.2rem 0 0;
  }

  .cs-next-title {
    font-size: 3rem;
  }
}