/* =========================================================================
   CV Next — /case-study page (server-rendered on the apex).
   Self-contained stylesheet: the :root tokens below are a deliberate copy of
   frontend/src/index.css (as static/blog/assets/blog.css also does) — KEEP THE
   THREE IN SYNC. Component classes are ported from frontend/src/App.css
   (the arch-page classes become cs-prefixed, plus sheet, ledger, sec, stack,
   masthead, colophon, btn). Avoid the sequence star-slash in comments here — it
   closes the comment early and would drop the :root token block below.
   ========================================================================= */

:root {
  --paper: #ece4d6;
  --paper-2: #e4dac8;
  --paper-3: #f3ede1;
  --ink: #1a1714;
  --ink-soft: #4a4338;
  --ink-mute: #837866;
  --ink-faint: #a89c87;

  --signal: #d8381a;
  --signal-deep: #b32c12;
  --ochre: #b07d1d;
  --blue-ink: #284b8c;

  --rule: rgba(26, 23, 20, 0.16);
  --rule-strong: rgba(26, 23, 20, 0.32);
  --rule-faint: rgba(26, 23, 20, 0.08);

  --display: 'Fraunces', 'Times New Roman', serif;
  --body: 'Hanken Grotesk', ui-sans-serif, system-ui, sans-serif;
  --mono: 'IBM Plex Mono', 'SFMono-Regular', Consolas, monospace;

  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--paper);
}

body {
  position: relative;
  min-width: 320px;
  min-height: 100svh;
  margin: 0;
  font-family: var(--body);
  color: var(--ink);
  background:
    radial-gradient(120% 80% at 100% 0%, rgba(216, 56, 26, 0.05), transparent 60%),
    radial-gradient(100% 70% at 0% 100%, rgba(40, 75, 140, 0.045), transparent 55%),
    var(--paper);
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Fine grain overlay — pinned behind the content (which carries z-index: 2). */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.5;
  mix-blend-mode: multiply;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.4'/%3E%3C/svg%3E");
}

h1, h2, h3, p {
  margin: 0;
  overflow-wrap: anywhere;
}

::selection {
  background: var(--signal);
  color: var(--paper-3);
}

.sheet {
  width: min(80rem, 100% - 5rem);
  margin-inline: auto;
}

/* ---- Registration / crop marks ---- */
.reg-marks {
  position: fixed;
  inset: 0.85rem;
  z-index: 60;
  pointer-events: none;
}
.reg-marks span {
  position: absolute;
  width: 12px;
  height: 12px;
  opacity: 0.45;
}
.reg-marks span::before,
.reg-marks span::after {
  content: '';
  position: absolute;
  background: var(--ink);
}
.reg-marks span::before { width: 12px; height: 1px; top: 0; }
.reg-marks span::after { width: 1px; height: 12px; left: 0; }
.reg-marks .tl { top: 0; left: 0; }
.reg-marks .tr { top: 0; right: 0; transform: scaleX(-1); }
.reg-marks .bl { bottom: 0; left: 0; transform: scaleY(-1); }
.reg-marks .br { bottom: 0; right: 0; transform: scale(-1); }

/* ---- Masthead ---- */
.masthead {
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 1.5rem;
  min-height: 3.75rem;
  padding: 0 clamp(1rem, 3vw, 2.4rem);
  border-bottom: 1px solid var(--rule);
  background: color-mix(in srgb, var(--paper) 82%, transparent);
  backdrop-filter: blur(10px) saturate(1.1);
}
.masthead__brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  text-decoration: none;
  color: var(--ink);
}
.masthead__mark {
  display: inline-grid;
  place-items: center;
  width: 2.05rem;
  height: 2.05rem;
  border: 1.2px solid var(--ink);
  border-radius: 5px;
  font-family: var(--mono);
  font-weight: 600;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
}
.masthead__id {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-mute);
  line-height: 1.3;
}
.masthead__id b {
  display: block;
  color: var(--ink);
  font-weight: 600;
}
.masthead__nav {
  grid-column: 3;
  display: flex;
  justify-content: flex-end;
  gap: clamp(0.8rem, 2vw, 2rem);
}
.masthead__nav a {
  position: relative;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink-soft);
  padding-bottom: 2px;
}
.masthead__nav a span {
  color: var(--signal);
  margin-right: 0.35em;
}
/* Signature datasheet underline — grows from the left on hover (matches the SPA masthead). */
.masthead__nav a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1.5px;
  background: var(--ink);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.32s var(--ease);
}
.masthead__nav a:hover {
  color: var(--ink);
}
.masthead__nav a:hover::after {
  transform: scaleX(1);
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  min-height: 2.85rem;
  padding: 0 1.15rem;
  border: 1.4px solid var(--ink);
  border-radius: 2px;
  font-family: var(--mono);
  font-size: 0.76rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink);
  background: transparent;
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease), background 0.2s var(--ease), border-color 0.2s var(--ease);
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 4px 4px 0 var(--ink);
}
.btn--primary {
  color: var(--paper-3);
  background: var(--signal);
  border-color: var(--signal);
}
.btn--primary:hover {
  background: var(--signal-deep);
  border-color: var(--ink);
}
.btn--ghost {
  border-color: var(--rule-strong);
}
.btn--ghost:hover {
  border-color: var(--ink);
}

/* ---- Shared datasheet primitives ---- */
.sec__no {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--signal);
}
.sec__kicker {
  display: block;
  margin-top: 0.5rem;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-mute);
}

.ledger {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: clamp(2rem, 5vw, 3rem) 0 0;
  border-top: 1.5px solid var(--ink);
  border-bottom: 1px solid var(--rule);
}
.ledger > div {
  padding: 1.1rem 1.1rem 1.2rem 0;
  border-right: 1px solid var(--rule);
}
.ledger > div:last-child { border-right: 0; }
.ledger dt {
  font-family: var(--display);
  font-size: clamp(1.9rem, 4vw, 2.9rem);
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.01em;
}
.ledger dd {
  margin: 0.5rem 0 0;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-mute);
  line-height: 1.45;
}

.stack {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 1.4rem;
}
.stack span {
  padding: 0.28rem 0.55rem;
  border: 1px solid var(--rule-strong);
  border-radius: 2px;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
  background: var(--paper-3);
}

/* ---- Page layout ---- */
.cs {
  position: relative;
  z-index: 2;
  min-height: 100svh;
  /* Clear the fixed masthead (min-height 3.75rem). */
  padding-top: 3.75rem;
  padding-bottom: clamp(2rem, 6vw, 4rem);
}
.cs__intro {
  margin-top: clamp(1.8rem, 5vw, 3rem);
}
.cs__title {
  margin-top: 0.8rem;
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(2rem, 6vw, 3.4rem);
  line-height: 1;
  letter-spacing: -0.02em;
  text-wrap: balance;
}
.cs__lede {
  max-width: 46rem;
  margin-top: 1.1rem;
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--ink-soft);
}
.cs__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 1.6rem;
}

.cs code {
  font-family: var(--mono);
  font-size: 0.85em;
  padding: 0.1em 0.35em;
  border-radius: 2px;
  background: var(--paper-3);
  border: 1px solid var(--rule-faint);
}

/* ---- Request-flow diagram (ported from .arch__flow / .arch-node) ---- */
.cs__flow {
  display: flex;
  flex-wrap: wrap;
  align-items: stretch;
  gap: 0.6rem;
  margin-top: clamp(1.8rem, 5vw, 2.8rem);
  padding-top: clamp(1.6rem, 4vw, 2.4rem);
  border-top: 1.5px solid var(--ink);
}
.cs-node {
  flex: 1 1 12rem;
  min-width: 9rem;
  display: grid;
  gap: 0.3rem;
  padding: 1rem;
  border: 1px solid var(--rule);
  background: var(--paper-3);
}
.cs-node--primary {
  border: 1.4px solid var(--ink);
  border-top: 3px solid var(--signal);
  box-shadow: 4px 4px 0 var(--ink);
}
.cs-node strong {
  font-family: var(--display);
  font-size: 1.1rem;
  letter-spacing: -0.01em;
}
.cs-node span {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  color: var(--ink-mute);
  line-height: 1.45;
}
.cs-arrow {
  display: grid;
  place-items: center;
  font-family: var(--mono);
  font-size: 1.2rem;
  color: var(--signal-deep);
}

/* ---- Decision cards (ported from .arch__decisions / .arch-card) ---- */
.cs__decisions {
  display: grid;
  gap: 1.4rem;
  margin-top: clamp(2rem, 5vw, 3rem);
}
.cs-card {
  display: grid;
  grid-template-columns: 4rem 1fr;
  gap: 1.2rem;
  padding-top: 1.4rem;
  border-top: 1px solid var(--rule);
}
.cs-card__no {
  font-family: var(--mono);
  font-size: 0.74rem;
  letter-spacing: 0.04em;
  color: var(--signal-deep);
}
.cs-card__body h2 {
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(1.3rem, 3vw, 1.7rem);
  letter-spacing: -0.01em;
}
.cs-card__body p {
  margin-top: 0.6rem;
  line-height: 1.65;
  color: var(--ink-soft);
}
.cs-card__tradeoff {
  border-left: 3px solid var(--ink-mute);
  padding-left: 0.9rem;
}
.cs-card__tradeoff span {
  display: block;
  margin-bottom: 0.25rem;
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-mute);
}

.cs__more {
  margin-top: 1.8rem;
}
.cs__morelink {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--signal-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--signal);
}
.cs__morelink:hover {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ---- Closing band ---- */
.cs__close {
  margin-top: clamp(2.4rem, 5vw, 3.4rem);
  padding-top: clamp(2rem, 5vw, 3rem);
  border-top: 1.5px solid var(--ink);
}
.cs__closetitle {
  margin-top: 0.8rem;
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  line-height: 1.05;
  letter-spacing: -0.015em;
  text-wrap: balance;
}
.cs__closenote {
  max-width: 48rem;
  margin-top: 1rem;
  font-size: 1.02rem;
  line-height: 1.65;
  color: var(--ink-soft);
}

/* ---- Colophon ---- */
.colophon {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  margin-top: clamp(2.4rem, 5vw, 3.4rem);
  padding: 2rem 0 3rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-mute);
}
.colophon__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 1.4rem;
}
.colophon__link {
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
}
.colophon__link:hover {
  color: var(--ink);
  border-bottom-color: var(--ink);
}
.colophon__credit {
  color: var(--ink);
}
.colophon__credit::before {
  content: '●';
  margin-right: 0.5em;
  color: var(--signal);
  font-size: 0.7em;
  vertical-align: middle;
}

/* ---- Focus ---- */
.focusable:focus-visible,
.btn:focus-visible,
.masthead__brand:focus-visible,
.masthead__nav a:focus-visible {
  outline: 2.5px solid var(--signal);
  outline-offset: 3px;
  border-radius: 1px;
}

/* ---- Responsive ---- */
@media (max-width: 1080px) {
  .sheet { width: min(80rem, 100% - 2.5rem); }
}
@media (max-width: 680px) {
  .cs-arrow { transform: rotate(90deg); padding: 0.2rem 0; }
  .cs-node { flex-basis: 100%; }
  .cs-card { grid-template-columns: 1fr; gap: 0.5rem; }
  .ledger { grid-template-columns: repeat(2, 1fr); }
  .ledger > div:nth-child(2) { border-right: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn, .masthead__nav a::after { transition: none; }
  .btn:hover { transform: none; }
  .masthead__nav a:hover::after { transform: none; }
}