/* =====================================================================
   STUDIO HANDBOOK — reading view styled onto the platform tokens.
   Editorial, gallery-grade: display title, mono eyebrows, hairline
   collapsible sections, blueprint blockquotes, dash-marker lists.
   ===================================================================== */

.hb-root { max-width: 820px; }

/* ---- hero ---------------------------------------------------------- */
.hb-hero {
  padding-bottom: 30px; margin-bottom: 8px;
  border-bottom: 1px solid var(--fg-1);
}
.hb-eyebrow {
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--fg-4); margin-bottom: 26px;
}
.hb-title {
  font-family: var(--font-display); font-weight: 300; font-size: 52px;
  letter-spacing: -0.04em; line-height: 1.0; color: var(--fg-1); margin: 0;
}
.hb-subtitle {
  font-family: var(--font-mono); font-size: 13px; letter-spacing: 0.02em;
  color: var(--fg-3); margin: 14px 0 0;
}

/* ---- part dividers ------------------------------------------------- */
.hb-part { margin-top: 38px; }
.hb-part:first-of-type { margin-top: 26px; }
.hb-part-label {
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--fg-3); font-weight: 500;
  padding-bottom: 12px; margin-bottom: 4px; border-bottom: 1px solid var(--border-1);
}
.hb-part-sections { display: flex; flex-direction: column; }

/* ---- collapsible sections ----------------------------------------- */
.hb-sec { border-bottom: 1px solid var(--border-1); }
.hb-sec-head {
  display: flex; align-items: center; gap: 18px; width: 100%;
  padding: 20px 4px; background: none; border: none; cursor: pointer;
  text-align: left; transition: background var(--dur-fast) var(--ease-stf);
  border-radius: var(--radius-sm);
}
.hb-sec-head:hover { background: var(--bg-2); }
.hb-sec-id {
  font-family: var(--font-mono); font-size: 13px; font-weight: 500;
  color: var(--stf-blueprint); font-variant-numeric: tabular-nums;
  flex: none; min-width: 34px;
}
.hb-sec-title {
  flex: 1; font-size: 13px; font-weight: 600; letter-spacing: 0.05em;
  text-transform: uppercase; color: var(--fg-1);
}
.hb-sec-toggle {
  flex: none; color: var(--fg-4);
  transition: transform var(--dur-base) var(--ease-stf), color var(--dur-fast) var(--ease-stf);
}
.hb-sec.is-open .hb-sec-toggle { transform: rotate(180deg); color: var(--stf-blueprint); }
.hb-sec.is-open .hb-sec-id { color: var(--stf-blueprint); }

.hb-sec-body {
  padding: 4px 4px 32px;
  animation: hb-reveal 0.28s var(--ease-stf) both;
}
@keyframes hb-reveal { from { opacity: 0; transform: translateY(-4px); } to { opacity: 1; transform: none; } }

/* ---- typography ---------------------------------------------------- */
.hb-p {
  font-size: 15px; font-weight: 400; line-height: 1.72; color: var(--fg-2);
  margin: 0 0 18px; max-width: 70ch; text-wrap: pretty;
}
.hb-p:last-child { margin-bottom: 0; }
.hb-p--strong { font-weight: 600; color: var(--fg-1); font-size: 16px; }

.hb-h3 {
  font-family: var(--font-mono); font-size: 12.5px; font-weight: 600;
  letter-spacing: 0.01em; color: var(--fg-1); margin: 28px 0 13px;
}
.hb-h3:first-child { margin-top: 4px; }

.hb-quote {
  border-left: 2px solid var(--stf-blueprint); padding: 2px 0 2px 20px;
  margin: 24px 0; font-style: italic; font-size: 16px; line-height: 1.6;
  color: var(--fg-1); max-width: 64ch; text-wrap: pretty;
}

.hb-ul { list-style: none; padding: 0; margin: 0 0 18px; display: flex; flex-direction: column; gap: 11px; }
.hb-ul:last-child { margin-bottom: 0; }
.hb-ul li {
  position: relative; padding-left: 22px;
  font-size: 14.5px; line-height: 1.62; color: var(--fg-2); max-width: 70ch; text-wrap: pretty;
}
.hb-ul li::before {
  content: ""; position: absolute; left: 0; top: 11px;
  width: 9px; height: 1px; background: var(--stf-blueprint);
}
.hb-ul li strong { color: var(--fg-1); font-weight: 600; }

/* ---- footer -------------------------------------------------------- */
.hb-footer {
  margin-top: 40px; padding: 30px 28px;
  background: var(--bg-2); border: 1px solid var(--border-1); border-radius: var(--radius-lg);
}
.hb-footer p {
  font-size: 13.5px; line-height: 1.7; color: var(--fg-3);
  margin: 0; max-width: 74ch; text-wrap: pretty;
}

@media (max-width: 600px) {
  .hb-title { font-size: 38px; }
  .hb-sec-head { gap: 12px; }
}