/* ============================================================
 * BSS Design System · pages.css
 * Shared page-shell layout for multi-page documentation.
 * Layout only — no token / component invention.
 * Requires tokens.css + components.css to be loaded first.
 * ============================================================ */

/* ---------- Page shell ---------- */
body { background: var(--c-canvas); }

.page-shell {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
}

/* ---------- Left side nav ---------- */
.side-nav {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow-y: auto;
  background: var(--c-canvas);
  border-right: var(--line-hairline);
  padding: var(--sp-xl) var(--sp-lg);
  display: flex;
  flex-direction: column;
  gap: var(--sp-xl);
}

.side-brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--sp-sm);
  text-decoration: none;
  color: var(--c-ink-deep);
  padding: 0 var(--sp-sm);
}
.side-brand img { display: block; height: 44px; width: auto; }
.side-brand .b-name {
  font: 600 var(--fs-caption)/1.4 var(--ff);
  letter-spacing: var(--tracking);
  color: var(--c-ink-deep);
}

.side-group {
  margin: var(--sp-lg) 0 var(--sp-xs);
  padding: 0 var(--sp-md);
  color: var(--c-grey);
  font: 600 var(--fs-caption)/1.3 var(--ff);
  letter-spacing: var(--tracking);
  text-transform: none;
}

.side-nav nav ul,
.side-nav nav > a + ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.side-nav nav a {
  display: block;
  padding: var(--sp-sm) var(--sp-md);
  border-radius: var(--r-md);
  text-decoration: none;
  color: var(--c-body);
  font: var(--fw-body) var(--fs-caption)/1.4 var(--ff);
  letter-spacing: var(--tracking);
  transition: background 0.15s, color 0.15s;
}
.side-nav nav a:hover {
  background: var(--c-light-grey);
  color: var(--c-ink-deep);
}
.side-nav nav a.is-current {
  background: var(--c-sky-light);
  color: var(--c-primary);
}
.side-nav nav a.is-disabled {
  opacity: 0.45;
  pointer-events: none;
}

/* ---------- Main content area ---------- */
.page-main { min-width: 0; }
.page-body {
  max-width: 920px;
  padding: var(--sp-5xl) var(--sp-4xl);
}

/* ---------- Page hero ---------- */
.page-head {
  margin-bottom: var(--sp-4xl);
  padding-bottom: var(--sp-3xl);
  border-bottom: var(--line-hairline);
}
.page-head .eyebrow {
  color: var(--c-grey);
  text-transform: uppercase;
  font: 600 var(--fs-caption)/1.2 var(--ff-en);
  letter-spacing: 0.06em;
  margin: 0 0 var(--sp-md);
}
.page-head h1 { margin: 0 0 var(--sp-lg); }
.page-head .lead { margin: 0; max-width: 720px; color: var(--c-body); }

/* ---------- In-page section ---------- */
.doc-section { margin: 0 0 var(--sp-5xl); }
.doc-section:last-child { margin-bottom: 0; }
.doc-section h2 { margin: 0 0 var(--sp-md); }
.doc-section .sec-lead { margin: 0 0 var(--sp-2xl); color: var(--c-body); max-width: 720px; }
.doc-section h3 { margin: var(--sp-3xl) 0 var(--sp-lg); }
.doc-section h3:first-child + * + h3 { margin-top: var(--sp-3xl); }

/* ---------- Hub cards (used on overview page) ---------- */
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--sp-lg);
}
.hub-card {
  display: flex;
  flex-direction: column;
  gap: var(--sp-md);
  padding: var(--sp-2xl);
  background: var(--c-canvas);
  border: 1px solid var(--c-line-default);
  border-radius: var(--r-lg);
  text-decoration: none;
  color: var(--c-ink-deep);
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}
.hub-card:hover {
  border-color: var(--c-line-hover);
  transform: translateY(-2px);
  box-shadow: var(--sh-soft);
  color: var(--c-ink-deep);
}
.hub-card .hc-eyebrow {
  color: var(--c-grey);
  font: 600 var(--fs-caption)/1.2 var(--ff-en);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.hub-card h3 { margin: 0; }
.hub-card p { margin: 0; color: var(--c-body); }
.hub-card .hc-arrow {
  margin-top: auto;
  color: var(--c-primary);
}
.hub-card.is-soon { opacity: 0.55; pointer-events: none; }

/* ---------- Mobile: stack sidebar above ---------- */
@media (max-width: 960px) {
  .page-shell { grid-template-columns: 1fr; }
  .side-nav {
    position: sticky;
    top: 0;
    height: auto;
    max-height: none;
    border-right: 0;
    border-bottom: var(--line-hairline);
    padding: var(--sp-md) var(--sp-lg);
    gap: var(--sp-md);
    flex-direction: column;
    z-index: 50;
  }
  .side-brand { padding: 0; }
  .side-brand img { height: 28px; }
  .side-group {
    margin: var(--sp-md) 0 var(--sp-xs);
    padding: 0;
  }
  .side-nav nav { display: flex; flex-direction: column; gap: var(--sp-sm); }
  .side-nav nav > a:not(.side-group) {
    padding: var(--sp-xs) var(--sp-sm);
  }
  .side-nav nav ul {
    flex-direction: row;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: var(--sp-xs);
    scrollbar-width: none;
  }
  .side-nav nav ul::-webkit-scrollbar { display: none; }
  .side-nav nav ul a {
    white-space: nowrap;
    padding: var(--sp-xs) var(--sp-md);
  }
  .page-body { padding: var(--sp-3xl) var(--sp-xl); }
}