/* rail.css — the cross-project navigation rail (public/rail.html). Loaded by the
   landing, the 404, and every proxied project page (api/proxy.ts injects it), so it
   styles only .rail* and the page offset; components and tokens are ui.css's.
   Unlayered on purpose: it must beat each page's ui.css component layer.
   Breakpoint: 900px (docked ≥ 900, strip below) is docs.css's desktop constant,
   stated once in its header comment beside 640px (phone, the shell's own) —
   media queries cannot read custom properties, so a change there lands here too. */

:root {
  --rail-strip-h: 48px;
  --rail-w: 224px;
}

.rail-foot {
  display: flex;
  flex-direction: column;
  gap: var(--ui-space-3);
  margin-top: auto;
  padding-top: var(--ui-space-5);
}

.rail-foot .segmented {
  align-self: flex-start;
}

.rail-head {
  align-items: center;
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--ui-space-3);
  min-height: 32px;
  padding-inline: var(--ui-space-2);
}

.rail-mark {
  color: var(--ui-accent);
  font-size: var(--ui-text-xl);
  font-weight: var(--ui-weight-bold);
  letter-spacing: -0.04em;
  line-height: 1;
  text-decoration: none;
}

/* [popover] carries UA chrome (border, padding, Canvas colours, inset: 0 with
   auto margins); every one of those is reset here so the panel is ours in both
   the docked and the drawer form. */
.rail-panel {
  background: var(--ui-surface);
  border: 0;
  border-inline-end: 1px solid var(--ui-border);
  color: var(--ui-fg);
  flex-direction: column;
  font-family: var(--ui-font-sans);
  font-size: var(--ui-text-md);
  gap: var(--ui-space-1);
  height: 100%;
  inset: 0 auto 0 0;
  line-height: var(--ui-leading-body);
  margin: 0;
  max-height: none;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: var(--ui-space-4) var(--ui-space-3);
  position: fixed;
  width: var(--rail-w);
}

.rail-panel .eyebrow {
  margin-top: var(--ui-space-2);
  padding-inline: var(--ui-space-2);
}

.rail-panel .hr {
  margin: var(--ui-space-3) var(--ui-space-2) var(--ui-space-1);
}

.rail-panel .listrow {
  font-size: var(--ui-text-sm);
  text-decoration: none;
}

.rail-panel .listrow-meta {
  margin-inline-start: auto;
}

.rail-strip {
  align-items: center;
  background: var(--ui-surface);
  border-bottom: 1px solid var(--ui-border);
  display: flex;
  height: var(--rail-strip-h);
  inset: 0 0 auto;
  justify-content: space-between;
  padding-inline: var(--ui-space-4) var(--ui-space-2);
  position: fixed;
  z-index: 30;
}

/* docked: the panel is always shown, so the UA's
   [popover]:not(:popover-open) { display: none } is overridden — author rules
   outrank UA rules whatever the specificity. */
@media (min-width: 900px) {
  html {
    padding-inline-start: var(--rail-w);
  }

  .rail-close,
  .rail-strip {
    display: none;
  }

  .rail-panel {
    display: flex;
    z-index: 30;
  }
}

/* drawer: a slim fixed strip on top; the panel opens from it as a popover
   (top layer, light-dismiss, Esc) — no script involved. */
@media (max-width: 899.98px) {
  html {
    padding-block-start: var(--rail-strip-h);
    scroll-padding-top: var(--rail-strip-h);
  }

  .rail-panel {
    box-shadow: var(--ui-shadow-lg);
    max-width: 85vw;
  }

  .rail-panel:popover-open {
    display: flex;
  }

  .rail-panel::backdrop {
    background: rgb(0 0 0 / 0.4);
  }
}