/*
  Embedded Pandora — components.css
  Reusable UI pieces: site header, breadcrumb, layout shell,
  cards, callouts, tables-of-contents, prev/next, related-topics, search.
*/

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

.page {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2.2rem 1.25rem 5rem;
}

.page--wide {
  max-width: var(--wide-width);
}

/* ---------- site header ---------- */

.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg-raised);
  position: sticky;
  top: 0;
  z-index: 20;
}

.site-header__bar {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.site-header__brand {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.4em;
}

.site-header__brand:visited { color: var(--ink); }

.site-header__brand .mark {
  color: var(--accent);
}

.site-header__nav {
  display: flex;
  gap: 0.9rem;
  flex-wrap: wrap;
  font-size: 0.92rem;
}

.site-header__nav a {
  color: var(--ink-soft);
  text-decoration: none;
}

.site-header__nav a:hover {
  color: var(--accent);
}

.site-header__spacer {
  flex: 1;
}

.site-header__search {
  position: relative;
}

.site-header__search input {
  font: inherit;
  font-size: 0.88rem;
  background: var(--bg);
  color: var(--ink);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.4em 0.9em;
  width: 11rem;
}

.theme-toggle {
  font: inherit;
  font-size: 0.9rem;
  background: var(--bg);
  color: var(--ink);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.35em 0.7em;
  cursor: pointer;
  line-height: 1;
}

.theme-toggle:hover {
  border-color: var(--accent);
}

/* ---------- breadcrumb ---------- */

.breadcrumb {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0.9rem 1.25rem 0;
  font-size: 0.85rem;
  color: var(--ink-faint);
  display: flex;
  flex-wrap: wrap;
  gap: 0.35em;
}

.breadcrumb a {
  color: var(--ink-faint);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--accent);
}

.breadcrumb .sep {
  opacity: 0.6;
}

.breadcrumb .current {
  color: var(--ink-soft);
}

/* ---------- kicker / eyebrow ---------- */

.kicker {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--teal);
  font-weight: 700;
  margin-bottom: 0.4em;
}

.lede {
  font-size: 1.1rem;
  color: var(--ink-soft);
}

/* ---------- card grid ---------- */

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.card {
  display: block;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-raised);
  padding: 1.1rem 1.2rem;
  text-decoration: none;
  color: var(--ink);
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.card:visited { color: var(--ink); }

.card:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.card__icon {
  font-size: 1.4rem;
  display: block;
  margin-bottom: 0.5rem;
}

.card__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.08rem;
  margin: 0 0 0.3em;
}

.card__desc {
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin: 0;
}

.card__meta {
  margin-top: 0.6em;
  font-size: 0.76rem;
  color: var(--ink-faint);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* topic list rows, used on domain index pages under each category */
.topic-list {
  list-style: none;
  padding: 0;
  margin: 0.8em 0 1.6em;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.topic-list li {
  border-top: 1px solid var(--border);
}

.topic-list li:first-child {
  border-top: none;
}

.topic-list a {
  display: flex;
  justify-content: space-between;
  gap: 1em;
  align-items: baseline;
  padding: 0.65em 0.9em;
  text-decoration: none;
  color: var(--ink);
  background: var(--bg-raised);
}

.topic-list a:hover {
  background: var(--accent-soft);
}

.topic-list .status {
  font-size: 0.74rem;
  color: var(--ink-faint);
  white-space: nowrap;
}

/* ---------- callouts ---------- */

.callout {
  border: 1px solid var(--border);
  border-left: 4px solid var(--teal);
  background: var(--bg-raised);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 0.9rem 1.1rem;
  margin: 1.4rem 0;
}

.callout p:last-child { margin-bottom: 0; }

.callout--note { border-left-color: var(--teal); }
.callout--warn { border-left-color: var(--accent); }
.callout--todo { border-left-color: var(--ink-faint); }

.callout__label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-faint);
  display: block;
  margin-bottom: 0.35em;
}

/* ---------- table of contents ---------- */

.toc {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.9rem 1.2rem;
  margin: 1.4rem 0;
  font-size: 0.92rem;
}

.toc__label {
  font-weight: 700;
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 0.5em;
  display: block;
}

.toc ul {
  margin: 0;
  padding-left: 1.1em;
}

/* ---------- related topics ---------- */

.related {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

.related h2 {
  border: none;
  padding: 0;
  font-size: 1.05rem;
  margin-top: 0;
}

.related ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.related a {
  display: inline-block;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.35em 0.9em;
  font-size: 0.86rem;
  text-decoration: none;
  color: var(--ink-soft);
  background: var(--bg-raised);
}

.related a:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- prev / next ---------- */

.pager {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2rem;
}

.pager__link {
  flex: 1;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.7em 0.9em;
  text-decoration: none;
  color: var(--ink);
  font-size: 0.88rem;
}

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

.pager__link--next {
  text-align: right;
}

.pager__dir {
  display: block;
  font-size: 0.72rem;
  color: var(--ink-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.2em;
}

/* ---------- footer ---------- */

.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 3rem;
  padding: 1.5rem 1.25rem 3rem;
  font-size: 0.82rem;
  color: var(--ink-faint);
}

.site-footer__bar {
  max-width: var(--wide-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.site-footer a {
  color: var(--ink-faint);
}

.site-footer a:hover {
  color: var(--accent);
}

/* ---------- search results (homepage) ---------- */

.search-results {
  margin: 1rem 0 2rem;
}

.search-results ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.search-results li {
  border-bottom: 1px solid var(--border);
  padding: 0.6em 0;
}

.search-results a {
  text-decoration: none;
  font-weight: 600;
}

.search-results .path {
  display: block;
  font-size: 0.78rem;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

.search-hidden {
  display: none !important;
}

/* ---------- hero (homepage) ---------- */

.hero {
  padding: 2.5rem 0 1.5rem;
}

.hero h1 {
  font-size: 2.4rem;
}

/* ---------- misc utility ---------- */

.badge {
  display: inline-block;
  font-size: 0.72rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.15em 0.6em;
  color: var(--ink-faint);
  font-family: var(--font-sans);
}

.figure {
  margin: 1.5rem 0;
  text-align: center;
}

.figure figcaption {
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin-top: 0.5em;
}

.kv {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.3em 1em;
  font-size: 0.92rem;
  margin: 1em 0;
}

.kv dt {
  color: var(--ink-faint);
  font-family: var(--font-mono);
  font-size: 0.85em;
}

.kv dd {
  margin: 0;
}

/* ---------- sequence / frame diagrams ---------- */
/* Reusable across any topic that needs to show a message exchange —
   see protocols/*, networking/coap for usage. SVGs inside use these
   classes instead of hardcoded colors so they follow the page theme. */

.diagram {
  margin: 1.6rem 0;
  padding: 1rem;
  background: var(--bg-raised);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow-x: auto;
}

.diagram__caption {
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin: 0.6em 0 0;
  text-align: center;
}

.diagram svg { display: block; margin: 0 auto; min-width: 480px; }

.seq-actor-chip { fill: var(--bg-inset); stroke: var(--border); }
.seq-actor-text { font-family: var(--font-sans); font-weight: 700; font-size: 12px; fill: var(--ink); }
.seq-lifeline { stroke: var(--border); stroke-width: 1.5; stroke-dasharray: 4 3; }
.seq-arrow { stroke: var(--ink-soft); stroke-width: 1.6; fill: none; }
.seq-arrow-lost { stroke: var(--ink-faint); stroke-width: 1.6; fill: none; stroke-dasharray: 5 4; }
.seq-arrowhead { fill: var(--ink-soft); }
.seq-x-mark { stroke: var(--accent); stroke-width: 2; }
.seq-label { font-family: var(--font-mono); font-size: 11px; fill: var(--ink); }
.seq-sub { font-family: var(--font-sans); font-size: 10px; fill: var(--ink-faint); }
.seq-note { font-family: var(--font-sans); font-size: 10.5px; fill: var(--ink-faint); font-style: italic; }
.seq-tag-con { fill: var(--accent); font-weight: 700; }
.seq-tag-ack { fill: var(--teal); font-weight: 700; }
.seq-tag-non { fill: var(--ink-faint); font-weight: 700; }
.seq-bracket { stroke: var(--ink-faint); stroke-width: 1; }

.frame-box { fill: var(--bg-inset); stroke: var(--border); stroke-width: 1.5; }
.frame-box--variable { fill: var(--bg-inset); stroke: var(--ink-faint); stroke-width: 1.3; stroke-dasharray: 4 3; }
.frame-label { font-family: var(--font-mono); font-size: 11px; fill: var(--ink); }
.frame-caption { font-family: var(--font-sans); font-size: 9.5px; fill: var(--ink-faint); }
.frame-divider { stroke: var(--accent); stroke-width: 1.2; stroke-dasharray: 2 2; }

/* ---------- quick reference ---------- */
/* A scan-in-30-seconds summary placed right after the lede, before the
   table of contents. Every topic page should have one — see GUIDE.md. */

.quickref {
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
  border-radius: var(--radius);
  background: var(--bg-raised);
  padding: 1.1rem 1.3rem 1.2rem;
  margin: 1.6rem 0;
}

.quickref__label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
  margin-bottom: 0.7em;
}

.quickref dl {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.5em 1em;
  margin: 0;
  font-size: 0.94rem;
}

.quickref dt {
  font-weight: 700;
  color: var(--ink);
  white-space: nowrap;
}

.quickref dd {
  margin: 0;
  color: var(--ink-soft);
}

/* ---------- point list ---------- */
/* Tight, scannable bullets for "here's what you actually need to know" —
   denser than a normal <ul>, used for real-world-application lists and
   quick facts inside a section. */

.point-list {
  list-style: none;
  padding: 0;
  margin: 1em 0;
  display: grid;
  gap: 0.55em;
}

.point-list li {
  padding-left: 1.4em;
  position: relative;
}

.point-list li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--accent);
}

.point-list strong {
  color: var(--ink);
}

/* ---------- colorful block diagrams ---------- */
/* Color variants for multi-stage/multi-block diagrams (boot stages,
   architecture layers, protocol stacks) — combine with .frame-box, e.g.
   class="frame-box block-blue". Defined after .frame-box in this file so
   the color wins the fill/stroke tie-break; each hue stays legible in
   both themes since it's built from the theme's own color tokens. */

.block-amber   { fill: var(--accent-soft); stroke: var(--accent); }
.block-teal    { fill: color-mix(in srgb, var(--teal) 22%, var(--bg-inset)); stroke: var(--teal); }
.block-blue    { fill: color-mix(in srgb, var(--blue) 22%, var(--bg-inset)); stroke: var(--blue); }
.block-green   { fill: color-mix(in srgb, var(--green) 22%, var(--bg-inset)); stroke: var(--green); }
.block-violet  { fill: color-mix(in srgb, var(--violet) 22%, var(--bg-inset)); stroke: var(--violet); }

/* ---------- animated diagrams ---------- */
/* Motion is opt-in per element (not every diagram needs it) and always
   respects prefers-reduced-motion. Use .flow-path on a dashed line to
   suggest current/data/signal movement; .pulse-dot on a circle for a
   "something is happening here" heartbeat. */

.flow-path {
  stroke-dasharray: 6 5;
  animation: flow-dash 1.1s linear infinite;
}

.flow-path--slow {
  animation-duration: 2.4s;
}

.flow-path--reverse {
  animation-direction: reverse;
}

@keyframes flow-dash {
  to { stroke-dashoffset: -22; }
}

.pulse-dot {
  animation: pulse-grow 1.6s ease-in-out infinite;
  transform-box: fill-box;
  transform-origin: center;
}

@keyframes pulse-grow {
  0%, 100% { opacity: 0.55; transform: scale(0.85); }
  50% { opacity: 1; transform: scale(1.15); }
}

@media (prefers-reduced-motion: reduce) {
  .flow-path, .pulse-dot {
    animation: none;
  }
}

@media (max-width: 640px) {
  .site-header__nav { display: none; }
  .site-header__search input { width: 8rem; }
  .pager { flex-direction: column; }
  .pager__link--next { text-align: left; }
  .quickref dl { grid-template-columns: 1fr; gap: 0.15em 0; }
}