/* ---------- Accessibility ---------- */

.skip-link {
  position: absolute;
  top: -100px;
  left: 15px;
  z-index: 40;
  padding: 10px;
  background: var(--paper);
  color: var(--ink);
}

.skip-link:focus {
  top: 10px;
}


/* ---------- Navigation ---------- */

.wordmark,
.topbar nav a,
.resource-link,
.next-pages a {
  text-decoration: none;
}

.wordmark {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.04em;
}

.wordmark span {
  margin-left: 16px;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 400;
  letter-spacing: 0;
}

.topbar nav {
  display: flex;
  flex-wrap: wrap;
  gap: 25px;
}

.topbar nav a {
  padding: 6px 0;
  color: var(--muted);
  font-size: 0.95rem;
}

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

.topbar nav a[aria-current="page"] {
  color: var(--accent);
  border-bottom: 2px solid var(--accent);
}


/* ---------- Paper header ---------- */

.paper-title {
  max-width: 650px;
  color: var(--muted);
  font-size: 1.13rem;
}

.authors {
  margin: 27px 0 22px;
  font-size: 0.94rem;
}

.authors span,
.placeholder-copy {
  color: var(--muted);
}


/* ---------- Paper, code, and slides buttons ---------- */

.resources {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-top: calc(var(--topbar-height) + 24px);
}

.resource-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-width: 112px;
  min-height: 44px;
  padding: 10px 20px;
  background: var(--paper);
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.4;
}

.resource-link svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.resource-link .icon-github {
  fill: currentColor;
  stroke: none;
}

.resource-link:hover {
  background: var(--soft);
  color: var(--accent);
  border-color: var(--accent);
}

.resource-link:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
}


/* ---------- Section labels and figure placeholders ---------- */

.section-number {
  margin-bottom: 12px;
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 700;
}

.figure-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 240px;
  padding: 30px;
  background: var(--soft);
  color: var(--muted);
  border: 1px dashed #b5c5d8;
  border-radius: 5px;
  text-align: center;
}

.figure-placeholder span {
  color: var(--accent);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
}

.figure-placeholder p {
  margin: 12px 0 0;
}

figcaption {
  padding-top: 12px;
  color: var(--muted);
  font-size: 0.875rem;
  line-height: 1.6;
  text-align: center;
}


/* ---------- Side-by-side behavior videos ---------- */

.behavior-comparison {
  width: 100%;
  max-width: 680px;
  margin: 32px auto;
}

.behavior-grid,
.next-pages {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.behavior-grid {
  align-items: start;
  gap: 24px;
}

.behavior-panel {
  min-width: 0;
  text-align: center;
}

.behavior-label {
  margin: 0 0 12px;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
}

.behavior-media {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  max-width: 320px;
  aspect-ratio: 1;
  margin: 0 auto;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.behavior-media img,
.behavior-media video {
  display: block;
  width: 100%;
  height: 100%;
  max-width: none;
  max-height: none;
  margin: 0;
  object-fit: contain;
  border: 0;
  border-radius: 5px;
  background: transparent;
}

.behavior-comparison figcaption {
  max-width: 640px;
  margin: 14px auto 0;
  padding: 0;
}


/* ---------- Three-panel behavior videos ---------- */

.behavior-comparison--three {
  max-width: 900px;
}

.behavior-comparison--three .behavior-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.behavior-comparison .behavior-grid + .behavior-grid {
  margin-top: 16px;
}


/* ---------- ADiCo framework diagram ---------- */

.framework-figure {
  width: 100%;
  margin: 30px 0;
}

.framework-figure > a {
  display: block;
}

.framework-figure .framework-image {
  display: block;
  width: 100%;
  height: auto;
  max-height: none;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.framework-figure figcaption {
  max-width: 760px;
  margin: 0 auto;
  padding-top: 14px;
}


/* ---------- Related pages ---------- */

.next-pages {
  gap: 20px;
  margin-top: 25px;
}

.next-pages a {
  padding: 20px 0;
  border-top: 2px solid var(--accent);
  font-size: 1.1rem;
}

.next-pages span {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 0.8rem;
}

.next-pages b {
  font-weight: 400;
}

/* ---------- Row of small plots ---------- */

.plot-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin: 24px 0 30px;
}

.plot-row img {
  display: block;
  width: 100%;
  height: auto;
}

.plot-row figcaption {
  grid-column: 1 / -1;
}


/* ---------- Mobile layout ---------- */

@media (max-width: 540px) {
  .behavior-grid,
  .next-pages {
    grid-template-columns: 1fr;
  }

  .behavior-comparison--three .behavior-grid {
    grid-template-columns: 1fr;
  }

  .behavior-panel {
    width: 100%;
    max-width: 320px;
    margin: 0 auto;
  }

  .wordmark span {
    display: none;
  }

  .figure-placeholder {
    min-height: 190px;
  }

  .plot-row {
    grid-template-columns: 1fr;
  }
}


/* ---------- Side navigation ---------- */

.sidenav-box ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidenav-box a {
  display: flex;
  gap: 12px;
  padding: 7px 0 7px 14px;
  color: var(--muted);
  border-left: 2px solid var(--line);
  font-size: 0.9rem;
  line-height: 1.4;
  text-decoration: none;
}

.sidenav-box a span {
  flex-shrink: 0;
  padding-top: 2px;
  color: var(--accent);
  font-size: 0.75rem;
}

.sidenav-box a:hover,
.sidenav-box a.active {
  color: var(--accent);
  border-left-color: var(--accent);
}

.sidenav-box summary {
  list-style: none;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
}

.sidenav-box summary::-webkit-details-marker {
  display: none;
}

/* Desktop: fixed on the side */
@media (min-width: 901px) {
  .page {
    display: grid;
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 56px;
  }

  .sidenav {
    align-self: start;
    position: sticky;
    top: calc(var(--topbar-height) + 24px);
    max-height: calc(100dvh - var(--topbar-height) - 48px);
    overflow-y: auto;
  }

  .sidenav-box summary {
    display: none;
  }
}

/* Mobile: collapsible menu box */
@media (max-width: 900px) {
  .page {
    display: block;
  }

  .sidenav {
    position: sticky;
    top: var(--topbar-height);
    z-index: 20;
    max-height: calc(100dvh - var(--topbar-height));
    overflow-y: auto;
    margin-bottom: 24px;
    padding: 12px 0;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
  }

  .sidenav-box summary {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .sidenav-box summary::after {
    content: "▾";
    color: var(--accent);
    transition: transform 0.2s;
  }

  .sidenav-box[open] summary::after {
    transform: rotate(180deg);
  }

  .sidenav-box ol {
    padding-top: 12px;
  }

  main section[id] {
    scroll-margin-top: calc(var(--topbar-height) + 70px);
  }
}