/* ==========================================================================
   Layout — site header, footer, section rhythm, grids
   ========================================================================== */

/* --- Header --------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  transition:
    background var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease),
    backdrop-filter var(--dur) var(--ease);
}

.site-header.is-stuck {
  background: color-mix(in srgb, var(--color-bg) 90%, transparent);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  min-height: var(--header-h);
  max-width: var(--wrap);
  margin-inline: auto;
  padding: var(--space-3) var(--space-6);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-right: auto;
  color: inherit;
  font-family: var(--font-heading);
  font-weight: var(--font-heading-weight);
  font-size: 1.125rem;
  text-decoration: none;
  white-space: nowrap;
}

.nav-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  flex: none;
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  font-family: var(--font-heading);
  font-size: 0.8rem;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav-links a {
  position: relative;
  color: inherit;
  font-size: 0.875rem;
  text-decoration: none;
}

.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  width: 100%;
  height: 1px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur) var(--ease);
}

.nav-links a:hover,
.nav-links a[aria-current="page"] { color: var(--color-accent); }

.nav-links a:hover::after,
.nav-links a[aria-current="page"]::after { transform: scaleX(1); }

.nav-social {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: var(--space-2);
  padding-left: var(--space-4);
  border-left: 1px solid var(--color-divider);
}

.nav-social a {
  display: flex;
  color: inherit;
  transition: color var(--dur-fast) var(--ease);
}

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

.nav-toggle {
  display: none;
  width: 38px;
  height: 38px;
  padding: 0;
  border: 1px solid var(--color-divider);
  background: transparent;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 16px;
  height: 1px;
  margin: 3px auto;
  background: currentColor;
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(4px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-4px) rotate(-45deg); }

/* --- Sections ------------------------------------------------------------- */

.section {
  padding-block: var(--space-16);
}

.section-tight { padding-block: var(--space-12); }

.section-alt { background: var(--color-surface); }

.split {
  display: grid;
  grid-template-columns: minmax(34ch, 1.05fr) minmax(0, 1fr);
  gap: clamp(var(--space-8), 4vw, var(--space-16));
  align-items: center;
}

.split-reverse { grid-template-columns: minmax(0, 1fr) minmax(34ch, 1.05fr); }

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
}

.grid-7 {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: var(--space-3);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

/* --- Hero ----------------------------------------------------------------- */

.hero { padding-block: var(--space-12) var(--space-16); }

.hero h1 { margin-top: var(--space-4); max-width: 17ch; }

.hero .lede {
  max-width: 64ch;
  font-size: clamp(1rem, 0.94rem + 0.3vw, 1.1875rem);
  opacity: 0.85;
}

/* The hero animation is 16:10 and carries labels near its edges, so the frame
   matches that ratio exactly and the video is contained rather than cropped. */
.hero-media {
  aspect-ratio: 16 / 10;
  background: #ecebe7;
}

.hero-media > video {
  object-fit: contain;
}

.grid-3 { grid-template-columns: repeat(auto-fit, minmax(min(300px, 100%), 1fr)); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(min(360px, 100%), 1fr)); }

/* --- SIGNALS acronym ------------------------------------------------------ */

.signal-tile {
  padding: var(--space-4) var(--space-2);
  border: 1px solid var(--color-divider);
  text-align: center;
  transition:
    transform var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
}

.signal-tile:hover {
  transform: translateY(-6px) scale(1.03);
  box-shadow: var(--shadow-md);
  border-color: var(--color-accent);
}

.signal-tile .glyph {
  color: var(--color-accent-700);
  font-family: var(--font-heading);
  font-size: 2.125rem;
  line-height: 1;
}

.signal-tile .label {
  margin-top: var(--space-2);
  font-size: 0.75rem;
}

/* --- Footer --------------------------------------------------------------- */

.site-footer {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: var(--space-8);
  max-width: var(--wrap);
  margin-inline: auto;
  padding: var(--space-12) var(--space-6) var(--space-6);
  border-top: 1px solid var(--color-divider);
}

.site-footer h5 { margin-bottom: var(--space-3); }

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: flex-start;
}

.footer-social {
  display: flex;
  gap: 10px;
  margin-top: var(--space-3);
}

.colophon {
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 0 var(--space-6) var(--space-8);
  font-size: 0.75rem;
  opacity: 0.6;
}

/* --- Responsive ----------------------------------------------------------- */

@media (max-width: 900px) {
  .nav-toggle { display: block; }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-2) var(--space-6) var(--space-4);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-divider);
    box-shadow: var(--shadow-md);
    display: none;
  }

  .nav-links.is-open { display: flex; }

  .nav-links a {
    padding: var(--space-3) 0;
    border-bottom: 1px solid var(--color-divider);
    font-size: 1rem;
  }

  .nav-links a::after { display: none; }

  .nav-social { margin-left: 0; }

  .split,
  .split-reverse,
  .grid-3,
  .grid-2 {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .grid-7 { grid-template-columns: repeat(4, 1fr); }

  .site-footer { grid-template-columns: 1fr; gap: var(--space-6); }

  .section { padding-block: var(--space-12); }

  .hero h1 { max-width: none; }
}

@media (max-width: 520px) {
  .grid-7 { grid-template-columns: repeat(2, 1fr); }

  .nav-social { display: none; }

  .wrap { padding-inline: var(--space-4); }
}


/* --- Text-only hero --------------------------------------------------------
   On pages with no hero figure the heading sat alone against an empty right
   half. Setting the heading and the standfirst side by side fills the row and
   removes a screenful of scrolling. */

.hero-head {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
  gap: clamp(var(--space-6), 3vw, var(--space-12));
  align-items: end;
}

.hero-head > .tag { grid-column: 1 / -1; justify-self: start; }
.hero-head > h1 { margin-bottom: 0; max-width: 16ch; }
.hero-head > .lede { max-width: none; margin-bottom: 0; }
.hero-head > .actions { grid-column: 1 / -1; }

@media (max-width: 900px) {
  .hero-head { grid-template-columns: 1fr; align-items: start; }
  .hero-head > h1 { max-width: none; }
}