.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color 150ms linear, background-color 180ms linear, color 180ms linear;
}

.site-header.on-dark {
  --paper: var(--d-paper);
  --ink: var(--d-ink);
  --ink-2: var(--d-ink-2);
  --accent: var(--d-accent);
  --rule: var(--d-rule);
  --rule-2: var(--d-rule-2);
  --idx: var(--d-idx);
  background: color-mix(in srgb, var(--d-paper) 88%, transparent);
  color: var(--d-ink);
}

.site-header.is-stuck { border-bottom-color: var(--rule); }

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s4);
  height: var(--headerH);
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: var(--s3);
  padding-block: var(--s3);
  font-size: var(--step-0);
  font-weight: 600;
  letter-spacing: -0.02em;
  text-decoration: none;
  white-space: nowrap;
}

.wordmark .dot {
  width: 7px;
  height: 7px;
  flex: none;
  border-radius: 1px;
  background: var(--accent);
}

/* The nav is pushed right so that it and the format toggle read as one group
   at the end of the bar, rather than being spread apart by space-between. */
.site-nav {
  display: flex;
  gap: var(--s2);
  min-width: 0;
  margin-left: auto;
  overflow-x: auto;
  scrollbar-width: none;
}
.site-nav::-webkit-scrollbar { display: none; }

.site-nav a,
.site-nav button {
  position: relative;
  display: inline-flex;
  align-items: center;
  flex: none;
  min-height: 44px;
  padding-inline: var(--s3);
  border: 0;
  background: none;
  color: var(--ink-2);
  font-family: var(--font-mono);
  font-size: var(--step--2);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: color 150ms linear;
}

.site-nav a::after,
.site-nav button::after {
  content: "";
  position: absolute;
  left: var(--s3);
  right: var(--s3);
  bottom: 12px;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 180ms cubic-bezier(0.2,0,0,1);
}

.site-nav a:hover,
.site-nav a.is-active,
.site-nav button:hover { color: var(--ink); }
.site-nav a:hover::after,
.site-nav a.is-active::after,
.site-nav button:hover::after { transform: scaleX(1); }

.nav-contact { color: var(--ink) !important; }
.nav-contact::before {
  content: "";
  width: 5px;
  height: 5px;
  margin-right: var(--s2);
  background: var(--accent);
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: var(--s2);
  flex: none;
  min-height: 44px;
  padding-inline: var(--s3);
  border: 0;
  background: none;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: var(--step--2);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  cursor: pointer;
}

.nav-toggle-icon {
  position: relative;
  width: 15px;
  height: 11px;
  flex: none;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after,
.nav-toggle-icon span {
  content: "";
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background: currentColor;
  transition: transform 180ms cubic-bezier(0.2,0,0,1), top 180ms cubic-bezier(0.2,0,0,1), opacity 120ms linear;
}

.nav-toggle-icon::before { top: 0; }
.nav-toggle-icon span { top: 5px; }
.nav-toggle-icon::after { top: 10px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  top: 5px;
  transform: rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-icon span { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  top: 5px;
  transform: rotate(-45deg);
}

.site-nav-back {
  margin-right: auto;
  margin-left: 0;
}
.nav-back::before {
  content: "";
  width: 5px;
  height: 5px;
  margin-right: var(--s2);
  background: var(--accent);
}

/* ---------------------------------------------------------- format toggle */

.view-toggle {
  display: flex;
  align-items: center;
  flex: none;
  margin-left: var(--s2);
  padding-left: var(--s2);
  border-left: 1px solid var(--rule);
}

.view-option {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  min-height: 44px;
  padding-inline: var(--s3);
  border: 0;
  background: none;
  color: var(--ink-2);
  font-family: var(--font-mono);
  font-size: var(--step--2);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  white-space: nowrap;
  cursor: pointer;
  transition: color 150ms linear;
}

.view-option:hover,
.view-option[aria-checked="true"] { color: var(--ink); }
.view-option:focus-visible { outline: 2px solid var(--accent); outline-offset: -6px; }

.view-option .box::before { content: "[ ]"; }
.view-option[aria-checked="true"] .box::before { content: "[×]"; color: var(--accent); }

.view-option .short { display: none; }

.header-live {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

.progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 0;
  height: 1px;
  background: var(--accent);
  transform-origin: left;
}

/* On narrow screens the shared navigation unfolds beneath the header. */
@media (max-width: 1059px) {
  .view-option .long { display: none; }
  .view-option .short { display: inline; }
}

@media (max-width: 760px) {
  .site-header .container { gap: var(--s2); }
  .wordmark { min-width: 28px; padding-inline: var(--s2); }
  .wordmark-label { display: none; }

  .nav-toggle { display: inline-flex; margin-left: auto; }

  .site-nav:not(.site-nav-back) {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: flex;
    flex-direction: column;
    gap: 0;
    max-height: calc(100dvh - var(--headerH));
    margin: 0;
    padding: var(--s2) var(--gutter) var(--s3);
    overflow-y: auto;
    border-bottom: 1px solid var(--rule-2);
    background: color-mix(in srgb, var(--paper) 96%, transparent);
    box-shadow: 0 18px 40px rgb(11 11 10 / 10%);
    backdrop-filter: saturate(1.4) blur(10px);
    opacity: 0;
    transform: translateY(-8px);
    visibility: hidden;
    pointer-events: none;
    transition: opacity 150ms linear, transform 180ms cubic-bezier(0.2,0,0,1), visibility 0s linear 180ms;
  }

  .site-header.menu-open {
    border-bottom-color: var(--rule);
    background: color-mix(in srgb, var(--paper) 96%, transparent);
  }

  .site-header.menu-open .site-nav:not(.site-nav-back) {
    opacity: 1;
    transform: translateY(0);
    visibility: visible;
    pointer-events: auto;
    transition-delay: 0s;
  }

  .site-nav:not(.site-nav-back) a,
  .site-nav:not(.site-nav-back) button {
    width: 100%;
    min-height: 48px;
    padding-inline: var(--s3);
    border-top: 1px solid var(--rule);
  }

  .site-nav:not(.site-nav-back) a::after,
  .site-nav:not(.site-nav-back) button::after {
    bottom: 10px;
  }

  .site-nav.site-nav-back {
    gap: 0;
    margin-right: auto;
    margin-left: 0;
    overflow: visible;
  }

  .site-nav-back a { padding-inline: var(--s2); }
}

@media (max-width: 520px) {
  .nav-toggle { padding-inline: var(--s2); }
  .view-toggle { margin-left: var(--s1); padding-left: var(--s1); }
  .view-option { padding-inline: var(--s2); }
  .view-option .box { display: none; }
  .view-option[aria-checked="true"] { color: var(--accent); }
}

/* ---------------------------------------------------------- contact card */

html.contact-open { overflow: hidden; }

.contact-dialog {
  width: min(64rem, calc(100vw - 2rem));
  max-width: none;
  max-height: calc(100dvh - 2rem);
  margin: auto;
  padding: 0;
  border: 0;
  background: transparent;
  color: #0B0B0A;
  overflow: visible;
}

.contact-dialog::backdrop {
  background: rgb(11 11 10 / 58%);
  backdrop-filter: blur(8px);
}

.contact-card {
  display: grid;
  grid-template-columns: clamp(1.25rem, 5vw, 4.5rem) minmax(0, 1fr);
  height: min(42rem, calc(100dvh - 2rem));
  min-height: 30rem;
  border: 1px solid #0B0B0A;
  background: #F7F6F3;
  box-shadow: 0 32px 100px rgb(11 11 10 / 34%);
  animation: contact-enter 260ms cubic-bezier(0.2, 0, 0, 1) both;
}

.contact-accent {
  border-right: 1px solid #0B0B0A;
  background: #1B4DFF;
}

.contact-content {
  display: flex;
  min-width: 0;
  flex-direction: column;
  padding: clamp(1.25rem, 4vw, 3rem);
}

.contact-top {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 1rem;
  padding-bottom: clamp(1rem, 2vw, 1.5rem);
  border-bottom: 1px solid #0B0B0A;
}

.contact-close,
.contact-sign {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--step--2);
  font-weight: 500;
  line-height: 1.3;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.contact-close {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  min-height: 44px;
  padding: 0 0.8rem;
  border: 1px solid #0B0B0A;
  background: transparent;
  cursor: pointer;
}
.contact-close:hover { background: #0B0B0A; color: #F7F6F3; }

.contact-content h2 {
  max-width: none;
  margin: clamp(2.5rem, 7vh, 5rem) 0 auto;
  font-size: clamp(4.5rem, 11vw, 9rem);
  font-weight: 650;
  line-height: 0.78;
  letter-spacing: -0.075em;
  text-wrap: balance;
}

.contact-email {
  align-self: flex-start;
  max-width: 100%;
  margin-top: clamp(2rem, 5vh, 4rem);
  color: #0B0B0A;
  font-size: clamp(1.4rem, 4.4vw, 4rem);
  font-weight: 550;
  line-height: 1;
  letter-spacing: -0.055em;
  overflow-wrap: anywhere;
  text-decoration-line: underline;
  text-decoration-color: #1B4DFF;
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.14em;
}
.contact-email:hover { text-decoration-color: #0B0B0A; }

.contact-sign {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: clamp(2.5rem, 7vh, 5rem);
  padding-top: 1rem;
  border-top: 1px solid #0B0B0A;
}

@keyframes contact-enter {
  from { opacity: 0; transform: translateY(18px) scale(0.985); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@media (max-width: 600px) {
  .contact-dialog {
    width: calc(100vw - 1rem);
    max-height: calc(100dvh - 1rem);
  }
  .contact-card {
    grid-template-columns: 0.875rem minmax(0, 1fr);
    height: calc(100dvh - 1rem);
    min-height: 0;
  }
  .contact-content { padding: 1rem; }
  .contact-content h2 {
    margin-top: clamp(2rem, 9vh, 4.5rem);
    font-size: clamp(4rem, 24vw, 7rem);
  }
  .contact-email { font-size: clamp(1.25rem, 7vw, 2.25rem); }
  .contact-sign { align-items: flex-end; }
  .contact-sign span { max-width: 9rem; text-align: right; }
}

@media (prefers-reduced-motion: reduce) {
  .contact-card { animation: none; }
  .site-nav:not(.site-nav-back),
  .nav-toggle-icon::before,
  .nav-toggle-icon::after,
  .nav-toggle-icon span { transition: none; }
}