/* ============================================================
   chrome.css — site chrome (header, wordmark, lang, mobile sheet,
                scroll-progress hairline)
   ============================================================ */

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

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-header);
  padding: var(--space-4) 0;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition:
    background-color var(--duration-normal) var(--ease-out),
    backdrop-filter var(--duration-normal) var(--ease-out),
    border-color var(--duration-normal) var(--ease-out),
    transform var(--duration-normal) var(--ease-out),
    padding var(--duration-normal) var(--ease-out);
  -webkit-backdrop-filter: blur(0px);
  backdrop-filter: blur(0px);
  will-change: transform, backdrop-filter;
}

.header[data-scrolled="true"] {
  background: rgba(245, 241, 234, 0.72);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  backdrop-filter: blur(18px) saturate(140%);
  border-bottom-color: var(--line);
  padding: var(--space-3) 0;
}

.header[data-hidden="true"] { transform: translateY(-100%); }

.header__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
}

.header__nav {
  display: none;
  gap: var(--space-5);
  font-family: var(--font-mono);
  font-size: var(--size-mono);
  letter-spacing: var(--track-loose);
  text-transform: uppercase;
}

@media (min-width: 900px) { .header__nav { display: flex; } }

.header__nav a { color: var(--ink-faint); transition: color var(--duration-fast) var(--ease-out); }
.header__nav a:hover { color: var(--ink); }

.header__right {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

/* ---- wordmark with oxblood period ---- */

.wordmark {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  letter-spacing: var(--track-normal);
  color: var(--ink);
  display: inline-flex;
  align-items: baseline;
}

.wordmark__dot {
  color: var(--accent);
  display: inline-block;
  transform-origin: center bottom;
}

/* ---- language switcher ---- */

.lang {
  font-family: var(--font-mono);
  font-size: var(--size-mono);
  letter-spacing: var(--track-loose);
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.lang a {
  color: var(--ink-faint);
  padding: 0 4px;
  transition: color var(--duration-fast) var(--ease-out);
}

.lang a[aria-current="true"] { color: var(--ink); }
.lang a:hover { color: var(--ink); }
.lang__sep { color: var(--ink-faint); }

/* ---- mobile sheet ---- */

.menu-toggle {
  display: inline-flex;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
}

@media (min-width: 900px) { .menu-toggle { display: none; } }

.menu-toggle__bar {
  width: 18px;
  height: 1px;
  background: var(--ink);
  position: relative;
}

.menu-toggle__bar::before,
.menu-toggle__bar::after {
  content: '';
  position: absolute;
  left: 0;
  width: 100%;
  height: 1px;
  background: var(--ink);
}

.menu-toggle__bar::before { top: -6px; }
.menu-toggle__bar::after  { top:  6px; }

.sheet {
  position: fixed;
  inset: 0;
  z-index: var(--z-overlay);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  padding: var(--space-9) var(--gutter);
  gap: var(--space-6);
  transform: translateY(-100%);
  transition: transform var(--duration-normal) var(--ease-out);
}

.sheet[data-open="true"] { transform: translateY(0); }

.sheet a {
  font-family: var(--font-serif);
  font-size: 2rem;
  color: var(--ink);
}

.sheet__close {
  position: absolute;
  top: var(--space-5);
  right: var(--gutter);
  font-family: var(--font-mono);
  font-size: var(--size-mono);
  letter-spacing: var(--track-loose);
  text-transform: uppercase;
  color: var(--ink-faint);
}

/* ---- scroll progress hairline ---- */

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 1.5px;
  width: 0%;
  background: var(--accent);
  z-index: calc(var(--z-header) + 1);
  transition: width 50ms linear;
  pointer-events: none;
}