/* ---------------------------------------------------------------------------
   Base
   Almost everything is sized in em off a root that tracks the viewport height,
   so the whole composition scales as one piece.
--------------------------------------------------------------------------- */

:root {
  --fs: 20px;                 /* set from JS: viewport height / 50, clamped */
  --header-h: 114px;          /* set from JS: measured header height */
  --ink: #000;
  --ink-soft: rgba(0, 0, 0, 0.4);
  --ink-faint: rgba(0, 0, 0, 0.16);
  --paper: #fff;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-soft: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-zoom: cubic-bezier(0.55, 0.05, 0.15, 1);   /* the open / close zoom */
}

html, body {
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  padding: 0;
  margin: 0;
  overflow: hidden;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto,
               'Helvetica Neue', sans-serif;
  font-size: 20px;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overscroll-behavior: none;
  -webkit-user-select: none;
  user-select: none;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

*, *::before, *::after { box-sizing: border-box; }
h1, h2, h3, h4 { margin: 0; padding: 0; font-weight: 400; }
p { margin: 0; }
a { color: inherit; text-decoration: none; }
::-webkit-scrollbar { display: none; }

[data-clickable] { cursor: pointer; }

body.is-loading .chrome,
body.is-loading .timeline { opacity: 0; }

/* ---------------------------------------------------------------------------
   The shared grid every layer sits in.
--------------------------------------------------------------------------- */

.layer {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.layer--timeline { z-index: 10; }
.layer--trip { z-index: 20; }
.layer--header { z-index: 50; }   /* above the article, so back is always there */
.layer--timeline.is-inert, .layer--timeline.is-inert .tl-item { pointer-events: none; }

.grid {
  display: grid;
  grid-template-columns: [full-start] 1fr [content-start] min(1000px, 100% - 300px) [content-end] 1fr [full-end];
  grid-template-rows: 1fr min(740px, 100vh - 200px) 1fr;
  align-items: center;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  max-height: 100vh;
  font-size: var(--fs);
  pointer-events: none;
}

.grid > * { grid-column: content; grid-row: 2; }

.grid-content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: space-between;
  width: 100%;
  height: 100%;
}

.grid-content--bottom { justify-content: flex-end; }
.grid-content--middle { justify-content: center; padding-top: var(--header-h); }

/* ---------------------------------------------------------------------------
   Header. Opening a trip clears the name, the year and the nav, and brings in
   the back chevron in their place.
--------------------------------------------------------------------------- */

.chrome {
  position: relative;
  width: 100%;
  transition: opacity 0.8s var(--ease-soft);
}

.header {
  display: flex;
  height: var(--header-h);
  justify-content: space-between;
  align-self: flex-start;
  width: 100%;
}

.header-title-block {
  font-size: 20px;
  transform-origin: top left;
  flex: 1;
}

.header-name,
.header-year {
  font-size: 2em;
  line-height: 1.2em;
  font-weight: 400;
  white-space: nowrap;
}

/* Tabular figures plus a floor of one character width: a digit cell keeps the
   same box whether it holds plain text or a rolling pair, so nothing shifts
   sideways while some of the digits animate. */
.header-year {
  position: relative;
  display: inline-block;
  font-variant-numeric: tabular-nums;
  font-feature-settings: 'tnum' 1;
}
.header-year .year-digit {
  position: relative;
  display: inline-block;
  min-width: 1ch;
  text-align: center;
}
.header-year .year-out,
.header-year .year-in { display: block; }
.header-year .year-out { position: absolute; top: 0; left: 0; right: 0; }

@keyframes yearIn  { from { opacity: 0; transform: translateY(0.42em); } to { opacity: 1; transform: none; } }
@keyframes yearOut { from { opacity: 1; transform: none; } to { opacity: 0; transform: translateY(-0.42em); } }
.header-year .year-in  { animation: yearIn 0.42s var(--ease) both; }
.header-year .year-out { animation: yearOut 0.42s var(--ease) both; }

.header-nav {
  display: flex;
  flex-direction: column;
  margin-right: 4em;
  align-self: flex-start;
  margin-top: 2px;
  font-size: 20px;
  font-weight: 200;
  transform-origin: top right;
  pointer-events: auto;
}

.header-nav a {
  display: inline-block;
  font-size: 1em;
  line-height: 1.35em;
  color: var(--ink-soft);
  white-space: nowrap;
  transition: color 0.35s var(--ease-soft);
}

.header-nav a:hover { color: var(--ink); }

/* back chevron — no stem, sitting where the name was */
.back {
  position: absolute;
  top: 0;
  left: -0.35em;
  width: 2.2em;
  height: 2.2em;
  padding: 0.35em;
  border: none;
  background: none;
  color: var(--ink-soft);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s var(--ease-soft), color 0.3s var(--ease-soft),
              transform 0.4s var(--ease);
  transform: translateX(6px);
}

.back svg { width: 100%; height: 100%; display: block; overflow: visible; }
.back:hover { color: var(--ink); }

/* who is on screen decides what the header shows */
.header-title-block,
.header-nav {
  transition: opacity 0.45s var(--ease-soft), transform 0.45s var(--ease-soft);
}

body.level-trip .header-title-block,
body.level-post .header-title-block,
body.level-trip .header-nav,
body.level-post .header-nav {
  opacity: 0;
  transform: translateY(-8px);
  pointer-events: none;
}

body.level-trip .back,
body.level-post .back {
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

/* ---------------------------------------------------------------------------
   Level 0 — timeline. Trips stand on a common baseline, sized by how recent
   they are and spaced by how much time passed in between.
--------------------------------------------------------------------------- */

.layer--timeline { pointer-events: auto; touch-action: pan-y; }

.timeline {
  position: relative;
  height: 100%;
  width: auto;
  flex-shrink: 0;
  will-change: transform;
  transition: opacity 0.42s var(--ease-soft);
}

.tl-item {
  position: absolute;
  bottom: 0;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  flex-shrink: 0;
  pointer-events: auto;
}

/* While a trip is open the whole line clears out of the way as one layer.
   Fading the items one by one could leave a sliver of a half-off-screen
   photo stranded against the edge of the screen. */
.timeline.is-out { opacity: 0; }

.tl-shot {
  width: 100%;
  height: 100%;
  background-size: contain;
  background-position: bottom center;
  background-repeat: no-repeat;
}

.tl-item::after {
  content: attr(data-label);
  position: absolute;
  left: 50%;
  bottom: -2.8em;
  transform: translateX(-50%) translateY(0.4em);
  font-size: 0.8em;
  font-weight: 200;
  letter-spacing: 0.02em;
  white-space: nowrap;
  color: var(--ink-soft);
  opacity: 0;
  transition: opacity 0.35s var(--ease-soft), transform 0.35s var(--ease-soft);
  pointer-events: none;
}

.tl-item.is-focused::after { opacity: 1; transform: translateX(-50%); }

/* ---------------------------------------------------------------------------
   Level 1 — one trip. All trips live side by side on one track that slides.
--------------------------------------------------------------------------- */

.layer--trip { pointer-events: auto; touch-action: none; }
.layer--trip[hidden] { display: none; }

/* The window runs the full width of the screen so a trip slides in from
   one edge and out of the other. Only the rail inside it moves. */
.layer--trip .grid > .grid-content { grid-column: full; }

.trip-window {
  width: 100%;
  flex: 1 1 auto;
  min-height: 0;
  overflow: hidden;
}

.trip-rail {
  display: flex;
  width: 100%;
  height: 100%;
  will-change: transform;
}

.trip {
  flex: 0 0 100%;
  height: 100%;
  pointer-events: none;
}

/* the trip itself still lines up with the content column */
.trip-inner {
  width: min(1000px, 100% - 300px);
  height: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: flex-end;
}

.trip.is-active { pointer-events: auto; }

.trip-meta {
  display: flex;
  align-items: flex-start;
  margin-right: 7.5em;
  flex-shrink: 0;
  opacity: 0;
}

.trip-col { margin-right: 2.2em; }
.trip-col:last-child { margin-right: 0; }

.trip-title { font-size: 1em; font-weight: 600; white-space: nowrap; }

.trip-sub {
  font-size: 1em;
  font-weight: 200;
  display: flex;
  flex-direction: column;
}

.trip-sub span { display: inline-block; white-space: nowrap; }
.trip-sub .trip-date { margin-top: 0.5em; }

.trip-people-label { font-size: 1em; font-weight: 200; color: var(--ink-soft); }

.trip-people {
  display: flex;
  flex-direction: column;
  font-size: 1em;
  font-weight: 200;
  color: var(--ink-soft);
}

.trip-read {
  width: 2.2em;
  height: 2.2em;
  margin-top: 2em;
  border: none;
  padding: 0;
  background: none;
  overflow: visible;
  display: block;
}

.trip-read svg { width: 100%; height: 100%; overflow: visible; display: block; }
.trip-read circle { fill: transparent; stroke: var(--ink); stroke-width: 2.5px; }
.trip-read polygon { fill: var(--ink); }
.trip-read-circle { transition: transform 0.5s var(--ease); transform-origin: 34px 34px; }
.trip-read:hover .trip-read-circle { transform: scale(1.12); }

.trip-shot {
  flex-shrink: 0;
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
}

/* the element that carries a photo between two levels */
.flyer {
  position: fixed;
  z-index: 60;
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  pointer-events: none;
  will-change: transform;
}

/* ---------------------------------------------------------------------------
   Level 2 — the post. The photo lands at the top of it.
--------------------------------------------------------------------------- */

.post {
  position: fixed;
  inset: 0;
  background: var(--paper);
  z-index: 40;
  opacity: 0;
  pointer-events: auto;
}

.post[hidden] { display: none; }

.post-scroll {
  width: 100%;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
}

.post-inner {
  max-width: 44em;
  margin: 0 auto;
  padding: 6vh 2em 10em;
  font-size: var(--fs);
  -webkit-user-select: text;
  user-select: text;
}

.post-hero {
  margin: 0 auto 3.4em;
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
}

.post-kicker {
  font-size: 0.9em;
  font-weight: 200;
  color: var(--ink-soft);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 1.4em;
}

.post-title {
  font-size: 3.2em;
  line-height: 1.05;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 0.25em;
}

.post-standfirst {
  font-size: 1.5em;
  line-height: 1.45;
  font-weight: 200;
  color: var(--ink-soft);
  margin-bottom: 2.2em;
}

.post-body { font-size: 1.05em; line-height: 1.75; font-weight: 300; }
.post-body p { margin: 0 0 1.5em; }
.post-body h3 { font-size: 1.35em; font-weight: 600; line-height: 1.3; margin: 2.4em 0 0.9em; }

.post-body blockquote {
  margin: 2.4em 0;
  padding-left: 1.2em;
  border-left: 1px solid var(--ink-faint);
  font-size: 1.3em;
  line-height: 1.45;
  font-weight: 200;
}

.post-body figure { margin: 2.6em 0; }
/* the aspect ratio is set per photo from JS, so nothing is cropped */
.post-body figure div {
  width: 100%;
  aspect-ratio: 3 / 2;
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
}
.post-body figcaption { margin-top: 0.7em; font-size: 0.8em; font-weight: 200; color: var(--ink-soft); }

/* ---------------------------------------------------------------------------
   About
--------------------------------------------------------------------------- */

.about {
  position: fixed;
  inset: 0;
  z-index: 70;
  background: var(--paper);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.5s var(--ease-soft);
  pointer-events: auto;
}

.about[hidden] { display: none; }
.about.is-open { opacity: 1; }

.about-inner {
  max-width: 34em;
  padding: 2em;
  font-size: 1.35em;
  line-height: 1.6;
  font-weight: 200;
}

.about-inner p { margin-bottom: 1.2em; }
.about-close { margin-top: 2em; font-size: 0.8em; color: var(--ink-soft); }

/* ---------------------------------------------------------------------------
   Narrow screens
--------------------------------------------------------------------------- */

@media only screen and (max-width: 700px) {
  .grid {
    grid-template-columns: [full-start] 24px [content-start] 1fr [content-end] 24px [full-end];
    grid-template-rows: 1fr min(740px, 100dvh - 120px) 1fr;
  }

  .header { flex-direction: column; height: auto; align-items: flex-start; }
  .header-title-block { font-size: 16px; margin-bottom: 0.9em; }
  .header-nav {
    flex-direction: row;
    gap: 1.2em;
    margin-right: 0;
    transform-origin: top left;
    font-size: 15px;
  }

  .back { top: -0.2em; }

  .trip-inner {
    width: calc(100% - 48px);
    flex-direction: column-reverse;
    justify-content: center;
    align-items: flex-start;
  }
  .trip-meta { margin-right: 0; margin-top: 2.2em; }
  .trip-col { margin-right: 1.8em; }

  .post-inner { padding: 5vh 1.5em 8em; }
  .post-title { font-size: 2.4em; }
  .post-standfirst { font-size: 1.25em; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}