/* ============================================================================
   tour.css — SHARED tour/guide styling (D-058).

   Single source of truth for the deck's design tokens + slide/nav/motion CSS.
   Loaded by BOTH the phone page (mobile.html) and the laptop intro overlay
   (index.html + intro.js), so the two render the same slides — edit once, both
   stay in sync. Host-specific chrome (the phone bezel; the laptop overlay
   backdrop + boot button) lives in each host, NOT here.

   One direction — "Instrument" — that follows the environment's light/dark.
   Tokens live on :root; the media query and the data-theme overrides swap them.
   ========================================================================== */
:root {
  --bg:#f4f7fa; --surface:#ffffff; --surface-2:#eef2f6;
  --ink:#111925; --muted:#54606f; --faint:#aeb8c4; --line:rgba(17,25,37,.13);
  --accent:#2f6bdb; --follower:#c2621a;
  --stage: radial-gradient(120% 90% at 50% -8%, #ffffff, #d9e1ea 78%);
  --bezel-a:#e7ebf0; --bezel-b:#c9d2dc; --frame: rgba(40,54,74,.4);
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg:#0d1117; --surface:#161b22; --surface-2:#1c232d;
    --ink:#e6edf3; --muted:#8b98a6; --faint:#46505e; --line:rgba(139,152,166,.16);
    --accent:#4c8dff; --follower:#f0883e;
    --stage: radial-gradient(120% 90% at 50% -8%, #1b2431, #0a0d12 72%);
    --bezel-a:#232c38; --bezel-b:#05070a; --frame: rgba(0,0,0,.8);
    color-scheme: dark;
  }
}
:root[data-theme="light"] {
  --bg:#f4f7fa; --surface:#ffffff; --surface-2:#eef2f6;
  --ink:#111925; --muted:#54606f; --faint:#aeb8c4; --line:rgba(17,25,37,.13);
  --accent:#2f6bdb; --follower:#c2621a;
  --stage: radial-gradient(120% 90% at 50% -8%, #ffffff, #d9e1ea 78%);
  --bezel-a:#e7ebf0; --bezel-b:#c9d2dc; --frame: rgba(40,54,74,.4);
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg:#0d1117; --surface:#161b22; --surface-2:#1c232d;
  --ink:#e6edf3; --muted:#8b98a6; --faint:#46505e; --line:rgba(139,152,166,.16);
  --accent:#4c8dff; --follower:#f0883e;
  --stage: radial-gradient(120% 90% at 50% -8%, #1b2431, #0a0d12 72%);
  --bezel-a:#232c38; --bezel-b:#05070a; --frame: rgba(0,0,0,.8);
  color-scheme: dark;
}

/* ---- deck wrapper: typography baseline the host inherits from ---- */
.flp-deck { font-family: var(--sans); color: var(--ink);
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
.flp-deck button { font: inherit; color: inherit; cursor: pointer; border: none; background: none; }
.flp-deck :focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

/* ----------------------------------------------------------- the slide track */
.track {
  display: flex; height: 100%; width: 100%;
  overflow-x: auto; overflow-y: hidden;
  scroll-snap-type: x mandatory;   /* smooth programmatic scroll fights mandatory snap
     (it reverts to 0), so button/dot nav jumps instantly + the content fade carries the
     transition; native touch swipe animates on its own. */
  -webkit-overflow-scrolling: touch; scrollbar-width: none;
}
.track::-webkit-scrollbar { display: none; }

.slide {
  flex: 0 0 100%; scroll-snap-align: start; scroll-snap-stop: always;
  height: 100%; overflow-y: auto; scrollbar-width: none;
  display: flex; flex-direction: column;
  padding: clamp(34px, 8vh, 68px) 26px calc(94px + env(safe-area-inset-bottom, 0px));
}
.slide::-webkit-scrollbar { display: none; }
.slide-top { flex: 0 0 auto; margin-bottom: 26px; }
.slide-body {
  flex: 1 1 auto; display: flex; flex-direction: column;
  justify-content: safe center;   /* 'safe' → never clip the top when content overflows */
  gap: 20px; min-height: 0;
}
.slide[data-kind="cover"] .slide-body,
.slide[data-kind="outro"] .slide-body { justify-content: safe flex-end; }

/* content-entry motion, keyed off the active slide */
.slide > *, .slide-body > * { opacity: 0; transform: translateY(9px); }
.slide.is-active > *, .slide.is-active .slide-body > * {
  opacity: 1; transform: none;
  transition: opacity .5s ease, transform .55s cubic-bezier(.2,.7,.2,1);
}
.slide.is-active .slide-body > *:nth-child(2) { transition-delay: .05s; }
.slide.is-active .slide-body > *:nth-child(3) { transition-delay: .10s; }
.slide.is-active .slide-body > *:nth-child(n+4) { transition-delay: .15s; }

/* ---- content atoms ---- */
.eyebrow {
  font-family: var(--mono); font-size: 11px; letter-spacing: .18em; text-transform: uppercase;
  color: var(--follower); display: flex; align-items: center; gap: 10px;
}
.eyebrow::after {
  content: ""; flex: 1 1 auto; height: 1px;
  background: repeating-linear-gradient(90deg, var(--line) 0 6px, transparent 6px 12px);
}
.title {
  margin: 0; font-weight: 700; letter-spacing: -.015em; line-height: 1.12; text-wrap: balance;
  font-size: clamp(25px, 6.6vw, 32px); color: var(--ink);
}
.slide[data-kind="cover"] .title { font-size: clamp(33px, 9.2vw, 42px); line-height: 1.04; }
.gloss { margin: 0; color: var(--muted); font-size: 15.5px; line-height: 1.6; text-wrap: pretty; }
.gloss b, .list b { color: var(--ink); font-weight: 650; }

/* the equation — a roomy, prominent readout */
.eq {
  font-family: var(--mono); font-size: clamp(19px, 5.3vw, 23px); color: var(--ink);
  background: var(--surface); border: 1px solid var(--line); border-left: 3px solid var(--accent);
  border-radius: 10px; padding: 24px 20px; min-height: 92px;
  display: flex; flex-direction: column; justify-content: center; gap: .2em;
  overflow-x: auto; scrollbar-width: none; line-height: 1.5;
}
.eq::-webkit-scrollbar { display: none; }
.eq .line { white-space: nowrap; }
.eq .big { white-space: nowrap; font-size: 1.16em; color: var(--follower); margin-top: .35em; letter-spacing: .01em; }
.eq i { font-style: italic; }
.eq sup, .eq sub { font-size: .66em; font-style: normal; }
.eq sup sup, .eq sup sub { font-size: .82em; }
.eq .mo { padding: 0 .32em; opacity: .78; }
.eq .mo.dot { padding: 0 .18em; opacity: .55; }
.eq .amp { padding: 0 .5em; opacity: .45; font-style: italic; font-size: .8em; }

/* calibration ledger — shown only for well-graded parameters (A / B) */
.params { margin: 0; padding: 0; list-style: none; display: flex; flex-direction: column;
  border-top: 1px solid var(--line); }
.params li { display: flex; flex-direction: column; gap: 4px; padding: 13px 0; border-bottom: 1px solid var(--line); }
.params .row1 { display: flex; align-items: baseline; gap: 12px; }
.params .sym { font-family: var(--mono); font-size: 14px; color: var(--muted); flex: 0 0 auto; }
.params .val { font-family: var(--mono); font-size: 15px; font-weight: 700; color: var(--accent); }
.params .note { color: var(--muted); font-size: 13px; line-height: 1.45; }

.list { margin: 0; padding: 0; list-style: none; display: grid;
  grid-template-columns: 76px 1fr; column-gap: 16px; row-gap: 16px; align-items: baseline; }
.list li { display: contents; }
.list .k { font-family: var(--mono); font-size: 12.5px; letter-spacing: .04em; color: var(--accent);
  text-transform: uppercase; text-align: right; }
.list span:last-child { color: var(--muted); font-size: 15px; line-height: 1.5; text-align: left; text-wrap: pretty; }

.foot { margin: 0; font-size: 13.5px; color: var(--muted); text-wrap: pretty; }
.foot a { color: var(--accent); text-decoration: none; border-bottom: 1px solid currentColor; }
.credit { margin: 4px 0 0; font-family: var(--mono); font-size: 11px; line-height: 1.6; color: var(--faint);
  letter-spacing: .02em; }

/* ---- the model-note link (D-097) — the "while you wait" reading -------------
   Shared by both hosts, so the wording and the href can never drift: the phone
   renders it inside the cover/outro slides (it has no chrome), the laptop overlay
   inside its boot bar (sizing tweaks in intro.css). Deliberately a quiet PANEL,
   not a button — unmistakably clickable, but never mistaken for the laptop's
   primary "Go to the widget" action. */
.note-link {
  display: flex; align-items: center; gap: 12px;
  padding: 11px 13px; border-radius: 12px; text-decoration: none;
  background: var(--surface); border: 1px solid var(--line); color: var(--ink);
  transition: border-color .18s ease, background .18s ease;
}
.note-link:hover { border-color: var(--accent); background: var(--surface-2); }
.note-tag {
  flex: 0 0 auto; font-family: var(--mono); font-size: 10px; letter-spacing: .1em;
  padding: 4px 7px; border-radius: 6px; color: var(--accent);
  background: color-mix(in srgb, var(--accent) 13%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 34%, transparent);
}
.note-txt  { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.note-lead { font-size: 13.5px; font-weight: 650; line-height: 1.3; color: var(--ink); }
.note-sub  { font-size: 12px; line-height: 1.4; color: var(--muted); text-wrap: pretty; }
.note-ar   { margin-left: auto; flex: 0 0 auto; color: var(--muted); font-size: 15px; }
.note-link:hover .note-ar { color: var(--accent); }

.swipehint { display: inline-flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted);
  font-family: var(--mono); letter-spacing: .04em; }
.swipehint .ar { animation: nudge 1.6s ease-in-out infinite; font-style: normal; }
@keyframes nudge { 0%,100% { transform: translateX(0); } 50% { transform: translateX(5px); } }

/* ------------------------------------------------------ bottom navigator -- */
.nav {
  position: absolute; left: 0; right: 0; bottom: 0; z-index: 5;
  padding: 12px 20px calc(14px + env(safe-area-inset-bottom, 0px));
  display: flex; align-items: center; gap: 12px;
  background: linear-gradient(to top, var(--bg) 42%, transparent);
}
.nav.is-hidden { display: none; }   /* single-slide (minimal) mount → no navigator */
.progress { position: absolute; left: 0; top: 0; height: 2px; width: 100%; background: var(--line); }
.progress > i { display: block; height: 100%; width: 0; background: var(--accent); transition: width .3s ease; }
.dots { display: flex; gap: 7px; flex: 1 1 auto; align-items: center; }
.dots button { width: 7px; height: 7px; border-radius: 999px; background: var(--faint); padding: 0;
  transition: transform .2s, background .2s; flex: 0 0 auto; }
.dots button[aria-current="true"] { background: var(--accent); transform: scale(1.5); }
.count { font-family: var(--mono); font-size: 12px; color: var(--muted); font-variant-numeric: tabular-nums;
  letter-spacing: .04em; min-width: 46px; text-align: right; }
.arrow { width: 34px; height: 34px; border-radius: 999px; display: grid; place-items: center;
  background: var(--surface); border: 1px solid var(--line); color: var(--ink); font-size: 18px; }
.arrow[disabled] { opacity: .3; cursor: default; }

@media (prefers-reduced-motion: reduce) {
  .track { scroll-behavior: auto; }
  .slide > *, .slide-body > * { opacity: 1 !important; transform: none !important; transition: none !important; }
  .swipehint .ar { animation: none; }
}