/* Worldtick Ltd — worldtick.co.uk
   Mobile-first, designed at 390px. No build step: edit this file directly. */

/* ---------- Fonts ---------- */

@font-face {
  font-family: 'IBM Plex Mono';
  src: url('../fonts/ibm-plex-mono-400.woff2') format('woff2');
  font-weight: 400; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'IBM Plex Mono';
  src: url('../fonts/ibm-plex-mono-500.woff2') format('woff2');
  font-weight: 500; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'IBM Plex Sans';
  src: url('../fonts/ibm-plex-sans-400.woff2') format('woff2');
  font-weight: 400; font-style: normal; font-display: swap;
}
@font-face {
  font-family: 'IBM Plex Sans';
  src: url('../fonts/ibm-plex-sans-600.woff2') format('woff2');
  font-weight: 600; font-style: normal; font-display: swap;
}

/* ---------- Tokens ----------
   Two deviations from the spec's table, both for contrast. See README. */

:root {
  --viewport:      #0C1116;
  --viewport-grid: #1A2129;
  --paper:         #F2F4F3;
  --ink:           #101418;
  --slate:         #5A6167;  /* spec had #697077 (4.58:1 on paper); this is 5.65:1 */
  --rule:          #D6DAD8;
  --signal:        #0B5FFF;
  --signal-dim:    #3D6E9E;

  /* Added: the spec's palette assumes a light document, but the hero and
     contact sections put the same roles on --viewport. */
  --paper-dim:     #B8C0C6;  /* body text on viewport — 10.3:1 */
  --slate-dark:    #7E878E;  /* secondary text on viewport — 5.19:1 */
  --signal-bright: #4D8BFF;  /* accent on viewport — 5.83:1 */

  --mono: 'IBM Plex Mono', ui-monospace, 'Cascadia Mono', Consolas, monospace;
  --sans: 'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;

  --gutter: 1.25rem;
  --measure: 34rem;
}

/* ---------- Reset / base ---------- */

*, *::before, *::after { box-sizing: border-box; }

html {
  overflow-x: clip;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--viewport);
  color: var(--paper);
  font-family: var(--sans);
  font-size: 1.0625rem;   /* 17px */
  line-height: 1.6;
  font-synthesis-weight: none;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, p { margin: 0; }
img { max-width: 100%; display: block; }

:focus-visible {
  outline: 2px solid var(--signal-bright);
  outline-offset: 3px;
  border-radius: 2px;
}
.doc :focus-visible { outline-color: var(--signal); }

.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 10;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.875rem;
  padding: 0.75rem 1rem;
  text-decoration: none;
}
.skip:focus { left: 0; }

.wrap {
  width: min(100% - (var(--gutter) * 2), 66rem);
  margin-inline: auto;
}

/* ---------- The persistent 3D stage ----------
   Fixed behind everything. Opaque .doc sections scroll over it, so the
   scene is visible in the hero and again behind contact and the footer. */

.stage {
  position: fixed;
  inset: 0;
  z-index: 0;
  background: var(--viewport);
  pointer-events: none;
}
.stage__poster,
.stage__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}
.stage__poster { object-fit: cover; }

.stage__canvas {
  opacity: 0;
  transition: opacity 600ms ease;
}
/* Set by js/stage.js once the first frame has actually rendered, so the
   poster is never swapped out for an empty canvas. */
.stage.is-live .stage__canvas { opacity: 1; }
.stage.is-live .stage__poster { opacity: 0; transition: opacity 600ms ease; }

/* Dimmed by scroll position — the hero recedes rather than scrolling away. */
.stage__scrim {
  position: absolute;
  inset: 0;
  background: var(--viewport);
  opacity: 0;
}

.page { position: relative; z-index: 1; }

/* Transparent sections let the stage through. */
.viewport { background: transparent; color: var(--paper); }

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

.hero__inner {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding-block: 5rem 1.5rem;
}

.wordmark {
  font-family: var(--mono);
  font-weight: 500;
  font-size: clamp(2.125rem, 11.5vw, 4.5rem);
  line-height: 1.05;
  letter-spacing: -0.03em;
  overflow-wrap: anywhere;
}
.wordmark__a { color: var(--paper); }
.wordmark__b { color: var(--signal-bright); }
.wordmark__c { color: var(--slate-dark); }

.readout {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  font-variant-numeric: tabular-nums;
  color: var(--slate-dark);
  margin-top: 1.125rem;
  display: flex;
  gap: 0.75rem;
  align-items: baseline;
}
.readout__label::after { content: ''; }
.readout__value { color: var(--signal-bright); }

/* Reads as an instrument control rather than a web button. Sized for a
   comfortable thumb: the visible bracket is small, the tap target is not. */
.rerun {
  align-self: flex-start;
  margin-top: 0.75rem;
  margin-left: -0.75rem;      /* optical alignment with the text above */
  padding: 0.6875rem 0.75rem;
  min-height: 44px;
  background: none;
  border: 0;
  font-family: var(--mono);
  font-weight: 500;
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--slate-dark);
  cursor: pointer;
  transition: color 200ms ease;
}
.rerun::before { content: '['; margin-right: 0.5em; }
.rerun::after  { content: ']'; margin-left: 0.5em; }
.rerun:hover, .rerun:focus-visible { color: var(--signal-bright); }
.rerun[hidden] { display: none; }

.hero__line {
  margin-top: 1.25rem;
  max-width: 26ch;
  color: var(--paper-dim);
  text-wrap: pretty;
}

.scrollcue {
  margin-top: 3rem;
  font-family: var(--mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--slate-dark);
  display: flex;
  align-items: center;
  gap: 0.625rem;
}
.scrollcue::after {
  content: '';
  width: 1px;
  height: 2rem;
  background: linear-gradient(var(--slate-dark), transparent);
}

/* ---------- Document sections ---------- */

.doc {
  background: var(--paper);
  color: var(--ink);
  padding-block: 4.5rem;
}
.doc--tail { padding-top: 0; }
.doc--tail .wrap { border-top: 1px solid var(--rule); padding-top: 4.5rem; }

.label {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--slate);
  margin-bottom: 2.5rem;
}
.label--dark { color: var(--slate-dark); }

.caps { display: grid; gap: 2.75rem; }

/* ---------- Capability figures ----------
   Technical drawings rather than icons: hairlines on graph paper, drawn in
   on reveal. The grid deliberately echoes the one in the hero, so the two
   registers of the page read as the same world. */

.defs { position: absolute; width: 0; height: 0; overflow: hidden; }

.pat-line { fill: none; stroke: var(--rule); stroke-width: 1; }
.pat-dot { fill: var(--signal-dim); }

.fig {
  display: block;
  width: 100%;
  height: auto;
  margin-bottom: 1.375rem;
}
.fig__grid { opacity: 0.5; }
.fig__fill { opacity: 0.85; }

.fig__rule   { fill: none; stroke: var(--rule); stroke-width: 1.4; }
.fig__ink    { fill: none; stroke: var(--ink); stroke-width: 1.6;
               stroke-linejoin: round; stroke-linecap: round; }
.fig__signal { fill: none; stroke: var(--signal); stroke-width: 1.6;
               stroke-linejoin: round; stroke-linecap: round; }
.fig__dot    { fill: var(--signal); }
.fig__scan   { fill: none; stroke: var(--signal); stroke-width: 1.4; opacity: 0.55; }

/* Every drawable path carries pathLength="1", so one dash length works for
   all of them regardless of their real geometry. Only hidden when JS is
   running — with JS off the figures are simply already drawn. */
.js .fig .draw {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
}
/* Two selectors because the figure is sometimes inside the revealed element
   and sometimes is the revealed element itself. */
.js .is-in .fig .draw,
.js .fig.is-in .draw {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 950ms cubic-bezier(0.22, 0.61, 0.36, 1) var(--d, 0ms);
}

/* One moving element per figure, each on its own period so they never fall
   into step with each other. */
.fig__pulse--sync { animation: fig-sync 3.4s ease-in-out infinite; }
.fig__pulse--ray  { animation: fig-ray 4.6s ease-in-out infinite; }
.fig__pulse--scan  { animation: fig-scan 5.2s ease-in-out infinite; }
.fig__pulse--layer { animation: fig-layer 6.1s ease-in-out infinite; }

.how { display: grid; gap: 2.75rem; }
.fig--how { margin-bottom: 0; }

@keyframes fig-sync {
  0%, 6%   { transform: translateX(0); opacity: 0; }
  14%      { opacity: 1; }
  86%      { opacity: 1; }
  100%     { transform: translateX(64px); opacity: 0; }
}
@keyframes fig-ray {
  0%, 8%   { transform: translate(0, 0); opacity: 0; }
  16%      { opacity: 1; }
  84%      { opacity: 1; }
  100%     { transform: translate(206px, -29px); opacity: 0; }
}
@keyframes fig-scan {
  0%, 5%   { transform: translateX(0); opacity: 0; }
  12%      { opacity: 1; }
  88%      { opacity: 1; }
  100%     { transform: translateX(120px); opacity: 0; }
}
@keyframes fig-layer {
  0%, 4%   { transform: translateX(0); opacity: 0; }
  10%      { opacity: 1; }
  90%      { opacity: 1; }
  100%     { transform: translateX(252px); opacity: 0; }
}

.cap__title {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 1.0625rem;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin-bottom: 0.625rem;
}
.cap p { color: var(--slate); max-width: var(--measure); text-wrap: pretty; }

.lede {
  font-size: 1.1875rem;
  max-width: var(--measure);
  color: var(--ink);
  text-wrap: pretty;
}

/* ---------- Contact ---------- */

.contact { padding-block: 5rem; }

.mailto {
  display: inline-block;
  font-family: var(--mono);
  font-weight: 500;
  font-size: clamp(1.0625rem, 5vw, 2rem);
  letter-spacing: -0.02em;
  color: var(--signal-bright);
  text-decoration: none;
  overflow-wrap: anywhere;
  /* Keeps the tap target well over 44px at every size. */
  padding-block: 0.625rem;
  background-image: linear-gradient(var(--signal-bright), var(--signal-bright));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0 1px;
  transition: background-size 260ms ease;
}
.mailto:hover, .mailto:focus-visible { background-size: 100% 1px; }
/* Touch has no hover, so give it a permanent solid state instead. */
@media (hover: none) {
  .mailto { background-size: 100% 1px; }
}

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

.foot {
  padding-block: 0 3.5rem;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--slate-dark);
}
.foot strong { font-weight: 600; color: var(--paper-dim); }
.todo { border-bottom: 1px dashed currentColor; }

/* ---------- Scroll reveals ----------
   Only hidden when JS is running, so the no-JS page is complete. */

.js .reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 300ms ease, transform 300ms ease;
}
.js .reveal.is-in { opacity: 1; transform: none; }
.js .caps .reveal:nth-child(2) { transition-delay: 60ms; }
.js .caps .reveal:nth-child(3) { transition-delay: 120ms; }

/* ---------- Wider viewports ---------- */

@media (min-width: 48rem) {
  :root { --gutter: 2.5rem; }
  body { font-size: 1.125rem; }
  .caps { grid-template-columns: repeat(3, 1fr); gap: 2.5rem; }
  .cap p { font-size: 1rem; }
  .doc { padding-block: 7rem; }
  .doc--tail { padding-top: 0; }
  .doc--tail .wrap { padding-top: 7rem; }
  .how { grid-template-columns: 1.05fr 1fr; gap: 4.5rem; align-items: center; }
  .how .lede { margin: 0; }
  .contact { padding-block: 8rem; }
  .hero__inner { padding-block: 6rem 2.5rem; }
  .lede { font-size: 1.375rem; }
}

@media (min-width: 64rem) {
  .hero__line { font-size: 1.25rem; max-width: 32ch; }
}

/* ---------- Reduced motion ----------
   Everything becomes an instant state change. The stage renders one
   resolved static frame; js/tick.js never starts the counter. */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .js .reveal { opacity: 1; transform: none; }
}