/* Tropism — a living research figure.
   Layout concept: one figure on white paper. Panel a (the dish) holds the left
   column at full height; panels b, c, d and the caption stack on the right.
   Hue only ever encodes data; every piece of chrome is ink. */

:root {
  --paper: #ffffff;
  --paper-2: #f6f7f8;            /* keycap fill in the Methods tables */
  --ink: #111316;
  --ink-2: #3f444b;
  --ink-3: #626871;              /* tick labels, still >= 4.5:1 on paper */
  --rule: #d9dce0;
  --rule-faint: #eceef1;
  --hilite: rgb(17 19 22 / 0.055);
  --hilite-2: rgb(17 19 22 / 0.11);
  --select: rgb(17 19 22 / 0.14);      /* an ink wash: hue stays reserved for data */

  --font-label: "Archivo", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-text: "STIX Two Text", "STIX Two", "Times New Roman", Times, serif;
  --font-code: ui-monospace, "SF Mono", "Cascadia Mono", "Roboto Mono", Menlo, Consolas, monospace;

  --fs-tick: 11px;
  --fs-axis: 12px;
  --fs-label: 12.5px;
  --fs-ui: 13.5px;
  --fs-panel: 18px;
  --fs-caption: 15.5px;
  --fs-body: 17px;

  --gap-1: 4px;
  --gap-2: 8px;
  --gap-3: 12px;
  --gap-4: 16px;
  --gap-5: 24px;
  --gap-6: 32px;
  --gap-7: 48px;
  --gap-8: 72px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0c0d0f;
    --paper-2: #070809;
    --ink: #eceef0;
    --ink-2: #c3c7cd;
    --ink-3: #9aa0a8;
    --rule: #2c3036;
    --rule-faint: #1b1e22;
    --hilite: rgb(236 238 240 / 0.07);
    --hilite-2: rgb(236 238 240 / 0.14);
    --select: rgb(236 238 240 / 0.22);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --paper: #0c0d0f;
  --paper-2: #070809;
  --ink: #eceef0;
  --ink-2: #c3c7cd;
  --ink-3: #9aa0a8;
  --rule: #2c3036;
  --rule-faint: #1b1e22;
  --hilite: rgb(236 238 240 / 0.07);
  --hilite-2: rgb(236 238 240 / 0.14);
  --select: rgb(236 238 240 / 0.22);
  color-scheme: dark;
}

/* ---------- SVG / figure text classes (used by components) ---------- */

.t-tick  { font: 400 var(--fs-tick)/1 var(--font-label); fill: var(--ink-3); font-variant-numeric: tabular-nums; }
.t-axis  { font: 500 var(--fs-axis)/1 var(--font-label); fill: var(--ink-2); }
.t-label { font: 500 var(--fs-label)/1 var(--font-label); fill: var(--ink-2); font-variant-numeric: tabular-nums; }
.t-value { font: 600 var(--fs-label)/1 var(--font-label); fill: var(--ink); font-variant-numeric: tabular-nums; }
.t-math  { font-family: var(--font-text); font-style: italic; font-weight: 400; }

/* ---------- Page ---------- */

/* Base reset: phones with notches keep content clear of the system bars. */
:root {
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}
body { margin: 0; }
img { max-width: 100%; }
[hidden] { display: none !important; }


html {
  background: var(--paper);
  scrollbar-color: var(--rule) var(--paper);
  -webkit-text-size-adjust: 100%;
}

body {
  background: var(--paper);
  color: var(--ink);
  font: 400 var(--fs-ui)/1.45 var(--font-label);
  font-variant-numeric: tabular-nums;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--select); color: inherit; }

:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

input, button { font: inherit; color: inherit; }
button { cursor: pointer; }
sub, sup { line-height: 0; }
sub { font-size: 0.72em; }
i, em { font-family: var(--font-text); }
b { font-weight: 700; }

.sr-only {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap; border: 0;
}

.page {
  color: var(--ink);
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
  padding-block: 0;
  max-width: 1720px;
  margin-inline: auto;
}

@media (min-width: 900px) {
  .page {
    padding-left: max(32px, env(safe-area-inset-left, 0px));
    padding-right: max(32px, env(safe-area-inset-right, 0px));
  }
}

/* ---------- Running head ---------- */

.runhead {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 18px;
  padding-block: 12px;
  border-bottom: 1px solid var(--ink);
}

.runhead__name {
  margin: 0;
  font: 750 21px/1 var(--font-label);
  font-variation-settings: "wdth" 118;
  letter-spacing: -0.01em;
}

.runhead__note {
  margin: 0;
  font: 400 15px/1.35 var(--font-text);
  color: var(--ink-2);
}
.runhead__note b { font-family: var(--font-text); color: var(--ink); }

.runhead .actions {
  margin: 0 0 0 auto;
  align-self: center;
}

.runhead .paste {
  flex-basis: 100%;
  margin: 2px 0 0;
}

/* ---------- Figure layout ---------- */

.fig {
  /* Axis margins around the dish plate; main.js overwrites them from plots.js. */
  --ax-l: 40px;
  --ax-r: 10px;
  --ax-t: 10px;
  --ax-b: 38px;
  --plate: min(calc(100vw - 32px - var(--ax-l) - var(--ax-r)), 640px);
  margin: 0;
  padding-block: 18px 40px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  row-gap: 28px;
}

.fig__side {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-template-areas: "b" "c" "d" "cap";
  gap: 24px;
  min-width: 0;
}

.panel { min-width: 0; }
.panel--a { justify-self: center; width: calc(var(--plate) + var(--ax-l) + var(--ax-r)); max-width: 100%; }
.panel--b { grid-area: b; }
.panel--c { grid-area: c; }
.panel--d { grid-area: d; }
.caption  { grid-area: cap; }

@media (min-width: 640px) {
  .fig__side {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    grid-template-areas: "b c" "d d" "cap cap";
    column-gap: 28px;
  }
}

@media (min-width: 760px) {
  .fig { --plate: min(calc(100vw - 64px - var(--ax-l) - var(--ax-r)), 720px); }
}

@media (min-width: 1100px) {
  .fig {
    --plate: clamp(420px, min(calc(100svh - 214px), calc(57vw - 96px)), 1040px);
    grid-template-columns: calc(var(--plate) + var(--ax-l) + var(--ax-r)) minmax(360px, 1fr);
    column-gap: 40px;
    align-items: start;
  }
  .panel--a { justify-self: start; }
  .fig__side { row-gap: 22px; }
}

@media (min-width: 1100px) and (max-height: 700px) {
  .fig { --plate: clamp(420px, calc(57vw - 96px), 760px); }
}

/* ---------- Panel heads ---------- */

.panel__head {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0 0 8px;
  font: 500 var(--fs-label)/1.2 var(--font-label);
  color: var(--ink-2);
}

.panel__letter {
  font: 750 var(--fs-panel)/1 var(--font-label);
  color: var(--ink);
}

.panel__title i { font-size: 1.08em; }
.panel__body { position: relative; min-width: 0; }

/* ---------- Panel a: the dish ---------- */

.dish { position: relative; }

.dish__axes {
  position: absolute;
  inset: 0;
  z-index: 2;            /* above the plate, so the scale bar sits over the particles */
  pointer-events: none;
}
.dish__axes > svg { position: absolute; inset: 0; width: 100%; height: 100%; overflow: visible; }

.dish__plate {
  position: relative;
  margin: var(--ax-t) var(--ax-r) var(--ax-b) var(--ax-l);
  aspect-ratio: 1 / 1;
  max-width: 100%;
  background: var(--paper);
  overflow: hidden;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  cursor: grab;
}
.dish__plate[data-tool="stir"].is-dragging { cursor: grabbing; }
.dish__plate[data-tool="seed"],
.dish__plate[data-tool="erase"] { cursor: crosshair; }
.dish__plate[data-tool="pan"] { cursor: move; }

.dish__canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.dish__brush {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  overflow: visible;
  opacity: 0;
}
.dish__brush.is-on { opacity: 1; }
.dish__brush circle {
  fill: none;
  stroke: var(--ink);
  stroke-width: 1;
  stroke-dasharray: 3 3;
}

.dish__clock,
.dish__track,
.dish__paused {
  position: absolute;
  margin: 0;
  font: 500 var(--fs-label)/1 var(--font-label);
  color: var(--ink);
  pointer-events: none;
  text-shadow:
    0 0 2px var(--paper), 0 0 2px var(--paper), 0 0 2px var(--paper),
    1px 0 0 var(--paper), -1px 0 0 var(--paper), 0 1px 0 var(--paper), 0 -1px 0 var(--paper);
}
.dish__clock { top: 10px; left: 12px; }
.dish__clock i { font-size: 1.12em; }
.dish__paused {
  top: 10px; right: 12px;
  font-weight: 650;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-size: 11.5px;
}
.dish__track {
  top: 0; left: 0;
  display: flex;
  align-items: baseline;
  white-space: nowrap;
  transform: translate(-9999px, 0);
  will-change: transform;
}
.dish__track i { font-size: 1.1em; margin-left: 0.1em; }
.dish__track-marker { display: inline-flex; align-self: center; margin-right: 4px; }

.dish__fallback {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  margin: 0;
  padding: 24px;
  font: 400 16px/1.45 var(--font-text);
  color: var(--ink-2);
  text-align: center;
}

/* ---------- Tools under the dish ---------- */

.tools {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 24px;
  margin-top: 6px;
  padding-left: var(--ax-l);
  padding-right: var(--ax-r);
}

@media (max-width: 640px) {
  .tools { padding-left: 0; padding-right: 0; }
  .tools__run { margin-left: 0; }
}

.seg { display: inline-flex; align-items: baseline; flex-wrap: wrap; column-gap: 14px; }
.seg[hidden] { display: none !important; }

.seg__label {
  font: 500 var(--fs-label)/1 var(--font-label);
  color: var(--ink-2);
}

/* Options read like a figure legend: plain ink words, the chosen one set bold and ruled. */
.seg__opt {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-height: 32px;
  padding: 6px 1px 4px;
  border: 0;
  border-bottom: 2px solid transparent;
  border-radius: 0;
  background: none;
  font: 500 var(--fs-ui)/1 var(--font-label);
  color: var(--ink-2);
  transition: color 120ms var(--ease-out), border-color 120ms var(--ease-out);
}
.seg__opt:hover { color: var(--ink); border-bottom-color: var(--rule); }
.seg__opt[aria-checked="true"] { color: var(--ink); font-weight: 700; border-bottom-color: var(--ink); }
.seg__opt .marker { flex: none; }

.tools__run { display: inline-flex; align-items: baseline; flex-wrap: wrap; column-gap: 18px; margin-left: auto; }
.tools__speed { font: 500 var(--fs-ui)/1 var(--font-label); color: var(--ink-2); }

/* ---------- Buttons ----------
   Text controls in the figure grammar: ink words on paper with a hairline rule beneath.
   Toggles carry a small legend square, filled when on. */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  padding: 6px 1px;
  border: 0;
  border-radius: 0;
  background: none;
  color: var(--ink);
  font: 500 var(--fs-ui)/1.1 var(--font-label);
  white-space: nowrap;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--rule);
  text-underline-offset: 5px;
  transition: text-decoration-color 120ms var(--ease-out), color 120ms var(--ease-out);
}
.btn:hover { text-decoration-color: var(--ink); }
.btn:active { color: var(--ink-2); }
.btn:disabled {
  color: var(--ink-3);
  text-decoration-color: transparent;
  cursor: default;
}
.btn--primary {
  font-weight: 750;
  text-decoration-color: var(--ink);
  text-decoration-thickness: 2px;
}
.btn[aria-pressed]::before {
  content: "";
  flex: none;
  width: 8px;
  height: 8px;
  border: 1px solid currentColor;
  background: transparent;
}
.btn[aria-pressed="true"]::before { background: currentColor; }

kbd {
  font: 500 11px/1 var(--font-label);
  font-variant-numeric: tabular-nums;
}
.btn kbd {
  display: inline-block;
  padding: 2px 4px 1px;
  border: 1px solid var(--rule);
  color: var(--ink-2);
  text-decoration: none;
  letter-spacing: 0.02em;
}
.btn:disabled kbd { color: var(--ink-3); border-color: var(--rule-faint); }
@media (hover: none) and (pointer: coarse) {
  .btn kbd { display: none; }
}

/* ---------- Caption ---------- */

.caption {
  min-width: 0;
  font: 400 var(--fs-caption)/1.44 var(--font-text);
  color: var(--ink);
}

.caption__text { margin: 0; max-width: 74ch; }
.caption__text b { font-family: var(--font-text); }
.caption__title { font-weight: 700; }
.caption i { font-size: 1.04em; }

.slot, .live {
  font-family: var(--font-label);
  font-size: 0.9em;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
.slot { white-space: nowrap; }
.live { color: var(--ink-2); }

.actions {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 20px;
}

.paste {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 12px;
}
.paste[hidden] { display: none !important; }
.paste__label { font: 500 var(--fs-label)/1 var(--font-label); color: var(--ink-2); }
.paste__input {
  flex: 1 1 22ch;
  min-width: 0;
  max-width: 46ch;
  min-height: 32px;
  padding: 5px 2px;
  border: 0;
  border-bottom: 1px solid var(--ink);
  border-radius: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 13px/1 var(--font-code);
  caret-color: var(--ink);
}
.paste__input::placeholder { color: var(--ink-3); }
.paste__error {
  flex-basis: 100%;
  margin: 0;
  min-height: 1.2em;
  font: 600 var(--fs-label)/1.3 var(--font-label);
  color: var(--ink);
}

.worldline {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 2px 8px;
  margin: 12px 0 0;
  font: 500 var(--fs-label)/1.4 var(--font-label);
  color: var(--ink-2);
}
.worldline--rev { margin-top: 4px; }
.worldline__code {
  min-width: 0;
  font: 400 12px/1.4 var(--font-code);
  color: var(--ink);
  word-break: break-all;
  user-select: all;
  -webkit-user-select: all;
}

/* ---------- Extended Data ---------- */

.ed {
  margin-left: calc(-1 * max(16px, env(safe-area-inset-left, 0px)));
  margin-right: calc(-1 * max(16px, env(safe-area-inset-right, 0px)));
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
  padding-block: 48px 56px;
  background: var(--paper);
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--rule);
}
@media (min-width: 900px) {
  .ed {
    margin-left: calc(-1 * max(32px, env(safe-area-inset-left, 0px)));
    margin-right: calc(-1 * max(32px, env(safe-area-inset-right, 0px)));
    padding-left: max(32px, env(safe-area-inset-left, 0px));
    padding-right: max(32px, env(safe-area-inset-right, 0px));
  }
}

.ed__title, .methods__title {
  margin: 0 0 10px;
  font: 750 24px/1.1 var(--font-label);
  font-variation-settings: "wdth" 112;
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.ed__lede {
  margin: 0 0 28px;
  max-width: 64ch;
  font: 400 16.5px/1.5 var(--font-text);
  color: var(--ink-2);
}

.ed__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 32px 24px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.ed__item {
  display: grid;
  gap: 10px;
  width: 100%;
  padding: 0;
  border: 0;
  background: none;
  text-align: left;
  color: var(--ink);
}
.ed__item canvas {
  display: block;
  width: 100%;
  aspect-ratio: 1 / 1;
  height: auto;
  background: var(--paper);
  outline: 1px solid var(--ink);
  outline-offset: -1px;
  transition: outline-width 120ms var(--ease-out);
}
.ed__item:hover canvas { outline-width: 2px; outline-offset: -2px; }
.ed__item:focus-visible { outline: none; }
.ed__item:focus-visible canvas { outline: 2px solid var(--ink); outline-offset: 3px; }
.ed__item[aria-current="true"] canvas { outline-width: 3px; outline-offset: -3px; }

.ed__cap {
  font: 400 14.5px/1.42 var(--font-text);
  color: var(--ink);
}
.ed__cap b { font-weight: 700; }
.ed__meta {
  display: block;
  margin-top: 4px;
  font: 500 var(--fs-label)/1.2 var(--font-label);
  color: var(--ink-3);
}

/* ---------- Methods ---------- */

.methods {
  padding-block: 56px 48px;
  font: 400 var(--fs-body)/1.56 var(--font-text);
  color: var(--ink);
}

.methods__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 40px 72px;
  align-items: start;
}
.methods__text { max-width: 70ch; min-width: 0; }
.methods__aside { display: grid; gap: 36px; min-width: 0; }

@media (min-width: 1100px) {
  .methods__grid { grid-template-columns: minmax(0, 70ch) minmax(320px, 520px); }
  .methods__aside { position: sticky; top: max(24px, env(safe-area-inset-top, 0px)); margin-top: 34px; }
}

.methods h3 {
  margin: 34px 0 8px;
  font: 650 16px/1.25 var(--font-label);
  color: var(--ink);
  text-wrap: balance;
}
.methods p { margin: 0 0 14px; }
.methods i { font-size: 1.03em; }

.methods__list { margin: 0 0 14px; padding-left: 1.3em; }
.methods__list li { margin-bottom: 6px; padding-left: 0.2em; }
.methods__list li::marker { color: var(--ink-3); }

.eq {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  margin: 18px 0 20px;
  padding: 14px 0 14px 2ch;
  font: 400 18px/1.5 var(--font-text);
  overflow-x: auto;
}
.eq__brace {
  flex: none;
  align-self: stretch;
  width: 11px;
  height: auto;
  margin-right: -4px;
  overflow: visible;
}
.eq__brace path {
  fill: none;
  stroke: var(--ink);
  stroke-width: 1.3;
  vector-effect: non-scaling-stroke;
}
.eq__cases {
  display: grid;
  gap: 4px;
}
.eq__case {
  display: grid;
  grid-template-columns: minmax(max-content, 1fr) auto;
  column-gap: 2.4em;
}
.eq__when { color: var(--ink-2); }

/* Reference tables beside the Methods prose. */
.tbl { margin: 0; min-width: 0; }
.tbl__cap {
  margin: 0 0 10px;
  font: 400 15px/1.45 var(--font-text);
  color: var(--ink);
}
.tbl__cap b { font-weight: 700; }
.tbl__scroll { overflow-x: auto; }
.tbl table {
  width: 100%;
  border-collapse: collapse;
  font: 400 14px/1.4 var(--font-label);
  font-variant-numeric: tabular-nums;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
}
.tbl th {
  padding: 8px 14px 6px 0;
  border-bottom: 1px solid var(--ink);
  font-weight: 600;
  font-size: 12.5px;
  color: var(--ink-2);
  text-align: left;
  white-space: nowrap;
}
.tbl td {
  padding: 7px 14px 7px 0;
  border-bottom: 1px solid var(--rule);
  vertical-align: baseline;
}
.tbl tr:last-child td { border-bottom: 0; }
.tbl th:last-child, .tbl td:last-child { padding-right: 0; }
.tbl .num { text-align: right; white-space: nowrap; }
.tbl td i { font-size: 1.1em; }
.tbl--keys td:first-child { width: 9.5em; }
.tbl--keys kbd { white-space: nowrap; }
.tbl kbd {
  display: inline-block;
  min-width: 1.7em;
  padding: 2px 6px;
  border: 1px solid var(--rule);
  background: var(--paper-2);
  font-size: 12px;
  text-align: center;
}

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

.foot {
  padding-block: 20px 28px;
  border-top: 1px solid var(--rule);
  font: 500 var(--fs-label)/1.4 var(--font-label);
  color: var(--ink-2);
}
.foot p { margin: 0; }

/* ---------- Motion ---------- */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}