/* noise-poster — a sheet of paper lying on a slightly darker table.
   Layout constraints worth stating:
   - min-height, never height/100dvh: when the viewport is shorter than the
     layout the page must fall back to ordinary document scrolling instead of
     collapsing a box to zero.
   - no scroller has a percentage floor, and there is no media query: the two
     arrangements below are both laid out on every resize and the one that
     gives the poster more area wins (app.js, relayout()).
   - every type size is in rem, so a large default font size actually enlarges
     the page instead of being overridden by an absolute px on body. */

:root {
  /* Overwritten by app.js from the active palette. The literals are the `ink`
     palette, so the page is dressed before scripts run. */
  --paper: #f2efe9;      /* stop 0 — the sheet, and the poster's own margins */
  --page: #dcdad3;       /* a shade darker than the paper: the table */
  --ink: #1b2126;        /* stop 3 — text and the primary button */
  --line: #535f6a;       /* stop 2 — every interactive boundary */
  --muted: #414c56;      /* secondary text, measured against --page */
  --wash: #dfdcd6;       /* hover tint */
  --ink-hover: #2c353c;
  --shadow: rgba(27, 33, 38, 0.22);
}

* { box-sizing: border-box; }

html { font-size: 100%; }

html, body {
  margin: 0;
  padding: 0;
}

body {
  /* min-height, never height: if the viewport is shorter than the layout the
     page falls back to ordinary document scrolling instead of clipping. */
  min-height: 100vh;
  background: var(--page);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.45;
  -webkit-text-size-adjust: 100%;
}

/* ---- the two arrangements ------------------------------------------------
   --col is the controls column, written by app.js after it has measured. */

.page {
  display: grid;
  padding: 16px;
  column-gap: 16px;
  row-gap: 14px;
  justify-content: center;
  align-content: start;
}

.page.lay-stack {
  grid-template-columns: var(--col, 440px);
  grid-template-areas:
    "head"
    "sheet"
    "ctl";
}

.page.lay-side {
  grid-template-columns: max-content var(--col, 280px);
  /* max-content then 1fr: the poster spanning both rows must lengthen the
     second row, not the first, or the controls float away from the masthead. */
  grid-template-rows: max-content 1fr;
  grid-template-areas:
    "sheet head"
    "sheet ctl";
}

/* align-self: start, so neither box is stretched by the poster spanning both
   rows beside it — a stretched box measures the poster, not itself. */
.masthead { grid-area: head; margin: 0; align-self: start; }
.sheet { grid-area: sheet; min-width: 0; align-self: start; display: flex; justify-content: center; }
.controls { grid-area: ctl; min-width: 0; align-self: start; }

h1 {
  margin: 0;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.tagline {
  margin: 2px 0 0;
  font-size: 0.82rem;
  color: var(--muted);
}

/* ---- the sheet -----------------------------------------------------------
   content-box, because app.js writes the content width and height in px and
   the canvas backing store is derived from clientWidth/clientHeight — the two
   must not disagree by the border. */

.poster {
  display: block;
  box-sizing: content-box;
  width: 100%;
  aspect-ratio: 2480 / 3508;
  border: 1px solid var(--line);
  background: var(--paper);
  /* The sheet lies on the page rather than being cut out of it. */
  box-shadow: 0 3px 12px var(--shadow);
}

/* ---- controls ------------------------------------------------------------ */

.row {
  display: flex;
  flex-wrap: wrap;          /* at 200% zoom the row must wrap, not overflow */
  align-items: flex-end;
  gap: 8px;
}

.field {
  flex: 1 1 120px;
  min-width: 0;
}

label, .group-label {
  display: block;
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 4px;
}

input[type="text"] {
  width: 100%;
  min-height: 44px;
  padding: 8px 10px;
  font: inherit;
  font-size: 1rem;   /* >= 16px at the default root size: iOS will not zoom */
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 2px;
}

button {
  font: inherit;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 2px;
  cursor: pointer;
  /* Every control keeps a 44x44 CSS px hit box at 320 px wide. */
  min-height: 44px;
  min-width: 44px;
  transition: background-color 120ms ease, border-color 120ms ease,
              box-shadow 120ms ease, color 120ms ease;
}

input[type="text"] { transition: border-color 120ms ease, box-shadow 120ms ease; }

button:hover:not([disabled]) { background: var(--wash); }
button:active:not([disabled]) { background: var(--wash); box-shadow: inset 0 2px 0 var(--shadow); }
input[type="text"]:hover { border-color: var(--ink); }

#shuffle {
  flex: 0 0 auto;
  padding: 0 14px;
  font-size: 0.95rem;
}

.palette { margin-top: 14px; }

.swatches {
  display: flex;
  flex-wrap: wrap;          /* zoomed in, the five swatches wrap onto rows */
  gap: 8px;
}

.swatch {
  flex: 1 1 44px;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 3px;
  overflow: hidden;
}

.swatch .bar {
  /* Four hard stops of the palette, painted from app.js so the ramp has one
     source of truth. */
  display: block;
  height: 22px;
}

.swatch .name {
  font-size: 0.7rem;
  letter-spacing: 0.03em;
  text-align: center;
  padding: 1px 0 3px;
}

/* Selected is a filled name plate; focus (below) is a detached ring. The two
   states used to be the same black rectangle. */
.swatch[aria-pressed="true"] {
  border-color: var(--ink);
}

.swatch[aria-pressed="true"] .name {
  background: var(--ink);
  color: var(--paper);
}

.download {
  display: block;
  width: 100%;
  margin-top: 16px;
  padding: 10px;
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  /* The one primary action on the page: filled, not outlined like the rest. */
  color: var(--paper);
  background: var(--ink);
  border-color: var(--ink);
}

.download:hover:not([disabled]) { background: var(--ink-hover); border-color: var(--ink-hover); }
.download:active:not([disabled]) { background: var(--ink-hover); }

button[disabled] {
  opacity: 0.55;
  cursor: default;
}

.export-note {
  margin: 8px 0 0;
  font-size: 0.82rem;
  /* One line reserved so the status region does not shove the layout when it
     speaks. A floor only: longer text grows the box, it is never clipped. */
  min-height: 1.45em;
  color: var(--muted);
}

/* A ring outside the control, with a gap, in the ink colour — visibly not the
   filled name plate that marks the selected swatch. */
:focus-visible {
  outline: 3px solid var(--ink);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}