:root {
  color-scheme: dark;
  --page: #1b1c1e;
  --panel: #25272a;
  --line: #3b3e43;
  --ink: #e6e6e6;
  --muted: #9da1a8;
  --accent: #8ab4ff;
}

* { box-sizing: border-box; }

html, body { height: 100%; margin: 0; }

body {
  display: flex;
  flex-direction: column;
  background: var(--page);
  color: var(--ink);
  font: 14px/1.4 -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

header {
  display: flex;
  justify-content: center;
  padding: 8px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}

.toolbar { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; justify-content: center; }
.toolbar .spacer { width: 10px; }

button, select {
  font: inherit;
  color: var(--ink);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
}
button { display: inline-flex; align-items: center; justify-content: center; gap: 4px; }
select {
  appearance: none;
  padding-right: 26px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='m4 6 4 4 4-4' fill='none' stroke='%239da1a8' stroke-width='1.8' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") no-repeat right 8px center / 12px;
}
select option { color: var(--ink); background: var(--panel); }
button:hover, select:hover { border-color: var(--muted); }
button:focus-visible, select:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.glyph {
  flex: none;
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* The Actions menu: a popover that main.js places under its button. */
.menu {
  position: fixed;
  inset: auto;
  margin: 0;
  padding: 4px;
  min-width: 11em;
  color: var(--ink);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.45);
}
.menu button {
  display: flex;
  width: 100%;
  justify-content: flex-start;
  border: 0;
  border-radius: 5px;
  padding: 8px 12px;
}
.menu button:hover, .menu button:focus-visible { background: var(--line); outline: none; }
button[aria-pressed="true"] {
  background: var(--ink);
  color: var(--page);
  border-color: var(--ink);
}
button[hidden] { display: none; }
/* Quick taps on buttons never double-tap zoom; panning and pinch-zoom stay the browser's. */
header, .toolbar, .menu, .sheet-dialog, .sheet-dialog .sheet { touch-action: manipulation; }

#stage {
  flex: 1 1 0;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
#stage:fullscreen { background: #000; overflow: hidden; }

#game {
  position: relative;
  flex: none;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
}
#game canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
#pixels { image-rendering: pixelated; touch-action: none; }
#text { pointer-events: none; }

/* The touch layouts: main.js sets html.touch, and data-layout to "portrait" or "landscape". */
.part, #texts { display: none; }
.part {
  flex: none;
  image-rendering: pixelated;
  touch-action: none;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
}
.touch body { height: auto; min-height: 100%; }
/* No pull-to-refresh or rubber-banding mid-drag. */
.touch, .touch body { overscroll-behavior: none; }
.touch header { position: sticky; top: 0; z-index: 2; padding: 4px 8px; }
.touch .toolbar {
  flex: 1;
  min-width: 0;
  flex-wrap: nowrap;
  justify-content: flex-start;
  gap: 2px;
  overflow-x: auto;
  scrollbar-width: none;
}
.touch .toolbar::-webkit-scrollbar { display: none; }
.touch .toolbar > * { flex: none; }
.touch .toolbar .spacer { flex: 1 1 0; width: auto; }
.touch .toolbar button, .touch .toolbar select { height: 36px; }
.touch .toolbar button { position: relative; min-width: 32px; padding: 0 7px; }
.touch .toolbar select { padding: 0 22px 0 8px; background-position: right 6px center; }
/* Icons only; the words stay for screen readers. */
.touch .toolbar .label {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}
.touch #stage { flex: none; }
.touch #stage #message { position: fixed; top: auto; bottom: 0; z-index: 3; padding: 8px 16px; background: var(--panel); }
/* Portrait scrolls as a page under the sticky toolbar: the board and the toolbox fill the small
   viewport (main.js), and the texts, the Next level button and the credits follow below them. */
[data-layout="portrait"] #stage {
  flex-direction: column;
  justify-content: flex-start;
  gap: 12px;
  padding: 12px 0 20px;
}
[data-layout="portrait"] #game { display: none; }
[data-layout="portrait"] .part:not([hidden]) { display: block; }
[data-layout="portrait"] #texts {
  display: block;
  width: 100%;
  max-width: 40em;
  padding: 0 16px;
  font-size: 16px;
  line-height: 1.45;
  white-space: pre-line;
}
/* No long-press selection or callout on the game, its texts and the toolbar (the help keeps its own). */
#stage, header {
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
}
#texts p { margin: 0 0 10px; }
#next-level {
  display: flex;
  width: 100%;
  min-height: 48px;
  margin: 0 0 10px;
  padding: 10px 16px;
  font-size: 18px;
  font-weight: 600;
  color: var(--page);
  background: var(--accent);
  border-color: var(--accent);
  border-radius: 10px;
  touch-action: manipulation;
}
#next-level[hidden] { display: none; }
/* Portrait: the toolbar's ▶ while the level is won, visible with the texts scrolled out of view. */
.toolbar button.won,
.toolbar button.won:hover {
  color: var(--page);
  background: var(--accent);
  border-color: var(--accent);
}
/* The small viewport's height (Safari's bars shown), which main.js reads: the bars collapsing as
   the page scrolls changes nothing. */
#small-viewport {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 100vh;
  height: 100svh;
  visibility: hidden;
  pointer-events: none;
}
#texts p:last-child { margin-bottom: 0; }
#texts footer { padding: 16px 0 0; }
/* Landscape: the toolbar runs down the left side, so the frame gets the whole height. */
[data-layout="landscape"] header {
  position: fixed;
  inset: 0 auto 0 0;
  flex-direction: column;
  padding: 6px 4px;
  border-bottom: 0;
  border-right: 1px solid var(--line);
}
[data-layout="landscape"] .toolbar { flex-direction: column; align-items: stretch; overflow: hidden auto; }
[data-layout="landscape"] body { height: 100vh; height: 100svh; overflow: hidden; }
[data-layout="landscape"] #stage { height: 100vh; height: 100svh; }
#help footer { padding: 20px 0 0; }

#fatal { max-width: 32em; padding: 0 16px; text-align: center; }

#message, footer {
  margin: 0;
  padding: 4px 16px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}
#message { color: var(--ink); }
#stage #message { position: absolute; left: 0; right: 0; top: 100%; z-index: 1; background: var(--page); pointer-events: none; }
#stage:fullscreen #message { top: auto; bottom: 0; background: transparent; }
#message:empty { display: none; }
footer { padding-top: 28px; padding-bottom: 10px; }
a { color: var(--accent); }

/* The "How to play" and Levels dialogs. */
.sheet-dialog {
  width: calc(100% - 32px);
  max-width: 880px;
  max-height: calc(100% - 32px);
  margin: auto;
  padding: 0;
  overflow: hidden;
  color: var(--ink);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  font-size: 15px;
  line-height: 1.5;
}
.sheet-dialog::backdrop { background: rgba(0, 0, 0, 0.65); }
.sheet-dialog[open] { display: flex; }
/* The sheet scrolls, not the dialog, so a click on a scrollbar is not a click on the backdrop. */
.sheet-dialog .sheet { flex: 1; min-height: 0; overflow: auto; padding: 0 24px 24px; }
.sheet-dialog .sheet-head {
  position: sticky;
  top: 0;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0 12px;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}
.sheet-dialog h2 { margin: 0; font-size: 22px; font-weight: 600; }
#help h3 {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
#help p { margin: 0; }
#help .sheet-body { display: grid; gap: 22px 32px; padding-top: 18px; }
#help section { min-width: 0; }
#help .rows { margin: 0; padding: 0; list-style: none; }
#help .rows li { display: flex; align-items: center; gap: 12px; padding: 5px 0; }
#help .rows.plain li { padding: 3px 0; }
#help .icon { flex: none; width: 40px; height: 32px; color: var(--muted); }
#help b { font-weight: 600; }
#help kbd {
  display: inline-block;
  min-width: 1.7em;
  padding: 0 6px;
  font: 600 13px/1.6 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  text-align: center;
  color: var(--ink);
  background: var(--page);
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 5px;
}
#help kbd.mod { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif; font-size: 14px; }
@media (min-width: 720px) {
  #help .sheet-body { grid-template-columns: 1fr 1fr; }
  #help .wide { grid-column: 1 / -1; }
}
@media (max-width: 480px) {
  .sheet-dialog .sheet { padding: 0 16px 20px; }
}

/* The Levels picker: each level's number as the strip draws it, copied from the frame. */
#levels { max-width: 480px; }
#levels .level-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; padding-top: 16px; }
#levels .level-grid button { position: relative; padding: 10px 0; border-radius: 8px; }
/* Solved levels carry a tick, so solved and open do not differ by colour alone. */
#levels .level-grid button[data-state="solved"]::after {
  content: "\2713";
  position: absolute;
  top: 1px;
  right: 5px;
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.2;
}
#levels .level-grid canvas { width: 40px; height: 24px; image-rendering: pixelated; }
#levels .level-grid button[aria-current="true"] {
  color: var(--ink);
  background: transparent;
  border-color: var(--accent);
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}
#levels .level-grid button:disabled { opacity: 0.45; cursor: default; }