:root {
  --bg: #0c0c0e;
  --surface: #17171a;
  --text: #f4f4f5;
  --muted: #a1a1aa;
  --line: #27272a;
  --accent: #34d399;
  --accent-fg: #052e1f;
  --danger: #f87171;

  --sq-light: #a1a1aa;
  --sq-dark: #6b6b74;

  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
  --font-sans: "Geist", ui-sans-serif, system-ui, sans-serif;
  --font-mono: "Geist Mono", ui-monospace, monospace;

  --board: min(600px, calc(100vw - 64px));
  color-scheme: dark;
}

* { box-sizing: border-box; }

html, body { margin: 0; }

body {
  min-height: 100dvh;
  background:
    radial-gradient(50% 45% at 20% 0%, color-mix(in oklab, var(--accent) 9%, transparent), transparent 70%),
    var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

button, input { font: inherit; color: inherit; }

.app {
  max-width: 1080px;
  margin: 0 auto;
  padding: 48px 32px;
  display: grid;
  grid-template-columns: auto minmax(280px, 1fr);
  gap: 56px;
  align-items: start;
}

/* ---------- Board ---------- */

.board-wrap {
  position: relative;
  display: grid;
  grid-template-columns: 20px var(--board);
  grid-template-rows: var(--board) 24px;
  column-gap: 8px;
}

.ranks, .files {
  display: grid;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
}
.ranks { grid-template-rows: repeat(8, 1fr); align-items: center; justify-items: end; }
.files { grid-column: 2; grid-template-columns: repeat(8, 1fr); justify-items: center; align-items: end; }

.board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow: 0 30px 80px -30px rgb(0 0 0 / 0.8);
}

.sq {
  position: relative;
  display: grid;
  place-items: center;
  border: 0;
  padding: 0;
  background: var(--sq-dark);
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.sq.light { background: var(--sq-light); }
.sq:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; z-index: 1; }

/* last move, check, selection: tints over the square color */
.sq::before {
  content: "";
  position: absolute;
  inset: 0;
  background: transparent;
  transition: background-color 160ms var(--ease-out);
}
.sq.last::before { background: color-mix(in oklab, var(--accent) 16%, transparent); }
.sq.check::before { background: color-mix(in oklab, var(--danger) 38%, transparent); }
.sq.selected::before { background: color-mix(in oklab, var(--accent) 30%, transparent); }

/* legal targets: a dot on empty squares, a ring around pieces */
.sq.target::after {
  content: "";
  position: absolute;
  width: 26%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: color-mix(in oklab, var(--accent) 75%, transparent);
  pointer-events: none;
}
.sq.target.capture::after {
  width: 84%;
  background: transparent;
  box-shadow: inset 0 0 0 4px color-mix(in oklab, var(--accent) 80%, transparent);
}

/* pieces: the cburnett SVG set */
.piece {
  position: relative;
  width: 86%;
  height: 86%;
  pointer-events: none;
  user-select: none;
  filter: drop-shadow(0 2px 2px rgb(0 0 0 / 0.25));
  transition: transform 160ms var(--ease-out);
}

@media (hover: hover) and (pointer: fine) {
  .sq.own:hover .piece { transform: translateY(-2px); }
}
.sq.selected .piece { transform: scale(1.06); }

/* ---------- Promotion ---------- */

.promotion {
  position: absolute;
  inset: 0 0 24px 28px;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 16px;
  border-radius: 14px;
  background: color-mix(in oklab, var(--bg) 82%, transparent);
  backdrop-filter: blur(4px);
}
.promotion[hidden] { display: none; }
.promotion p { margin: 0; color: var(--muted); font-size: 14px; }
.promotion-choices { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; }
.promotion-choices button {
  padding: 12px 18px;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: var(--surface);
  cursor: pointer;
  transition: transform 160ms var(--ease-out), border-color 160ms var(--ease-out);
}
.promotion-choices button:hover { border-color: var(--accent); }
.promotion-choices button:active { transform: scale(0.97); }

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

.panel { display: grid; gap: 28px; }

h1 { margin: 0; font-size: 40px; font-weight: 600; letter-spacing: -0.03em; }
h2 { margin: 0 0 12px; font-size: 13px; font-weight: 500; color: var(--muted); font-family: var(--font-mono); }
.lead { margin: 10px 0 0; color: var(--muted); line-height: 1.6; max-width: 40ch; }

.status { padding: 18px 20px; border: 1px solid var(--line); border-radius: 14px; background: var(--surface); }
.turn { margin: 0; display: flex; align-items: center; gap: 10px; font-weight: 500; font-size: 17px; }
.swatch { width: 14px; height: 14px; border-radius: 50%; background: #ececef; flex: none; }
.swatch.b { background: #0e0e11; box-shadow: inset 0 0 0 1.5px #71717a; }
.turn.over .swatch { background: var(--accent); box-shadow: none; }
.message { margin: 8px 0 0; min-height: 1.5em; color: var(--muted); font-size: 14px; line-height: 1.5; }
.message.warn { color: var(--danger); }

.credit { margin: 0; font-size: 12px; color: var(--muted); }
.credit a { color: inherit; }

.typed label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 8px; }
.typed-row { display: flex; gap: 8px; }
.typed input {
  flex: 1;
  min-width: 0;
  padding: 10px 14px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--bg);
  font-family: var(--font-mono);
  font-size: 16px;
}
.typed input:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.history ol {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: 2.5em 1fr 1fr;
  row-gap: 4px;
  max-height: 180px;
  overflow-y: auto;
  font-family: var(--font-mono);
  font-size: 14px;
}
.history li { display: contents; }
.history .n { color: var(--muted); }
.history li.empty { display: block; grid-column: 1 / -1; color: var(--muted); font-family: var(--font-sans); }

.actions { display: flex; gap: 10px; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--text);
  text-decoration: none;
  font-weight: 500;
  font-size: 15px;
  cursor: pointer;
  transition: transform 160ms var(--ease-out), border-color 160ms var(--ease-out);
}
.btn:hover { border-color: #52525b; }
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--text); color: var(--bg); border-color: var(--text); }
.btn-primary:hover { border-color: var(--text); }
.link { background: none; border: 0; color: var(--muted); cursor: pointer; font-size: 14px; }

/* ---------- Welcome screen (the console intro) ---------- */

.welcome {
  position: fixed;
  inset: 0;
  z-index: 10;
  display: grid;
  place-items: center;
  padding: 24px 16px;
  background: color-mix(in oklab, var(--bg) 88%, transparent);
  backdrop-filter: blur(6px);
  cursor: pointer;
  transition: opacity 200ms var(--ease-out);
}
.welcome[hidden] { display: none; }
.welcome.leaving { opacity: 0; }

.terminal {
  width: min(900px, 100%);
  max-height: 100%;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--bg);
  box-shadow: 0 30px 80px -30px rgb(0 0 0 / 0.9);
  transition: transform 200ms var(--ease-out);
}
.welcome.leaving .terminal { transform: scale(0.98); }

.terminal-bar {
  display: flex;
  align-items: flex-end;
  gap: 14px;
  height: 40px;
  padding: 0 14px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}
.dots { display: flex; gap: 7px; align-self: center; }
.dots i { width: 11px; height: 11px; border-radius: 50%; background: var(--line); }
.tab {
  padding: 8px 16px 9px;
  border-radius: 8px 8px 0 0;
  background: var(--bg);
  font-size: 13px;
  font-weight: 500;
}

.terminal-text {
  margin: 0;
  padding: 24px 28px 28px;
  font-family: var(--font-mono);
  font-size: 14.5px;
  line-height: 1.65;
  color: #d4d4d8;
  white-space: pre-wrap;
}
.terminal-text strong { color: var(--text); font-weight: 600; }
.terminal-text em { font-style: normal; color: var(--accent); }

.cursor {
  display: inline-block;
  width: 0.6em;
  height: 1.1em;
  margin-left: 2px;
  vertical-align: -0.2em;
  background: var(--text);
  animation: blink 1.1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.tap-hint { display: none; color: var(--muted); }
@media (hover: none) { .tap-hint { display: inline; } }

/* ---------- Small screens ---------- */

@media (max-width: 900px) {
  .terminal-text { font-size: 12.5px; padding: 18px 16px 22px; }
  :root { --board: min(600px, calc(100vw - 60px)); }
  .app { grid-template-columns: 1fr; gap: 36px; padding: 28px 16px 48px; justify-items: center; }
  .panel { width: 100%; max-width: calc(var(--board) + 28px); }
  h1 { font-size: 32px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; }
  .cursor { animation: none; }
}