:root {
  --term-black: #050805;
  --term-bg: #0a120a;
  --term-dim: #153015;
  --term-med: #2f5e2f;
  --term-green: #33ff33;
  --term-dim-green: #55aa55;
  --term-error: #ff5555;
  --accent: #33ff33;
  --focus: #aaffaa;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  min-height: 100%;
  background: var(--term-black);
  color: var(--term-green);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", "Courier New", monospace;
  font-size: 16px;
  line-height: 1.4;
  text-shadow: 0 0 2px rgba(51, 255, 51, 0.35), 0 0 8px rgba(51, 255, 51, 0.12);
  animation: turn-on 0.25s ease-out;
}

/* CRT scanline + vignette overlays */
body::before,
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
}

body::before {
  z-index: 9999;
  background: repeating-linear-gradient(
    to bottom,
    rgba(0, 0, 0, 0) 0px,
    rgba(0, 0, 0, 0) 1px,
    rgba(0, 0, 0, 0.18) 1px,
    rgba(0, 0, 0, 0.18) 2px
  );
}

body::after {
  z-index: 9998;
  background: radial-gradient(circle at center, transparent 55%, rgba(0, 0, 0, 0.5) 100%);
}

.app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--term-dim);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.header h1 {
  margin: 0;
  font-size: 2rem;
  letter-spacing: 0.18em;
  color: var(--term-green);
  text-shadow: 0 0 6px rgba(51, 255, 51, 0.5);
}

.connection {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--term-dim-green);
}

.connection .label {
  text-transform: uppercase;
}

.dot {
  width: 10px;
  height: 10px;
  background: var(--term-dim);
  border: 1px solid var(--term-green);
  transition: background 0.15s ease, box-shadow 0.15s ease;
}

.connection.connecting .dot {
  background: var(--term-dim-green);
  animation: blink 1s step-end infinite;
}

.connection.connected .dot {
  background: var(--term-green);
  box-shadow: 0 0 8px var(--term-green);
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 1.5rem;
  align-items: start;
}

.board-wrap {
  position: relative;
  background: var(--term-black);
  border: 2px solid var(--term-dim);
  box-shadow:
    0 0 24px rgba(51, 255, 51, 0.08),
    inset 0 0 50px rgba(0, 0, 0, 0.85);
}

.board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  aspect-ratio: 1 / 1;
  background: var(--term-dim);
}

.cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1 / 1;
}

.cell.light {
  background: var(--term-dim);
}

.cell.dark {
  background: var(--term-black);
}

.cell:focus {
  outline: 2px dashed var(--term-green);
  outline-offset: -2px;
  z-index: 1;
}

.cell .idx {
  position: absolute;
  bottom: 2px;
  right: 4px;
  font-size: clamp(0.5rem, 1.1vw, 0.7rem);
  color: var(--term-dim-green);
  opacity: 0.55;
  pointer-events: none;
}

.piece {
  width: 72%;
  height: 72%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1.2rem, 3.2vw, 2rem);
  font-weight: bold;
  cursor: pointer;
  user-select: none;
  border-radius: 50%;
  transition: transform 0.06s ease;
}

.piece:hover {
  transform: scale(1.06);
}

.piece.white {
  color: var(--term-black);
  background: var(--term-green);
  border: 2px solid var(--term-green);
  box-shadow: 0 0 6px rgba(51, 255, 51, 0.25);
}

.piece.black {
  color: var(--term-green);
  background: transparent;
  border: 2px solid var(--term-green);
  box-shadow: 0 0 6px rgba(51, 255, 51, 0.25);
}

.piece.king {
  font-size: clamp(1rem, 2.6vw, 1.7rem);
  letter-spacing: -0.04em;
}

.piece.selected {
  box-shadow:
    0 0 0 2px var(--term-green),
    0 0 16px var(--term-green),
    inset 0 0 8px rgba(51, 255, 51, 0.25);
}

.busy {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(5, 8, 5, 0.88);
  color: var(--term-green);
  font-size: 1.2rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  text-shadow: 0 0 10px rgba(51, 255, 51, 0.6);
}

.busy span::before {
  content: "> ";
}

/* Ensure the [hidden] attribute actually hides the overlay, overriding the display:flex above. */
.busy[hidden] {
  display: none !important;
}

.panel {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.status-card,
.history-card {
  background: var(--term-black);
  border: 1px solid var(--term-dim);
  padding: 1rem;
  box-shadow: 0 0 18px rgba(51, 255, 51, 0.05);
}

.turn-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
  font-size: 1.05rem;
  text-transform: uppercase;
}

.turn-label {
  color: var(--term-dim-green);
}

.turn-value {
  font-weight: bold;
  letter-spacing: 0.08em;
}

.turn-value::after {
  content: "█";
  display: inline-block;
  margin-left: 0.25rem;
  animation: blink 1s step-end infinite;
}

.turn-value.white {
  color: var(--term-green);
}

.turn-value.black {
  color: var(--term-black);
  background: var(--term-green);
  padding: 0 0.3rem;
}

.winner-banner {
  margin: 0.5rem 0;
  padding: 0.5rem;
  text-align: center;
  font-weight: bold;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--term-green);
  color: var(--term-black);
  border: 1px solid var(--term-green);
  box-shadow: 0 0 12px rgba(51, 255, 51, 0.45);
}

.status-line {
  margin: 0.5rem 0 0;
  font-size: 0.9rem;
  min-height: 1.4em;
  color: var(--term-dim-green);
  text-transform: uppercase;
}

.status-line::before {
  content: "> ";
  color: var(--term-green);
}

.status-line.error {
  color: var(--term-error);
  text-shadow: 0 0 6px rgba(255, 85, 85, 0.35);
}

.controls {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

button,
input[type="text"],
select {
  font: inherit;
  border-radius: 0;
  border: 1px solid var(--term-green);
  padding: 0.55rem 0.9rem;
  background: var(--term-black);
  color: var(--term-green);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: background 0.1s ease, color 0.1s ease;
}

button:hover,
select:hover {
  background: var(--term-dim);
}

button:active,
select:active {
  background: var(--term-green);
  color: var(--term-black);
}

button:disabled,
select:disabled,
input[type="text"]:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

#btn-engine {
  border-width: 2px;
  font-weight: bold;
}

.llm-row {
  display: flex;
  gap: 0.5rem;
}

.llm-row button {
  flex: 0 0 auto;
}

#model {
  flex: 1 1 auto;
  border-color: var(--term-dim);
}

#model:focus {
  outline: none;
  border-color: var(--term-green);
}

.toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
  text-transform: uppercase;
}

.toggle input[type="checkbox"] {
  appearance: none;
  -webkit-appearance: none;
  width: 1em;
  height: 1em;
  margin: 0;
  border: 1px solid var(--term-green);
  background: var(--term-black);
  cursor: pointer;
}

.toggle input[type="checkbox"]:checked {
  background: var(--term-green);
  box-shadow: inset 0 0 0 2px var(--term-black);
}

.toggle input[type="checkbox"]:focus-visible {
  outline: 1px dashed var(--term-green);
  outline-offset: 2px;
}

.history-card h2 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--term-green);
}

.history {
  margin: 0;
  padding-left: 0;
  list-style: none;
  max-height: 320px;
  overflow-y: auto;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--term-dim-green);
  counter-reset: move;
}

.history li {
  cursor: pointer;
  padding: 0.1rem 0;
}

.history li::before {
  counter-increment: move;
  content: counter(move, decimal-leading-zero) "> ";
  color: var(--term-green);
}

.history li:hover {
  color: var(--term-green);
  background: rgba(51, 255, 51, 0.06);
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

@keyframes turn-on {
  0% { opacity: 0; filter: brightness(2); }
  80% { opacity: 1; filter: brightness(1.3); }
  100% { opacity: 1; filter: brightness(1); }
}

/* ── Mobile: board-first, panel scrolls below ── */
@media (max-width: 800px) {
  html, body {
    height: 100%;
    overflow: hidden;
  }

  .app {
    height: 100dvh;
    height: 100vh; /* fallback */
    display: flex;
    flex-direction: column;
    overflow: hidden;
    padding: 0.5rem;
    padding-top: calc(env(safe-area-inset-top, 0px) + 0.5rem);
    padding-bottom: calc(env(safe-area-inset-bottom, 0px) + 0.5rem);
    max-width: 100%;
  }

  /* ── Compact header ── */
  .header {
    flex-shrink: 0;
    margin-bottom: 0.4rem;
    padding-bottom: 0.35rem;
  }

  .header h1 {
    font-size: 1.25rem;
    letter-spacing: 0.12em;
  }

  .connection {
    font-size: 0.75rem;
  }

  /* ── Layout: board on top, panel scrolls below ── */
  .layout {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-height: 0;
    gap: 0.5rem;
  }

  .board-wrap {
    flex-shrink: 0;
    /* Square board: constrained by width OR by remaining viewport height */
    width: 100%;
    width: min(100%, calc(100dvh - 180px));
    margin: 0 auto;
  }

  /* ── Panel: scrollable in remaining space ── */
  .panel {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    gap: 0.5rem;
    padding-bottom: env(safe-area-inset-bottom, 0px);
  }

  .status-card {
    padding: 0.5rem 0.7rem;
  }

  .controls {
    gap: 0.5rem;
  }

  /* ── Touch targets ≥ 44px ── */
  button, select, input[type="text"] {
    min-height: 44px;
  }

  button {
    padding: 0.6rem 1rem;
  }

  .history {
    max-height: 150px;
  }

  /* Bigger checkbox for touch */
  .toggle input[type="checkbox"] {
    width: 1.25em;
    height: 1.25em;
  }

  /* Touch feedback on cells */
  .cell:active {
    outline: 2px solid var(--term-green);
    outline-offset: -2px;
  }

  /* LLM row: stack on very narrow screens */
  .llm-row {
    flex-wrap: wrap;
  }

  #model {
    min-width: 0;
  }
}

/* Legal landing squares (issue #24): small filled dot on the empty cell. */
.cell.legal-target {
  cursor: pointer;
}
.cell.legal-target::after {
  content: "";
  position: absolute;
  width: 24%;
  height: 24%;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 10px rgba(51, 255, 51, 0.7);
  pointer-events: none;
  z-index: 1;
}

/* Capture targets (issue #24): inset ring on the enemy piece. */
.cell.capture-target {
  cursor: pointer;
  box-shadow: inset 0 0 0 2px var(--accent);
}