:root {
  --bg: #F2F5F8;
  --paper: #FAFCFD;
  --board-bg: #FFFFFF;
  --ink: #1B1F27;
  --grid-line: #CDD8E3;
  --grid-line-major: #AFC0D1;
  --accent: #2B5C8A;
  --accent-soft: #E4ECF3;
  --text: #1F2733;
  --text-muted: #5B6B7D;
  --frame: #B7C4D2;
  --shadow: rgba(43, 92, 138, 0.18);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #17212C;
    --paper: #1B2733;
    --board-bg: #2C3D4F;
    --ink: #E8ECEF;
    --grid-line: #3E5268;
    --grid-line-major: #4E6880;
    --accent: #6FA8D8;
    --accent-soft: #223244;
    --text: #DDE4EA;
    --text-muted: #8FA0B2;
    --frame: #37516B;
    --shadow: rgba(0, 0, 0, 0.35);
  }
}

:root[data-theme="dark"] {
  --bg: #17212C;
  --paper: #1B2733;
  --board-bg: #2C3D4F;
  --ink: #E8ECEF;
  --grid-line: #3E5268;
  --grid-line-major: #4E6880;
  --accent: #6FA8D8;
  --accent-soft: #223244;
  --text: #DDE4EA;
  --text-muted: #8FA0B2;
  --frame: #37516B;
  --shadow: rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: "IBM Plex Sans JP", "Hiragino Sans", sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 10px 20px 20px;
}

.stage {
  width: 100%;
  max-width: 900px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.masthead {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

h1 {
  margin: 0;
  font-family: "IBM Plex Mono", monospace;
  font-weight: 700;
  font-size: clamp(28px, 6vw, 38px);
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.drafting {
  --cell: 16px;
  display: flex;
  justify-content: center;
  max-width: 100%;
}

.board-column {
  display: inline-flex;
  flex-direction: column;
  gap: 6px;
  max-width: 100%;
}

.score-row {
  display: flex;
  justify-content: flex-end;
}

.board-wrap {
  position: relative;
  padding: 3px;
  background: var(--paper);
  border: 1px solid var(--frame);
  border-radius: 3px;
  box-shadow: 0 12px 32px -16px var(--shadow);
}

.board {
  position: relative;
  width: calc(var(--cell) * var(--nx));
  height: calc(var(--cell) * var(--ny));
  background-color: var(--board-bg);
  background-image:
    repeating-linear-gradient(to right, var(--grid-line-major) 0 1px, transparent 1px calc(var(--cell) * 5)),
    repeating-linear-gradient(to bottom, var(--grid-line-major) 0 1px, transparent 1px calc(var(--cell) * 5)),
    repeating-linear-gradient(to right, var(--grid-line) 0 1px, transparent 1px var(--cell)),
    repeating-linear-gradient(to bottom, var(--grid-line) 0 1px, transparent 1px var(--cell));
  outline: 1px solid var(--frame);
}

.corner-tick {
  position: absolute;
  width: 10px;
  height: 10px;
  border: 1.5px solid var(--accent);
  opacity: 0.6;
}
.corner-tick.tl { top: -4px; left: -4px; border-right: none; border-bottom: none; }
.corner-tick.tr { top: -4px; right: -4px; border-left: none; border-bottom: none; }
.corner-tick.bl { bottom: -4px; left: -4px; border-right: none; border-top: none; }
.corner-tick.br { bottom: -4px; right: -4px; border-left: none; border-top: none; }

.square {
  position: absolute;
  top: 0;
  left: 0;
  width: var(--cell);
  height: var(--cell);
  background: var(--ink);
  transform: translate(calc(var(--x) * var(--cell)), calc(var(--y) * var(--cell)));
  z-index: 2;
}

.heart {
  position: absolute;
  top: 0;
  left: 0;
  width: var(--cell);
  height: var(--cell);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: calc(var(--cell) * 0.9);
  line-height: 1;
  transform: translate(calc(var(--x) * var(--cell)), calc(var(--y) * var(--cell)));
  pointer-events: none;
  z-index: 1;
}

.segment {
  position: absolute;
  top: 0;
  left: 0;
  width: var(--cell);
  height: var(--cell);
  background: #FFFFFF;
  border: 1px solid var(--grid-line-major);
  box-sizing: border-box;
  transform: translate(calc(var(--x) * var(--cell)), calc(var(--y) * var(--cell)));
  z-index: 2;
}

.bomb {
  position: absolute;
  top: 0;
  left: 0;
  width: var(--cell);
  height: var(--cell);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: calc(var(--cell) * 0.9);
  line-height: 1;
  transform: translate(calc(var(--x) * var(--cell)), calc(var(--y) * var(--cell)));
  pointer-events: none;
  z-index: 1;
}

.score-badge {
  font-family: "IBM Plex Mono", monospace;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text);
  background: var(--accent-soft);
  border: 1px solid var(--frame);
  border-radius: 4px;
  padding: 4px 9px;
  font-variant-numeric: tabular-nums;
}

.board:not(.started) .heart {
  visibility: hidden;
}

.footer-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  width: 100%;
  gap: 16px;
}

.howto {
  display: flex;
  flex-direction: column;
  gap: 3px;
  color: var(--text-muted);
  font-size: 12px;
  line-height: 1.6;
}

.howto-title {
  font-family: "IBM Plex Mono", monospace;
  font-weight: 700;
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--text);
}

.howto-list {
  margin: 0;
  padding-left: 1.1em;
}

.howto-list + .howto-title {
  margin-top: 6px;
}

.dpad {
  display: grid;
  grid-template-columns: repeat(3, 46px);
  grid-template-rows: repeat(3, 46px);
  gap: 4px;
  justify-content: center;
}

.dpad-btn {
  font-family: "IBM Plex Mono", monospace;
  font-size: 18px;
  font-weight: 600;
  color: var(--accent);
  background: var(--paper);
  border: 1px solid var(--frame);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
  touch-action: manipulation;
  padding: 0;
}
.dpad-btn:active,
.dpad-btn:hover { background: var(--accent-soft); }

.dpad-up { grid-column: 2; grid-row: 1; }
.dpad-left { grid-column: 1; grid-row: 2; }
.dpad-right { grid-column: 3; grid-row: 2; }
.dpad-down { grid-column: 2; grid-row: 3; }

.hint {
  font-size: 12.5px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

kbd {
  font-family: "IBM Plex Mono", monospace;
  font-size: 11px;
  background: var(--paper);
  border: 1px solid var(--frame);
  border-bottom-width: 2px;
  border-radius: 3px;
  padding: 2px 6px;
  color: var(--text);
}

.board-wrap:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.frag {
  position: absolute;
  top: 0;
  left: 0;
  width: calc(var(--cell) * 0.32);
  height: calc(var(--cell) * 0.32);
  background: var(--ink);
  transform: translate(
    calc(var(--x) * var(--cell) + var(--cell) / 2 - (var(--cell) * 0.16)),
    calc(var(--y) * var(--cell) + var(--cell) / 2 - (var(--cell) * 0.16))
  );
  opacity: 1;
  transition: transform 0.55s cubic-bezier(.2,.7,.3,1), opacity 0.55s ease-in;
  z-index: 4;
  pointer-events: none;
}
.frag.go {
  transform: translate(
    calc(var(--x) * var(--cell) + var(--cell) / 2 - (var(--cell) * 0.16) + var(--tx)),
    calc(var(--y) * var(--cell) + var(--cell) / 2 - (var(--cell) * 0.16) + var(--ty))
  ) rotate(var(--rot));
  opacity: 0;
}

.ready {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(14, 22, 32, 0.35);
  z-index: 5;
}
.ready[hidden] {
  display: none;
}

.ready-title {
  font-family: "IBM Plex Mono", monospace;
  font-weight: 700;
  font-size: clamp(20px, 5vw, 30px);
  letter-spacing: 0.06em;
  color: #EFF4F9;
  text-shadow: 0 0 12px rgba(0,0,0,0.5);
  transform: translateY(calc(var(--cell) * -2));
}

.gameover {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  background: rgba(14, 22, 32, 0.55);
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 5;
}
.gameover.show { opacity: 1; }
.gameover[hidden] {
  display: none;
}

.gameover .go-title {
  font-family: "IBM Plex Mono", monospace;
  font-weight: 700;
  font-size: clamp(20px, 5vw, 30px);
  letter-spacing: 0.06em;
  color: #F4C6C6;
  text-shadow: 0 0 12px rgba(0,0,0,0.5);
}

.gameover .go-score {
  font-family: "IBM Plex Mono", monospace;
  font-size: 13px;
  letter-spacing: 0.08em;
  color: #EFF4F9;
}

.replay-btn {
  margin-top: 6px;
  font-family: "IBM Plex Mono", monospace;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #17212C;
  background: #EFF4F9;
  border: 1px solid rgba(255, 255, 255, 0.5);
  border-radius: 4px;
  padding: 8px 18px;
  cursor: pointer;
}
.replay-btn:hover { background: #FFFFFF; }