:root {
  --board: min(80vmin, calc(100vh - 180px));
  --sq: calc(var(--board) / 8);
  --bg: var(--k-bg);
  --bg2: var(--k-surface-2);
  --ink: var(--k-text);
  --muted: var(--k-text-2);
  --line: var(--k-line);
  --panel: var(--k-surface);
  --accent: var(--k-accent);
  --accent-ink: var(--k-accent-ink);
  --good: var(--k-good);
  --bad: var(--k-danger);
  --light: #6b7a8f;
  --dark: #3b4654;
  --white-p: #f4f4f0;
  --black-p: #1b1b1f;
  --glow-w: #ffe39a;
  --glow-b: #7fd1ff;
}

html[data-theme="dark"] {
  --k-bg: #1a1f29;
  --k-surface: #232a36;
  --k-surface-2: #2b3340;
  --k-text: #e8edf4;
  --k-text-2: #8b97a8;
  --k-text-3: #6b7686;
  --k-line: #3a4350;
  --k-line-2: #4a5562;
  --k-accent: #ffcc4d;
  --k-accent-ink: #211b14;
  --k-good: #7bbf6a;
  --k-warn: #e0b256;
  --k-danger: #d8694e;
}

* { box-sizing: border-box; scrollbar-width: none; -ms-overflow-style: none; -webkit-tap-highlight-color: transparent; }
*::-webkit-scrollbar { width: 0; height: 0; display: none; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Inter", system-ui, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 700px at 75% -10%, #28303f 0%, transparent 60%),
    radial-gradient(900px 600px at 0% 110%, #20283440 0%, transparent 55%),
    var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 28px 18px;
  user-select: none;
  -webkit-user-select: none;
}

header { text-align: center; margin-bottom: 22px; }

h1 {
  margin: 0;
  font-family: "Fraunces", Georgia, serif;
  font-weight: 600;
  font-size: clamp(26px, 4vw, 40px);
  letter-spacing: .3px;
  color: var(--ink);
}

h1 em { font-style: italic; color: var(--accent); }

.stage {
  display: flex;
  gap: 26px;
  align-items: flex-start;
  flex-wrap: wrap;
  justify-content: center;
}

.board-wrap {
  position: relative;
  padding: 18px;
  border-radius: 18px;
  background: linear-gradient(160deg, #2c3543, #1c232e);
  box-shadow: 0 1px 0 rgba(255, 255, 255, .06) inset, 0 26px 60px rgba(0, 0, 0, .55);
}

.board-frame {
  position: relative;
  width: var(--board);
  height: var(--board);
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 0 0 2px rgba(0, 0, 0, .4);
  touch-action: none;
  user-select: none;
}

.grid {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(8, var(--sq));
  grid-template-rows: repeat(8, var(--sq));
}

.cell { position: relative; cursor: pointer; }
.cell.light { background: var(--light); }
.cell.dark { background: var(--dark); }

.cell .lbl {
  position: absolute;
  font-size: calc(var(--sq) * .16);
  font-weight: 600;
  opacity: .5;
  pointer-events: none;
}

.cell .lbl.file { right: 5px; bottom: 3px; }
.cell .lbl.rank { left: 4px; top: 2px; }
.cell.light .lbl { color: #3b4654; }
.cell.dark .lbl { color: #aebac9; }

.cell.sel::after {
  content: "";
  position: absolute;
  inset: 0;
  box-shadow: inset 0 0 0 max(3px, calc(var(--sq) * .06)) var(--accent);
  background: color-mix(in srgb, var(--accent) 18%, transparent);
}

.cell.tgt::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 30%;
  height: 30%;
  transform: translate(-50%, -50%);
  background: rgba(15, 20, 28, .34);
  border-radius: 50%;
  transition: background .12s ease, border-color .12s ease, width .12s ease, height .12s ease;
}

.cell.tgt.cap::before {
  width: 86%;
  height: 86%;
  background: transparent;
  border: max(3px, calc(var(--sq) * .055)) solid color-mix(in srgb, var(--bad) 85%, transparent);
  border-radius: 50%;
}

.cell.tgt:hover::before { background: color-mix(in srgb, var(--accent) 55%, transparent); }
.cell.tgt.cap:hover::before { background: transparent; border-color: var(--accent); }
.cell.tgt.over::before { background: color-mix(in srgb, var(--accent) 75%, transparent); }
.cell.tgt.cap.over::before { background: transparent; border-color: var(--accent); }
.cell.over { box-shadow: inset 0 0 0 max(3px, calc(var(--sq) * .055)) var(--accent); }

.pieces { position: absolute; inset: 0; pointer-events: none; }

.piece {
  position: absolute;
  width: var(--sq);
  height: var(--sq);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: calc(var(--sq) * .74);
  line-height: 1;
}

.piece.white .g { color: var(--white-p); text-shadow: 0 0 1px #000, 0 1px 1px #000; }
.piece.black .g { color: var(--black-p); text-shadow: 0 0 1px #efe2cb, 0 1px 0 #000; }
.piece.moving { opacity: .95; }
.piece.moving .g { filter: drop-shadow(0 0 10px var(--glow)); }
.piece.drag { z-index: 5; }
.piece.drag .g { filter: drop-shadow(0 6px 9px rgba(0, 0, 0, .6)); }

.piece .bar {
  position: absolute;
  bottom: calc(var(--sq) * .1);
  left: 20%;
  width: 60%;
  height: 4px;
  background: rgba(0, 0, 0, .4);
  border-radius: 3px;
  overflow: hidden;
  display: none;
}

.piece.moving .bar { display: block; }
.piece .bar i {
  display: block;
  height: 100%;
  width: 100%;
  background: var(--glow);
  border-radius: 3px;
  transform: scaleX(0);
  transform-origin: left;
}

.banner {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: rgba(14, 18, 24, .84);
  backdrop-filter: blur(3px);
  z-index: 6;
  border-radius: 6px;
  opacity: 0;
  visibility: hidden;
  transition: opacity .25s ease, visibility .25s ease;
}

.banner.show { opacity: 1; visibility: visible; }
.banner h3 { margin: 0 0 6px; font-family: "Fraunces", serif; font-size: clamp(24px, 4vw, 34px); }
.banner p { margin: 0 0 18px; color: var(--muted); }
.bRate { margin: -12px 0 18px; font-size: 13px; line-height: 1.4; color: var(--muted); max-width: 84%; }
.bRate:empty { display: none; margin: 0; }
.bRate.ok { color: var(--good); }
.bRate.err { color: var(--bad); }

.panel { width: 300px; display: flex; flex-direction: column; gap: 14px; }

#settings { display: flex; flex-direction: column; gap: 14px; }
#aiGroup { display: flex; flex-direction: column; gap: 14px; }

.collapsible {
  overflow: hidden;
  transition: max-height .3s var(--k-ease, ease), opacity .22s ease,
    margin .3s var(--k-ease, ease), padding .3s var(--k-ease, ease);
}
#settings.collapsible { max-height: 1200px; }
#netBox.collapsible { max-height: 320px; }
#aiGroup.collapsible { max-height: 560px; }
#surrenderBtn.collapsible { max-height: 64px; }

.collapsed {
  max-height: 0 !important;
  min-height: 0 !important;
  margin-top: -7px !important;
  margin-bottom: -7px !important;
  padding-top: 0 !important;
  padding-bottom: 0 !important;
  border-top-width: 0 !important;
  border-bottom-width: 0 !important;
  opacity: 0;
  pointer-events: none;
}

.seg {
  width: 100%;
  display: flex;
  gap: 4px;
  padding: 4px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
}

.seg-opt {
  flex: 1;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-family: inherit;
  font-weight: 600;
  font-size: 14px;
  padding: 9px;
  border-radius: 9px;
  cursor: pointer;
  transition: .15s;
}

.seg-opt:hover { color: var(--ink); }
.seg-opt.is-on { background: var(--accent); color: var(--accent-ink); }

.aiCard { display: flex; flex-direction: column; gap: 12px; }

.aiHead {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 14px;
  color: var(--ink);
}

.aiHead::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--accent); }
.aiCard .fld { gap: 6px; }

.row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 7px 0;
  font-size: 14px;
}

.row b { font-variant-numeric: tabular-nums; font-size: 15px; }
.aiSwitchRow { padding: 4px 16px; }
.aiSwitchRow > span { color: var(--ink); }
.aiSwitchRow .k-switch { flex: 0 0 auto; }

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  margin-right: 8px;
  vertical-align: middle;
}

.dot.w { background: var(--white-p); }
.dot.b { background: #2b333f; box-shadow: 0 0 0 1px #5d6b7c; }

.fld { display: flex; flex-direction: column; gap: 8px; }

.lblRow,
.fld > span {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: var(--muted);
}

.lblRow span:last-child { color: var(--accent); font-weight: 600; }
.k-range { width: 100%; }
.dual { display: flex; flex-direction: column; gap: 6px; }

.codeRow { display: flex; gap: 8px; }
.codeRow .k-field { flex: 1; }
#code { user-select: text; -webkit-user-select: text; }

#netBox {
  display: flex;
  flex-direction: column;
  gap: 10px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--k-r-lg, 12px);
  padding: 14px 16px;
}

.netStatus { margin: 2px 0 0; font-size: 13px; line-height: 1.5; color: var(--muted); }
.netStatus.ok { color: var(--good); }
.netStatus.err { color: var(--bad); }

#rulesAcc { font-size: 13px; line-height: 1.6; }
.rulesText { color: var(--muted); }
.rulesText b { color: var(--ink); }

.hidden { display: none !important; }
a { color: var(--accent); }

.board-frame.flip { transform: rotate(180deg); }
.board-frame.flip .piece .g,
.board-frame.flip .cell .lbl,
.board-frame.flip .banner { transform: rotate(180deg); }

.burger { display: none; }
.scrim { display: none; }

.gear {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--ink);
  font-size: 20px;
  cursor: pointer;
  transition: color .15s, border-color .15s;
}
.gear:hover { color: var(--accent); border-color: var(--accent); }

.modal {
  position: fixed;
  inset: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(0, 0, 0, .55);
  opacity: 0;
  visibility: hidden;
  transition: opacity .2s ease, visibility .2s ease;
}
.modal.open { opacity: 1; visibility: visible; }

.modal-card {
  width: min(380px, 92vw);
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 16px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, .5);
  transform: translateY(8px) scale(.98);
  transition: transform .2s ease;
}
.modal.open .modal-card { transform: none; }

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: "Fraunces", serif;
  font-size: 20px;
  color: var(--ink);
}
.modal-x {
  border: 0;
  background: transparent;
  color: var(--muted);
  font-size: 18px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 8px;
}
.modal-x:hover { color: var(--ink); }
.optRow { padding: 12px 16px; }
.optRow > span { color: var(--ink); }
.optRow .k-switch { flex: 0 0 auto; }

.lbList { display: flex; flex-direction: column; gap: 2px; max-height: 60vh; overflow-y: auto; }
.lbRow { display: flex; align-items: center; gap: 10px; padding: 8px 10px; border-radius: 8px; font-size: 14px; }
.lbRow:nth-child(odd) { background: var(--bg2); }
.lbRow .pos { width: 1.8em; color: var(--muted); font-variant-numeric: tabular-nums; }
.lbRow .n { flex: 1; color: var(--ink); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.lbRow .r { color: var(--accent); font-weight: 600; font-variant-numeric: tabular-nums; }

@media (max-width: 1200px) {
  :root { --board: min(100vw, 100dvh); }

  html, body { overflow: hidden; height: 100dvh; }
  body { padding: 0; justify-content: center; }
  .stage { gap: 0; }

  header {
    position: absolute;
    top: 10px;
    left: 0;
    right: 0;
    margin: 0;
    z-index: 5;
    pointer-events: none;
  }

  .board-wrap {
    padding: 0;
    background: none;
    box-shadow: none;
    border-radius: 0;
  }

  .board-frame {
    border-radius: 0;
    box-shadow: none;
  }

  .banner { border-radius: 0; }
  .piece.moving .g { filter: none; }

  .burger {
    display: flex;
    align-items: center;
    justify-content: center;
    position: fixed;
    top: 12px;
    right: 12px;
    z-index: 30;
    width: 44px;
    height: 44px;
    border-radius: 10px;
    background: var(--panel);
    border: 1px solid var(--line);
    color: var(--ink);
    font-size: 20px;
    cursor: pointer;
  }

  .panel {
    position: fixed;
    top: 0;
    right: 0;
    height: 100dvh;
    width: min(330px, 88vw);
    background: var(--bg2);
    border-left: 1px solid var(--line);
    transform: translateX(100%);
    transition: transform .25s ease;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    z-index: 29;
    overflow-y: auto;
    padding: 64px 16px 24px;
  }

  .panel.open {
    transform: translateX(0);
    box-shadow: -20px 0 50px rgba(0, 0, 0, .5);
  }

  .scrim {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, .5);
    opacity: 0;
    pointer-events: none;
    transition: opacity .25s;
    z-index: 28;
  }

  .scrim.open { opacity: 1; pointer-events: auto; }
}