:root {
  color-scheme: dark;
  --ink: #17110d;
  --paper: #e8c68c;
  --paper-deep: #d7aa69;
  --red: #c84b3e;
  --gold: #d6a85e;
  --muted: #a89888;
  --card: rgba(39, 29, 22, .78);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  min-height: 100vh;
  color: #f5eee5;
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  background:
    radial-gradient(circle at 20% 10%, rgba(150, 84, 45, .22), transparent 32%),
    radial-gradient(circle at 85% 80%, rgba(107, 48, 37, .18), transparent 30%),
    linear-gradient(145deg, #211812, #100c09 70%);
  padding: 28px 20px;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .16;
  background-image: repeating-linear-gradient(90deg, transparent 0 3px, rgba(255,255,255,.025) 3px 4px);
}

#app {
  width: min(1040px, 100%);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 620px) 320px;
  gap: 28px;
  align-items: start;
}

.stage-heading {
  min-height: 65px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 14px;
}

.eyebrow, .section-title {
  color: var(--gold);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.stage-heading h1 {
  margin-top: 3px;
  font: 500 34px/1 "STKaiti", "KaiTi", serif;
  letter-spacing: .16em;
}

.connection {
  display: flex;
  align-items: center;
  gap: 7px;
  color: var(--muted);
  font-size: 12px;
  padding-bottom: 4px;
}
.connection i { width: 7px; height: 7px; border-radius: 50%; background: #b47e46; }
.connection.online i { background: #75aa72; box-shadow: 0 0 10px #75aa72; }
.connection.offline i { background: #bd5148; }

#board-shell {
  position: relative;
  padding: 13px;
  border: 1px solid rgba(222, 178, 112, .32);
  background: #332217;
  box-shadow: 0 18px 60px rgba(0,0,0,.45), inset 0 0 0 4px rgba(0,0,0,.15);
  border-radius: 4px;
}

#check-alert {
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 5;
  transform: translate(-50%, -50%) scale(.75);
  display: grid;
  place-items: center;
  width: 116px;
  height: 116px;
  border: 4px double rgba(255, 226, 177, .92);
  border-radius: 50%;
  color: #fff3dc;
  background: rgba(157, 40, 31, .93);
  box-shadow: 0 10px 35px rgba(73, 9, 4, .55), inset 0 0 0 5px rgba(255,255,255,.08);
  font: 700 43px/1 "STKaiti", "KaiTi", serif;
  letter-spacing: .08em;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

#check-alert.show {
  visibility: visible;
  animation: check-in 1.55s ease both;
}

@keyframes check-in {
  0% { opacity: 0; transform: translate(-50%, -50%) scale(1.55) rotate(-7deg); }
  18%, 72% { opacity: 1; transform: translate(-50%, -50%) scale(1) rotate(0); }
  100% { opacity: 0; transform: translate(-50%, -50%) scale(.92); visibility: hidden; }
}

#board {
  width: 100%;
  height: auto;
  display: block;
  background:
    linear-gradient(rgba(255,255,255,.04), rgba(0,0,0,.035)),
    var(--paper);
  box-shadow: inset 0 0 30px rgba(105, 61, 24, .18);
}

#board .grid-line { stroke: #573718; stroke-width: 1.35; }
#board .grid-line.thick { stroke-width: 2.4; }
#board .river-text {
  fill: #6f4723;
  font: 31px "STKaiti", "KaiTi", "SimSun", serif;
  letter-spacing: 7px;
}
#board .star { fill: #573718; }
#board .palace-line { stroke: #573718; stroke-width: 1.2; }
#board .marker { fill: rgba(49, 112, 74, .58); pointer-events: none; }
#board .marker.capture { fill: none; stroke: rgba(173, 55, 44, .9); stroke-width: 3; }
#board .marker.last-from { fill: rgba(34, 71, 92, .13); stroke: #547f91; stroke-width: 2; stroke-dasharray: 5 4; }
#board .marker.last-to { fill: none; stroke: #ce7f38; stroke-width: 4; }
#board .selected { fill: rgba(222, 166, 58, .10); stroke: #d6a23f; stroke-width: 4; }
#board image.piece { cursor: pointer; filter: drop-shadow(1px 3px 2px rgba(0,0,0,.35)); }

#status-bar {
  min-height: 46px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(255,255,255,.10);
  color: #ead8c1;
  font-size: 14px;
}
#move-count { color: var(--muted); font-size: 12px; }
#status-text.thinking::after { content: " ···"; animation: blink 1.1s infinite; }
@keyframes blink { 50% { opacity: .25; } }

#panel { padding-top: 79px; display: grid; gap: 12px; }
.card {
  border: 1px solid rgba(255,255,255,.09);
  background: var(--card);
  backdrop-filter: blur(10px);
  border-radius: 8px;
  padding: 15px;
  box-shadow: 0 10px 30px rgba(0,0,0,.15);
}
.section-title { margin-bottom: 10px; }
.btn-group { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
button {
  border: 1px solid rgba(255,255,255,.12);
  border-radius: 6px;
  background: rgba(255,255,255,.045);
  color: #f6eee5;
  padding: 10px 12px;
  cursor: pointer;
  transition: background .15s, border-color .15s, transform .15s;
}
button:hover { background: rgba(255,255,255,.09); transform: translateY(-1px); }
button:focus-visible, input:focus-visible { outline: 2px solid var(--gold); outline-offset: 2px; }
.mode-btn { display: flex; justify-content: space-between; align-items: baseline; }
.mode-btn b { font-size: 15px; font-weight: 600; }
.mode-btn small { color: var(--muted); }
.mode-btn.active { border-color: #bd8f4d; background: rgba(185, 120, 55, .20); }

.difficulty-head { display: flex; justify-content: space-between; align-items: center; }
#difficulty-name { font-size: 15px; }
#difficulty-value {
  min-width: 48px;
  text-align: center;
  color: #18100b;
  background: var(--gold);
  border-radius: 20px;
  padding: 5px 9px;
  font-size: 14px;
  font-weight: 700;
}
input[type="range"] {
  width: 100%;
  margin: 17px 0 5px;
  accent-color: var(--red);
  cursor: ew-resize;
}
.range-labels { display: flex; justify-content: space-between; color: #8f8174; font-size: 10px; }
.hint { margin-top: 10px; color: #8f8174; font-size: 11px; line-height: 1.5; }
.actions { display: grid; grid-template-columns: 2fr 1fr; gap: 8px; }
.primary { background: var(--red); border-color: #e06a5c; font-size: 14px; }
.primary:hover { background: #d45749; }
.secondary { color: #cab9a8; }

#last-move { min-height: 28px; display: flex; align-items: center; gap: 10px; }
#last-move strong { font: 18px "STKaiti", "KaiTi", serif; color: #f4ddbd; }
#last-move code { color: #a99888; font-size: 11px; }
.empty { color: #85786d; font-size: 12px; }
#history { max-height: 195px; overflow-y: auto; font-size: 13px; scrollbar-color: #72513a transparent; }
#history .row { display: grid; grid-template-columns: 25px 1fr 1fr; gap: 8px; padding: 6px 2px; border-bottom: 1px solid rgba(255,255,255,.055); }
#history .no { color: #796d62; }
#history .red-move { color: #f09b8e; }
#history .black-move { color: #a9c9d6; }
#captured-row { min-height: 30px; opacity: .8; }
.captured { min-height: 18px; }
.captured img { width: 21px; height: 21px; margin-right: -7px; filter: grayscale(.15); }

#toast {
  position: fixed;
  left: 50%; bottom: 24px;
  transform: translate(-50%, 20px);
  opacity: 0;
  padding: 9px 14px;
  color: #f8eee5;
  background: #9f3d32;
  border-radius: 5px;
  font-size: 13px;
  transition: .2s;
  pointer-events: none;
}
#toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 850px) {
  body { padding: 16px 10px 28px; }
  #app { display: flex; flex-direction: column; width: min(620px, 100%); }
  .game-stage, #panel { width: 100%; }
  #panel { padding-top: 0; }
}

@media (max-width: 480px) {
  .stage-heading { min-height: 50px; }
  .stage-heading h1 { font-size: 28px; }
  #board-shell { padding: 7px; }
  #panel { gap: 9px; }
  .card { padding: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  #check-alert.show { opacity: 1; visibility: visible; transform: translate(-50%, -50%); }
}