/* ================= 五子棋 · 全设备自适应样式 ================= */

/* ---------- 主题变量（4 套配色，可在设置中切换） ---------- */
:root {
  --radius: 14px;
  --radius-sm: 9px;
  --danger: #d9534f;
  /* 玻璃拟态基础（开启态由各主题覆盖，关闭态回退实体面板） */
  --glass-filter: blur(16px) saturate(165%);
  --glass-filter-soft: blur(10px) saturate(150%);
  --glass-filter-strong: blur(26px) saturate(180%);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.28);
  --glass-highlight: inset 0 1px 0 rgba(255, 255, 255, 0.18);
}


/* 🌌 深空（默认）：现代深色 + 蓝紫强调 */
html[data-theme="midnight"] {
  --bg: radial-gradient(1200px 700px at 50% -10%, #2a3242 0%, #1a1f29 45%, #12151b 100%);
  --panel: linear-gradient(160deg, #262c38, #1d222b);
  --panel-2: rgba(255, 255, 255, 0.05);
  --border: rgba(255, 255, 255, 0.13);
  --text: #e7eaf0;
  --text-dim: #97a1b2;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.55);
  --accent: #5b8cff;
  --accent-2: #3a63d8;
  --btn-bg: #2e3644;
  --btn-text: #e2e7f0;
  --drawer-bg: linear-gradient(160deg, #20252f, #171b23);
  --modal-bg: linear-gradient(160deg, #ffffff, #eef1f7);
  --modal-text: #232a36;
  --switch-off: rgba(255, 255, 255, 0.12);
  /* 棋盘 */
  --board-bg: linear-gradient(145deg, #eccfa1, #d8b47c);
  --board-line: rgba(140, 100, 62, 0.9);
  --board-star: rgba(120, 84, 48, 0.95);
  --board-coord: #9c7c52;
  --board-edge: rgba(0, 0, 0, 0.35);
  --glass-bg: rgba(255, 255, 255, 0.07);
  --glass-bg-soft: rgba(255, 255, 255, 0.045);
  --glass-bg-strong: rgba(18, 22, 31, 0.60);
  --glass-border: rgba(255, 255, 255, 0.16);
  --glass-border-soft: rgba(255, 255, 255, 0.09);
  --blob-1: rgba(91, 140, 255, 0.50);
  --blob-2: rgba(150, 90, 255, 0.34);
  --blob-3: rgba(45, 200, 190, 0.26);

}

/* 🪵 暖木：经典棋室木质风 */
html[data-theme="wood"] {
  --bg: radial-gradient(1100px 650px at 50% -5%, #6b5138 0%, #4c3925 45%, #33261a 100%);
  --panel: linear-gradient(160deg, #6d5238, #523d29);
  --panel-2: rgba(0, 0, 0, 0.2);
  --border: rgba(233, 196, 133, 0.28);
  --text: #f7ead4;
  --text-dim: #d6bd94;
  --shadow: 0 18px 48px rgba(0, 0, 0, 0.5);
  --accent: #d9a441;
  --accent-2: #b3801f;
  --btn-bg: #f0e2c6;
  --btn-text: #3d2c14;
  --drawer-bg: linear-gradient(160deg, #57412c, #3d2e1e);
  --modal-bg: linear-gradient(160deg, #fdf3e0, #edd9b4);
  --modal-text: #4a3316;
  --switch-off: rgba(0, 0, 0, 0.28);
  --board-bg: linear-gradient(145deg, #e6c08a, #cda268);
  --board-line: rgba(120, 84, 48, 0.92);
  --board-star: rgba(100, 68, 36, 0.95);
  --board-coord: #8a6438;
  --board-edge: rgba(0, 0, 0, 0.4);
  --glass-bg: rgba(255, 240, 214, 0.09);
  --glass-bg-soft: rgba(255, 240, 214, 0.055);
  --glass-bg-strong: rgba(50, 37, 24, 0.60);
  --glass-border: rgba(255, 228, 175, 0.20);
  --glass-border-soft: rgba(255, 228, 175, 0.11);
  --blob-1: rgba(217, 164, 65, 0.42);
  --blob-2: rgba(190, 110, 50, 0.30);
  --blob-3: rgba(120, 170, 90, 0.22);

}

/* 📄 米白：清爽纸质极简风 */
html[data-theme="paper"] {
  --bg: radial-gradient(1100px 650px at 50% -5%, #ffffff 0%, #f2efe8 50%, #e4e0d6 100%);
  --panel: linear-gradient(160deg, #ffffff, #f6f4ef);
  --panel-2: rgba(0, 0, 0, 0.045);
  --border: rgba(0, 0, 0, 0.12);
  --text: #2f2c27;
  --text-dim: #7d766c;
  --shadow: 0 14px 38px rgba(80, 74, 64, 0.16);
  --accent: #e08b3c;
  --accent-2: #c26f24;
  --btn-bg: #f2ede3;
  --btn-text: #4a4136;
  --drawer-bg: linear-gradient(160deg, #ffffff, #f4f1ea);
  --modal-bg: linear-gradient(160deg, #ffffff, #f5f1e8);
  --modal-text: #3a332a;
  --switch-off: rgba(0, 0, 0, 0.14);
  --board-bg: linear-gradient(145deg, #f3ddb4, #e3c48f);
  --board-line: rgba(150, 112, 68, 0.8);
  --board-star: rgba(130, 95, 55, 0.9);
  --board-coord: #a07d54;
  --board-edge: rgba(90, 70, 45, 0.22);
  --glass-bg: rgba(255, 255, 255, 0.55);
  --glass-bg-soft: rgba(255, 255, 255, 0.40);
  --glass-bg-strong: rgba(255, 255, 255, 0.78);
  --glass-border: rgba(255, 255, 255, 0.90);
  --glass-border-soft: rgba(0, 0, 0, 0.07);
  --glass-shadow: 0 8px 30px rgba(120, 105, 80, 0.16);
  --glass-highlight: inset 0 1px 0 rgba(255, 255, 255, 0.95);
  --blob-1: rgba(224, 139, 60, 0.30);
  --blob-2: rgba(120, 170, 220, 0.26);
  --blob-3: rgba(230, 190, 120, 0.28);

}

/* 🀄 水墨：宣纸留白 + 墨色 */
html[data-theme="ink"] {
  --bg: radial-gradient(1100px 650px at 50% -5%, #f4efe3 0%, #e7e0d1 50%, #d5cbb8 100%);
  --panel: linear-gradient(160deg, rgba(255, 255, 255, 0.75), rgba(246, 241, 230, 0.7));
  --panel-2: rgba(60, 50, 40, 0.06);
  --border: rgba(70, 60, 48, 0.22);
  --text: #2b2723;
  --text-dim: #6f6759;
  --shadow: 0 16px 40px rgba(80, 70, 55, 0.18);
  --accent: #8c5a3c;
  --accent-2: #6d4229;
  --btn-bg: rgba(255, 255, 255, 0.8);
  --btn-text: #3b352d;
  --drawer-bg: linear-gradient(160deg, #f6f1e5, #e9e2d3);
  --modal-bg: linear-gradient(160deg, #fbf7ee, #eee7d8);
  --modal-text: #2f2a24;
  --switch-off: rgba(70, 60, 48, 0.2);
  --board-bg: linear-gradient(145deg, #f4e5c4, #e5d1a8);
  --board-line: rgba(110, 88, 60, 0.72);
  --board-star: rgba(90, 70, 46, 0.85);
  --board-coord: #8b7452;
  --board-edge: rgba(90, 75, 50, 0.2);
  --glass-bg: rgba(255, 255, 255, 0.45);
  --glass-bg-soft: rgba(255, 255, 255, 0.32);
  --glass-bg-strong: rgba(250, 246, 238, 0.72);
  --glass-border: rgba(255, 255, 255, 0.75);
  --glass-border-soft: rgba(70, 60, 48, 0.10);
  --glass-shadow: 0 8px 30px rgba(90, 78, 60, 0.16);
  --glass-highlight: inset 0 1px 0 rgba(255, 255, 255, 0.85);
  --blob-1: rgba(140, 90, 60, 0.22);
  --blob-2: rgba(90, 110, 90, 0.18);
  --blob-3: rgba(180, 160, 120, 0.24);

}

/* ---------- 玻璃拟态关闭态：回退实体面板（放在主题之后以覆盖变量） ---------- */
html[data-glass="off"] {
  --glass-bg: var(--panel);
  --glass-bg-soft: var(--panel-2);
  --glass-bg-strong: var(--panel);
  --glass-border: var(--border);
  --glass-border-soft: var(--border);
  --glass-filter: none;
  --glass-filter-soft: none;
  --glass-filter-strong: none;
  --glass-shadow: var(--shadow);
  --glass-highlight: none;
}
html[data-glass="off"] body::before { display: none; }
/* 关闭态下棋盘恢复普通描边 */
html[data-glass="off"] .difficulty-bar { background: var(--panel-2); }
html[data-glass="off"] .slider-track {
  background: var(--border);
  border-color: transparent;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, .2);
}
html[data-glass="off"] .slider-fill {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  box-shadow: none;
}
html[data-glass="off"] .slider-thumb {
  border-radius: 9px;
  background: linear-gradient(145deg, var(--accent), var(--accent-2));
  border: 2px solid var(--panel);
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .38);
}
html[data-glass="off"] canvas#board {
  border: 1px solid var(--border);
  box-shadow: inset 0 2px 8px rgba(0,0,0,.3), var(--shadow);
}


* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body { height: 100%; overflow: hidden; }

body {
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", system-ui, sans-serif;
  background: var(--bg);
  background-attachment: fixed;
  color: var(--text);
  user-select: none;
  touch-action: manipulation;
}

/* ---------- 页面背景与彩色光斑（玻璃拟态的依托） ---------- */
body {
  position: relative;
}

body::before {
  content: "";
  position: fixed;
  inset: -25%;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(closest-side, var(--blob-1, transparent), transparent 100%),
    radial-gradient(closest-side, var(--blob-2, transparent), transparent 100%),
    radial-gradient(closest-side, var(--blob-3, transparent), transparent 100%);
  background-size: 62% 62%, 55% 55%, 60% 60%;
  background-position: 12% 16%, 86% 22%, 50% 96%;
  background-repeat: no-repeat;
  filter: blur(46px);
  opacity: .95;
  animation: blobFloat 28s ease-in-out infinite alternate;
  will-change: transform;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(520px 520px at var(--mx, 50%) var(--my, 42%),
    color-mix(in srgb, var(--accent) 20%, transparent), transparent 68%);
}
html[data-follow="off"] body::after { display: none; }
html[data-blobs="off"] body::before,
html[data-blobs="off"] body::after { display: none; }

@keyframes blobFloat {
  0%   { transform: translate3d(0, 0, 0) scale(1); }
  50%  { transform: translate3d(1.5%, -2%, 0) scale(1.05); }
  100% { transform: translate3d(-1.5%, 1.5%, 0) scale(1.02); }
}

@media (prefers-reduced-motion: reduce) {
  body::before { animation: none; }
}

/* ---------- 布局骨架 ---------- */
.app {
  height: 100%;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: calc(8px + env(safe-area-inset-top)) calc(10px + env(safe-area-inset-right))
           calc(8px + env(safe-area-inset-bottom)) calc(10px + env(safe-area-inset-left));
  max-width: 1200px;
  margin: 0 auto;
}

/* ---------- 顶栏 ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex: 0 0 auto;
}

.topbar h1 {
  font-size: clamp(16px, 4.2vw, 24px);
  letter-spacing: 3px;
  display: flex;
  align-items: center;
  gap: 8px;
  text-shadow: 0 2px 6px rgba(0, 0, 0, 0.35);
}

.stone-ico {
  width: 0.85em; height: 0.85em;
  border-radius: 50%;
  display: inline-block;
  box-shadow: inset 0 -2px 3px rgba(0,0,0,.4);
}
.stone-ico.black { background: radial-gradient(circle at 35% 30%, #666, #050505); }
.stone-ico.white { background: radial-gradient(circle at 35% 30%, #fff, #bdbdbd); }

.top-actions { display: flex; gap: 6px; }

.icon-btn {
  width: 38px; height: 38px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  font-size: 17px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter);
  -webkit-backdrop-filter: var(--glass-filter);
  box-shadow: var(--glass-highlight);
  border-radius: 11px;
  color: var(--text);
  cursor: pointer;
  transition: transform .1s ease, background .15s ease;
  flex: 0 0 auto;
  /* 图标按钮以 emoji 为主，指定 emoji 字体保证各系统渲染一致、居中不偏 */
  font-family: "Segoe UI Emoji", "Apple Color Emoji", "Noto Color Emoji", "Microsoft YaHei", sans-serif;
}
.icon-btn:hover { transform: translateY(-1px); }
.icon-btn:active { transform: scale(.94); }

/* ---------- 状态栏 ---------- */
.statusbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex: 0 0 auto;
  flex-wrap: wrap;
}

.status {
  display: flex; align-items: center; gap: 7px;
  font-size: clamp(13px, 3.4vw, 16px);
  font-weight: 700;
}

.dot {
  width: 15px; height: 15px; border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .5);
  flex: 0 0 auto;
}
.black-dot { background: radial-gradient(circle at 35% 30%, #555, #0a0a0a); }
.white-dot { background: radial-gradient(circle at 35% 30%, #fff, #c9c9c9); }

.meta { display: flex; gap: 6px; flex-wrap: wrap; }

.pill {
  font-size: clamp(11px, 2.9vw, 13px);
  color: var(--text-dim);
  background: var(--glass-bg-soft);
  border: 1px solid var(--glass-border-soft);
  backdrop-filter: var(--glass-filter-soft);
  -webkit-backdrop-filter: var(--glass-filter-soft);
  padding: 3px 10px;
  border-radius: 99px;
  white-space: nowrap;
}
.pill.warn { color: #fff; background: var(--danger); border-color: transparent; }

/* ---------- 棋盘 ---------- */
.board-wrap {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

canvas#board {
  display: block;
  border-radius: 12px;
  background: var(--board-bg);
  border: 1px solid var(--glass-border);
  box-shadow: inset 0 2px 8px rgba(0,0,0,.3), 0 18px 50px rgba(0, 0, 0, .38), 0 0 0 8px var(--glass-bg-soft);
  touch-action: none;
  cursor: pointer;
  max-width: 100%;
  max-height: 100%;
}

.float-tip {
  position: absolute;
  top: 10px; left: 50%;
  transform: translateX(-50%);
  background: rgba(0,0,0,.72);
  color: #fff;
  font-size: 13px;
  padding: 6px 14px;
  border-radius: 99px;
  display: flex; align-items: center; gap: 7px;
  pointer-events: none;
  backdrop-filter: blur(4px);
  white-space: nowrap;
}
.float-tip.hint { top: auto; bottom: 10px; background: rgba(217,164,65,.92); }
.float-tip.warn {
  background: rgba(217, 83, 79, .95);
  box-shadow: 0 4px 18px rgba(217, 83, 79, .4);
  font-weight: 700;
}

.spinner {
  width: 12px; height: 12px;
  border: 2px solid rgba(255,255,255,.35);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 控制区 ---------- */
.controls {
  flex: 0 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

/* ---------- 难度栏（滑块 + 双人切换） ---------- */
.difficulty-bar {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  max-width: 760px;
  padding: 8px 16px;
  /* 内部彩色微光：让栏内的玻璃件（轨道/滑块）有内容可透出 */
  background:
    radial-gradient(140px 70px at 18% 25%, color-mix(in srgb, var(--accent) 20%, transparent), transparent 72%),
    radial-gradient(160px 80px at 78% 78%, color-mix(in srgb, var(--accent-2) 16%, transparent), transparent 74%),
    var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter);
  -webkit-backdrop-filter: var(--glass-filter);
  box-shadow: var(--glass-highlight);
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
}

.pvp-toggle {
  flex: 0 0 auto;
  font-size: clamp(12px, 3.2vw, 14px);
  padding: 8px 14px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter);
  -webkit-backdrop-filter: var(--glass-filter);
  box-shadow: var(--glass-highlight);
  color: var(--btn-text);
  border-radius: var(--radius-sm);
  font-weight: 700;
}
.pvp-toggle.active {
  background: linear-gradient(145deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 2px 8px rgba(0,0,0,.28);
}

.slider-wrap {
  flex: 1 1 0;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

/* 两个滑块之间的竖向分隔线 */
.slider-sep {
  flex: 0 0 auto;
  width: 1px;
  align-self: stretch;
  margin: 2px 0;
  background: linear-gradient(180deg,
    transparent,
    var(--glass-border) 22%,
    var(--glass-border) 78%,
    transparent);
  opacity: .9;
}

/* 棋盘滑块：与难度滑块完全等宽 */
.slider-wrap-board { flex: 1 1 0; min-width: 0; }

.slider-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  font-size: 11px;
  color: var(--text-dim);
}
.slider-title { letter-spacing: .5px; }
.diff-name {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
}

/* ---------- 自定义滑块（点击平滑滑动，拖动实时跟手） ---------- */
.slider {
  position: relative;
  padding: 11px 0 9px;
  cursor: pointer;
  touch-action: none;
  outline: none;
}
.slider:focus-visible .slider-thumb {
  box-shadow: 0 0 0 3px rgba(128, 128, 128, .45), 0 2px 8px rgba(0, 0, 0, .35);
}

.slider-track {
  position: relative;
  height: 10px;
  border-radius: 99px;
  /* 凹槽玻璃：半透明 + 内部斜向反光 */
  background:
    linear-gradient(180deg, rgba(255, 255, 255, .16), rgba(255, 255, 255, .04)),
    rgba(255, 255, 255, .06);
  border: 1px solid rgba(255, 255, 255, .24);
  backdrop-filter: blur(16px) saturate(190%) brightness(1.06);
  -webkit-backdrop-filter: blur(16px) saturate(190%) brightness(1.06);
  box-shadow:
    inset 0 2px 7px rgba(0, 0, 0, .34),
    inset 0 -1px 0 rgba(255, 255, 255, .30),
    0 1px 2px rgba(0, 0, 0, .14);
}

.slider-fill {
  position: absolute;
  left: 0; top: 0;
  height: 100%;
  width: 0;
  border-radius: 99px;
  /* 彩色玻璃：低不透明度，透过它可见背景 */
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--accent) 34%, transparent),
    color-mix(in srgb, var(--accent-2) 48%, transparent));
  backdrop-filter: blur(9px) saturate(190%);
  -webkit-backdrop-filter: blur(9px) saturate(190%);
  box-shadow:
    0 0 18px color-mix(in srgb, var(--accent) 38%, transparent),
    inset 0 1px 0 rgba(255, 255, 255, .55),
    inset 0 -1px 0 rgba(255, 255, 255, .18);
  transition: width .3s cubic-bezier(.25, .9, .35, 1);
}

.slider-dots {
  position: absolute;
  inset: 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 9px;
  pointer-events: none;
}
.slider-dots i {
  width: 4px; height: 4px;
  border-radius: 50%;
  background: rgba(255, 255, 255, .3);
}
html[data-theme="paper"] .slider-dots i,
html[data-theme="ink"] .slider-dots i { background: rgba(0, 0, 0, .18); }

.slider-thumb {
  position: absolute;
  top: 50%;
  left: 0;
  width: 26px; height: 30px;
  margin: -15px 0 0 -13px;
  /* 圆角玻璃块：高度透明，能透出背后内容 */
  border-radius: 9px;
  background:
    /* 斜向玻璃反光 */
    linear-gradient(150deg,
      rgba(255, 255, 255, .62) 0%,
      rgba(255, 255, 255, .14) 28%,
      rgba(255, 255, 255, .03) 50%,
      rgba(255, 255, 255, .30) 100%),
    /* 边缘折射：像玻璃棱边的彩色聚集 */
    radial-gradient(125% 125% at 50% 50%,
      transparent 52%,
      color-mix(in srgb, var(--accent) 42%, transparent) 88%,
      color-mix(in srgb, var(--accent-2) 55%, transparent) 100%),
    /* 通透本体 */
    color-mix(in srgb, var(--accent) 26%, transparent);
  backdrop-filter: blur(16px) saturate(200%) brightness(1.08);
  -webkit-backdrop-filter: blur(16px) saturate(200%) brightness(1.08);
  border: 1.5px solid rgba(255, 255, 255, .68);
  box-shadow:
    0 10px 26px rgba(0, 0, 0, .36),
    0 2px 6px rgba(0, 0, 0, .20),
    inset 0 1.5px 1px rgba(255, 255, 255, .95),
    inset 0 -2px 3px rgba(255, 255, 255, .35),
    inset 3px 0 8px rgba(255, 255, 255, .16),
    inset -3px 0 8px rgba(255, 255, 255, .16);
  transition: left .3s cubic-bezier(.25, .9, .35, 1), transform .14s ease, box-shadow .14s ease;
  will-change: left;
  cursor: grab;
  overflow: hidden;
}
/* 玻璃块内部斜向反光扫过 */
.slider-thumb::after {
  content: "";
  position: absolute;
  top: -20%; left: -60%;
  width: 55%; height: 140%;
  background: linear-gradient(100deg, transparent, rgba(255, 255, 255, .55), transparent);
  transform: rotate(12deg);
  pointer-events: none;
}
/* 玻璃块顶部高光条 */
.slider-thumb::before {
  content: "";
  position: absolute;
  left: 4px; right: 4px; top: 2.5px;
  height: 1.5px;
  border-radius: 99px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, .95), transparent);
  z-index: 1;
  pointer-events: none;
}

/* 拖动中：取消过渡，实时跟手 */
.slider.dragging .slider-fill,
.slider.dragging .slider-thumb { transition: none; }
.slider.dragging .slider-thumb {
  transform: scale(1.12);
  cursor: grabbing;
  box-shadow:
    0 14px 32px rgba(0, 0, 0, .42),
    0 3px 8px rgba(0, 0, 0, .24),
    inset 0 1.5px 1px rgba(255, 255, 255, 1),
    inset 0 -2px 3px rgba(255, 255, 255, .4),
    inset 3px 0 8px rgba(255, 255, 255, .2),
    inset -3px 0 8px rgba(255, 255, 255, .2),
    0 0 26px color-mix(in srgb, var(--accent) 55%, transparent);
}
.slider:not(.dragging):hover .slider-thumb {
  box-shadow:
    0 12px 28px rgba(0, 0, 0, .38),
    0 2px 6px rgba(0, 0, 0, .22),
    inset 0 1.5px 1px rgba(255, 255, 255, 1),
    inset 0 -2px 3px rgba(255, 255, 255, .4),
    inset 3px 0 8px rgba(255, 255, 255, .2),
    inset -3px 0 8px rgba(255, 255, 255, .2),
    0 0 16px color-mix(in srgb, var(--accent) 30%, transparent);
}

/* 禁用态（双人模式） */
.slider.disabled { opacity: .35; pointer-events: none; }

.slider-labels {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  color: var(--text-dim);
  padding: 0 2px;
}
.slider-labels span { transition: color .15s ease; }
.slider-labels span.active { color: var(--accent); font-weight: 700; }
.slider-labels span.active::before { content: "·"; }
.slider-labels span.active::after { content: "·"; }


.btn-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}

button {
  font-family: inherit;
  font-size: clamp(12px, 3.2vw, 15px);
  padding: 9px 16px;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter);
  -webkit-backdrop-filter: var(--glass-filter);
  box-shadow: var(--glass-highlight);
  color: var(--btn-text);
  font-weight: 600;
  cursor: pointer;
  transition: transform .08s ease, filter .15s ease, background .2s ease;
  /* 统一内容居中，避免 emoji 与文字基线造成的偏移 */
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  line-height: 1;
  white-space: nowrap;
  vertical-align: middle;
}
button:hover { filter: brightness(1.06); }
button:active { transform: scale(.95); }
button:disabled { opacity: .4; cursor: not-allowed; }

button.primary {
  background: linear-gradient(145deg, var(--accent), var(--accent-2));
  color: #fff;
  text-shadow: 0 1px 2px rgba(0,0,0,.35);
}

button.danger { background: var(--danger); color: #fff; }

/* ---------- 抽屉 ---------- */
.overlay {
  position: fixed; inset: 0;
  background: rgba(0, 0, 0, .35);
  z-index: 40;
  backdrop-filter: blur(6px) saturate(120%);
  -webkit-backdrop-filter: blur(6px) saturate(120%);
  animation: fade .2s ease;
}
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }

.drawer {
  position: fixed;
  top: 0; right: 0;
  height: 100%;
  height: 100dvh;
  width: min(400px, 92vw);
  background: var(--glass-bg-strong);
  border-left: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter-strong);
  -webkit-backdrop-filter: var(--glass-filter-strong);
  box-shadow: -12px 0 40px rgba(0,0,0,.45);
  z-index: 50;
  transform: translateX(105%);
  transition: transform .28s cubic-bezier(.22,.8,.3,1);
  display: flex;
  flex-direction: column;
  padding-bottom: env(safe-area-inset-bottom);
}
.drawer.open { transform: translateX(0); }

.drawer-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}
.drawer-head h2 { font-size: 17px; letter-spacing: 1px; }

.drawer-body {
  flex: 1 1 auto;
  overflow-y: auto;
  padding: 12px 16px 24px;
  -webkit-overflow-scrolling: touch;
}

.group { margin-bottom: 18px; }
.group h3 {
  font-size: 13px;
  color: var(--text-dim);
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 8px;
  padding-left: 2px;
}
.group.about p { font-size: 12px; line-height: 1.7; color: var(--text-dim); }

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 12px;
  margin-bottom: 6px;
  background: var(--glass-bg-soft);
  border: 1px solid var(--glass-border-soft);
  backdrop-filter: var(--glass-filter-soft);
  -webkit-backdrop-filter: var(--glass-filter-soft);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 14px;
}
.row > span { display: flex; flex-direction: column; gap: 2px; justify-content: center; min-width: 0; }
.row small { font-size: 11px; color: var(--text-dim); font-weight: 400; }
.row > select, .row > .switch, .row > .num-input { flex: 0 0 auto; margin-left: auto; }

select, .num-input {
  font-family: inherit;
  font-size: 14px;
  padding: 7px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--btn-bg);
  color: var(--btn-text);
  font-weight: 600;
  cursor: pointer;
  outline: none;
  height: 36px;
  line-height: 1;
}
/* 下拉框统一宽度，保证设置面板内左右对齐 */
.row > select { width: min(132px, 38vw); text-align: center; text-align-last: center; }
.num-input { width: 90px; text-align: center; }

/* 开关 */
.switch {
  appearance: none;
  -webkit-appearance: none;
  width: 46px; height: 26px;
  backdrop-filter: var(--glass-filter-soft);
  -webkit-backdrop-filter: var(--glass-filter-soft);
  background: var(--switch-off);
  border-radius: 99px;
  position: relative;
  cursor: pointer;
  transition: background .2s ease;
  flex: 0 0 auto;
  border: 1px solid var(--border);
}
.switch::after {
  content: "";
  position: absolute;
  top: 2px; left: 2px;
  width: 20px; height: 20px;
  border-radius: 50%;
  background: #fff;
  transition: transform .2s cubic-bezier(.3,1.4,.5,1);
  box-shadow: 0 1px 3px rgba(0,0,0,.4);
}
.switch:checked { background: linear-gradient(145deg, var(--accent), var(--accent-2)); }
.switch:checked::after { transform: translateX(20px); }

.btn-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 8px;
}
/* 危险操作按钮单独占满一行，避免出现半行空位显得错位 */
.btn-grid button.danger { grid-column: 1 / -1; }

/* 主题选择器 */
.theme-picker {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.theme-swatch {
  font-size: 13px;
  padding: 11px 8px;
  background: var(--glass-bg-soft);
  border: 1px solid var(--glass-border-soft);
  backdrop-filter: var(--glass-filter-soft);
  -webkit-backdrop-filter: var(--glass-filter-soft);
  color: var(--text);
  border-radius: var(--radius-sm);
  font-weight: 600;
}
.theme-swatch.active {
  background: linear-gradient(145deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 2px 10px rgba(0,0,0,.25);
}

/* 棋谱列表 */
.notation-info { font-size: 13px; color: var(--text-dim); margin-bottom: 10px; }
.notation-list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 14px;
  max-height: 52vh;
  overflow-y: auto;
}
.notation-item {
  font-size: 12px;
  padding: 4px 9px;
  border-radius: 7px;
  background: var(--glass-bg-soft);
  border: 1px solid var(--glass-border-soft);
  backdrop-filter: var(--glass-filter-soft);
  -webkit-backdrop-filter: var(--glass-filter-soft);
  font-variant-numeric: tabular-nums;
}
.notation-item.black { border-color: rgba(255,255,255,.3); }
.notation-item.white { border-color: rgba(255,255,255,.14); }
.notation-item.last { background: linear-gradient(145deg, var(--accent), var(--accent-2)); color: #fff; border-color: transparent; }

/* ---------- 结果弹窗 ---------- */
.modal {
  position: fixed; inset: 0;
  background: rgba(0,0,0,.55);
  display: grid; place-items: center;
  z-index: 60;
  padding: 20px;
  backdrop-filter: blur(3px);
}

.modal-box {
  background: var(--glass-bg-strong);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-filter-strong);
  -webkit-backdrop-filter: var(--glass-filter-strong);
  border-radius: 18px;
  padding: 28px 30px;
  text-align: center;
  box-shadow: 0 18px 50px rgba(0,0,0,.5);
  animation: pop .25s ease;
  max-width: 92vw;
}
@keyframes pop { from { transform: scale(.85); opacity: 0; } to { transform: scale(1); opacity: 1; } }

.result-title { font-size: clamp(20px, 6vw, 28px); font-weight: 800; color: var(--text); margin-bottom: 8px; }
.result-sub { font-size: 14px; color: var(--text-dim); line-height: 1.7; margin-bottom: 20px; }
.modal-actions { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.modal-actions button { background: var(--btn-bg); color: var(--btn-text); }

/* ---------- 工具类 ---------- */
.hidden { display: none !important; }

/* =========================================================
   全设备适配
   ========================================================= */

@media (min-width: 760px) {
  .app { gap: 12px; padding: 14px 20px; }
  button { padding: 10px 20px; }
}

@media (min-width: 900px) {
  .controls { gap: 10px; }
  .btn-row button { min-width: 96px; }
}

/* 中等宽度：两块并排但更紧凑 */
@media (max-width: 760px) {
  .difficulty-bar { gap: 10px; padding: 8px 12px; }
  .slider-wrap-board { flex: 1 1 0; min-width: 0; }
  .slider-labels { font-size: 9px; }
}

/* 手机竖屏：紧凑 */
@media (max-width: 480px) {
  .app { gap: 6px; padding: 6px calc(8px + env(safe-area-inset-right)) 6px calc(8px + env(safe-area-inset-left)); }
  /* 手机上两个滑块竖排，避免过窄 */
  .difficulty-bar { flex-wrap: wrap; gap: 8px; }
  .difficulty-bar .pvp-toggle { flex: 1 1 100%; }
  .slider-wrap { flex: 1 1 100%; }
  .slider-wrap-board { flex: 1 1 100%; }
  .slider-sep { display: none; }
  .topbar h1 { letter-spacing: 1px; }
  .icon-btn { width: 34px; height: 34px; font-size: 15px; }
  button { padding: 8px 12px; }
  .btn-row { gap: 6px; }
  .btn-row button { flex: 1 1 44%; }
  .drawer { width: 100vw; border-left: none; }
  .row { padding: 9px 10px; font-size: 13px; }
  select { max-width: 120px; }
}

/* 横屏（高度受限）：横向布局，棋盘占左列，控制区收窄在右 */
@media (orientation: landscape) and (max-height: 600px) {
  .app {
    display: grid;
    grid-template-columns: min(56vw, calc(100dvh - 20px)) 1fr;
    grid-template-rows: auto auto 1fr;
    grid-template-areas:
      "board top"
      "board status"
      "board controls";
    gap: 6px 10px;
    align-items: start;
  }
  .topbar { grid-area: top; }
  .topbar h1 { font-size: 15px; letter-spacing: 1px; }
  .icon-btn { width: 30px; height: 30px; font-size: 14px; }
  .statusbar { grid-area: status; flex-direction: row; align-items: center; flex-wrap: wrap; }
  .meta { flex-direction: row; }
  .pill { font-size: 10px; padding: 2px 7px; }
  .board-wrap { grid-area: board; width: 100%; height: 100%; min-height: 0; }
  .controls {
    grid-area: controls;
    align-self: stretch;
    justify-content: flex-start;
    gap: 6px;
    overflow-y: auto;
  }
  .difficulty-bar {
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
    width: 100%;
    padding: 6px 10px;
  }
  .slider-sep { display: none; }
  .slider-wrap-board { flex: 1 1 auto; min-width: 0; }
  .pvp-toggle { width: 100%; font-size: 11px; padding: 6px 4px; }
  .slider-labels { font-size: 9px; }
  .slider-head { font-size: 10px; }
  .btn-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4px;
    width: 100%;
  }
  .btn-row button { font-size: 11px; padding: 7px 4px; width: 100%; min-width: 0; }
}

/* 超小屏 */
@media (max-width: 360px) {
  .pill { font-size: 10px; padding: 2px 7px; }
  #score { display: none; }
}

@media (hover: none) {
  canvas#board { cursor: default; }
  .icon-btn:hover, button:hover { transform: none; filter: none; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* ---------- 移动端性能优化：降低模糊开销 ---------- */
@media (max-width: 640px) {
  :root {
    --glass-filter: blur(12px) saturate(150%);
    --glass-filter-soft: blur(8px) saturate(140%);
    --glass-filter-strong: blur(18px) saturate(160%);
  }
  body::before { filter: blur(34px); }
}