*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{
  margin:0;height:100%;overflow:hidden;
  background:#000;color:#fff;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}
#c{position:fixed;inset:0;display:block;z-index:1}

body::after{
  content:'';position:fixed;inset:0;pointer-events:none;z-index:2;
  background:radial-gradient(ellipse 78% 68% at 50% 50%,
    transparent 38%, rgba(0,0,0,.5) 82%, rgba(0,0,0,.85) 100%);
}

/* ================= 顶部 HUD ================= */
#hud{
  position:fixed;left:clamp(16px,3.2vw,40px);top:clamp(14px,2.6vh,32px);
  z-index:4;pointer-events:none;user-select:none;
}
#bpmRow{display:flex;align-items:baseline;gap:8px}
#bpmVal{
  font-family:ui-monospace,"SF Mono","JetBrains Mono",Menlo,Consolas,monospace;
  font-size:clamp(44px,10vw,86px);
  font-weight:200;line-height:.9;letter-spacing:-.05em;
  color:#fff;
  font-variant-numeric:tabular-nums;
  transform-origin:left center;will-change:transform;
  text-shadow:0 0 22px rgba(255,255,255,.55), 0 0 60px rgba(255,255,255,.22);
}
#bpmUnit{
  font-family:ui-monospace,"SF Mono",Menlo,monospace;
  font-size:clamp(10px,1.5vw,13px);
  letter-spacing:.36em;color:#8a8a8a;
}
#bpmSub{
  margin-top:9px;
  font-family:ui-monospace,"SF Mono",Menlo,monospace;
  font-size:10px;letter-spacing:.26em;
  color:#4a4a4a;text-transform:uppercase;
}
#bpmSub b{color:#c8c8c8;font-weight:500}

/* ================= 关于按钮 ================= */
#aboutBtn{
  position:fixed;right:clamp(16px,3.2vw,40px);top:clamp(14px,2.6vh,32px);
  z-index:6;
  padding:9px 18px;
  border-radius:100px;
  border:1px solid rgba(255,255,255,.22);
  background:rgba(255,255,255,.04);
  color:#d8d8d8;
  font-size:12px;letter-spacing:.16em;font-weight:500;
  cursor:pointer;transition:.22s;
  backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);
  font-family:inherit;
}
#aboutBtn:hover{background:rgba(255,255,255,.12);border-color:rgba(255,255,255,.45);color:#fff}
#aboutBtn:active{transform:scale(.96)}

/* ================= 关于面板 ================= */
#aboutPanel{
  position:fixed;inset:0;z-index:20;
  display:flex;align-items:center;justify-content:center;
  padding:20px;
  background:rgba(0,0,0,.86);
  backdrop-filter:blur(22px);-webkit-backdrop-filter:blur(22px);
  opacity:0;pointer-events:none;
  transition:opacity .3s ease;
}
#aboutPanel.show{opacity:1;pointer-events:auto}

.aboutCard{
  position:relative;
  width:min(600px,100%);
  max-height:82vh;overflow-y:auto;
  padding:clamp(24px,4vw,38px);
  background:#0a0a0a;
  border:1px solid rgba(255,255,255,.14);
  border-radius:22px;
  transform:translateY(16px) scale(.98);
  transition:transform .34s cubic-bezier(.22,1,.36,1);
  box-shadow:0 30px 90px rgba(0,0,0,.9);
}
#aboutPanel.show .aboutCard{transform:translateY(0) scale(1)}
.aboutCard::-webkit-scrollbar{width:5px}
.aboutCard::-webkit-scrollbar-thumb{background:rgba(255,255,255,.18);border-radius:4px}

.aboutClose{
  position:absolute;right:16px;top:16px;
  width:34px;height:34px;border-radius:50%;
  border:1px solid rgba(255,255,255,.16);
  background:transparent;color:#999;
  font-size:15px;line-height:1;cursor:pointer;
  transition:.2s;font-family:inherit;
}
.aboutClose:hover{background:rgba(255,255,255,.1);color:#fff;border-color:rgba(255,255,255,.4)}

.aboutTitle{
  font-size:23px;font-weight:600;letter-spacing:.01em;color:#fff;
}
.aboutSub{
  margin-top:7px;font-size:11px;letter-spacing:.22em;
  color:#555;text-transform:uppercase;
  font-family:ui-monospace,"SF Mono",Menlo,monospace;
}

.aboutSection{margin-top:28px}
.aboutSection h3{
  margin:0 0 11px;font-size:11px;letter-spacing:.24em;
  color:#7a7a7a;text-transform:uppercase;font-weight:600;
  font-family:ui-monospace,"SF Mono",Menlo,monospace;
}
.aboutSection p{
  margin:0;font-size:13.5px;line-height:1.8;color:#a4a4a4;
}
.aboutSection p.note{
  font-size:12px;color:#6e6e6e;margin-bottom:16px;line-height:1.7;
}
.aboutSection p b{color:#e8e8e8;font-weight:600}

/* 设备分组 */
.devGrid{
  display:grid;
  grid-template-columns:repeat(auto-fill,minmax(158px,1fr));
  gap:10px;
}
.devGroup{
  padding:13px 15px 14px;
  border:1px solid rgba(255,255,255,.09);
  border-radius:12px;
  background:rgba(255,255,255,.018);
  transition:.2s;
}
.devGroup:hover{background:rgba(255,255,255,.05);border-color:rgba(255,255,255,.2)}
.devGroup h4{
  margin:0 0 8px;font-size:12px;font-weight:600;
  color:#efefef;letter-spacing:.04em;
  display:flex;align-items:center;gap:7px;
}
.devGroup h4::before{
  content:'';width:5px;height:5px;border-radius:50%;
  background:#fff;flex:0 0 auto;
  box-shadow:0 0 8px rgba(255,255,255,.9);
}
.devGroup ul{margin:0;padding:0;list-style:none}
.devGroup li{
  font-size:11.5px;line-height:1.85;color:#8e8e8e;
  padding-left:12px;position:relative;
}
.devGroup li::before{
  content:'·';position:absolute;left:2px;color:#4a4a4a;
}
.devGroup.hw{border-color:rgba(255,255,255,.26);background:rgba(255,255,255,.045)}

/* ================= 底部面板 ================= */
#panel{
  position:fixed;left:50%;bottom:max(16px,env(safe-area-inset-bottom));
  transform:translateX(-50%);
  width:min(440px,calc(100vw - 26px));
  padding:13px 16px 11px;
  background:rgba(10,10,10,.72);
  border:1px solid rgba(255,255,255,.11);
  border-radius:18px;
  backdrop-filter:blur(20px) saturate(1.2);
  -webkit-backdrop-filter:blur(20px) saturate(1.2);
  box-shadow:0 18px 50px rgba(0,0,0,.7);
  z-index:4;
}
#btnConnect{
  width:100%;padding:11px 14px;
  border-radius:11px;
  border:1px solid rgba(255,255,255,.26);
  background:rgba(255,255,255,.05);
  color:#e8e8e8;font-size:13.5px;font-weight:600;letter-spacing:.05em;
  cursor:pointer;transition:.2s;font-family:inherit;
}
#btnConnect:hover{background:rgba(255,255,255,.14);border-color:rgba(255,255,255,.5);color:#fff}
#btnConnect:active{transform:scale(.985)}
#btnConnect[data-on="1"]{
  background:rgba(255,255,255,.9);
  border-color:#fff;color:#000;
}
#btnConnect[data-on="1"]:hover{background:#fff}
#btnConnect:disabled{opacity:.3;cursor:not-allowed}

.row{display:flex;align-items:center;gap:12px;margin-top:12px;font-size:12px;color:#6e6e6e}
.row .lbl{flex:0 0 auto;letter-spacing:.1em}
input[type=range]{
  -webkit-appearance:none;appearance:none;
  flex:1 1 auto;height:2px;border-radius:2px;outline:none;cursor:pointer;
  background:linear-gradient(90deg,#3a3a3a,#fff);
}
input[type=range]::-webkit-slider-thumb{
  -webkit-appearance:none;width:14px;height:14px;border-radius:50%;
  background:#fff;border:none;
  box-shadow:0 0 0 3px rgba(255,255,255,.12),0 0 14px rgba(255,255,255,.7);
}
input[type=range]::-moz-range-thumb{
  width:14px;height:14px;border-radius:50%;border:none;background:#fff;
  box-shadow:0 0 0 3px rgba(255,255,255,.12),0 0 14px rgba(255,255,255,.7);
}
input[type=range]:disabled{opacity:.24;cursor:not-allowed}
#speedVal{
  flex:0 0 auto;min-width:76px;text-align:right;
  font-family:ui-monospace,"SF Mono",Menlo,monospace;
  font-size:11.5px;color:#9a9a9a;font-variant-numeric:tabular-nums;
}
#status{
  margin-top:10px;font-size:11px;line-height:1.5;
  color:#4d4d4d;text-align:center;letter-spacing:.03em;
}
#status.warn{color:#d8b070}
#status.ok{color:#e0e0e0}