:root{
  --bg:#0b1220;
  --panel:#0f1724;
  --accent:#6ee7b7;
  --muted:#94a3b8;
}
*{box-sizing:border-box;font-family:ui-sans-serif,system-ui,Segoe UI,Roboto,"Noto Sans JP",sans-serif}
html,body{height:100%}
body{
  margin:0;
  display:flex;
  align-items:center;
  justify-content:center;
  gap:12px;
  padding:20px;
  background:linear-gradient(180deg,var(--bg),#071023);
  color:#e6eef7;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  flex-direction:column;
}
.ui{
  width:480px;
  max-width:calc(100% - 40px);
  display:flex;
  justify-content:space-between;
  align-items:center;
  margin-bottom:8px;
}
.info{display:flex;gap:12px;font-weight:600}
.controls{display:flex;flex-direction:column;align-items:flex-end;gap:4px}
#startBtn{
  background:var(--panel);
  border:1px solid rgba(255,255,255,0.06);
  color:var(--accent);
  padding:6px 10px;
  border-radius:8px;
  cursor:pointer;
}
#startBtn:hover{transform:translateY(-1px)}
canvas{
  width:100%;
  max-width:480px;
  height:auto;
  border-radius:10px;
  box-shadow:0 10px 30px rgba(2,6,23,0.7), inset 0 1px 0 rgba(255,255,255,0.02);
  background:linear-gradient(180deg,#021027 0%, #031228 40%, #071022 100%);
  display:block;
}
small{color:var(--muted)}