* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(circle at 20% 10%, rgba(91, 176, 255, 0.24), transparent 28%),
    radial-gradient(circle at 80% 16%, rgba(255, 203, 94, 0.24), transparent 24%),
    linear-gradient(135deg, #1d2433 0%, #1f1b2e 46%, #17302d 100%);
  color: #f7f1d5;
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", sans-serif;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px;
  overflow-x: hidden;
  text-rendering: geometricPrecision;
}

.shell {
  width: min(100%, 1040px);
  position: relative;
}

.shell::before {
  content: "";
  position: absolute;
  inset: -18px 8px auto;
  height: 120px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(121, 212, 255, 0.16), rgba(255, 209, 102, 0.18), rgba(199, 125, 255, 0.14));
  filter: blur(30px);
  pointer-events: none;
  z-index: -1;
}

#gameCanvas {
  display: block;
  width: 100%;
  max-width: 1000px;
  height: auto;
  margin: 0 auto;
  background: #151923;
  border: 1px solid rgba(255, 232, 163, 0.8);
  border-radius: 12px;
  box-shadow:
    0 0 34px rgba(121, 212, 255, 0.08),
    0 0 52px rgba(240, 201, 106, 0.14),
    0 26px 70px rgba(0, 0, 0, 0.52),
    0 0 0 6px rgba(14, 18, 28, 0.85),
    0 0 0 8px rgba(240, 201, 106, 0.62),
    inset 0 0 0 1px rgba(255, 255, 255, 0.16);
  image-rendering: auto;
  cursor: crosshair;
}

.manual {
  max-width: 1000px;
  margin: 12px auto 0;
  padding: 12px 14px;
  border: 2px solid rgba(240, 201, 106, 0.7);
  background: linear-gradient(180deg, rgba(22, 30, 46, 0.88), rgba(12, 17, 27, 0.82));
  border-radius: 8px;
  line-height: 1.7;
  font-size: 14px;
  box-shadow:
    0 12px 30px rgba(0, 0, 0, 0.28),
    inset 0 1px 0 rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(8px);
}