:root {
  --font: "Be Vietnam Pro", Arial, sans-serif;
  --title: "Baloo 2", "Be Vietnam Pro", sans-serif;
  --cyan: #4de8ff;
  --pink: #ff4fa3;
  /* đấu trường vuông, vừa cả chiều ngang lẫn chiều cao màn hình */
  --size: min(600px, 94vw, max(260px, calc(100vh - 200px)));
}
* {
  box-sizing: border-box;
}
[hidden] {
  display: none !important;
}
html,
body {
  margin: 0;
}
body {
  min-height: 100vh;
  overflow-x: hidden;
  background: radial-gradient(ellipse at 50% 0%, #1b2257, #0b0f2a 55%, #05060f);
  color: #e6ecff;
  font-family: var(--font);
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}
button {
  font-family: var(--font);
  color: inherit;
  cursor: pointer;
}
kbd {
  padding: 0 5px;
  border: 1px solid rgba(160, 185, 255, 0.35);
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.06);
  font: 700 11px var(--font);
}
.back {
  position: fixed;
  top: 12px;
  left: 14px;
  z-index: 5;
  color: #9fb0e0;
  font-weight: 700;
  font-size: 13px;
  text-decoration: none;
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 10px 8px 14px;
}

/* ---------- Chỉ số ---------- */
.stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}
.stat {
  min-width: 84px;
  padding: 5px 12px 3px;
  border: 1px solid rgba(120, 150, 255, 0.25);
  border-radius: 12px;
  background: rgba(25, 32, 80, 0.75);
  text-align: center;
}
.stat small {
  display: block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: #8f9fd6;
}
.stat b {
  display: block;
  font: 800 26px/1.15 var(--title);
}
#stTime {
  color: var(--cyan);
}
#stScore {
  color: #ffd23f;
}
#stBest {
  color: #52e3a4;
}
.stat b.lives {
  min-width: 60px;
  color: #ff5470;
  font-size: 20px;
  line-height: 1.6;
  letter-spacing: 1px;
}
.lives s {
  color: rgba(255, 255, 255, 0.18);
  text-decoration: none;
}
.bump {
  animation: bump 0.3s ease;
}
@keyframes bump {
  40% {
    transform: scale(1.25);
  }
}

/* ---------- Đấu trường ---------- */
.arena-wrap {
  position: relative;
  width: var(--size);
  height: var(--size);
  border-radius: 18px;
  box-shadow:
    0 0 0 1px rgba(110, 140, 255, 0.35),
    0 0 40px rgba(77, 232, 255, 0.15),
    0 20px 50px rgba(0, 0, 0, 0.5);
  overflow: hidden;
}
canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

/* ---------- Nút ---------- */
.tools {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}
.tool {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 42px;
  padding: 0 14px;
  border: 1px solid rgba(120, 150, 255, 0.28);
  border-radius: 12px;
  background: rgba(30, 40, 95, 0.8);
  font-weight: 700;
  font-size: 14px;
}
.tool:hover {
  background: rgba(45, 60, 130, 0.9);
}
.tool.dash {
  position: relative;
  overflow: hidden;
  border-color: var(--cyan);
  color: var(--cyan);
}
/* thanh hồi lướt chạy ngang nút */
.tool.dash::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: var(--cd, 100%);
  background: var(--cyan);
}
.tool.dash.cooling {
  opacity: 0.55;
}
.keys {
  margin: 0;
  font-size: 12px;
  color: #8f9fd6;
  text-align: center;
}
@media (hover: none) {
  .keys {
    display: none;
  }
}

/* ---------- Hộp thoại ---------- */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  padding: 16px;
  background: rgba(3, 6, 20, 0.55);
  backdrop-filter: blur(5px);
  -webkit-backdrop-filter: blur(5px);
}
.card {
  width: min(460px, 100%);
  max-height: calc(100vh - 32px);
  overflow: auto;
  padding: 18px 22px;
  border: 1px solid rgba(120, 150, 255, 0.3);
  border-radius: 20px;
  background: linear-gradient(180deg, #1a2160, #10143a);
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.55);
  text-align: center;
  animation: cardIn 0.3s cubic-bezier(0.3, 1.5, 0.5, 1);
}
@keyframes cardIn {
  from {
    transform: scale(0.85);
    opacity: 0;
  }
}
.ico {
  font-size: 40px;
  line-height: 1;
}
.card h2 {
  margin: 4px 0 10px;
  font: 800 30px/1.1 var(--title);
  color: var(--cyan);
  text-shadow: 0 0 18px rgba(77, 232, 255, 0.45);
}
.card p {
  margin: 0 0 14px;
  color: #c9d3f5;
  line-height: 1.55;
}
.seg {
  display: flex;
  gap: 4px;
  margin-bottom: 12px;
  padding: 4px;
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.3);
}
.seg button {
  flex: 1;
  padding: 6px 4px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  font-weight: 800;
  font-size: 15px;
  color: #aab6e8;
}
.seg button small {
  display: block;
  font-size: 11px;
  font-weight: 600;
  opacity: 0.8;
}
.seg button.on {
  background: rgba(77, 232, 255, 0.16);
  color: var(--cyan);
  box-shadow: inset 0 0 0 1px rgba(77, 232, 255, 0.5);
}
.legend {
  margin: 0 0 10px;
  padding: 0;
  list-style: none;
  text-align: left;
}
.legend li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 4px 6px;
  border-bottom: 1px dashed rgba(120, 150, 255, 0.2);
  font-size: 13.5px;
  color: #d5ddff;
}
.legend li > span {
  flex: none;
  width: 30px;
  font-size: 20px;
  text-align: center;
}
.legend li em {
  margin-left: auto;
  font-style: normal;
  font-size: 12px;
  color: #8f9fd6;
  white-space: nowrap;
}
.legend .laser {
  display: inline-block;
  width: 26px;
  height: 4px;
  border-radius: 2px;
  background: #ff3b5c;
  box-shadow: 0 0 8px #ff3b5c;
  vertical-align: middle;
}
.legend .meteor {
  display: inline-block;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, #ffd08a, #ff7a2f 55%, #b8360f);
  box-shadow: 0 0 8px #ff7a2f;
  vertical-align: middle;
}
.card p.tip {
  font-size: 12.5px;
  color: #aab6e8;
}
.btns {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}
.btn {
  min-width: 110px;
  height: 46px;
  padding: 0 18px;
  border: 1px solid rgba(120, 150, 255, 0.35);
  border-radius: 14px;
  background: rgba(40, 52, 120, 0.9);
  font-weight: 800;
  font-size: 16px;
}
.btn.primary {
  border-color: var(--cyan);
  background: linear-gradient(#5cf0ff, #18b7d8);
  color: #062a35;
  box-shadow: 0 0 20px rgba(77, 232, 255, 0.35);
}
.final {
  font: 800 60px/1 var(--title);
  color: #ffd23f;
}
.final-sub {
  margin-top: 2px;
  font-size: 13px;
  font-weight: 700;
  color: #8f9fd6;
}
.results {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin: 12px 0 16px;
}
.results div {
  padding: 7px 6px;
  border-radius: 12px;
  background: rgba(0, 0, 0, 0.25);
}
.results small {
  display: block;
  font-size: 12px;
  font-weight: 700;
  color: #8f9fd6;
}
.results b {
  font: 800 22px/1.2 var(--title);
}

@media (max-width: 520px) {
  :root {
    --size: min(600px, 96vw, max(260px, calc(100vh - 210px)));
  }
  .back {
    position: static;
    align-self: flex-start;
  }
  .stats {
    gap: 6px;
  }
  .stat {
    min-width: 0;
    padding: 4px 9px 2px;
  }
  .stat small {
    font-size: 9px;
  }
  .stat b {
    font-size: 21px;
  }
  .stat b.lives {
    font-size: 16px;
  }
  .tool {
    padding: 0 10px;
    font-size: 13px;
  }
}