:root {
  --bg: #07111f;
  --panel: #102033;
  --text: #f7fbff;
  --muted: #b8c6d8;
  --accent: #7c5cff;
  --accent-2: #36f3c8;
  --border: rgba(255,255,255,0.15);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: radial-gradient(circle at top left, #273a68 0, var(--bg) 48%, #030810 100%);
  color: var(--text);
  line-height: 1.6;
}

.container {
  width: min(980px, calc(100% - 32px));
  margin: 0 auto;
  padding: 32px 0;
}

header {
  border-bottom: 1px solid var(--border);
  background: rgba(7,17,31,0.78);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 5;
}

nav {
  width: min(980px, calc(100% - 32px));
  margin: 0 auto;
  padding: 14px 0;
  display: flex;
  gap: 18px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.logo {
  font-weight: 900;
  letter-spacing: 0.05em;
}

.nav-links { display: flex; gap: 14px; flex-wrap: wrap; }

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.hero {
  padding: 56px 0 32px;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 32px;
  align-items: center;
}

h1 {
  font-size: clamp(2.8rem, 8vw, 5.7rem);
  line-height: 0.95;
  margin: 0 0 18px;
}

h2 { margin-top: 36px; }

.tagline {
  font-size: clamp(1.2rem, 3vw, 1.7rem);
  color: var(--muted);
  margin: 0 0 24px;
}

.card {
  background: rgba(16,32,51,0.86);
  border: 1px solid var(--border);
  border-radius: 22px;
  padding: 24px;
  box-shadow: 0 20px 60px rgba(0,0,0,0.28);
}

.cube-art {
  min-height: 340px;
  position: relative;
  overflow: hidden;
  perspective: 900px;
}

.cube-art::before {
  content: "";
  position: absolute;
  inset: 28px;
  border-radius: 28px;
  background: radial-gradient(circle, rgba(54,243,200,0.18), transparent 60%);
}

.cube-board {
  position: absolute;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: 5px;
  width: 190px;
  height: 190px;
  padding: 8px;
  border: 2px solid rgba(255,255,255,0.42);
  border-radius: 16px;
  background: rgba(255,255,255,0.06);
  box-shadow: 0 18px 45px rgba(0,0,0,0.34);
  transform: rotateX(58deg) rotateZ(-24deg);
}

.cube-board span {
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 0;
  border: 1px solid rgba(255,255,255,0.24);
  border-radius: 8px;
  color: white;
  font-weight: 900;
  font-size: 1.1rem;
  background: rgba(255,255,255,0.06);
}

.cube-board span:nth-child(odd) { color: var(--accent-2); }
.cube-board span:nth-child(even) { color: #ffd166; }

.board-one { left: 34px; top: 52px; }
.board-two { right: 22px; bottom: 38px; opacity: 0.86; }

.win-line {
  position: absolute;
  left: 78px;
  top: 142px;
  width: 245px;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transform: rotate(28deg);
  box-shadow: 0 0 22px rgba(54,243,200,0.65);
}

.button {
  display: inline-block;
  padding: 12px 18px;
  border-radius: 999px;
  background: var(--accent);
  color: white;
  font-weight: 800;
  text-decoration: none;
}
.button:hover { text-decoration: none; filter: brightness(1.08); }

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

input, textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  font: inherit;
  background: #07111f;
  color: var(--text);
}

label { display: block; margin: 14px 0 6px; font-weight: 700; }

button {
  margin-top: 16px;
  border: 0;
  cursor: pointer;
  padding: 12px 18px;
  border-radius: 999px;
  background: var(--accent);
  color: white;
  font-weight: 800;
  font: inherit;
}

.notice {
  border-left: 4px solid var(--accent-2);
  padding: 12px 16px;
  background: rgba(54,243,200,0.08);
  border-radius: 10px;
}

footer {
  margin-top: 48px;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.95rem;
}

@media (max-width: 760px) {
  .hero, .grid { grid-template-columns: 1fr; }
  header { position: static; }
  .cube-art { min-height: 300px; }
  .cube-board { width: 155px; height: 155px; }
  .board-one { left: 18px; top: 48px; }
  .board-two { right: 10px; bottom: 42px; }
  .win-line { left: 62px; top: 132px; width: 190px; }
}