*,
*::before,
*::after {
  box-sizing: border-box;
}
:root {
  --bg: #0c1016;
  --surface: #fbfcfe;
  --accent: #b7780f;
  --accent-soft: rgba(183, 120, 15, 0.12);
  --text: #1a2733;
  --muted: #52657a;
  --border: rgba(26, 39, 51, 0.1);
  --thumb-slot: #e8eef5;
}
html {
  font-family: "Segoe UI", "Microsoft JhengHei", sans-serif;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
  min-height: 100%;
}
body {
  margin: 0;
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem 1.25rem 3rem;
  background:
    radial-gradient(ellipse 80% 50% at 50% -18%, rgba(232, 180, 76, 0.09), transparent),
    var(--bg);
}
.neuron-bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  display: block;
}
.card {
  position: relative;
  z-index: 1;
  width: 80%;
  max-width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 1rem;
  padding: clamp(1.75rem, 5vw, 2.25rem);
  box-shadow:
    0 4px 6px rgba(0, 0, 0, 0.15),
    0 22px 50px rgba(0, 0, 0, 0.45);
}
h1 {
  font-size: clamp(1.35rem, 4vw, 1.65rem);
  font-weight: 600;
  text-align: center;
  letter-spacing: 0.02em;
  margin: 0 0 0.5rem;
  line-height: 1.35;
}
.subtitle {
  text-align: center;
  color: var(--muted);
  font-size: 0.925rem;
  margin: 0 0 1.75rem;
}
.actions {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.875rem;
  align-items: stretch;
}
.demo-card {
  display: flex;
  flex-direction: column;
  text-align: center;
  text-decoration: none;
  color: var(--text);
  border-radius: 0.5rem;
  overflow: hidden;
  background: var(--accent-soft);
  border: 1px solid var(--border);
  transition:
    background 0.15s ease,
    border-color 0.15s ease,
    transform 0.15s ease,
    box-shadow 0.15s ease;
}
.demo-card:hover {
  background: rgba(183, 120, 15, 0.16);
  border-color: rgba(183, 120, 15, 0.35);
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(26, 39, 51, 0.12);
}
.demo-card:active {
  transform: translateY(0);
}
.demo-card-thumb-wrap {
  aspect-ratio: 16 / 9;
  width: 100%;
  background: var(--thumb-slot);
}
.demo-card-thumb {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}
.demo-card-label {
  display: block;
  font-weight: 500;
  padding: 0.75rem 1rem 0.85rem;
}

.notice {
  margin-top: 1.75rem;
  padding-top: 1.25rem;
  border-top: 1px solid rgba(26, 39, 51, 0.1);
  font-size: 0.8125rem;
  color: var(--muted);
  text-align: center;
  line-height: 1.55;
}

@media (max-width: 520px) {
  .actions {
    gap: 0.5rem;
  }
  .demo-card-label {
    padding: 0.55rem 0.4rem 0.65rem;
    font-size: 0.875rem;
  }
}