* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #0f0c29, #302b63, #24243e);
  color: #fff;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
.container { max-width: 960px; padding: 40px 20px; text-align: center; }
header h1 { font-size: 2.4rem; margin-bottom: 8px; }
header p { color: #b7b0d9; margin-bottom: 40px; }
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}
.demo {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  padding: 30px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}
.demo h2 { font-size: 0.95rem; font-weight: 500; color: #b7b0d9; }
.btn {
  position: relative;
  overflow: hidden;
  border: 2px solid #6c63ff;
  background: transparent;
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  padding: 14px 34px;
  border-radius: 8px;
  cursor: pointer;
  transition: color 0.3s ease, border-color 0.3s ease, letter-spacing 0.3s ease;
  z-index: 1;
}
/* Slide fill */
.btn.slide-fill::before {
  content: "";
  position: absolute;
  inset: 0;
  background: #6c63ff;
  transform: translateX(-101%);
  transition: transform 0.4s ease;
  z-index: -1;
}
.btn.slide-fill:hover::before { transform: translateX(0); }
/* Ripple */
.btn.ripple { background: #ff6584; border-color: #ff6584; }
.btn.ripple::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 8px;
  border: 2px solid #ff6584;
  opacity: 0;
  animation: ripple 0.8s ease-out infinite;
}
.btn.ripple:hover::after { animation: ripple 0.8s ease-out infinite; }
@keyframes ripple {
  from { transform: scale(0.8); opacity: 1; }
  to { transform: scale(1.4); opacity: 0; }
}
/* Glow */
.btn.glow { border-color: #00d4ff; }
.btn.glow:hover {
  box-shadow: 0 0 20px #00d4ff, 0 0 40px rgba(0, 212, 255, 0.5);
  border-color: #00d4ff;
  background: rgba(0, 212, 255, 0.1);
}
/* Border grow */
.btn.border-grow::before {
  content: "";
  position: absolute;
  top: -2px; left: -2px; right: -2px; bottom: -2px;
  border: 2px solid #38d39f;
  border-radius: 8px;
  transform: scale(0.6);
  opacity: 0;
  transition: transform 0.35s ease, opacity 0.35s ease;
}
.btn.border-grow:hover::before { transform: scale(1); opacity: 1; }
/* Letter spacing */
.btn.letter-spacing:hover { letter-spacing: 4px; border-color: #ffb347; color: #ffb347; }
/* Swap */
.btn.swap { padding: 0; border: none; background: #6c63ff; height: 52px; width: 170px; overflow: hidden; }
.btn.swap span {
  display: block;
  line-height: 52px;
  transition: transform 0.35s ease;
}
.btn.swap .swap-bottom { transform: translateY(100%); }
.btn.swap:hover .swap-top { transform: translateY(-100%); }
.btn.swap:hover .swap-bottom { transform: translateY(0); }
@media (max-width: 600px) {
  header h1 { font-size: 1.8rem; }
}