.btn {
  display: inline-grid;
  grid-auto-flow: column;
  align-items: center;
  gap: 12px;
  padding: 9px 20px; /* vertical | horizontal */
  border-radius: 999px; /* pill */
  border: 1px solid transparent;
  cursor: pointer;
  font:
    600 15.5px/1 "Inter",
    system-ui,
    -apple-system,
    "Segoe UI",
    Roboto,
    Arial;
  color: #ffffff;

  /* layered backgrounds: subtle frosted surface + animated conic border */
  background:
    linear-gradient(
        180deg,
        rgba(255, 255, 255, 0.03),
        rgba(255, 255, 255, 0.01)
      )
      padding-box,
    conic-gradient(from 120deg at 50% 50%, #7c3aed, #06b6d4, #8b5cf6) border-box;
  background-size: 200% 200%;
  animation: gradientShift 6s linear infinite;

  box-shadow:
    0 8px 30px rgba(2, 6, 23, 0.56),
    0 3px 10px rgba(6, 182, 212, 0.04) inset;

  position: relative;
  overflow: hidden;
  transform-origin: center;
  transform-style: preserve-3d;
  transition:
    transform 0.28s cubic-bezier(0.2, 0.9, 0.3, 1),
    box-shadow 0.28s,
    filter 0.28s;
  -webkit-tap-highlight-color: transparent;
}

/* inner frosted panel */
.btn::before {
  content: "";
  position: absolute;
  inset: 0;
  margin: 3px;
  border-radius: 996px; /* slightly smaller than outer */
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.04),
    rgba(255, 255, 255, 0.02)
  );
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.02);
  pointer-events: none;
  backdrop-filter: blur(8px) saturate(120%);
  mix-blend-mode: overlay;
}

/* moving sheen */
.btn::after {
  content: "";
  position: absolute;
  left: -45%;
  top: -30%;
  width: 65%;
  height: 160%;
  background: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0.3),
    rgba(255, 255, 255, 0.06),
    rgba(255, 255, 255, 0)
  );
  transform: rotate(-20deg) translateX(0);
  transition:
    transform 0.7s cubic-bezier(0.2, 0.9, 0.3, 1),
    opacity 0.4s;
  opacity: 0.95;
  pointer-events: none;
  filter: blur(6px);
}

/* content alignment */
.btn .content {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  z-index: 1;
}
.btn .icon {
  width: 18px;
  height: 18px;
  display: inline-block;
  flex: 0 0 18px;
  transition: transform 0.36s cubic-bezier(0.2, 0.9, 0.3, 1);
}

/* hover interactions: depth + 3D tilt */
.btn:hover {
  transform: perspective(800px) translateY(-12px) rotateX(6deg) scale(1.02);
  box-shadow:
    0 36px 80px rgba(2, 6, 23, 0.64),
    0 10px 34px rgba(6, 182, 212, 0.06) inset;
}
.btn:hover .icon {
  transform: translateX(10px) rotate(8deg);
}
.btn:hover::after {
  transform: rotate(-20deg) translateX(240%);
  opacity: 1;
}

.btn:active {
  transform: perspective(800px) translateY(-3px) rotateX(2deg) scale(0.995);
}

/* elegant focus ring */
.btn:focus {
  outline: none;
  box-shadow:
    0 0 0 6px rgba(124, 58, 237, 0.08),
    0 18px 40px rgba(2, 6, 23, 0.5);
}

/* subtle badge */
.btn .badge {
  font-size: 11px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 2px 6px rgba(2, 6, 23, 0.35);
  transform: translateZ(30px);
  z-index: 1;
}

/* disabled state */
.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* reduced motion */
@media (prefers-reduced-motion: reduce) {
  .btn {
    animation: none;
    transition: none;
  }
  .btn:hover {
    transform: none;
  }
  .btn::after {
    transition: none;
  }
  .btn .icon {
    transition: none;
  }
}

@keyframes gradientShift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

@media (max-width: 420px) {
  .btn {
    gap: 8px;
    padding: 8px 14px;
    font-size: 15px;
  }
  .btn .icon {
    width: 16px;
    height: 16px;
  }
}