:root {
  color-scheme: dark;
  --bg: #0b1020;
  --fg: #eef3ff;
  --muted: #9aa8c7;
  --card: rgba(18, 26, 48, 0.78);
  --line: rgba(140, 170, 255, 0.18);
  --accent: #6ea8ff;
  --accent-2: #8b5cf6;
  --good: #34d399;
  --danger: #fb7185;
  --font: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    system-ui, sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --space: clamp(1.1rem, 3vw, 2rem);
  --max: 28rem;
  --radius: 1.25rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100dvh;
  font-family: var(--font);
  color: var(--fg);
  background: var(--bg);
  line-height: 1.55;
  letter-spacing: -0.01em;
  overflow-x: clip;
  display: flex;
  flex-direction: column;
}

a {
  color: inherit;
  text-decoration: none;
}

h1,
p {
  margin: 0;
}

button,
input {
  font: inherit;
}

.stage {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(90% 60% at 50% -10%, rgba(110, 168, 255, 0.18), transparent 55%),
    radial-gradient(70% 50% at 100% 100%, rgba(139, 92, 246, 0.16), transparent 50%),
    #070b16;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  opacity: 0.55;
}

.orb-1 {
  width: min(48vw, 26rem);
  height: min(48vw, 26rem);
  top: -8%;
  right: 4%;
  background: rgba(110, 168, 255, 0.45);
}

.orb-2 {
  width: min(40vw, 22rem);
  height: min(40vw, 22rem);
  bottom: 5%;
  left: -6%;
  background: rgba(139, 92, 246, 0.4);
}

.grain {
  position: absolute;
  inset: 0;
  opacity: 0.045;
  mix-blend-mode: soft-light;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

.top,
.shell,
.foot {
  position: relative;
  z-index: 1;
  width: min(100% - var(--space) * 2, 64rem);
  margin-inline: auto;
}

.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: var(--space);
}

.logo {
  font-weight: 700;
  letter-spacing: 0.08em;
  font-size: 0.85rem;
}

.ghost {
  color: var(--muted);
  font-size: 0.85rem;
}

.ghost:hover {
  color: var(--fg);
}

.shell {
  flex: 1;
  display: grid;
  place-items: center;
  padding-block: clamp(1rem, 4vh, 3rem) 2rem;
}

.card {
  width: min(100%, var(--max));
  padding: clamp(1.4rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 0.25rem);
  background: var(--card);
  backdrop-filter: blur(16px);
  box-shadow:
    0 20px 60px rgba(0, 0, 0, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.kicker {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

h1 {
  font-size: clamp(1.6rem, 4vw, 2rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
}

.lead {
  margin-top: 0.75rem;
  color: var(--muted);
}

.presets {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.55rem;
  margin-top: 1.5rem;
}

.chip {
  appearance: none;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.03);
  color: var(--fg);
  border-radius: 999px;
  padding: 0.65rem 0.4rem;
  cursor: pointer;
  transition:
    border-color 0.2s var(--ease),
    background 0.2s var(--ease),
    transform 0.2s var(--ease);
}

.chip:hover {
  border-color: rgba(110, 168, 255, 0.55);
  transform: translateY(-1px);
}

.chip.is-active {
  background: linear-gradient(
    135deg,
    rgba(110, 168, 255, 0.28),
    rgba(139, 92, 246, 0.22)
  );
  border-color: rgba(110, 168, 255, 0.7);
}

.form {
  margin-top: 1.1rem;
  display: grid;
  gap: 0.9rem;
}

.field {
  display: grid;
  gap: 0.45rem;
}

.label {
  font-size: 0.85rem;
  color: var(--muted);
}

.input-wrap {
  position: relative;
}

.prefix {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  pointer-events: none;
}

input[type="number"] {
  width: 100%;
  border: 1px solid var(--line);
  background: rgba(7, 11, 22, 0.55);
  color: var(--fg);
  border-radius: 0.9rem;
  padding: 0.95rem 1rem 0.95rem 2rem;
  outline: none;
  transition: border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

input[type="number"]:focus {
  border-color: rgba(110, 168, 255, 0.7);
  box-shadow: 0 0 0 3px rgba(110, 168, 255, 0.15);
}

input[type="number"].is-invalid {
  border-color: rgba(251, 113, 133, 0.7);
}

.error {
  margin: 0;
  color: var(--danger);
  font-size: 0.9rem;
}

.cta {
  appearance: none;
  border: 0;
  border-radius: 0.95rem;
  padding: 0.95rem 1.1rem;
  color: #061018;
  font-weight: 700;
  cursor: pointer;
  background: linear-gradient(135deg, #8ec5ff, #a78bfa);
  box-shadow: 0 10px 30px rgba(110, 168, 255, 0.25);
  transition:
    transform 0.2s var(--ease),
    filter 0.2s var(--ease),
    opacity 0.2s var(--ease);
}

.cta:hover:not(:disabled) {
  transform: translateY(-1px);
  filter: brightness(1.05);
}

.cta:disabled {
  opacity: 0.55;
  cursor: not-allowed;
  box-shadow: none;
}

.cta.linkish {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.note {
  margin-top: 1rem;
  color: var(--muted);
  font-size: 0.82rem;
}

.foot {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  align-items: center;
  justify-content: space-between;
  padding-block: 1rem 1.4rem;
  color: var(--muted);
  font-size: 0.82rem;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
}

.powered {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.powered img {
  display: block;
  height: 18px;
  width: auto;
  filter: brightness(1.35) grayscale(0.2);
}

.success-shell {
  place-items: center;
}

.success-card {
  text-align: center;
}

.bounce {
  animation: bounce 1.2s var(--ease) infinite;
}

.actions {
  margin-top: 1.5rem;
  display: grid;
  gap: 0.75rem;
}

.ghost-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 1rem;
  border-radius: 0.95rem;
  border: 1px solid var(--line);
  color: var(--muted);
}

.ghost-btn:hover {
  color: var(--fg);
  border-color: rgba(110, 168, 255, 0.45);
}

.burst {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.confetti {
  position: absolute;
  top: -10px;
  left: var(--x);
  width: 8px;
  height: 12px;
  border-radius: 2px;
  background: hsl(var(--h) 85% 65%);
  animation: fall var(--d) var(--ease) forwards;
  animation-delay: calc(var(--i) * 0.02s);
  opacity: 0.9;
}

@keyframes bounce {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-6px);
  }
}

@keyframes fall {
  0% {
    transform: translate3d(0, 0, 0) rotate(0deg);
    opacity: 0;
  }
  15% {
    opacity: 1;
  }
  100% {
    transform: translate3d(20px, 110vh, 0) rotate(540deg);
    opacity: 0;
  }
}

@media (max-width: 480px) {
  .presets {
    grid-template-columns: repeat(2, 1fr);
  }

  .foot {
    flex-direction: column;
    align-items: flex-start;
  }
}