* { margin: 0; padding: 0; box-sizing: border-box; }

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  overflow: hidden;
}

body {
  background: #050810;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

/* ---- 动态背景 ---- */
.bg {
  position: fixed;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(ellipse 80% 60% at 20% 10%, rgba(56, 120, 255, 0.35), transparent 60%),
    radial-gradient(ellipse 70% 55% at 85% 25%, rgba(140, 60, 255, 0.30), transparent 60%),
    radial-gradient(ellipse 60% 50% at 50% 90%, rgba(0, 200, 255, 0.22), transparent 60%),
    #050810;
}
.orb {
  position: fixed;
  border-radius: 50%;
  filter: blur(90px);
  z-index: 0;
  opacity: .55;
  animation: float 14s ease-in-out infinite;
}
.orb-1 { width: 420px; height: 420px; background: #2f6bff; top: -80px; left: -60px; }
.orb-2 { width: 360px; height: 360px; background: #8b3dff; top: 15%; right: -80px; animation-delay: -4s; }
.orb-3 { width: 300px; height: 300px; background: #00c2ff; bottom: -100px; left: 35%; animation-delay: -8s; }
@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(40px, -30px) scale(1.08); }
}

/* ---- 液态玻璃通用 ---- */
.glass {
  background: linear-gradient(135deg, rgba(255,255,255,0.14), rgba(255,255,255,0.05));
  backdrop-filter: blur(24px) saturate(160%);
  -webkit-backdrop-filter: blur(24px) saturate(160%);
  border: 1px solid rgba(255,255,255,0.22);
  box-shadow:
    0 8px 32px rgba(0,0,0,0.35),
    inset 0 1px 0 rgba(255,255,255,0.28),
    inset 0 -1px 0 rgba(255,255,255,0.06);
  border-radius: 24px;
  position: relative;
  overflow: hidden;
}
.glass::before {
  content: "";
  position: absolute;
  top: 0; left: -60%;
  width: 50%; height: 100%;
  background: linear-gradient(105deg, transparent, rgba(255,255,255,0.18), transparent);
  transform: skewX(-20deg);
  animation: sheen 7s ease-in-out infinite;
  pointer-events: none;
}
@keyframes sheen {
  0%, 70% { left: -60%; }
  100% { left: 130%; }
}

/* ---- 主页内容 ---- */
.hero {
  position: relative;
  z-index: 2;
  text-align: center;
  padding: 72px 90px;
  max-width: 720px;
  margin: 0 20px;
}
.hero h1 {
  font-size: clamp(56px, 10vw, 96px);
  font-weight: 800;
  letter-spacing: -2px;
  background: linear-gradient(120deg, #ffffff 20%, #9fc4ff 50%, #c9a6ff 80%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: 0 0 60px rgba(120,160,255,0.25);
  margin-bottom: 14px;
}
.hero p {
  color: rgba(255,255,255,0.65);
  font-size: 18px;
  letter-spacing: 2px;
  margin-bottom: 48px;
}

.btn-row {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  position: relative;
  padding: 16px 52px;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 1px;
  color: #fff;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.25);
  background: linear-gradient(135deg, rgba(255,255,255,0.16), rgba(255,255,255,0.05));
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  box-shadow:
    0 6px 24px rgba(0,0,0,0.3),
    inset 0 1px 0 rgba(255,255,255,0.3);
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease, background .25s ease;
  overflow: hidden;
}
.btn::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle at 30% 20%, rgba(255,255,255,0.25), transparent 55%);
  opacity: 0;
  transition: opacity .25s ease;
  pointer-events: none;
}
.btn:not(.disabled):hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 36px rgba(80,140,255,0.35), inset 0 1px 0 rgba(255,255,255,0.35);
  background: linear-gradient(135deg, rgba(255,255,255,0.24), rgba(255,255,255,0.09));
}
.btn:not(.disabled):hover::after { opacity: 1; }
.btn:not(.disabled):active { transform: translateY(-1px) scale(.98); }

.btn.disabled {
  cursor: not-allowed;
  opacity: .38;
  filter: grayscale(.6);
}

/* ---- 下载弹窗 ---- */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 10;
  background: rgba(5, 8, 16, 0.45);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s ease;
}
.modal-overlay.show {
  opacity: 1;
  pointer-events: auto;
}
.modal {
  width: min(420px, 88vw);
  padding: 40px 36px 32px;
  border-radius: 28px;
  transform: translateY(24px) scale(.95);
  transition: transform .35s cubic-bezier(.2, .9, .3, 1.2);
}
.modal-overlay.show .modal {
  transform: translateY(0) scale(1);
}
.modal h2 {
  color: #fff;
  font-size: 24px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 8px;
}
.modal .sub {
  color: rgba(255,255,255,0.55);
  font-size: 14px;
  text-align: center;
  margin-bottom: 30px;
}
.dl-option {
  display: flex;
  align-items: center;
  gap: 16px;
  width: 100%;
  padding: 18px 22px;
  margin-bottom: 16px;
  border-radius: 18px;
  border: 1px solid rgba(255,255,255,0.18);
  background: linear-gradient(135deg, rgba(255,255,255,0.12), rgba(255,255,255,0.04));
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.22);
}
.dl-option:hover {
  transform: translateY(-2px);
  background: linear-gradient(135deg, rgba(255,255,255,0.22), rgba(255,255,255,0.08));
  box-shadow: 0 8px 24px rgba(80,140,255,0.3), inset 0 1px 0 rgba(255,255,255,0.3);
}
.dl-option svg {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}
.dl-option small {
  display: block;
  font-weight: 400;
  font-size: 12px;
  color: rgba(255,255,255,0.5);
  margin-top: 2px;
}
.modal-close {
  position: absolute;
  top: 14px;
  right: 14px;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,0.18);
  background: rgba(255,255,255,0.08);
  color: rgba(255,255,255,0.8);
  font-size: 16px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background .2s ease;
  z-index: 2;
}
.modal-close:hover { background: rgba(255,255,255,0.18); }

/* ---- 弹窗步骤切换 ---- */
.modal-step {
  animation: stepIn .3s ease;
}
.modal-step.hidden { display: none; }
@keyframes stepIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
.modal-back {
  position: absolute;
  top: 16px;
  left: 16px;
  border: none;
  background: transparent;
  color: rgba(255,255,255,0.6);
  font-size: 14px;
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 10px;
  transition: background .2s ease, color .2s ease;
  z-index: 2;
}
.modal-back:hover { background: rgba(255,255,255,0.1); color: #fff; }
button.dl-option { font-family: inherit; text-align: left; }

@media (max-width: 560px) {
  .hero { padding: 56px 32px; }
  .btn { padding: 14px 40px; width: 100%; }
}