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

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #fff;
  background: #000;
}

/* 全屏背景视频 */
.bg-video {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  object-fit: cover;
  z-index: 0;
}

.overlay {
  position: fixed;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(0, 0, 0, 0.35) 0%,
    rgba(0, 0, 0, 0.1) 50%,
    rgba(0, 0, 0, 0.65) 100%
  );
  z-index: 1;
}

/* 主内容布局 */
.content {
  position: relative;
  z-index: 2;
  width: 100%;
  height: 100vh;
  padding: 32px 48px 64px;
}

.header {
  position: absolute;
  top: 32px;
  left: 48px;
}

.logo {
  height: 48px;
  width: auto;
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.5));
}

.hero {
  position: absolute;
  left: 50%;
  bottom: 64px;
  transform: translateX(-50%);
  width: 100%;
  max-width: 720px;
  padding: 0 48px;
  text-align: center;
}

.title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  letter-spacing: 0.04em;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.6);
  margin-bottom: 16px;
  background: linear-gradient(135deg, #fff 0%, #ffd700 50%, #ff8c00 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  line-height: 1.6;
  margin-bottom: 12px;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.7);
}

.desc {
  font-size: clamp(0.875rem, 2vw, 1rem);
  color: rgba(255, 255, 255, 0.85);
  line-height: 1.7;
  margin-bottom: 40px;
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.6);
}

/* 下载按钮 */
.download-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 18px 48px;
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  font-weight: 700;
  color: #fff;
  text-decoration: none;
  border: none;
  border-radius: 60px;
  cursor: pointer;
  overflow: hidden;
  background: linear-gradient(135deg, #ff6b00 0%, #ff9500 40%, #ffd700 100%);
  box-shadow:
    0 0 30px rgba(255, 140, 0, 0.6),
    0 8px 32px rgba(0, 0, 0, 0.4),
    inset 0 1px 0 rgba(255, 255, 255, 0.3);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  animation: pulse-glow 2.5s ease-in-out infinite;
}

.download-btn:hover {
  transform: scale(1.06);
  box-shadow:
    0 0 50px rgba(255, 180, 0, 0.8),
    0 12px 40px rgba(0, 0, 0, 0.5),
    inset 0 1px 0 rgba(255, 255, 255, 0.4);
}

.download-btn:active {
  transform: scale(0.98);
}

.download-btn.loading {
  pointer-events: none;
  opacity: 0.75;
  animation: none;
}

.download-btn.ready {
  animation: pulse-glow 2s ease-in-out infinite, bounce-subtle 3s ease-in-out infinite;
}

.btn-icon {
  display: flex;
  width: 28px;
  height: 28px;
  flex-shrink: 0;
}

.btn-icon svg {
  width: 100%;
  height: 100%;
}

.btn-shine {
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.35),
    transparent
  );
  animation: shine 3s ease-in-out infinite;
}

.download-tip {
  margin-top: 16px;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.6);
  min-height: 1.2em;
}

.download-tip.success {
  color: #7dff7d;
}

.download-tip.error {
  color: #ff6b6b;
}

/* SEO 内容区块 - 视觉隐藏但爬虫可读 */
.seo-content {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.footer {
  position: absolute;
  bottom: 16px;
  left: 0;
  right: 0;
  z-index: 2;
  text-align: center;
  font-size: 0.75rem;
  color: rgba(255, 255, 255, 0.45);
}

/* 动画 */
@keyframes pulse-glow {
  0%, 100% {
    box-shadow:
      0 0 30px rgba(255, 140, 0, 0.6),
      0 8px 32px rgba(0, 0, 0, 0.4),
      inset 0 1px 0 rgba(255, 255, 255, 0.3);
  }
  50% {
    box-shadow:
      0 0 50px rgba(255, 180, 0, 0.9),
      0 8px 32px rgba(0, 0, 0, 0.4),
      inset 0 1px 0 rgba(255, 255, 255, 0.3);
  }
}

@keyframes shine {
  0% { left: -100%; }
  50%, 100% { left: 150%; }
}

@keyframes bounce-subtle {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

/* 响应式 */
@media (max-width: 480px) {
  .content {
    padding: 20px 20px 56px;
  }

  .header {
    top: 20px;
    left: 20px;
  }

  .hero {
    bottom: 52px;
    padding: 0 20px;
  }

  .logo {
    height: 36px;
  }

  .download-btn {
    padding: 16px 36px;
  }
}