/* ===== GPT-6 Astra 星空螺旋动效 demo ===== */

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

html,
body {
  background: #04060b;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Inter",
    "Helvetica Neue", "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* ---------- Hero 容器 ---------- */
.astra-hero {
  position: fixed; /* 钉在视口：滚动只驱动相机，页面内容不移动 */
  inset: 0;
  width: 100%;
  height: 100vh;
  height: 100dvh; /* 动态视口：跟随手机地址栏收起/展开，避免内容超出可视区 */
  overflow: hidden;
  /* 深空底色：中心近黑 → 外围深蓝（与画布内背景一致） */
  background: radial-gradient(
    ellipse 90% 70% at 50% 55%,
    #010204 0%,
    #030408 30%,
    #071020 65%,
    #0b1728 100%
  );
}

.astra-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* 滚动行程占位：0~1 相机俯仰，1~2 星星分裂到两侧（实际滚动距离 = 450vh - 100vh = 350vh） */
.scroll-space {
  height: 450vh;
}

/* ---------- 两侧大字 ---------- */
.astra-word {
  position: absolute;
  top: 56%; /* 与 6 的螺旋中心大致同高 */
  transform: translateY(-50%);
  z-index: 2;
  color: #f5f7fa;
  font-weight: 300;
  font-size: clamp(30px, 6.5vw, 96px);
  letter-spacing: 0.01em;
  line-height: 1;
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  text-shadow: 0 0 24px rgba(180, 205, 255, 0.18);
  opacity: 0;
  animation: astra-word-in 2.2s cubic-bezier(0.22, 0.61, 0.21, 1) 0.9s forwards;
}

.astra-word--left {
  left: 7%;
}

.astra-word--right {
  right: 7%;
}

@keyframes astra-word-in {
  from {
    opacity: 0;
    filter: blur(6px);
  }
  to {
    opacity: 1;
    filter: blur(0);
  }
}

/* 窄屏（手机竖屏/卡片预览）：文字改为上下布局，水平居中，围绕 6 平衡排布 */
@media (max-width: 760px) {
  .astra-word {
    font-size: clamp(20px, 6vw, 36px);
    top: auto;
    left: 50%;
    right: auto;
    transform: translateX(-50%);
  }
  .astra-word--left {
    top: 13%;
  }
  .astra-word--right {
    top: auto;
    bottom: 11%;
  }
}

/* ---------- 重播按钮 ---------- */
.astra-replay {
  position: absolute;
  right: calc(22px + env(safe-area-inset-right, 0px));
  bottom: calc(22px + env(safe-area-inset-bottom, 0px));
  z-index: 3;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.14);
  background: rgba(255, 255, 255, 0.06);
  color: rgba(255, 255, 255, 0.75);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(6px);
  transition: background 0.25s ease, transform 0.25s ease, color 0.25s ease;
}

.astra-replay:hover {
  background: rgba(255, 255, 255, 0.14);
  color: #fff;
  transform: rotate(-40deg);
}

.astra-replay:active {
  transform: rotate(-40deg) scale(0.92);
}