/* ==========================================================================
   布局（Layout）
   ========================================================================== */

/* 顶栏 */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  height: var(--header-height);
  border-bottom: 1px solid transparent;
  transition: background-color 0.4s var(--ease-out),
    border-color 0.4s var(--ease-out),
    backdrop-filter 0.4s var(--ease-out);
}

.site-header.is-scrolled {
  background-color: rgba(5, 5, 10, 0.65);
  border-bottom-color: var(--color-border);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
}

.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
}

/* 主视觉区 */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--gradient-hero);
  overflow: hidden;
  isolation: isolate;
}

.hero__bg,
.vision__bg {
  position: absolute;
  inset: 0;
  z-index: -2;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  opacity: 0;
  will-change: opacity, transform;
}

.hero__bg.is-loaded,
.vision__bg.is-loaded {
  transition: opacity 1.2s var(--ease-out);
  opacity: 0.5; /* 与渐变叠加，保持文字可读性 */
}

.hero__canvas {
  position: absolute;
  inset: 0;
  z-index: -1;
  width: 100%;
  height: 100%;
}

.hero__content {
  max-width: 880px;
  padding-inline: 20px;
  text-align: center;
  z-index: 1;
}

.hero__scroll {
  position: absolute;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  color: var(--color-text-secondary);
  font-size: 12px;
  letter-spacing: 0.2em;
}

.hero__scroll::before {
  content: "向下探索";
  opacity: 0.85;
}

/* 章节 */
.section {
  position: relative;
  padding-block: clamp(96px, 12vh, 160px);
  background-color: var(--color-bg);
}

.section__header {
  max-width: 640px;
  margin: 0 auto clamp(48px, 7vh, 72px);
  text-align: center;
}

/* 愿景（视差）章节 */
.vision {
  position: relative;
  padding-block: clamp(140px, 26vh, 240px);
  background:
    radial-gradient(900px 500px at 50% 30%, rgba(80, 60, 180, 0.32), transparent 60%),
    linear-gradient(180deg, #05050a, #0a0d20);
  overflow: hidden;
  isolation: isolate;
}

.vision__bg.is-loaded {
  opacity: 0.4;
}

.vision__quote {
  max-width: 760px;
  margin-inline: auto;
  text-align: center;
}

/* 页脚 —— 底部半透明 */
.site-footer {
  flex-shrink: 0;
  padding-block: 24px;
  background-color: rgba(10, 10, 20, 0.55);
  border-top: 1px solid var(--color-border);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

/* 响应式 */
@media (max-width: 640px) {
  .footer__inner {
    justify-content: center;
  }
}