/* 全站固定导航、飘带与星轨背景效果。 */

/* 手机端保留星轨构图；不启动 SVG 变形与流动描边动画。 */
.songline-starstream-layer.is-static-starstream :is(.starstream-morph-group,.starstream-path){
  animation:none!important;
  filter:none!important;
  will-change:auto!important;
}
.songline-space-ribbon{
  filter:drop-shadow(0 0 14px rgba(125,211,252,.32)) drop-shadow(0 0 28px rgba(168,85,247,.12))!important;
}
.songline-space-ribbon.is-ribbon{
  filter:blur(.08px) drop-shadow(0 0 20px rgba(125,211,252,.34)) drop-shadow(0 0 36px rgba(168,85,247,.14))!important;
}
.songline-space-ribbon.is-wave{
  filter:drop-shadow(0 0 12px rgba(147,197,253,.38))!important;
}
.site-bg-layer{
  z-index:0!important;
}
.site-header,
.modern-site-header,
.container,
.footer,
.site-footer,
.site-boot-overlay{
  position:relative;
  z-index:3;
}

@media(max-width:980px){
  html.has-fixed-mobile-nav body{
    padding-top:var(--songline-mobile-nav-height, 118px)!important;
  }
  html.has-fixed-mobile-nav .site-header,
  html.has-fixed-mobile-nav .modern-site-header,
  .site-header.modern-site-header{
    position:fixed!important;
    top:0!important;
    left:0!important;
    right:0!important;
    width:100%!important;
    z-index:12000!important;
    margin:0!important;
    transform:none!important;
    opacity:1!important;
    visibility:visible!important;
    pointer-events:auto!important;
    will-change:auto!important;
    backface-visibility:hidden!important;
  }
  html.has-fixed-mobile-nav .modern-site-header,
  .modern-site-header{
    padding:8px var(--mobile-safe-r, 10px) 0 var(--mobile-safe-x, 10px)!important;
    background:linear-gradient(180deg, color-mix(in srgb, var(--bg) 98%, transparent), color-mix(in srgb, var(--bg) 84%, transparent), transparent)!important;
    backdrop-filter:none!important;
    -webkit-backdrop-filter:none!important;
  }
  html.has-fixed-mobile-nav .modern-navbar,
  .modern-navbar{
    transform:none!important;
  }
  html{
    scroll-padding-top:calc(var(--songline-mobile-nav-height, 118px) + 8px)!important;
  }
  .songline-space-ribbon{
    filter:drop-shadow(0 0 16px rgba(125,211,252,.42)) drop-shadow(0 0 32px rgba(168,85,247,.16))!important;
  }
}

@media(max-width:430px){
  html.has-fixed-mobile-nav body{
    padding-top:var(--songline-mobile-nav-height, 112px)!important;
  }
  html{
    scroll-padding-top:calc(var(--songline-mobile-nav-height, 112px) + 8px)!important;
  }
}


/* v20.18.5-cleanup：已移除旧随机飘带/慢漂/防闪/白线实验段，保留白色星轨流线实现。 */

/* v20.18.5：参考现代网页的白色星轨流线背景 */
.songline-starstream-layer{
  position:fixed!important;
  inset:-4vh -4vw!important;
  width:108vw!important;
  height:108vh!important;
  z-index:1!important;
  opacity:1!important;
  pointer-events:none!important;
  overflow:hidden!important;
  contain:layout paint style!important;
  isolation:isolate!important;
  transform:translate3d(0,0,0)!important;
  backface-visibility:hidden!important;
  -webkit-backface-visibility:hidden!important;
  mix-blend-mode:normal!important;
}

.songline-starstream-svg{
  width:100%!important;
  height:100%!important;
  display:block!important;
  transform:translateZ(0)!important;
  backface-visibility:hidden!important;
  -webkit-backface-visibility:hidden!important;
}

.starstream-path{
  fill:none!important;
  stroke-linecap:round!important;
  stroke-linejoin:round!important;
  vector-effect:non-scaling-stroke!important;
  filter:none!important;
  mix-blend-mode:normal!important;
  transform:none!important;
  will-change:auto!important;
}

.starstream-base{
  opacity:1!important;
  animation:none!important;
}

.starstream-flow{
  opacity:1!important;
  filter:none!important;
  animation:starstreamDashFlow var(--starstream-duration, 28000ms) linear infinite!important;
  will-change:stroke-dashoffset!important;
}

@keyframes starstreamDashFlow{
  from{
    stroke-dashoffset:0;
  }
  to{
    stroke-dashoffset:var(--starstream-distance, -1000);
  }
}

/* 旧版本各种 ribbon 规则全部降级，避免跟新星轨流线冲突 */
.songline-starstream-layer .songline-space-ribbon,
.songline-starstream-layer .white-flow-ribbon,
.songline-starstream-layer .safe-ribbon,
.songline-starstream-layer .slow-ribbon{
  animation:none!important;
  filter:none!important;
}

/* 开机动画期间仍不显示背景线条，避免抢首屏 */
html.is-boot-preparing .songline-starstream-layer,
body.is-boot-preparing .songline-starstream-layer{
  display:none!important;
}

@media(max-width:820px){
  .songline-starstream-layer{
    inset:-3vh -5vw!important;
    width:110vw!important;
    height:106vh!important;
  }
  .starstream-flow{
    animation-duration:calc(var(--starstream-duration, 26000ms) * .86)!important;
  }
}

@media(prefers-reduced-motion: reduce){
  .starstream-flow{
    animation:none!important;
  }
}


/* v20.18.5：星轨背景渐入 + 轨迹缓慢变形 */
.songline-starstream-layer.songline-starstream-morph-layer{
  opacity:0!important;
  transition:opacity 1200ms ease!important;
}
.songline-starstream-layer.songline-starstream-morph-layer.is-visible{
  opacity:1!important;
}

.starstream-morph-group{
  transform-box:fill-box!important;
  transform-origin:center!important;
  animation:starstreamGroupDrift var(--group-drift-duration, 62000ms) ease-in-out infinite alternate!important;
  animation-delay:var(--group-drift-delay, 0ms)!important;
  will-change:transform!important;
}

.starstream-morph-base,
.starstream-morph-flow{
  transition:none!important;
}

@keyframes starstreamGroupDrift{
  0%{
    transform:translate3d(-8px, -5px, 0) rotate(-.35deg) scale(1);
  }
  48%{
    transform:translate3d(5px, 4px, 0) rotate(.28deg) scale(1.006);
  }
  100%{
    transform:translate3d(11px, 7px, 0) rotate(-.18deg) scale(1.01);
  }
}

/* 让移动速度更容易观察，但仍保持背景感 */
.starstream-morph-flow{
  animation-timing-function:linear!important;
}

@media(max-width:820px){
  .songline-starstream-layer.songline-starstream-morph-layer{
    transition-duration:1050ms!important;
  }
  .starstream-morph-group{
    animation-duration:calc(var(--group-drift-duration, 56000ms) * .82)!important;
  }
}

@media(prefers-reduced-motion: reduce){
  .songline-starstream-layer.songline-starstream-morph-layer{
    opacity:1!important;
    transition:none!important;
  }
  .starstream-morph-group{
    animation:none!important;
  }
}


/* v20.18.5-cleanup：星轨速度统一入口。阅读浮动按钮统一由 body portal 段接管。 */
.starstream-morph-flow{
  animation-duration:calc(var(--starstream-duration, 22000ms) * .78)!important;
}
.starstream-morph-group{
  animation-duration:calc(var(--group-drift-duration, 56000ms) * .78)!important;
}

/* v20.18.5-cleanup：已移除旧阅读按钮 fixed 覆盖层，保留 body portal 作为唯一最终方案。 */

/* v20.18.5-cleanup 最终说明：
   当前稳定交互入口：
   - 星轨背景：.songline-starstream-layer / .starstream-*
   - 手机端目录：mobile-toc.js + .mobile-toc-drawer / .mobile-toc-fab
   - 阅读浮动按钮：reader-floating-controls.js + reader-floating-controls.css
   后续迭代优先修改这些最终入口，避免重新追加历史 override。
*/