@import url('https://fonts.googleapis.com/css2?family=Nunito+Sans:wght@300;400;500;600;700&family=Varela+Round&display=swap');

*,*::before,*::after{box-sizing:border-box}

:root{
  --ink:#192617;
  --deep:#0c140e;
  --neon:#87ff71;
  --cyan:#01cdfe;
  --txt:#e9f7e5;
  --dim:#a6c3a2;
  --line:rgba(135,255,113,.22);
  --r:18px;
  --font:'Varela Round','Nunito Sans',system-ui,-apple-system,'Segoe UI','PingFang SC','Hiragino Sans GB','Microsoft YaHei',sans-serif;
  --mono:ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
}

html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}

body{
  margin:0;
  font-family:var(--font);
  font-size:1.0625rem;
  line-height:1.78;
  color:var(--txt);
  background-color:var(--deep);
  background-image:
    radial-gradient(110% 55% at 50% -8%, rgba(1,205,254,.22), transparent 62%),
    radial-gradient(80% 45% at 88% 4%, rgba(135,255,113,.16), transparent 60%),
    linear-gradient(180deg,#0c140e,#192617 42%,#0c140e);
  background-attachment:fixed;
  min-height:100vh;
}

body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:3;
  pointer-events:none;
  background:repeating-linear-gradient(180deg, rgba(255,255,255,.055) 0 1px, transparent 1px 3px);
  opacity:.45;
}

body::after{
  content:"";
  position:fixed;
  left:0;
  right:0;
  bottom:0;
  height:34vh;
  z-index:0;
  pointer-events:none;
  opacity:.5;
  background-image:
    linear-gradient(to right, rgba(1,205,254,.22) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(135,255,113,.16) 1px, transparent 1px);
  background-size:58px 58px;
  transform:perspective(340px) rotateX(62deg);
  transform-origin:bottom center;
  -webkit-mask-image:linear-gradient(to bottom, transparent, #000 45%);
  mask-image:linear-gradient(to bottom, transparent, #000 45%);
}

a{color:var(--cyan);text-decoration-thickness:1px;text-underline-offset:3px}
a:focus-visible,button:focus-visible,input:focus-visible{outline:2px solid var(--cyan);outline-offset:3px}

.skip{
  position:fixed;
  top:8px;
  left:8px;
  z-index:20;
  display:flex;
  align-items:center;
  min-height:44px;
  padding:.4rem 1rem;
  border-radius:10px;
  background:var(--neon);
  color:#0b140d;
  text-decoration:none;
  transform:translateY(-180%);
}
.skip:focus{transform:none}

/* ---------- 顶部双行 ---------- */
.top{
  position:sticky;
  top:0;
  z-index:9;
  position:relative;
  position:sticky;
  background:rgba(9,16,11,.88);
  border-bottom:1px solid var(--line);
  backdrop-filter:blur(9px);
  -webkit-backdrop-filter:blur(9px);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:.6rem;
  min-height:44px;
  padding:13px 18px 4px;
  text-decoration:none;
  font-size:1.22rem;
  letter-spacing:.14em;
}

.brand-mark{
  width:15px;
  height:15px;
  border-radius:50%;
  background:conic-gradient(from 0deg, var(--neon), var(--cyan), var(--neon));
  box-shadow:0 0 14px rgba(135,255,113,.85);
}

.brand-name{
  background:linear-gradient(90deg, var(--neon), var(--cyan));
  -webkit-background-clip:text;
  background-clip:text;
  color:transparent;
  text-shadow:0 0 22px rgba(1,205,254,.28);
}

.menu{padding:2px 10px 9px}
.menu p{
  display:flex;
  flex-wrap:wrap;
  gap:2px;
  margin:0;
}
.menu a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:.3rem .78rem;
  border-radius:999px;
  font-size:1rem;
  line-height:1.35;
  color:var(--dim);
  text-decoration:none;
  transition:background .18s ease, color .18s ease, transform .18s ease;
}
.menu a:hover,.menu a:focus-visible{
  color:#0b140d;
  background:linear-gradient(120deg, var(--neon), var(--cyan));
  transform:translateY(-1px);
}

/* ---------- 首屏 ---------- */
.hero{
  position:relative;
  z-index:1;
  display:grid;
  grid-template-columns:1.05fr .95fr;
  gap:clamp(22px,4vw,56px);
  align-items:center;
  max-width:1180px;
  margin:0 auto;
  padding:clamp(26px,5vw,60px) clamp(18px,4vw,56px) clamp(34px,5vw,72px);
  min-height:calc(100svh - 112px);
}

.hero-copy{text-align:center}
.hero-copy h1{
  margin:0 0 .5em;
  font-size:clamp(1.85rem,4.6vw,3.25rem);
  line-height:1.24;
  letter-spacing:.01em;
  color:#fff;
  text-shadow:0 0 20px rgba(135,255,113,.45), 0 0 52px rgba(1,205,254,.28);
  animation:glow 7s ease-in-out infinite;
}
.lede{
  max-width:32em;
  margin:0 auto 1.5em;
  color:var(--dim);
  font-size:1.0625rem;
}
.hero-act{margin:0}
.cta{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-height:46px;
  padding:.4em 1.6em;
  border-radius:999px;
  background:linear-gradient(120deg, var(--neon), var(--cyan));
  color:#0b140d;
  font-weight:700;
  letter-spacing:.08em;
  text-decoration:none;
  box-shadow:0 0 0 1px rgba(135,255,113,.4), 0 10px 30px rgba(1,205,254,.28);
  transition:transform .2s ease, box-shadow .2s ease;
}
.cta:hover{transform:translateY(-2px);box-shadow:0 0 0 1px var(--neon), 0 14px 36px rgba(135,255,113,.36)}

.hero-art{
  position:relative;
  aspect-ratio:4/5;
  border-radius:999px 999px var(--r) var(--r);
  overflow:hidden;
  border:1px solid rgba(1,205,254,.4);
  background:
    radial-gradient(circle at 50% 40%, #efffd9 0%, var(--neon) 20%, var(--cyan) 52%, #13301f 82%);
  box-shadow:inset 0 0 70px rgba(12,20,14,.55), 0 0 46px rgba(1,205,254,.24);
}
.hero-art::after{
  content:"";
  position:absolute;
  inset:auto 0 0 0;
  height:46%;
  background-image:
    linear-gradient(to right, rgba(12,20,14,.42) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(12,20,14,.42) 1px, transparent 1px);
  background-size:34px 34px;
  transform:perspective(200px) rotateX(64deg);
  transform-origin:bottom center;
  opacity:.55;
  pointer-events:none;
}
.hero-img{
  position:relative;
  z-index:1;
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
  animation:hue 16s ease-in-out infinite;
}

/* ---------- 主体 ---------- */
.stage{
  position:relative;
  z-index:1;
  display:grid;
  grid-template-columns:250px minmax(0,1fr);
  gap:clamp(18px,3vw,38px);
  align-items:start;
  max-width:1180px;
  margin:0 auto;
  padding:0 clamp(16px,4vw,56px) 72px;
}

.rail{
  position:sticky;
  top:118px;
  display:grid;
  gap:14px;
}

.rail-box{
  position:relative;
  overflow:hidden;
  padding:14px 12px 18px;
  border:1px solid var(--line);
  border-radius:var(--r);
  background:linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.015));
}
.rail-box::after{
  content:"";
  position:absolute;
  left:14px;
  right:14px;
  bottom:0;
  height:2px;
  border-radius:2px;
  background:linear-gradient(90deg, var(--neon), var(--cyan));
  opacity:.85;
}

.rail-t{
  margin:0 0 .55rem;
  padding:0 .55rem;
  font-size:1rem;
  font-weight:600;
  letter-spacing:.1em;
  color:var(--neon);
}
.rail-t span{position:relative;display:inline-block}
.rail-t .deco{
  position:absolute;
  left:0;
  right:0;
  bottom:-4px;
  height:2px;
  background:linear-gradient(90deg, var(--neon), transparent);
}

.toc{
  margin:0;
  padding:0;
  list-style:none;
  display:grid;
  gap:3px;
}
.toc a{
  display:flex;
  align-items:center;
  gap:.55rem;
  min-height:40px;
  padding:.2rem .55rem;
  border-radius:10px;
  color:var(--txt);
  text-decoration:none;
  transition:background .18s ease, color .18s ease, transform .18s ease;
}
.toc a:hover{background:rgba(135,255,113,.13);color:var(--neon);transform:translateX(3px)}
.toc .n{font-family:var(--mono);color:var(--cyan);letter-spacing:.05em}

.rail-p{margin:0;padding:0 .55rem}
.up{
  display:inline-flex;
  align-items:center;
  min-height:40px;
  padding:.2rem 1.1rem;
  border-radius:999px;
  border:1px solid var(--line);
  color:var(--neon);
  text-decoration:none;
}
.up:hover{background:rgba(1,205,254,.16)}

.paper{min-width:0;counter-reset:sec}

.paper article{
  position:relative;
  margin:0 0 32px;
  padding:28px 26px;
  border:1px solid rgba(135,255,113,.16);
  border-radius:var(--r);
  background:linear-gradient(180deg, rgba(255,255,255,.05), rgba(255,255,255,.012));
  scroll-margin-top:140px;
}
.paper article::after{
  content:"";
  position:absolute;
  left:26px;
  right:26px;
  bottom:0;
  height:3px;
  border-radius:3px;
  background:linear-gradient(90deg, var(--neon), var(--cyan));
  opacity:.72;
}
.paper article::before{
  counter-increment:sec;
  content:counter(sec, decimal-leading-zero);
  position:absolute;
  top:14px;
  right:18px;
  font-family:var(--mono);
  font-size:1rem;
  letter-spacing:.1em;
  color:rgba(135,255,113,.55);
}

.paper h2{
  margin:0 0 .6em;
  padding-right:2.6em;
  font-size:clamp(1.25rem,2.6vw,1.72rem);
  line-height:1.35;
  color:#fff;
  text-shadow:0 0 20px rgba(1,205,254,.3);
}
.paper h2 span{
  background:linear-gradient(180deg, transparent 64%, rgba(1,205,254,.42) 64%);
  padding-bottom:2px;
}
.paper h3{
  margin:1.5em 0 .5em;
  font-size:1.14rem;
  line-height:1.4;
  color:var(--neon);
}
.paper h3 span{border-bottom:1px dashed rgba(135,255,113,.5);padding-bottom:2px}

.paper p{margin:0 0 1.05em}
.paper ul,.paper ol{margin:0 0 1.05em;padding-left:1.3em}
.paper li{margin:.3em 0}
.paper ul li::marker{color:var(--cyan)}
.paper ol li::marker{color:var(--neon)}
.paper img{max-width:100%;height:auto;border-radius:14px;border:1px solid var(--line)}
.paper blockquote{
  margin:1.2em 0;
  padding:.7em 1.1em;
  border-left:3px solid var(--cyan);
  border-radius:0 12px 12px 0;
  background:rgba(1,205,254,.09);
  color:var(--txt);
}
.paper strong{color:#fff}
.paper hr{border:0;height:1px;background:var(--line);margin:1.6em 0}

/* ---------- 页脚 ---------- */
.foot{
  position:relative;
  z-index:1;
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(0,1fr);
  gap:18px 34px;
  padding:44px clamp(16px,4vw,56px) 26px;
  border-top:1px solid var(--line);
  background:linear-gradient(180deg, rgba(12,20,14,.35), rgba(8,14,10,.94));
}
.foot p{margin:0;line-height:1.8}
.foot-brand strong{
  display:block;
  font-size:1.18rem;
  letter-spacing:.12em;
  color:var(--neon);
  text-shadow:0 0 20px rgba(135,255,113,.4);
}
.foot-links{display:flex;flex-wrap:wrap;gap:2px;align-content:start}
.foot-links a{
  display:flex;
  align-items:center;
  min-height:40px;
  padding:.2rem .72rem;
  border-radius:999px;
  color:var(--dim);
  text-decoration:none;
}
.foot-links a:hover{color:#0b140d;background:var(--cyan)}

.foot-sub{
  grid-column:1 / -1;
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  align-items:center;
}
.foot-sub input{
  flex:1 1 200px;
  min-height:44px;
  padding:.45rem 1rem;
  border-radius:999px;
  border:1px solid var(--line);
  background:rgba(255,255,255,.06);
  color:var(--txt);
  font-family:inherit;
  font-size:1rem;
}
.foot-sub input::placeholder{color:rgba(166,195,162,.85)}
.foot-sub button{
  min-height:44px;
  padding:.4rem 1.5rem;
  border:0;
  border-radius:999px;
  background:linear-gradient(120deg, var(--cyan), var(--neon));
  color:#0b140d;
  font-family:inherit;
  font-size:1rem;
  font-weight:700;
  letter-spacing:.06em;
  cursor:pointer;
}
.foot-copy{
  grid-column:1 / -1;
  padding-top:12px;
  border-top:1px dashed rgba(135,255,113,.18);
  text-align:center;
  font-size:1rem;
  letter-spacing:.08em;
  color:var(--dim);
}

/* ---------- 动效 ---------- */
@keyframes rise{
  from{opacity:0;transform:translateY(16px)}
  to{opacity:1;transform:none}
}
@keyframes glow{
  0%,100%{text-shadow:0 0 20px rgba(135,255,113,.45), 0 0 52px rgba(1,205,254,.28)}
  50%{text-shadow:2px 0 0 rgba(1,205,254,.6), -2px 0 0 rgba(135,255,113,.5), 0 0 60px rgba(1,205,254,.42)}
}
@keyframes hue{
  0%,100%{filter:hue-rotate(-8deg) saturate(1.03)}
  50%{filter:hue-rotate(14deg) saturate(1.12)}
}

.hero-copy > *,.hero-art,.rail-box,.paper article{
  animation:rise .62s cubic-bezier(.2,.7,.3,1) both;
}
.hero-copy .lede{animation-delay:.1s}
.hero-copy .hero-act{animation-delay:.18s}
.hero-art{animation-delay:.24s}
.rail-box:nth-child(2){animation-delay:.12s}
.paper article:nth-child(1){animation-delay:.05s}
.paper article:nth-child(2){animation-delay:.11s}
.paper article:nth-child(3){animation-delay:.17s}
.paper article:nth-child(4){animation-delay:.23s}
.paper article:nth-child(5){animation-delay:.29s}
.paper article:nth-child(6){animation-delay:.35s}
.paper article:nth-child(7){animation-delay:.41s}

/* ---------- 断点 ---------- */
@media (max-width:900px){
  .hero{
    grid-template-columns:1fr;
    min-height:0;
    padding-top:24px;
  }
  .hero-art{aspect-ratio:16/10;border-radius:var(--r);order:2}
  .stage{grid-template-columns:1fr}
  .rail{position:static;order:0;grid-template-columns:1fr}
  .foot{grid-template-columns:1fr}
  .paper article{padding:22px 18px;scroll-margin-top:180px}
  .paper article::after{left:18px;right:18px}
}

@media (max-width:520px){
  .brand{font-size:1.1rem;letter-spacing:.1em}
  .menu a{padding:.3rem .6rem}
  .paper h2{padding-right:0}
  .paper article::before{position:static;display:block;margin-bottom:.4em}
}

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *{animation:none !important;transition:none !important}
}

button[aria-expanded]{min-width:44px;min-height:44px}