:root{
  --paper:#F5EDDF;
  --white:#FBF8F0;
  --ink:#2A2118;
  --rock:#6F6A60;
  --loess:#B4762C;
  --goji:#B23A2A;
  --lake:#4E7B73;
  --deep:#2E514B;
  --sand:#E7D7BF;
  --signal:#D96A2E;
  --line:rgba(111,106,96,.30);
  --line-soft:rgba(111,106,96,.16);
  --line-strong:rgba(42,33,24,.58);
  --shell:1200px;
  --pad:clamp(1rem,4vw,2.5rem);
  --dur:180ms;
  --font-sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC","Noto Sans SC",sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,"Liberation Mono",monospace;
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background-color:var(--paper);
  background-image:
    repeating-linear-gradient(90deg,rgba(111,106,96,.075) 0 1px,transparent 1px 64px),
    repeating-linear-gradient(0deg,rgba(111,106,96,.075) 0 1px,transparent 1px 64px);
  color:var(--ink);
  font-family:var(--font-sans);
  font-size:clamp(1rem,.96rem + .2vw,1.125rem);
  line-height:1.8;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4{font-weight:900;line-height:1.18;letter-spacing:-.01em}
h1{font-size:clamp(2rem,4.4vw,3.4rem)}
h2{font-size:clamp(1.5rem,2.8vw,2.4rem)}
h3{font-size:clamp(1.15rem,2vw,1.5rem)}
h4{font-size:1.05rem}
p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
a{color:inherit;text-decoration:none}
img,svg,video{display:block;max-width:100%;height:auto}
button{font:inherit;color:inherit;background:none;border:0}
hr{border:0;border-top:1px solid var(--line);margin:0}

:focus-visible{outline:2px solid var(--signal);outline-offset:2px}
.site-footer :focus-visible{outline-color:var(--sand)}

.shell{
  width:100%;
  max-width:var(--shell);
  margin-inline:auto;
  padding-inline:var(--pad);
}
.u-mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}

/* ---------- skip link ---------- */
.skip-link{
  position:fixed;
  top:-5rem;
  left:1rem;
  z-index:300;
  padding:.6rem 1.1rem;
  background:var(--ink);
  color:var(--paper);
  font-size:.85rem;
  font-weight:700;
  letter-spacing:.06em;
  border:1px solid var(--signal);
  transition:top var(--dur) ease;
}
.skip-link:focus{top:.75rem}

/* ---------- header ---------- */
.site-header{position:relative;z-index:100}

.signal-strip{
  background:var(--ink);
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.12em;
  font-variant-numeric:tabular-nums;
}
.signal-strip__inner{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:.25rem 1.25rem;
  padding-block:.45rem;
}
.signal-strip__coord{color:var(--sand)}
.signal-strip__note{color:rgba(245,237,223,.68)}

.header-main{
  background:var(--white);
  border-bottom:1px solid var(--line-strong);
}
.header-main__inner{
  display:flex;
  align-items:center;
  gap:1.25rem;
  padding-block:clamp(.8rem,2vw,1.15rem);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:.7rem;
  flex:0 0 auto;
}
.brand-mark{
  display:grid;
  place-items:center;
  position:relative;
  width:2.7rem;
  height:2.7rem;
  background:var(--ink);
  color:var(--paper);
  font-size:1.12rem;
  font-weight:900;
  letter-spacing:.02em;
  transition:background-color var(--dur) ease;
}
.brand-mark::after{
  content:"";
  position:absolute;
  right:-3px;
  top:-3px;
  width:7px;
  height:7px;
  background:var(--signal);
}
.brand:hover .brand-mark{background:var(--goji)}
.brand-text{display:flex;flex-direction:column;line-height:1.15}
.brand-name{font-size:1.18rem;font-weight:900;letter-spacing:.03em}
.brand-tagline{
  margin-top:.22rem;
  font-family:var(--font-mono);
  font-size:.64rem;
  letter-spacing:.2em;
  color:var(--rock);
}
.header-claim{
  margin-right:auto;
  padding-left:1.1rem;
  border-left:1px solid var(--line);
  font-size:.82rem;
  letter-spacing:.05em;
  color:var(--rock);
}
.header-tools{
  display:flex;
  align-items:center;
  gap:.55rem;
  margin-left:auto;
}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.45rem;
  padding:.6rem 1rem;
  border:1px solid transparent;
  border-radius:0;
  font-size:.85rem;
  font-weight:700;
  letter-spacing:.06em;
  white-space:nowrap;
  cursor:pointer;
  transition:background-color var(--dur) ease,color var(--dur) ease,border-color var(--dur) ease;
}
.btn--signal{
  background:var(--goji);
  border-color:var(--goji);
  color:var(--white);
}
.btn--signal::before{
  content:"";
  width:6px;
  height:6px;
  background:currentColor;
  opacity:.85;
}
.btn--signal:hover{
  background:var(--signal);
  border-color:var(--signal);
  color:var(--white);
}
.btn--ghost{
  background:transparent;
  border-color:var(--line-strong);
  color:var(--ink);
}
.btn--ghost:hover{
  background:var(--sand);
  border-color:var(--ink);
}
.btn--line{
  background:transparent;
  border-color:var(--loess);
  color:var(--loess);
}
.btn--line:hover{background:var(--loess);color:var(--white)}

/* ---------- mobile nav toggle ---------- */
.nav-toggle{
  display:none;
  align-items:center;
  gap:.5rem;
  padding:.6rem .8rem;
  background:var(--ink);
  border:1px solid var(--ink);
  color:var(--paper);
  font-size:.78rem;
  font-weight:700;
  letter-spacing:.12em;
  cursor:pointer;
  transition:background-color var(--dur) ease;
}
.nav-toggle:hover{background:var(--deep)}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:center;gap:3px;width:16px}
.nav-toggle__bars span{
  display:block;
  height:2px;
  background:currentColor;
  transition:transform var(--dur) ease,opacity var(--dur) ease;
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1){transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg)}

/* ---------- site nav ---------- */
.site-nav{
  background:var(--paper);
  border-bottom:1px solid var(--line-strong);
}
.site-nav__inner{
  display:flex;
  align-items:stretch;
  justify-content:space-between;
  gap:1rem;
}
.nav-list{display:flex;flex-wrap:wrap;align-items:stretch}
.nav-item{display:flex}
.nav-link{
  position:relative;
  display:inline-flex;
  align-items:baseline;
  gap:.45rem;
  padding:.85rem clamp(.7rem,1.6vw,1.15rem);
  border-left:1px solid var(--line);
  font-size:.9rem;
  font-weight:700;
  letter-spacing:.03em;
  transition:background-color var(--dur) ease,color var(--dur) ease;
}
.nav-item:last-child .nav-link{border-right:1px solid var(--line)}
.nav-link::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:2px;
  background:var(--signal);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform var(--dur) ease;
}
.nav-link:hover{background:var(--sand);color:var(--goji)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-index{
  font-family:var(--font-mono);
  font-size:.68rem;
  font-weight:600;
  letter-spacing:.06em;
  color:var(--loess);
}
.nav-link[aria-current="page"]{background:var(--ink);color:var(--paper)}
.nav-link[aria-current="page"] .nav-index{color:var(--signal)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--goji)}

.nav-quick{
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  margin-left:auto;
  padding:.85rem 0 .85rem 1.1rem;
  border-left:1px solid var(--line);
  font-size:.8rem;
  font-weight:700;
  letter-spacing:.06em;
  color:var(--deep);
  transition:color var(--dur) ease;
}
.nav-quick:hover{color:var(--goji)}
.nav-quick__arrow{font-family:var(--font-mono);transition:transform var(--dur) ease}
.nav-quick:hover .nav-quick__arrow{transform:translateX(4px)}

/* ---------- page scaffolding ---------- */
.breadcrumb{
  padding-block:1rem;
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.08em;
  color:var(--rock);
}
.breadcrumb ol{display:flex;flex-wrap:wrap;align-items:center;gap:.4rem}
.breadcrumb li::after{content:"/";margin-left:.4rem;color:var(--line-strong)}
.breadcrumb li:last-child::after{content:""}
.breadcrumb a:hover{color:var(--goji)}

.section{
  padding-block:clamp(2.4rem,6vw,4.5rem);
  border-top:1px solid var(--line-soft);
}
.section:first-of-type{border-top:0}
.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:baseline;
  gap:.7rem 1rem;
  margin-bottom:clamp(1.25rem,3vw,2rem);
}
.section-num{
  font-family:var(--font-mono);
  font-size:.76rem;
  font-weight:700;
  letter-spacing:.14em;
  color:var(--loess);
  border:1px solid var(--loess);
  padding:.12rem .45rem;
}
.section-title{font-size:clamp(1.5rem,2.8vw,2.4rem);font-weight:900}
.section-desc{max-width:62ch;color:var(--rock);font-size:.95rem}

.prose{max-width:72ch;font-size:1.02rem;line-height:1.85}
.prose p + p{margin-top:1rem}
.prose h2{margin-top:2rem;margin-bottom:.6rem;font-size:clamp(1.35rem,2.4vw,1.9rem)}
.prose h3{margin-top:1.6rem;margin-bottom:.5rem}
.prose ul{margin-top:.75rem}
.prose li{position:relative;padding-left:1.15rem}
.prose li + li{margin-top:.45rem}
.prose li::before{
  content:"";
  position:absolute;
  left:0;
  top:.85em;
  width:.5rem;
  height:1px;
  background:var(--loess);
}

.grid-auto{
  display:grid;
  gap:clamp(1rem,2.5vw,1.5rem);
  grid-template-columns:repeat(auto-fit,minmax(min(100%,15rem),1fr));
}

.card{
  position:relative;
  background:var(--white);
  border:1px solid var(--line);
  padding:clamp(1rem,2.4vw,1.5rem);
  transition:border-color var(--dur) ease;
}
.card::before{
  content:"";
  position:absolute;
  left:0;
  top:0;
  bottom:0;
  width:3px;
  background:var(--goji);
  transform:scaleY(0);
  transform-origin:top center;
  transition:transform var(--dur) ease;
}
.card:hover{border-color:var(--line-strong)}
.card:hover::before{transform:scaleY(1)}
.card__title{font-size:1.08rem;font-weight:800;margin-bottom:.4rem}
.card__meta{
  font-family:var(--font-mono);
  font-size:.74rem;
  letter-spacing:.08em;
  color:var(--rock);
}

.tag{
  display:inline-flex;
  align-items:center;
  gap:.3rem;
  padding:.12rem .5rem;
  border:1px solid currentColor;
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.08em;
  color:var(--lake);
}
.tag--loess{color:var(--loess)}
.tag--goji{color:var(--goji)}
.tag--ink{color:var(--ink)}

.price-bar{border-top:1px solid var(--line-strong)}
.price-bar__row{
  display:grid;
  grid-template-columns:1fr auto auto;
  align-items:center;
  gap:1rem;
  padding:.85rem 1rem;
  background:var(--white);
  border-bottom:1px solid var(--line);
  transition:background-color var(--dur) ease;
}
.price-bar__row:hover{background:var(--sand)}
.price-bar__name{font-weight:700;font-size:.96rem}
.price-bar__value{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  font-weight:700;
  color:var(--loess);
}
.price-bar__unit{
  font-family:var(--font-mono);
  font-size:.74rem;
  color:var(--rock);
}

.accordion{border-top:1px solid var(--line-strong)}
.accordion__item{border-bottom:1px solid var(--line)}
.accordion__trigger{
  display:flex;
  width:100%;
  align-items:center;
  justify-content:space-between;
  gap:1rem;
  padding:1rem .25rem;
  font-size:1rem;
  font-weight:700;
  text-align:left;
  cursor:pointer;
  transition:color var(--dur) ease;
}
.accordion__trigger:hover{color:var(--goji)}
.accordion__trigger::after{
  content:"+";
  font-family:var(--font-mono);
  font-size:1.1rem;
  color:var(--loess);
}
.accordion__trigger[aria-expanded="true"]::after{content:"–"}
.accordion__panel{padding:0 .25rem 1.1rem;font-size:.95rem;color:var(--rock)}
.accordion__panel[hidden]{display:none}

.data-table{
  width:100%;
  border-collapse:collapse;
  background:var(--white);
  font-size:.9rem;
}
.data-table th,.data-table td{
  padding:.7rem .8rem;
  border-bottom:1px solid var(--line);
  text-align:left;
  vertical-align:top;
}
.data-table th{
  background:var(--sand);
  font-family:var(--font-mono);
  font-size:.74rem;
  font-weight:600;
  letter-spacing:.1em;
  color:var(--rock);
}
.data-table td.num{
  font-family:var(--font-mono);
  font-variant-numeric:tabular-nums;
  font-weight:700;
  color:var(--loess);
}

.note{
  padding:1rem 1.1rem;
  background:var(--sand);
  border-left:3px solid var(--loess);
  font-size:.92rem;
  color:var(--ink);
}

.toc{border-left:1px solid var(--line)}
.toc__link{
  display:block;
  margin-left:-1px;
  padding:.35rem 0 .35rem .9rem;
  border-left:2px solid transparent;
  font-size:.9rem;
  color:var(--rock);
  transition:color var(--dur) ease,border-color var(--dur) ease;
}
.toc__link:hover{color:var(--ink)}
.toc__link[aria-current="true"]{
  color:var(--goji);
  border-left-color:var(--goji);
  font-weight:700;
}

.media-frame{
  position:relative;
  display:block;
  overflow:hidden;
  aspect-ratio:4/3;
  background:var(--sand);
  border:1px solid var(--line);
}
.media-frame img{width:100%;height:100%;object-fit:cover}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  opacity:.55;
  background-image:
    linear-gradient(rgba(42,33,24,.08) 1px,transparent 1px),
    linear-gradient(90deg,rgba(42,33,24,.08) 1px,transparent 1px);
  background-size:32px 32px;
}
.media-frame--wide{aspect-ratio:16/9}
.media-frame--tall{aspect-ratio:3/4}

/* ---------- js-created ui ---------- */
.scroll-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:3px;
  z-index:150;
  background:linear-gradient(90deg,var(--loess),var(--goji));
  transform:scaleX(0);
  transform-origin:0 50%;
  pointer-events:none;
  will-change:transform;
}
.back-top{
  position:fixed;
  right:clamp(1rem,3vw,2rem);
  bottom:clamp(1rem,3vw,2rem);
  z-index:150;
  display:grid;
  place-items:center;
  width:2.9rem;
  height:2.9rem;
  border-radius:50%;
  border:1px solid var(--ink);
  background:var(--white);
  color:var(--ink);
  font-family:var(--font-mono);
  font-size:1rem;
  line-height:1;
  cursor:pointer;
  opacity:0;
  pointer-events:none;
  transform:translateY(8px);
  transition:opacity var(--dur) ease,transform var(--dur) ease,background-color var(--dur) ease,color var(--dur) ease;
}
.back-top[data-visible="true"]{opacity:1;pointer-events:auto;transform:none}
.back-top:hover{background:var(--ink);color:var(--paper)}

/* ---------- footer ---------- */
.site-footer{
  margin-top:clamp(3rem,8vw,6rem);
  background:var(--deep);
  color:var(--paper);
}
.footer-rule{
  height:4px;
  background:linear-gradient(90deg,
    var(--loess) 0 26%,
    var(--goji) 26% 46%,
    var(--lake) 46% 62%,
    var(--sand) 62% 100%);
}
.footer-main{
  display:grid;
  grid-template-columns:1.5fr .8fr .8fr 1.25fr;
  gap:clamp(1.5rem,4vw,3rem);
  padding-block:clamp(2.4rem,6vw,4rem);
}
.footer-brand{display:flex;flex-direction:column;gap:.85rem}
.footer-logo{display:inline-flex;align-items:center;gap:.65rem}
.footer-brand__name{font-size:1.16rem;font-weight:900;letter-spacing:.04em}
.footer-brand__line{
  max-width:30ch;
  font-size:.9rem;
  color:rgba(245,237,223,.76);
}
.footer-brand__coord{
  padding-top:.7rem;
  border-top:1px solid rgba(245,237,223,.22);
  font-family:var(--font-mono);
  font-size:.7rem;
  letter-spacing:.14em;
  color:var(--sand);
}
.footer-col__title{
  margin-bottom:.85rem;
  padding-bottom:.55rem;
  border-bottom:1px solid rgba(245,237,223,.24);
  font-family:var(--font-mono);
  font-size:.72rem;
  font-weight:600;
  letter-spacing:.2em;
  color:var(--sand);
}
.footer-list li + li{margin-top:.5rem}
.footer-link{
  position:relative;
  display:inline-block;
  font-size:.92rem;
  color:rgba(245,237,223,.86);
  transition:color var(--dur) ease,padding-left var(--dur) ease;
}
.footer-link::before{
  content:"";
  position:absolute;
  left:0;
  top:50%;
  width:.35rem;
  height:1px;
  background:var(--signal);
  opacity:0;
  transition:opacity var(--dur) ease;
}
.footer-link:hover{color:var(--white);padding-left:.65rem}
.footer-link:hover::before{opacity:1}

.footer-col--contact{min-width:0}
.footer-list--contact{display:grid;gap:.85rem}
.footer-contact__line{
  display:grid;
  grid-template-columns:3rem 1fr;
  gap:.6rem;
  font-size:.86rem;
  line-height:1.65;
}
.footer-contact__key{
  font-family:var(--font-mono);
  font-size:.68rem;
  letter-spacing:.12em;
  color:var(--sand);
  padding-top:.18rem;
}
.footer-text{color:rgba(245,237,223,.88);word-break:break-word}

.footer-meta{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:.75rem 1.5rem;
  padding-block:1.15rem;
  border-top:1px solid rgba(245,237,223,.22);
  font-size:.78rem;
  color:rgba(245,237,223,.72);
}
.footer-meta__copy{
  font-family:var(--font-mono);
  letter-spacing:.06em;
  font-variant-numeric:tabular-nums;
}
.footer-legal{display:flex;flex-wrap:wrap;gap:1rem}
.footer-legal__link{
  border-bottom:1px solid rgba(245,237,223,.32);
  transition:color var(--dur) ease,border-color var(--dur) ease;
}
.footer-legal__link:hover{color:var(--white);border-color:var(--signal)}
.footer-icp__link{
  font-family:var(--font-mono);
  letter-spacing:.06em;
  color:var(--sand);
  transition:color var(--dur) ease;
}
.footer-icp__link:hover{color:var(--white)}

/* ---------- responsive ---------- */
@media (max-width:1080px){
  .header-claim{display:none}
}
@media (max-width:960px){
  .nav-toggle{display:inline-flex}
  .site-nav{display:none;border-top:1px solid var(--line)}
  .site-nav[data-open="true"]{display:block;animation:nav-in 200ms ease both}
  .site-nav__inner{display:block;padding-block:.4rem}
  .nav-list{flex-direction:column}
  .nav-item{display:block}
  .nav-link{
    width:100%;
    padding:.8rem .3rem;
    border-left:0;
    border-right:0;
    border-bottom:1px solid var(--line);
    font-size:.95rem;
  }
  .nav-item:last-child .nav-link{border-right:0;border-bottom:0}
  .nav-link[aria-current="page"]{
    background:var(--sand);
    color:var(--ink);
    padding-left:.75rem;
  }
  .nav-link[aria-current="page"] .nav-index{color:var(--goji)}
  .nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--goji)}
  .nav-quick{display:none}
  .footer-main{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1 / -1}
}
@media (max-width:720px){
  .btn--ghost{display:none}
  .header-main__inner{gap:.75rem}
  .signal-strip__inner{font-size:.64rem;letter-spacing:.08em}
  .footer-main{grid-template-columns:1fr}
  .footer-brand__line{max-width:none}
  .footer-meta{justify-content:flex-start}
}
@media (max-width:600px){
  .nav-toggle__text{display:none}
  .brand-tagline{display:none}
  .price-bar__row{grid-template-columns:1fr auto;gap:.35rem 1rem}
  .price-bar__unit{grid-column:2;justify-self:end}
}
@keyframes nav-in{
  from{opacity:0;transform:translateY(-6px)}
  to{opacity:1;transform:none}
}

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.01ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.01ms !important;
    scroll-behavior:auto !important;
  }
  .back-top{transform:none}
}