/* ==========================================================================
   加拿大28指南 · 共享样式 /assets/site.css
   北境路线图：霜白底 + 冰蓝色带 + 枫叶红行动 + 暖金节点
   ========================================================================== */

/* 1. Reset ---------------------------------------------------------------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:96px}
body,h1,h2,h3,h4,h5,p,figure,blockquote,ul,ol,li,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{display:block;max-width:100%;height:auto}
a{color:inherit}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
summary{list-style:none}

/* 2. Tokens -------------------------------------------------------------- */
:root{
  --snow:#F7FBFC;
  --ice-pale:#DDEFF4;
  --ice:#2C7A94;
  --ink:#0B1F2A;
  --deep:#12384A;
  --maple:#C0392B;
  --maple-hot:#E4572E;
  --gold:#F2B544;
  --gold-ink:#8A5C00;
  --slate:#6F858F;
  --paper:#FFFFFF;

  --line:rgba(11,31,42,.14);
  --line-strong:rgba(11,31,42,.3);
  --line-invert:rgba(247,251,252,.2);

  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:ui-monospace,"SFMono-Regular","Roboto Mono",Menlo,Consolas,monospace;

  --w-max:1240px;
  --gutter:clamp(18px,4vw,56px);
  --step:clamp(52px,7vw,104px);
  --num-col:clamp(52px,7vw,72px);
  --scroll-progress:0;
}

/* 3. Base type ----------------------------------------------------------- */
body{
  min-height:100vh;
  background:var(--snow);
  color:var(--ink);
  font-family:var(--font-sans);
  font-size:17px;
  font-weight:400;
  line-height:1.8;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4{font-weight:900;line-height:1.18;letter-spacing:-.02em}
::selection{background:var(--maple);color:#fff}
:focus-visible{outline:2px solid var(--maple);outline-offset:3px}
.masthead :focus-visible,.footer-main :focus-visible,.footer-meta :focus-visible{outline-color:var(--gold)}

/* 4. Utilities ----------------------------------------------------------- */
.container{width:100%;max-width:var(--w-max);margin-inline:auto;padding-inline:var(--gutter)}
.skip-link{
  position:absolute;left:12px;top:-72px;z-index:120;
  padding:12px 18px;background:var(--gold);color:var(--ink);
  font-size:13px;font-weight:700;letter-spacing:.1em;line-height:1.4;
  text-decoration:none;transition:top .2s ease;
}
.skip-link:focus{top:12px}
.eyebrow{
  display:inline-block;font-size:11px;font-weight:700;letter-spacing:.28em;
  line-height:1.4;color:var(--ice);
}

/* 5. Header -------------------------------------------------------------- */
.site-header{position:relative;z-index:60}
.masthead{background:var(--deep);color:var(--snow);border-bottom:1px solid var(--line-invert)}
.masthead__inner{
  display:flex;align-items:center;gap:clamp(14px,2.4vw,34px);
  padding-block:16px;flex-wrap:wrap;
}
.brand{display:flex;align-items:center;gap:14px;text-decoration:none;color:inherit}
.brand__mark{
  position:relative;flex:0 0 auto;width:38px;height:38px;
  border:1px solid rgba(247,251,252,.34);background:rgba(247,251,252,.06);
}
.brand__mark::before{
  content:"";position:absolute;left:50%;top:6px;bottom:6px;width:1px;
  background:var(--gold);transform:rotate(24deg);transform-origin:center;
}
.brand__mark::after{
  content:"";position:absolute;top:6px;right:6px;width:7px;height:7px;background:var(--maple-hot);
}
.brand__mark--invert{width:34px;height:34px;border-color:rgba(247,251,252,.3)}
.brand__text{display:flex;flex-direction:column;gap:2px}
.brand__name{font-size:clamp(17px,1.6vw,20px);font-weight:800;letter-spacing:.04em;line-height:1.25}
.brand__tagline{font-size:11.5px;font-weight:400;letter-spacing:.2em;line-height:1.4;color:rgba(247,251,252,.6)}

.utility{display:flex;align-items:center;gap:clamp(10px,1.6vw,22px);margin-inline-start:auto}
.utility__link{
  padding-block:6px;font-size:12.5px;font-weight:500;letter-spacing:.14em;
  color:rgba(247,251,252,.74);text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .2s ease,border-color .2s ease;
}
.utility__link:hover{color:var(--gold);border-bottom-color:var(--gold)}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.6em;
  padding:.7em 1.15em;font-family:inherit;font-size:13px;font-weight:700;
  letter-spacing:.1em;line-height:1.2;text-decoration:none;
  border:1px solid transparent;border-radius:0;
  transition:background-color .2s ease,color .2s ease,border-color .2s ease,transform .2s ease;
}
.btn--maple{background:var(--maple);border-color:var(--maple);color:#fff}
.btn--maple:hover{background:var(--maple-hot);border-color:var(--maple-hot);transform:translateY(-1px)}
.btn--ghost{background:transparent;border-color:var(--line-strong);color:var(--ink)}
.btn--ghost:hover{border-color:var(--maple);color:var(--maple)}
.btn--invert{background:transparent;border-color:rgba(247,251,252,.42);color:var(--snow)}
.btn--invert:hover{border-color:var(--gold);color:var(--gold)}
.btn--gold{background:var(--gold);border-color:var(--gold);color:var(--ink)}
.btn--gold:hover{background:#FFC85C;border-color:#FFC85C}
.masthead__cta{flex:0 0 auto}

.navband{
  position:sticky;top:0;z-index:50;
  background:rgba(247,251,252,.94);
  border-bottom:1px solid var(--line);
  -webkit-backdrop-filter:saturate(150%) blur(6px);
  backdrop-filter:saturate(150%) blur(6px);
}
.navband__inner{
  position:relative;display:flex;align-items:center;
  gap:clamp(12px,2vw,30px);min-height:60px;padding-block:6px;
}
.nav-index{
  display:flex;align-items:center;gap:8px;white-space:nowrap;
  font-size:11px;font-weight:600;letter-spacing:.22em;line-height:1.4;color:var(--slate);
}
.nav-index__num{
  font-family:var(--font-mono);font-size:10px;letter-spacing:.08em;
  color:var(--maple);border:1px solid rgba(192,57,43,.36);padding:1px 5px;line-height:1.5;
}

.nav{margin-inline-start:auto}
.nav-list{counter-reset:nav;display:flex;align-items:center;gap:clamp(6px,1.7vw,26px)}
.nav-list__item{counter-increment:nav;display:flex}
.nav-list__link{
  position:relative;display:inline-flex;align-items:baseline;gap:.45em;
  padding:10px 2px;font-size:14px;font-weight:600;letter-spacing:.08em;
  color:var(--ink);text-decoration:none;transition:color .2s ease;
}
.nav-list__link::before{
  content:counter(nav,decimal-leading-zero);
  font-family:var(--font-mono);font-size:9.5px;font-weight:400;letter-spacing:0;
  color:var(--slate);
}
.nav-list__link::after{
  content:"";position:absolute;left:0;right:0;bottom:2px;height:2px;
  background:var(--maple);transform:scaleX(0);transform-origin:left center;
  transition:transform .22s ease;
}
.nav-list__link:hover{color:var(--ice)}
.nav-list__link:hover::after{transform:scaleX(1)}
.nav-list__link[aria-current="page"]{color:var(--maple)}
.nav-list__link[aria-current="page"]::before{color:var(--maple)}
.nav-list__link[aria-current="page"]::after{transform:scaleX(1)}

.nav-toggle{
  display:none;align-items:center;gap:10px;margin-inline-start:auto;
  padding:10px 12px;border:1px solid var(--line-strong);background:var(--paper);
  font-size:12px;font-weight:700;letter-spacing:.14em;color:var(--ink);
  transition:color .2s ease,border-color .2s ease;
}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:center;gap:4px;width:18px;height:12px}
.nav-toggle__bars span{display:block;height:1.5px;background:currentColor;transition:transform .2s ease,opacity .2s ease}
.nav-toggle__label{line-height:1}
.site-header[data-open] .nav-toggle{border-color:var(--maple);color:var(--maple)}
.site-header[data-open] .nav-toggle__bars span:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.site-header[data-open] .nav-toggle__bars span:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle__bars span:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

.scroll-line{
  position:absolute;left:var(--gutter);right:var(--gutter);bottom:-1px;height:2px;
  overflow:hidden;pointer-events:none;
}
.scroll-line::after{
  content:"";display:block;height:100%;width:100%;
  background:linear-gradient(90deg,var(--ice),var(--ice) 45%,var(--maple) 100%);
  transform:scaleX(var(--scroll-progress,0));transform-origin:left center;
  transition:transform .12s linear;
}

/* 6. Footer -------------------------------------------------------------- */
.site-footer{background:var(--snow)}
.footer-next{background:var(--ice-pale);border-top:1px solid rgba(44,122,148,.3)}
.footer-next__inner{
  display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);
  gap:clamp(22px,4vw,56px);align-items:center;
  padding-block:clamp(36px,5vw,64px);
}
.footer-next__lead{display:grid;align-content:start;gap:8px}
.footer-next__title{font-size:clamp(26px,3.6vw,44px);font-weight:900;line-height:1.14;letter-spacing:-.02em;color:var(--ink)}
.footer-next__routes{display:grid;gap:12px}
.route-card{
  display:grid;grid-template-columns:auto minmax(0,1fr);
  grid-template-areas:"num title" "num meta";gap:2px 16px;
  padding:16px 18px;background:var(--paper);border:1px solid rgba(44,122,148,.32);
  text-decoration:none;
  transition:border-color .2s ease,transform .2s ease,box-shadow .2s ease;
}
.route-card:hover,.route-card:focus-visible{
  border-color:var(--maple);transform:translateY(-2px);
  box-shadow:0 16px 26px -22px rgba(11,31,42,.65);
}
.route-card__num{
  grid-area:num;align-self:center;padding-right:14px;
  border-right:1px solid var(--line);
  font-family:var(--font-mono);font-size:13px;font-weight:700;letter-spacing:.06em;color:var(--maple);
}
.route-card__title{grid-area:title;font-size:16px;font-weight:700;letter-spacing:.02em;line-height:1.5;color:var(--ink)}
.route-card__meta{grid-area:meta;font-size:12.5px;letter-spacing:.06em;line-height:1.6;color:var(--slate)}

.footer-main{background:var(--deep);color:rgba(247,251,252,.8)}
.footer-main__inner{
  display:grid;grid-template-columns:minmax(0,1.35fr) repeat(3,minmax(0,1fr));
  gap:clamp(24px,3.4vw,52px);padding-block:clamp(40px,5.6vw,76px);
}
.footer-brand{display:grid;gap:14px;align-content:start;justify-items:start}
.footer-brand__name{font-size:20px;font-weight:800;letter-spacing:.06em;line-height:1.3;color:var(--snow)}
.footer-brand__note{max-width:34ch;font-size:14px;line-height:1.85;color:rgba(247,251,252,.64)}
.footer-col{display:grid;align-content:start}
.footer-col__title{margin-bottom:14px;font-size:11px;font-weight:700;letter-spacing:.24em;line-height:1.4;color:var(--gold)}
.footer-list{display:grid;gap:9px}
.footer-list__link{
  font-size:14px;line-height:1.65;color:rgba(247,251,252,.76);text-decoration:none;
  border-bottom:1px solid transparent;transition:color .2s ease,border-color .2s ease;
}
.footer-list__link:hover{color:var(--snow);border-bottom-color:var(--maple-hot)}
.footer-col__note{margin-top:12px;font-size:12px;letter-spacing:.06em;color:rgba(247,251,252,.46)}

.footer-meta{background:var(--ink);border-top:1px solid rgba(247,251,252,.1);color:rgba(247,251,252,.56)}
.footer-meta__inner{
  display:flex;flex-wrap:wrap;align-items:center;gap:10px 26px;
  padding-block:18px;font-size:12px;letter-spacing:.08em;line-height:1.6;
}
.footer-meta__legal{color:rgba(247,251,252,.6)}
.footer-meta__copy{font-family:var(--font-mono);font-size:11.5px;letter-spacing:.04em}
.footer-meta__links{display:flex;flex-wrap:wrap;gap:16px;margin-inline-start:auto}
.footer-meta__link{
  color:rgba(247,251,252,.62);text-decoration:none;border-bottom:1px solid transparent;
  transition:color .2s ease,border-color .2s ease;
}
.footer-meta__link:hover{color:var(--gold);border-bottom-color:var(--gold)}

/* 7. Page kit ------------------------------------------------------------ */
.section{padding-block:var(--step)}
.section--tint{background:var(--ice-pale)}
.section--deep{background:var(--deep);color:rgba(247,251,252,.88)}
.section--rule{border-top:1px solid var(--line)}
.section--deep.section--rule{border-top-color:var(--line-invert)}

.section-head{
  display:grid;grid-template-columns:var(--num-col) minmax(0,1fr);
  gap:clamp(14px,3vw,40px);align-items:start;
  margin-bottom:clamp(24px,3.4vw,48px);
}
.section-head__index{
  padding-top:.3em;font-family:var(--font-mono);
  font-size:clamp(18px,2.2vw,26px);font-weight:700;line-height:1;letter-spacing:.04em;color:var(--gold);
}
.section-head__title{font-size:clamp(27px,3.9vw,44px);font-weight:900;line-height:1.12;letter-spacing:-.025em}
.section-head__lede{max-width:62ch;margin-top:14px;font-size:17px;line-height:1.8;color:var(--slate)}
.section--deep .section-head__lede{color:rgba(247,251,252,.64)}
.lede{max-width:62ch;font-size:clamp(17px,1.6vw,19px);line-height:1.85;color:var(--slate)}

.grid{display:grid;gap:clamp(18px,2.6vw,34px)}
.grid--7-5{grid-template-columns:minmax(0,7fr) minmax(0,5fr)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr))}

.card{
  display:grid;gap:10px;padding:clamp(18px,2.4vw,28px);
  background:var(--paper);border:1px solid var(--line);text-decoration:none;
  transition:border-color .2s ease,transform .2s ease;
}
a.card:hover,a.card:focus-visible{border-color:var(--ice);transform:translateY(-2px)}
.card__index{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--slate)}
.card__title{font-size:20px;font-weight:800;line-height:1.35;letter-spacing:-.01em}
.card__text{font-size:15px;line-height:1.8;color:var(--slate)}
.card__meta{font-size:12px;font-weight:600;letter-spacing:.1em;color:var(--ice)}

.tag{
  display:inline-block;padding:4px 10px;border:1px solid rgba(44,122,148,.26);
  background:rgba(44,122,148,.1);color:var(--ice);
  font-size:11.5px;font-weight:600;letter-spacing:.14em;line-height:1.6;
}
.tag--maple{border-color:rgba(192,57,43,.28);background:rgba(192,57,43,.08);color:var(--maple)}
.tag--gold{border-color:rgba(242,181,68,.55);background:rgba(242,181,68,.18);color:var(--gold-ink)}

.filter-bar{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:clamp(20px,3vw,32px)}
.filter-btn{
  padding:8px 14px;border:1px solid var(--line-strong);background:var(--paper);
  font-size:12.5px;font-weight:600;letter-spacing:.12em;color:var(--deep);
  transition:background-color .18s ease,color .18s ease,border-color .18s ease;
}
.filter-btn:hover{border-color:var(--ice);color:var(--ice)}
.filter-btn[aria-pressed="true"]{background:var(--deep);border-color:var(--deep);color:var(--snow)}
.filter-item{transition:opacity .2s ease,transform .2s ease}
.filter-item[hidden]{display:none}

.steps{display:grid;gap:0;border-top:1px solid var(--line)}
.step{
  display:grid;grid-template-columns:var(--num-col) minmax(0,1fr);
  border-bottom:1px solid var(--line);background:var(--paper);
}
.step__num{
  display:flex;align-items:flex-start;justify-content:center;
  padding:22px 0 0;border-right:1px solid var(--line);background:rgba(221,239,244,.45);
  font-family:var(--font-mono);font-size:16px;font-weight:700;letter-spacing:.06em;color:var(--maple);
}
.step__body{padding:18px clamp(16px,2.4vw,28px) 22px}
.step__title{font-size:18px;font-weight:800;line-height:1.45;letter-spacing:.01em}
.step__text{margin-top:8px;font-size:15.5px;line-height:1.8;color:var(--slate)}
.steps--accordion .step{display:block}
.steps--accordion .step__head{
  display:grid;grid-template-columns:var(--num-col) minmax(0,1fr) 34px;
  align-items:center;cursor:pointer;
}
.steps--accordion .step__head::-webkit-details-marker{display:none}
.steps--accordion .step__head .step__num{align-self:stretch;align-items:center;padding:16px 0}
.steps--accordion .step__head .step__title{padding:16px clamp(16px,2.4vw,28px);font-size:17px}
.steps--accordion .step__body{margin-inline-start:var(--num-col)}
.step__sign{position:relative;justify-self:end;width:12px;height:12px;margin-inline-end:14px}
.step__sign::before,.step__sign::after{
  content:"";position:absolute;background:var(--ice);transition:transform .2s ease,opacity .2s ease;
}
.step__sign::before{left:0;right:0;top:5.25px;height:1.5px}
.step__sign::after{top:0;bottom:0;left:5.25px;width:1.5px}
.step[open] .step__sign::after{transform:scaleY(0);opacity:0}
.step[open] .step__title{color:var(--maple)}

.toc{display:grid;gap:10px;position:sticky;top:84px;align-content:start;font-size:13px}
.toc__title{font-size:11px;font-weight:700;letter-spacing:.24em;line-height:1.4;color:var(--slate)}
.toc__list{display:grid;gap:8px;padding-left:14px;border-left:1px solid var(--line)}
.toc__link{
  font-size:13px;letter-spacing:.06em;line-height:1.6;color:var(--slate);
  text-decoration:none;transition:color .2s ease;
}
.toc__link:hover{color:var(--ink)}
.toc__link[aria-current="true"]{color:var(--maple);font-weight:700}

.breadcrumb{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:12px;letter-spacing:.12em;color:var(--slate)}
.breadcrumb__link{color:var(--slate);text-decoration:none;border-bottom:1px solid transparent;transition:color .2s ease,border-color .2s ease}
.breadcrumb__link:hover{color:var(--ice);border-bottom-color:var(--ice)}
.breadcrumb__sep{color:var(--line-strong)}
.breadcrumb__current{color:var(--ink);font-weight:600}

.prose{max-width:70ch}
.prose p+p{margin-top:1.1em}
.prose h3{margin-top:1.8em;font-size:20px;font-weight:800;line-height:1.4}
.prose ul{display:grid;gap:.6em;margin-top:1em;padding-left:1.15em}
.prose li{position:relative;font-size:16.5px;line-height:1.8}
.prose li::before{content:"";position:absolute;left:-1.15em;top:.75em;width:7px;height:7px;background:var(--gold)}
.prose a{color:var(--ice);text-decoration:none;border-bottom:1px solid rgba(44,122,148,.42)}
.prose a:hover{color:var(--maple);border-bottom-color:var(--maple)}

.figure{display:grid;gap:10px;margin:0}
.figure__frame{
  position:relative;width:100%;aspect-ratio:16/10;overflow:hidden;
  border:1px solid var(--line);
  background:linear-gradient(135deg,var(--ice-pale),var(--snow) 62%,rgba(44,122,148,.16));
}
.figure__frame > img,.figure__frame > svg{width:100%;height:100%;object-fit:cover;display:block}
.figure__frame--tall{aspect-ratio:3/4}
.figure__frame--wide{aspect-ratio:21/9}
.figure__caption{font-size:12px;letter-spacing:.1em;line-height:1.7;color:var(--slate)}

.path{display:flex;flex-wrap:wrap;border:1px solid var(--line);background:var(--paper)}
.path__node{
  position:relative;flex:1 1 168px;display:grid;gap:4px;
  padding:18px;border-right:1px solid var(--line);text-decoration:none;
  transition:background-color .2s ease;
}
.path__node:last-child{border-right:0}
.path__node::before{content:"";position:absolute;left:18px;top:-4px;width:8px;height:8px;background:var(--gold)}
.path__node:hover{background:rgba(221,239,244,.55)}
.path__num{font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;color:var(--slate)}
.path__label{font-size:15px;font-weight:700;line-height:1.5;color:var(--ink)}

/* 8. Motion & responsive ------------------------------------------------- */
.js-ready [data-reveal]{
  opacity:0;transform:translateY(16px);
  transition:opacity .32s ease,transform .32s ease;
}
.js-ready [data-reveal].is-visible{opacity:1;transform:none}

@media (max-width:1080px){
  .nav-index{display:none}
}
@media (max-width:900px){
  .masthead__inner{flex-wrap:wrap;gap:12px 16px;padding-block:14px}
  .utility{
    order:3;flex-basis:100%;margin-inline-start:0;flex-wrap:wrap;
    gap:14px;padding-top:10px;border-top:1px solid rgba(247,251,252,.14);
  }
  .masthead__cta{order:2;margin-inline-start:auto}
  .nav-toggle{display:inline-flex}
  .nav{
    position:absolute;left:0;right:0;top:100%;margin-inline-start:0;display:none;
    background:var(--paper);border-bottom:1px solid var(--line);
    box-shadow:0 22px 34px -26px rgba(11,31,42,.55);
  }
  .site-header[data-open] .nav{display:block}
  .nav-list{flex-direction:column;align-items:stretch;gap:0;padding-block:4px}
  .nav-list__item{border-bottom:1px solid var(--line)}
  .nav-list__item:last-child{border-bottom:0}
  .nav-list__link{padding:14px var(--gutter);font-size:15px}
  .nav-list__link::after{left:var(--gutter);right:auto;width:24px;bottom:9px}
  .footer-next__inner{grid-template-columns:minmax(0,1fr)}
  .footer-main__inner{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid--7-5,.grid--2,.grid--3{grid-template-columns:minmax(0,1fr)}
  .toc{position:static;top:auto}
}
@media (max-width:640px){
  body{font-size:16.5px}
  .section-head{grid-template-columns:clamp(38px,10vw,48px) minmax(0,1fr);gap:12px}
  .section-head__index{font-size:17px}
  .step{grid-template-columns:clamp(40px,12vw,52px) minmax(0,1fr)}
  .step__num{font-size:14px;padding-top:20px}
  .footer-main__inner{grid-template-columns:minmax(0,1fr);gap:28px}
  .footer-meta__links{margin-inline-start:0}
  .brand__mark{width:34px;height:34px}
  .utility__link{font-size:12px;letter-spacing:.1em}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:.001ms !important;animation-duration:.001ms !important}
  .js-ready [data-reveal]{opacity:1;transform:none}
  .scroll-line::after{transition:none}
}