/* =========================================================
   鼎博指南 · assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 头尾 / 通用组件
   ========================================================= */

/* ---------- 1. 变量 ---------- */
:root{
  --ink:#081826;
  --ink-deep:#05121D;
  --ink-2:#0F2637;
  --ink-3:#0C2131;
  --line:#17384F;
  --paper:#F4F0E6;
  --mist:#A7B6C2;
  --orange:#FF6B35;
  --orange-soft:#FFB38A;
  --jade:#86CDB8;
  --jade-deep:#1E6B58;
  --white:#FFFFFF;

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

  --wrap:1200px;
  --gutter:clamp(16px,4vw,40px);
  --rail:200px;
  --ease:cubic-bezier(.2,.7,.2,1);
  --dur:220ms;
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:132px;
}
body{
  margin:0;
  background:var(--ink);
  color:var(--paper);
  font-family:var(--font-sans);
  font-size:clamp(16px,1.05vw,18px);
  font-weight:400;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}
h1,h2,h3,h4,h5,h6,p,ul,ol,dl,dd,figure,blockquote{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg,video{display:block;max-width:100%;height:auto;}
a{color:inherit;text-decoration:none;}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;}
table{border-collapse:collapse;width:100%;}
#main-content{display:block;outline:none;}

/* ---------- 3. 中文排版 ---------- */
h1,h2,h3,h4{
  font-weight:900;
  letter-spacing:-.03em;
  line-height:1.06;
  color:var(--paper);
  text-wrap:balance;
}
h1{font-size:clamp(38px,5vw,64px);}
h2{font-size:clamp(26px,3.2vw,42px);}
h3{font-size:clamp(20px,2vw,26px);letter-spacing:-.02em;line-height:1.22;}
p{text-wrap:pretty;}
strong,b{font-weight:700;color:var(--white);}
small{font-size:.82em;}

/* ---------- 4. 可访问性 ---------- */
:focus-visible{
  outline:2px solid var(--jade);
  outline-offset:3px;
  border-radius:2px;
}
.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:300;
  padding:10px 18px;
  background:var(--orange);
  color:#0A1420;
  font-size:14px;
  font-weight:700;
  border-radius:2px;
  transform:translateY(-180%);
  transition:transform var(--dur) var(--ease);
}
.skip-link:focus{transform:translateY(0);}

/* ---------- 5. 容器 ---------- */
.wrap{
  width:min(calc(100% - var(--gutter) * 2), var(--wrap));
  margin-inline:auto;
}
.page{
  display:block;
  padding:clamp(20px,3.4vw,42px) 0 clamp(48px,7vw,96px);
}
.grid-12{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(16px,2.4vw,32px);
}
.rail-layout{
  display:grid;
  grid-template-columns:var(--rail) minmax(0,1fr);
  gap:clamp(24px,4vw,56px);
  align-items:start;
}
.prose{max-width:70ch;}
.prose p{margin-bottom:1.05em;}
.prose p:last-child{margin-bottom:0;}

/* ---------- 6. 头部 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:120;
  background:var(--ink);
  border-bottom:1px solid var(--line);
  isolation:isolate;
}
.header-utility{
  background:#0B1E2E;
  border-bottom:1px solid var(--line);
}
.header-utility__inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:18px;
  min-height:38px;
  padding-block:6px;
}
.header-line{
  font-size:12.5px;
  letter-spacing:.03em;
  color:var(--mist);
  line-height:1.5;
}
.quick-nav{
  display:flex;
  align-items:center;
  gap:20px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
}
.quick-nav__link{
  color:var(--mist);
  padding-block:2px;
  border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.quick-nav__link:hover{
  color:var(--orange-soft);
  border-bottom-color:var(--orange);
}

.header-body__inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
  min-height:74px;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:12px;
  flex:0 0 auto;
}
.brand__mark{
  display:grid;
  place-items:center;
  width:40px;
  height:40px;
  background:var(--orange);
  color:#08131C;
  font-size:20px;
  font-weight:900;
  line-height:1;
  border-radius:2px;
}
.brand__text{
  display:flex;
  flex-direction:column;
  gap:3px;
}
.brand__name{
  font-size:19px;
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.1;
  color:var(--paper);
}
.brand__meta{
  font-family:var(--font-mono);
  font-size:9.5px;
  letter-spacing:.16em;
  line-height:1;
  color:var(--mist);
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:9px 13px;
  background:var(--ink-2);
  border:1px solid var(--line);
  border-radius:2px;
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  transition:border-color .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--orange);}
.nav-toggle__box{
  display:grid;
  gap:4px;
  width:16px;
}
.nav-toggle__box span{
  display:block;
  height:2px;
  background:var(--orange);
  transition:transform var(--dur) var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__box span:first-child{
  transform:translateY(3px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__box span:last-child{
  transform:translateY(-3px) rotate(-45deg);
}
.nav-toggle__text{line-height:1;}

.site-nav{
  display:flex;
  align-items:center;
  gap:22px;
}
.site-nav__list{
  display:flex;
  align-items:center;
  gap:clamp(10px,1.7vw,26px);
}
.site-nav__item{display:block;}
.site-nav__link{
  position:relative;
  display:inline-block;
  padding:8px 2px;
  font-size:15px;
  font-weight:500;
  letter-spacing:.01em;
  color:#CBD5DD;
  transition:color .18s var(--ease);
}
.site-nav__link::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:2px;
  background:var(--orange);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform var(--dur) var(--ease);
}
.site-nav__link:hover{color:var(--paper);}
.site-nav__link:hover::after,
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);}
.site-nav__link[aria-current="page"]{
  color:var(--white);
  font-weight:700;
}
.site-nav__aside{
  display:none;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--mist);
}

.scroll-meter{
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:2px;
  pointer-events:none;
}
.scroll-meter__bar{
  display:block;
  width:0;
  height:100%;
  background:var(--orange);
}

/* ---------- 7. 移动 / 平板导航 ---------- */
@media (max-width:1000px){
  .nav-toggle{display:inline-flex;}
  .quick-nav{display:none;}
  .site-nav{
    position:absolute;
    top:100%;
    left:0;
    right:0;
    display:block;
    max-height:0;
    overflow:hidden;
    background:var(--ink-2);
    border-top:1px solid var(--line);
    border-bottom:1px solid var(--line);
    box-shadow:0 24px 40px -30px #000;
    transition:max-height 260ms var(--ease);
  }
  .site-nav[data-open="true"]{
    max-height:min(80vh,640px);
    overflow-y:auto;
  }
  .site-nav__list{
    display:block;
    padding:4px var(--gutter) 10px;
    gap:0;
  }
  .site-nav__item{border-bottom:1px solid var(--line);}
  .site-nav__item:last-child{border-bottom:0;}
  .site-nav__link{
    display:block;
    padding:15px 0;
    font-size:16px;
  }
  .site-nav__link::after{display:none;}
  .site-nav__link[aria-current="page"]{
    padding-left:12px;
    border-left:3px solid var(--orange);
    color:var(--orange-soft);
  }
  .site-nav__aside{
    display:block;
    padding:10px var(--gutter) 20px;
  }
  .rail-layout{grid-template-columns:minmax(0,1fr);}
  .grid-12{grid-template-columns:repeat(6,minmax(0,1fr));}
  html{scroll-padding-top:120px;}
}

@media (max-width:560px){
  .header-line{font-size:11.5px;letter-spacing:0;}
  .brand__mark{width:34px;height:34px;font-size:17px;}
  .brand__name{font-size:17px;}
  .brand__meta{font-size:8.5px;letter-spacing:.12em;}
  .header-body__inner{min-height:64px;gap:14px;}
  .grid-12{grid-template-columns:repeat(2,minmax(0,1fr));}
}

/* ---------- 8. 页脚 ---------- */
.site-footer{
  margin-top:clamp(56px,9vw,110px);
  background:var(--ink-deep);
  border-top:1px solid var(--line);
  padding-top:clamp(38px,5vw,64px);
}
.footer-grid{
  display:grid;
  grid-template-columns:minmax(0,1.6fr) repeat(3,minmax(0,1fr));
  gap:clamp(26px,4vw,54px);
  padding-bottom:clamp(30px,4vw,52px);
}
.footer-lead{
  display:flex;
  flex-direction:column;
  align-items:flex-start;
  gap:16px;
}
.footer-lead__line{
  font-size:15px;
  line-height:1.7;
  color:var(--mist);
  max-width:26ch;
}
.footer-col__title{
  font-family:var(--font-mono);
  font-size:11px;
  font-weight:500;
  letter-spacing:.16em;
  line-height:1.4;
  color:var(--jade);
  padding-bottom:11px;
  margin-bottom:14px;
  border-bottom:1px solid var(--line);
}
.footer-col__list{
  display:grid;
  gap:9px;
  font-size:14.5px;
}
.footer-col__list a{
  color:#C9D3DB;
  transition:color .18s var(--ease);
}
.footer-col__list a:hover{color:var(--orange-soft);}

.footer-contact{
  display:grid;
  grid-template-columns:minmax(0,240px) minmax(0,1fr);
  gap:clamp(16px,3vw,44px);
  padding:clamp(22px,3vw,34px) 0;
  border-top:1px solid var(--line);
  border-bottom:1px solid var(--line);
}
.footer-contact__side{
  display:grid;
  gap:10px;
  align-content:start;
}
.footer-contact__kicker{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  color:var(--orange-soft);
  line-height:1.4;
}
.footer-contact__note{
  font-size:12.5px;
  line-height:1.7;
  color:var(--mist);
}
.footer-contact__list{
  display:grid;
  gap:10px;
  margin:0;
}
.footer-contact__row{
  display:flex;
  align-items:baseline;
  gap:14px;
  padding-bottom:8px;
  border-bottom:1px dashed rgba(23,56,79,.7);
}
.footer-contact__row:last-child{
  padding-bottom:0;
  border-bottom:0;
}
.footer-contact__row dt{
  flex:0 0 auto;
  min-width:42px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  color:var(--jade);
}
.footer-contact__row dd{
  margin:0;
  font-size:15px;
  color:var(--paper);
  word-break:break-word;
}

.footer-base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 24px;
  padding:22px 0 30px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--mist);
  line-height:1.6;
}
.footer-base__copy{margin:0;}
.footer-base__meta{
  margin:0;
  color:rgba(167,182,194,.7);
}

@media (max-width:860px){
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer-lead{grid-column:1 / -1;}
  .footer-contact{grid-template-columns:minmax(0,1fr);}
}
@media (max-width:520px){
  .footer-grid{grid-template-columns:minmax(0,1fr);}
  .footer-base{flex-direction:column;align-items:flex-start;}
}

/* ---------- 9. 通用组件 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  padding:12px 22px;
  font-size:14.5px;
  font-weight:700;
  letter-spacing:.01em;
  line-height:1.3;
  border:1px solid transparent;
  border-radius:2px;
  transition:transform var(--dur) var(--ease),
             background-color .18s var(--ease),
             border-color .18s var(--ease),
             color .18s var(--ease);
}
.btn:hover{transform:translateY(-2px);}
.btn--orange{background:var(--orange);color:#0A1420;}
.btn--orange:hover{background:var(--orange-soft);}
.btn--jade{background:var(--jade);color:#06231C;}
.btn--jade:hover{background:#A6E2CF;}
.btn--ghost{
  background:transparent;
  border-color:var(--line);
  color:var(--paper);
}
.btn--ghost:hover{
  border-color:var(--orange);
  color:var(--orange-soft);
}

.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 9px;
  border:1px solid var(--line);
  border-radius:2px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.1em;
  line-height:1.5;
  color:var(--mist);
  white-space:nowrap;
}
.tag--jade{
  color:var(--jade);
  border-color:rgba(134,205,184,.42);
  background:rgba(134,205,184,.09);
}
.tag--orange{
  color:var(--orange-soft);
  border-color:rgba(255,107,53,.45);
  background:rgba(255,107,53,.1);
}

.card{
  position:relative;
  background:var(--ink-2);
  border:1px solid var(--line);
  border-radius:3px;
  padding:clamp(18px,2.4vw,28px);
  transition:transform var(--dur) var(--ease),
             border-color var(--dur) var(--ease),
             box-shadow var(--dur) var(--ease);
}
.card:hover{
  transform:translateY(-2px);
  border-color:var(--orange);
  box-shadow:0 16px 34px -24px #000;
}

.breadcrumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding-top:clamp(18px,3vw,30px);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  color:var(--mist);
}
.breadcrumbs a{
  color:var(--mist);
  transition:color .18s var(--ease);
}
.breadcrumbs a:hover{color:var(--orange-soft);}
.breadcrumbs__sep{color:var(--line);}
.breadcrumbs [aria-current="page"]{color:var(--paper);}

.eyebrow{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.18em;
  line-height:1.6;
  color:var(--jade);
  text-transform:uppercase;
}
.note{
  font-size:13.5px;
  line-height:1.7;
  color:var(--mist);
}
.divider{
  height:1px;
  border:0;
  margin:0;
  background:var(--line);
}

/* ---------- 10. 图片容器基础 ---------- */
.media{
  position:relative;
  margin:0;
  background:var(--ink-2);
  border:1px solid var(--line);
  border-radius:3px;
  overflow:hidden;
}
.media__frame{
  position:relative;
  aspect-ratio:16 / 10;
  display:grid;
  place-items:center;
  background-color:var(--ink-3);
  background-image:
    repeating-linear-gradient(0deg, rgba(23,56,79,.75) 0 1px, transparent 1px 44px),
    repeating-linear-gradient(90deg, rgba(23,56,79,.75) 0 1px, transparent 1px 44px);
  color:#33566B;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.16em;
  overflow:hidden;
}
.media__frame > img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.media__caption{
  padding:10px 14px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.06em;
  line-height:1.6;
  color:var(--mist);
}
.media--wide .media__frame{aspect-ratio:21 / 9;}
.media--tall .media__frame{aspect-ratio:3 / 4;}
.media--square .media__frame{aspect-ratio:1 / 1;}

/* ---------- 11. 返回顶部 ---------- */
.to-top{
  position:fixed;
  right:clamp(14px,3vw,28px);
  bottom:clamp(14px,3vw,28px);
  z-index:110;
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:11px 15px;
  background:var(--ink-2);
  border:1px solid var(--line);
  border-radius:2px;
  color:var(--paper);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.12em;
  line-height:1;
  opacity:0;
  visibility:hidden;
  transform:translateY(10px);
  transition:opacity var(--dur) var(--ease),
             transform var(--dur) var(--ease),
             visibility var(--dur) var(--ease),
             border-color .18s var(--ease),
             color .18s var(--ease);
}
.to-top[data-visible="true"]{
  opacity:1;
  visibility:visible;
  transform:translateY(0);
}
.to-top:hover{
  border-color:var(--orange);
  color:var(--orange-soft);
}
.to-top__glyph{
  color:var(--orange);
  font-size:13px;
}

/* ---------- 12. 减弱动效 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
}