/* =========================================================
   51棋牌特色 · 共享样式表  /assets/site.css
   报头 · 页脚 · 排版 · 基础组件
   ========================================================= */

/* ---------- 1. 变量 ---------- */
:root{
  --ink-deep:#060A18;
  --ink-console:#101A33;
  --cyan:#22E0D6;
  --cyan-soft:#7FF3EA;
  --gold:#F5B94B;
  --rose:#FF4D8D;
  --white:#F2F6FF;
  --mist:#8B9AC0;
  --line:#1E2A47;
  --violet:#5A3E8C;

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

  --maxw:1180px;
  --gutter:clamp(18px,5vw,56px);
  --radius-lg:26px;
  --radius-md:16px;
  --radius-pill:999px;
  --glow-cyan:0 0 14px rgba(34,224,214,.75);
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body{
  margin:0;
  padding:0;
  background-color:var(--ink-deep);
  background-image:
    radial-gradient(60% 42% at 88% -8%, rgba(34,224,214,.10), transparent 70%),
    radial-gradient(52% 44% at -6% 18%, rgba(90,62,140,.18), transparent 72%),
    radial-gradient(70% 50% at 50% 118%, rgba(245,185,75,.06), transparent 70%);
  background-repeat:no-repeat;
  background-attachment:fixed;
  color:var(--white);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.75;
  font-weight:400;
  overflow-x:hidden;
}
img,svg{max-width:100%;display:block;}
button,input,select,textarea{font:inherit;color:inherit;}
ul,ol{margin:0;padding:0;}
::selection{background:rgba(34,224,214,.32);color:#04211F;}

/* ---------- 3. 中文排版 ---------- */
h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.16;
  margin:0 0 .55em;
  color:var(--white);
}
h1{font-size:clamp(34px,6vw,56px);}
h2{font-size:clamp(26px,3.8vw,38px);}
h3{font-size:clamp(19px,2.2vw,24px);letter-spacing:-.01em;}
h4{font-size:18px;letter-spacing:0;}
a{color:var(--cyan-soft);text-underline-offset:3px;}
a:hover{color:var(--cyan);}
p{margin:0 0 1em;}
p:last-child{margin-bottom:0;}
strong,b{font-weight:700;color:var(--gold);}
.mono,[data-mono]{font-family:var(--font-mono);}

/* ---------- 4. 焦点与无障碍 ---------- */
:focus{outline:none;}
:focus-visible{
  outline:2px solid var(--cyan-soft);
  outline-offset:3px;
  border-radius:6px;
}
.skip-link{
  position:fixed;
  left:50%;
  top:-120px;
  transform:translateX(-50%);
  z-index:400;
  padding:12px 26px;
  border-radius:0 0 var(--radius-md) var(--radius-md);
  background:var(--cyan);
  color:#04211F;
  font-weight:700;
  font-size:14px;
  text-decoration:none;
  transition:top .22s ease;
}
.skip-link:focus{top:0;color:#04211F;}

/* ---------- 5. 布局骨架 ---------- */
.container{
  width:100%;
  max-width:var(--maxw);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.container--narrow{max-width:820px;}
.section{
  position:relative;
  padding-block:clamp(46px,7.5vw,100px);
}
.section--tight{padding-block:clamp(26px,4vw,54px);}
.section-title{
  font-size:clamp(26px,3.8vw,38px);
  font-weight:900;
  letter-spacing:-.02em;
  line-height:1.15;
  margin:0 0 12px;
}
.lede{
  font-size:clamp(17px,2.2vw,21px);
  line-height:1.75;
  color:#CDD8F2;
  max-width:640px;
  margin:0 0 1em;
}
.prose{
  max-width:640px;
  font-size:17px;
  line-height:1.8;
  color:var(--white);
}
.prose p{margin:0 0 1.05em;}
.prose a{
  color:var(--cyan-soft);
  text-decoration:underline;
  text-decoration-color:rgba(127,243,234,.42);
  text-underline-offset:4px;
}
.prose a:hover{color:var(--cyan);}
.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:10px;
  margin:0 0 14px;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:700;
  letter-spacing:.28em;
  text-transform:uppercase;
  color:var(--cyan);
}
.eyebrow::before{
  content:"";
  width:28px;
  height:1px;
  background:var(--cyan);
  box-shadow:var(--glow-cyan);
}
.side-note{
  font-size:12.5px;
  line-height:1.7;
  letter-spacing:.04em;
  color:var(--mist);
  font-family:var(--font-mono);
  margin:0;
}
.side-note--vertical{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  letter-spacing:.24em;
}
.divider-neon{
  height:1px;
  border:0;
  margin:0;
  background:linear-gradient(90deg,transparent,var(--cyan) 18%,var(--violet) 62%,transparent);
  opacity:.65;
}
.grid{display:grid;gap:clamp(14px,2vw,22px);}
.grid--auto{grid-template-columns:repeat(auto-fill,minmax(230px,1fr));}
.grid--3{grid-template-columns:repeat(auto-fill,minmax(268px,1fr));}

/* ---------- 6. 章节滚动高亮 ---------- */
[data-section]{position:relative;}
[data-section]::before{
  content:"";
  position:absolute;
  left:0;
  top:0;
  width:3px;
  height:0;
  border-radius:0 3px 3px 0;
  background:linear-gradient(180deg,var(--cyan),var(--gold));
  box-shadow:var(--glow-cyan);
  transition:height .5s cubic-bezier(.22,1,.36,1);
  pointer-events:none;
}
[data-section].is-active::before{height:100%;}

/* ---------- 7. 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:11px 22px;
  border:1px solid transparent;
  border-radius:var(--radius-pill);
  font-family:var(--font-body);
  font-size:15px;
  font-weight:700;
  letter-spacing:.02em;
  line-height:1.2;
  text-decoration:none;
  white-space:nowrap;
  cursor:pointer;
  transition:transform .18s ease,background-color .18s ease,border-color .18s ease,color .18s ease;
}
.btn--primary{
  background:var(--cyan);
  color:#04211F;
  box-shadow:0 10px 32px -18px rgba(34,224,214,.95);
}
.btn--primary:hover{background:var(--cyan-soft);color:#04211F;transform:translateY(-1px);}
.btn--ghost{
  background:transparent;
  border-color:var(--line);
  color:var(--white);
}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan-soft);transform:translateY(-1px);}
.btn--rose{
  background:rgba(255,77,141,.07);
  border-color:rgba(255,77,141,.55);
  color:var(--rose);
}
.btn--rose:hover{background:rgba(255,77,141,.16);color:#FFD3E4;transform:translateY(-1px);}

/* ---------- 8. 徽章 · 卡片 · 数据 ---------- */
.badge{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 12px;
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  background:var(--ink-console);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--mist);
}
.badge--cyan{color:var(--cyan);border-color:rgba(34,224,214,.42);}
.badge--gold{color:var(--gold);border-color:rgba(245,185,75,.42);}
.badge--rose{color:var(--rose);border-color:rgba(255,77,141,.48);}

.card{
  position:relative;
  background:var(--ink-console);
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  padding:clamp(18px,2.6vw,26px);
}
.index-card{
  position:relative;
  display:block;
  background:var(--ink-console);
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  padding:22px 24px 24px;
  color:inherit;
  text-decoration:none;
  transition:border-color .2s ease,transform .2s ease,background-color .2s ease;
}
.index-card:hover{
  border-color:rgba(34,224,214,.55);
  background:#132043;
  transform:translateY(-3px);
  color:inherit;
}
.index-card__no{
  display:block;
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.18em;
  color:var(--cyan);
  margin-bottom:10px;
}
.index-card__title{
  display:block;
  font-family:var(--font-display);
  font-size:21px;
  font-weight:800;
  letter-spacing:-.01em;
  line-height:1.3;
  color:var(--white);
  margin-bottom:8px;
}
.index-card__meta{
  display:block;
  font-size:13.5px;
  line-height:1.7;
  color:var(--mist);
}
.stat{display:flex;flex-direction:column;gap:4px;}
.stat__num{
  font-family:var(--font-mono);
  font-size:clamp(32px,5.4vw,58px);
  font-weight:700;
  line-height:1;
  letter-spacing:-.02em;
  color:var(--gold);
}
.stat__label{
  font-size:13px;
  letter-spacing:.08em;
  color:var(--mist);
}

/* ---------- 9. 图形容器（供页面阶段放图） ---------- */
.media-frame{
  position:relative;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:var(--radius-lg);
  aspect-ratio:16/10;
  background-color:var(--ink-console);
  background-image:
    linear-gradient(rgba(30,42,71,.9) 1px,transparent 1px),
    linear-gradient(90deg,rgba(30,42,71,.9) 1px,transparent 1px),
    radial-gradient(120% 92% at 86% -6%, rgba(34,224,214,.17), transparent 62%),
    radial-gradient(110% 92% at 4% 104%, rgba(90,62,140,.42), transparent 68%);
  background-size:44px 44px,44px 44px,100% 100%,100% 100%;
}
.media-frame > img{
  width:100%;
  height:100%;
  object-fit:cover;
  display:block;
}
.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  background:repeating-linear-gradient(180deg, rgba(242,246,255,.05) 0 1px, transparent 1px 5px);
  pointer-events:none;
}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame--tall{aspect-ratio:3/4;}
.media-frame--square{aspect-ratio:1/1;}
.media-frame__label{
  position:absolute;
  left:14px;
  bottom:12px;
  z-index:2;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.16em;
  color:var(--cyan-soft);
  background:rgba(6,10,24,.72);
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  padding:4px 12px;
}

/* ---------- 10. 面包屑 ---------- */
.breadcrumb{padding-block:16px 0;}
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  list-style:none;
  margin:0;
  padding:0;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--mist);
}
.breadcrumb__list li{display:inline-flex;align-items:center;gap:8px;}
.breadcrumb__list li + li::before{
  content:"/";
  color:#3A4A72;
}
.breadcrumb__list a{color:var(--mist);text-decoration:none;}
.breadcrumb__list a:hover{color:var(--cyan);}
.breadcrumb__list [aria-current="page"]{color:var(--white);}

/* =========================================================
   11. 页头
   ========================================================= */
.site-header{
  position:sticky;
  top:0;
  z-index:60;
  background:rgba(6,10,24,.92);
  -webkit-backdrop-filter:blur(16px);
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--line);
}
.reading-progress{
  position:absolute;
  inset:0 0 auto 0;
  height:2px;
  background:rgba(30,42,71,.75);
  overflow:hidden;
}
.reading-progress__fill{
  display:block;
  height:100%;
  width:0;
  background:linear-gradient(90deg,var(--cyan),var(--gold));
  box-shadow:0 0 10px rgba(34,224,214,.7);
}
.masthead{
  position:relative;
  max-width:var(--maxw);
  margin-inline:auto;
  padding:18px var(--gutter) 0;
}
.masthead__row{
  display:grid;
  grid-template-columns:1fr auto 1fr;
  align-items:center;
  gap:16px;
}
.masthead__meta{
  justify-self:start;
  margin:0;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.2em;
  color:var(--mist);
  white-space:nowrap;
}
.masthead__meta strong{color:var(--gold);font-weight:700;}
.masthead__actions{
  justify-self:end;
  display:flex;
  align-items:center;
  gap:10px;
}
.brand{
  justify-self:center;
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:5px;
  text-decoration:none;
  color:inherit;
  padding-bottom:12px;
}
.brand__name{
  font-family:var(--font-display);
  font-size:clamp(22px,3.4vw,32px);
  font-weight:900;
  letter-spacing:.02em;
  line-height:1;
  color:var(--white);
}
.brand__accent{color:var(--cyan);}
.brand__tagline{
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.3em;
  text-transform:uppercase;
  color:var(--mist);
}

/* 主导航 */
.primary-nav{
  display:block;
  border-top:1px solid var(--line);
}
.nav-list{
  counter-reset:nav;
  list-style:none;
  display:flex;
  flex-wrap:wrap;
  justify-content:center;
  gap:2px 6px;
  padding:10px 0 12px;
}
.nav-link{
  position:relative;
  display:inline-flex;
  align-items:baseline;
  gap:7px;
  padding:8px 14px 10px;
  border-radius:var(--radius-pill);
  font-size:15px;
  font-weight:600;
  color:var(--mist);
  text-decoration:none;
  transition:color .18s ease,background-color .18s ease;
}
.nav-link::before{
  counter-increment:nav;
  content:counter(nav,decimal-leading-zero);
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.08em;
  color:#4E5D86;
  transition:color .18s ease;
}
.nav-link:hover{color:var(--white);background:rgba(34,224,214,.07);}
.nav-link[aria-current="page"]{color:var(--white);}
.nav-link[aria-current="page"]::before{color:var(--cyan);}
.nav-link[aria-current="page"]::after{
  content:"";
  position:absolute;
  left:16px;
  right:16px;
  bottom:3px;
  height:2px;
  border-radius:2px;
  background:var(--cyan);
  box-shadow:var(--glow-cyan);
}

/* 移动端栏目按钮 */
.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:9px 16px;
  border:1px solid var(--line);
  border-radius:var(--radius-pill);
  background:var(--ink-console);
  color:var(--white);
  font-size:14px;
  font-weight:600;
  cursor:pointer;
  transition:border-color .18s ease,color .18s ease;
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan-soft);}
.nav-toggle__bars{
  position:relative;
  width:16px;
  height:10px;
  display:inline-block;
  flex:none;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";
  position:absolute;
  left:0;
  width:100%;
  height:2px;
  border-radius:2px;
  background:var(--cyan);
  transition:transform .22s ease;
}
.nav-toggle__bars::before{top:0;}
.nav-toggle__bars::after{bottom:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{transform:translateY(4px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{transform:translateY(-4px) rotate(-45deg);}
.nav-toggle__label{letter-spacing:.08em;}

/* =========================================================
   12. 页脚
   ========================================================= */
.site-footer{
  position:relative;
  margin-top:clamp(56px,9vw,120px);
  padding-top:clamp(42px,6vw,76px);
  background:linear-gradient(180deg,#04060F 0%,#02030A 100%);
  border-top:1px solid var(--line);
  color:var(--mist);
  font-size:14.5px;
}
.site-footer::before{
  content:"";
  position:absolute;
  left:0;
  right:0;
  top:-1px;
  height:1px;
  background:linear-gradient(90deg,transparent,var(--cyan) 22%,var(--gold) 52%,var(--rose) 78%,transparent);
  opacity:.7;
}
.footer__top{
  display:grid;
  grid-template-columns:minmax(240px,1.5fr) minmax(150px,.8fr) minmax(150px,.8fr) minmax(220px,1.3fr);
  gap:clamp(24px,3.5vw,46px);
  padding-bottom:clamp(30px,4.5vw,52px);
}
.footer__brand{min-width:0;}
.footer__logo{
  margin:0 0 6px;
  font-family:var(--font-display);
  font-size:24px;
  font-weight:900;
  letter-spacing:.02em;
  line-height:1.2;
  color:var(--white);
}
.footer__tagline{
  margin:0 0 14px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.26em;
  text-transform:uppercase;
  color:var(--cyan-soft);
}
.footer__summary{
  margin:0;
  max-width:34ch;
  line-height:1.85;
  color:var(--mist);
}
.footer__col-title{
  margin:0 0 14px;
  font-family:var(--font-mono);
  font-size:11.5px;
  font-weight:700;
  letter-spacing:.24em;
  text-transform:uppercase;
  color:var(--mist);
}
.footer__list{
  list-style:none;
  display:grid;
  gap:9px;
}
.footer__list a{
  color:#B4C2E2;
  text-decoration:none;
  transition:color .16s ease;
}
.footer__list a:hover{color:var(--cyan);}
.footer__text{
  margin:0;
  max-width:30ch;
  line-height:1.9;
  color:#B4C2E2;
}
.footer__bottom{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 24px;
  padding:18px 0 28px;
  border-top:1px solid var(--line);
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  color:#5D6C90;
}
.footer__legal,
.footer__note{margin:0;}

/* =========================================================
   13. 响应式
   ========================================================= */
@media (max-width:1080px){
  .footer__top{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer__summary{max-width:46ch;}
  .footer__text{max-width:42ch;}
}

@media (max-width:860px){
  body{font-size:16.5px;}

  .masthead{padding-top:14px;}
  .masthead__row{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
  }
  .masthead__meta,
  .masthead__actions{display:none;}
  .brand{
    align-items:flex-start;
    justify-self:start;
    padding-bottom:6px;
  }
  .brand__name{font-size:23px;}
  .brand__tagline{letter-spacing:.2em;}
  .nav-toggle{display:inline-flex;}

  .primary-nav{
    position:absolute;
    left:0;
    right:0;
    top:100%;
    display:block;
    max-height:0;
    overflow:hidden;
    border-top:1px solid var(--line);
    border-bottom:1px solid var(--line);
    background:rgba(6,10,24,.985);
    -webkit-backdrop-filter:blur(18px);
    backdrop-filter:blur(18px);
    transition:max-height .34s cubic-bezier(.4,0,.2,1);
  }
  .primary-nav[data-open="true"]{
    max-height:min(72vh,540px);
    overflow-y:auto;
  }
  .nav-list{
    flex-direction:column;
    align-items:stretch;
    gap:2px;
    padding:12px var(--gutter) 20px;
  }
  .nav-link{
    justify-content:flex-start;
    padding:13px 16px;
    font-size:16px;
    border-radius:14px;
  }
  .nav-link[aria-current="page"]{
    background:rgba(34,224,214,.08);
  }
  .nav-link[aria-current="page"]::after{
    left:16px;
    right:auto;
    width:24px;
    bottom:9px;
  }
  .side-note--vertical{writing-mode:horizontal-tb;letter-spacing:.1em;}
}

@media (max-width:640px){
  .footer__top{grid-template-columns:minmax(0,1fr);gap:26px;}
  .footer__summary,
  .footer__text{max-width:none;}
  .footer__bottom{
    flex-direction:column;
    align-items:flex-start;
    gap:6px;
  }
  .media-frame{aspect-ratio:4/3;border-radius:20px;}
  .media-frame--wide{aspect-ratio:16/10;}
  .media-frame--tall{aspect-ratio:4/5;}
  .section{padding-block:clamp(36px,8vw,64px);}
}

/* =========================================================
   14. 动效降级
   ========================================================= */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .site-header{position:relative;}
  [data-section]::before{display:none;}
  .reading-progress__fill{transition:none;}
}