/* ==========================================================================
   四季体育 · four-seasons-arena.com.cn
   共享站点样式 /assets/site.css
   ========================================================================== */

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

:root{
  --fsa-ink:#070C16;
  --fsa-panel:#101B2D;
  --fsa-line:#22314A;
  --fsa-text:#F2F6FC;
  --fsa-muted:#9FB0C8;
  --fsa-accent:#2FD3E9;
  --fsa-spring:#A8E63C;
  --fsa-summer:#2B8CF0;
  --fsa-autumn:#F5A524;
  --fsa-winter:#D7E3F2;
  --fsa-alert:#FF6B4A;

  --fsa-font-body:"Inter","Segoe UI",system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --fsa-font-display:"Oswald","Archivo Narrow","Arial Narrow","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --fsa-font-mono:"JetBrains Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --fsa-shell:1320px;
  --fsa-gutter:clamp(16px,4vw,44px);
  --fsa-r-sm:10px;
  --fsa-r:16px;
  --fsa-r-lg:24px;
  --fsa-t-fast:180ms;
  --fsa-t-slow:240ms;
}

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

body{
  margin:0;
  background-color:var(--fsa-ink);
  color:var(--fsa-text);
  font-family:var(--fsa-font-body);
  font-size:17px;
  line-height:1.7;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}

body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:-1;
  pointer-events:none;
  background:
    radial-gradient(760px 460px at 86% -8%, rgba(43,140,240,.20), transparent 70%),
    radial-gradient(640px 420px at -6% 6%, rgba(47,211,233,.14), transparent 68%),
    radial-gradient(560px 380px at 50% 112%, rgba(245,165,36,.09), transparent 72%);
}

h1,h2,h3,h4,p,figure,blockquote{margin:0;}
ul,ol{margin:0;padding:0;list-style:none;}

a{color:var(--fsa-accent);text-decoration:none;}
a:hover{color:var(--fsa-text);}

img,svg,video{display:block;max-width:100%;}

button{font:inherit;color:inherit;}

:focus-visible{outline:2px solid var(--fsa-accent);outline-offset:3px;border-radius:4px;}

::selection{background:rgba(47,211,233,.32);color:var(--fsa-text);}

/* ---------- 容器与区块 ---------- */

.fsa-shell{
  width:min(100% - (var(--fsa-gutter) * 2), var(--fsa-shell));
  margin-inline:auto;
}

.fsa-main{
  display:block;
  padding-bottom:clamp(24px,4vw,56px);
}

.fsa-section{padding-block:clamp(34px,5.5vw,78px);}
.fsa-section + .fsa-section{border-top:1px solid rgba(34,49,74,.6);}

.fsa-section__head{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
  gap:16px 28px;
  margin-bottom:clamp(20px,2.6vw,34px);
}

.fsa-stack{display:grid;gap:14px;}
.fsa-actions{display:flex;flex-wrap:wrap;gap:12px;align-items:center;}

/* ---------- 排版 ---------- */

.fsa-display,.fsa-h1,.fsa-h2,.fsa-h3{
  font-family:var(--fsa-font-display);
  font-weight:800;
  letter-spacing:-.02em;
  line-height:1.05;
  color:var(--fsa-text);
}

.fsa-display{
  font-size:clamp(40px,7vw,96px);
  line-height:.94;
  letter-spacing:-.03em;
  text-transform:uppercase;
}

.fsa-h1{font-size:clamp(34px,5.2vw,64px);}
.fsa-h2{font-size:clamp(24px,3.2vw,44px);}
.fsa-h3{font-size:clamp(19px,1.8vw,24px);letter-spacing:-.01em;}

.fsa-kicker{
  display:inline-flex;
  align-items:center;
  gap:10px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--fsa-accent);
}
.fsa-kicker::before{
  content:"";
  width:22px;
  height:1px;
  background:currentColor;
}

.fsa-lede{
  font-size:clamp(17px,1.3vw,19px);
  line-height:1.75;
  color:var(--fsa-muted);
  max-width:64ch;
}

.fsa-text{color:var(--fsa-muted);max-width:64ch;}

.fsa-num{
  font-family:var(--fsa-font-mono);
  font-variant-numeric:tabular-nums;
  letter-spacing:-.01em;
}

.fsa-link{
  color:var(--fsa-accent);
  border-bottom:1px solid rgba(47,211,233,.42);
  padding-bottom:1px;
  transition:color var(--fsa-t-fast) ease,border-color var(--fsa-t-fast) ease;
}
.fsa-link:hover{color:var(--fsa-text);border-color:var(--fsa-text);}

/* ---------- 按钮 ---------- */

.fsa-btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:10px;
  padding:11px 20px;
  border:1px solid var(--fsa-line);
  border-radius:999px;
  background:transparent;
  color:var(--fsa-text);
  font-size:14px;
  font-weight:600;
  letter-spacing:.04em;
  line-height:1.2;
  cursor:pointer;
  transition:transform var(--fsa-t-fast) ease,border-color var(--fsa-t-fast) ease,color var(--fsa-t-fast) ease,background-color var(--fsa-t-fast) ease;
}
.fsa-btn:hover{
  transform:translateY(-2px);
  border-color:var(--fsa-accent);
  color:var(--fsa-accent);
}
.fsa-btn--primary{
  background:var(--fsa-accent);
  border-color:var(--fsa-accent);
  color:var(--fsa-ink);
}
.fsa-btn--primary:hover{
  background:#5CE1F2;
  border-color:#5CE1F2;
  color:var(--fsa-ink);
}

/* ---------- 标签 ---------- */

.fsa-tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:5px 11px;
  border:1px solid var(--fsa-line);
  border-radius:999px;
  font-size:12px;
  font-weight:600;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--fsa-muted);
  white-space:nowrap;
}
.fsa-tag--spring{color:var(--fsa-spring);border-color:rgba(168,230,60,.45);}
.fsa-tag--summer{color:var(--fsa-summer);border-color:rgba(43,140,240,.5);}
.fsa-tag--autumn{color:var(--fsa-autumn);border-color:rgba(245,165,36,.5);}
.fsa-tag--winter{color:var(--fsa-winter);border-color:rgba(215,227,242,.45);}
.fsa-tag--alert{color:var(--fsa-alert);border-color:rgba(255,107,74,.5);}

/* ---------- 面包屑 ---------- */

.fsa-crumbs{margin-bottom:clamp(18px,2.4vw,28px);}
.fsa-crumbs ol{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px;
  font-size:13px;
  letter-spacing:.04em;
  color:var(--fsa-muted);
}
.fsa-crumbs li{display:inline-flex;align-items:center;gap:10px;}
.fsa-crumbs li + li::before{content:"/";color:var(--fsa-line);}
.fsa-crumbs a{color:var(--fsa-muted);}
.fsa-crumbs a:hover{color:var(--fsa-accent);}
.fsa-crumbs [aria-current="page"]{color:var(--fsa-text);}

/* ---------- Bento 栅格与卡片 ---------- */

.fsa-bento{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(12px,1.5vw,20px);
}

.fsa-span-4{grid-column:span 4;}
.fsa-span-6{grid-column:span 6;}
.fsa-span-8{grid-column:span 8;}
.fsa-span-12{grid-column:span 12;}

.fsa-card{
  position:relative;
  display:flex;
  flex-direction:column;
  gap:14px;
  padding:clamp(18px,2vw,26px);
  background:var(--fsa-panel);
  border:1px solid var(--fsa-line);
  border-radius:var(--fsa-r-lg);
  transition:transform var(--fsa-t-fast) ease,border-color var(--fsa-t-fast) ease,box-shadow var(--fsa-t-fast) ease,background-color var(--fsa-t-fast) ease;
}
.fsa-card:hover,
.fsa-card:focus-within{
  transform:translateY(-2px);
  border-color:rgba(47,211,233,.5);
  box-shadow:0 26px 48px -32px rgba(47,211,233,.75);
}
.fsa-card--flat{background:transparent;}
.fsa-card--cut{
  border-radius:0;
  clip-path:polygon(0 0,100% 0,100% calc(100% - 22px),calc(100% - 22px) 100%,0 100%);
}
.fsa-card__title{
  font-family:var(--fsa-font-display);
  font-size:20px;
  font-weight:700;
  line-height:1.28;
  letter-spacing:.01em;
  color:var(--fsa-text);
}
.fsa-card__meta{
  display:flex;
  flex-wrap:wrap;
  gap:8px 14px;
  font-size:13px;
  color:var(--fsa-muted);
}
.fsa-card__body{
  font-size:15.5px;
  line-height:1.72;
  color:var(--fsa-muted);
}

/* ---------- 图片容器基础规则 ---------- */

.fsa-media{
  position:relative;
  display:block;
  overflow:hidden;
  border-radius:var(--fsa-r);
  background:linear-gradient(150deg,#14213A 0%,#0A1220 100%);
  isolation:isolate;
}
.fsa-media::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:linear-gradient(180deg,rgba(7,12,22,0) 42%,rgba(7,12,22,.74) 100%);
}
.fsa-media img{
  width:100%;
  height:100%;
  object-fit:cover;
  display:block;
}
.fsa-media--16x9{aspect-ratio:16/9;}
.fsa-media--4x3{aspect-ratio:4/3;}
.fsa-media--1x1{aspect-ratio:1/1;}
.fsa-media--tall{aspect-ratio:3/4;}
.fsa-media--diag{
  border-radius:0;
  clip-path:polygon(0 0,100% 0,100% calc(100% - 34px),0 100%);
}
.fsa-media--bw img{filter:grayscale(1) contrast(1.1);}
.fsa-media__cap{
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  z-index:1;
  padding:14px 16px;
  font-size:12.5px;
  letter-spacing:.06em;
  color:var(--fsa-muted);
}
.fsa-media__cap strong{color:var(--fsa-text);font-weight:600;}

.fsa-gridlines{
  background-image:repeating-linear-gradient(90deg,rgba(34,49,74,.55) 0 1px,transparent 1px 88px);
}

/* ---------- 显现动效 ---------- */

.js [data-reveal]{
  opacity:0;
  transform:translateY(12px);
  transition:opacity var(--fsa-t-slow) ease,transform var(--fsa-t-slow) ease;
}
.js [data-reveal].is-visible{opacity:1;transform:none;}

/* ==========================================================================
   跳过链接
   ========================================================================== */

.fsa-skip{
  position:fixed;
  top:10px;
  left:10px;
  z-index:200;
  padding:10px 18px;
  border-radius:999px;
  background:var(--fsa-accent);
  color:var(--fsa-ink);
  font-size:14px;
  font-weight:700;
  transform:translateY(-180%);
  transition:transform var(--fsa-t-fast) ease;
}
.fsa-skip:focus-visible{transform:translateY(0);color:var(--fsa-ink);}

/* ==========================================================================
   头部
   ========================================================================== */

.fsa-header{
  position:sticky;
  top:0;
  z-index:60;
  background:rgba(7,12,22,.9);
  border-bottom:1px solid var(--fsa-line);
  -webkit-backdrop-filter:blur(16px) saturate(140%);
  backdrop-filter:blur(16px) saturate(140%);
  transition:box-shadow var(--fsa-t-slow) ease;
}
.fsa-header.is-scrolled{box-shadow:0 22px 46px -34px rgba(0,0,0,.95);}

/* 上层：品牌说明层 */
.fsa-header__brandbar{
  overflow:hidden;
  max-height:150px;
  border-bottom:1px solid rgba(34,49,74,.7);
  transition:max-height var(--fsa-t-slow) ease,opacity var(--fsa-t-slow) ease,border-color var(--fsa-t-slow) ease;
}
.fsa-header.is-scrolled .fsa-header__brandbar{
  max-height:0;
  opacity:0;
  border-bottom-color:transparent;
}

.fsa-header__brandbar-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px 28px;
  padding-block:14px;
}

.fsa-brand{
  display:inline-flex;
  align-items:center;
  gap:14px;
  color:var(--fsa-text);
}
.fsa-brand:hover{color:var(--fsa-text);}

.fsa-brand__mark{
  display:grid;
  place-items:center;
  width:44px;
  height:44px;
  flex:none;
  background:var(--fsa-accent);
  color:var(--fsa-ink);
  font-family:var(--fsa-font-display);
  font-size:18px;
  font-weight:800;
  letter-spacing:.04em;
  clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
}

.fsa-brand__text{display:flex;flex-direction:column;gap:2px;min-width:0;}
.fsa-brand__name{font-size:19px;font-weight:800;letter-spacing:.02em;line-height:1.2;}
.fsa-brand__desc{
  font-size:12.5px;
  letter-spacing:.08em;
  color:var(--fsa-muted);
  line-height:1.4;
}

.fsa-header__meta{
  display:flex;
  align-items:center;
  gap:14px;
  flex-wrap:wrap;
  justify-content:flex-end;
}

.fsa-status{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:6px 13px;
  border:1px solid rgba(47,211,233,.38);
  border-radius:999px;
  font-size:12px;
  font-weight:600;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--fsa-accent);
  white-space:nowrap;
}
.fsa-status::before{
  content:"";
  width:6px;
  height:6px;
  border-radius:50%;
  background:var(--fsa-accent);
  box-shadow:0 0 0 4px rgba(47,211,233,.18);
}

/* 下层：栏目层 */
.fsa-header__navwrap{position:relative;}

.fsa-header__navinner{
  display:flex;
  align-items:center;
  gap:16px;
  min-height:58px;
}

.fsa-navtoggle{
  display:none;
  align-items:center;
  gap:10px;
  padding:11px 14px;
  border:1px solid var(--fsa-line);
  border-radius:12px;
  background:transparent;
  font-size:14px;
  font-weight:600;
  letter-spacing:.06em;
  cursor:pointer;
  transition:border-color var(--fsa-t-fast) ease,color var(--fsa-t-fast) ease;
}
.fsa-navtoggle:hover{border-color:var(--fsa-accent);color:var(--fsa-accent);}
.fsa-navtoggle__bars{display:grid;gap:4px;width:18px;flex:none;}
.fsa-navtoggle__bars i{
  display:block;
  height:2px;
  border-radius:2px;
  background:currentColor;
  transition:transform var(--fsa-t-fast) ease,opacity var(--fsa-t-fast) ease;
}
.fsa-navtoggle[aria-expanded="true"] i:nth-child(1){transform:translateY(6px) rotate(45deg);}
.fsa-navtoggle[aria-expanded="true"] i:nth-child(2){opacity:0;}
.fsa-navtoggle[aria-expanded="true"] i:nth-child(3){transform:translateY(-6px) rotate(-45deg);}
.fsa-navtoggle__label{line-height:1;}

.fsa-nav{flex:1;min-width:0;}

.fsa-nav__list{
  display:flex;
  align-items:center;
  gap:clamp(10px,2vw,34px);
}

.fsa-nav__link{
  position:relative;
  display:inline-flex;
  align-items:center;
  padding:17px 2px;
  color:var(--fsa-muted);
  font-size:15px;
  font-weight:600;
  letter-spacing:.03em;
  white-space:nowrap;
  transition:color var(--fsa-t-fast) ease;
}
.fsa-nav__link::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  bottom:10px;
  height:2px;
  border-radius:2px;
  background:var(--fsa-accent);
  transform:scaleX(0);
  transform-origin:left;
  transition:transform var(--fsa-t-fast) ease;
}
.fsa-nav__link:hover{color:var(--fsa-text);}
.fsa-nav__link:hover::after{transform:scaleX(1);}
.fsa-nav__link[aria-current="page"]{color:var(--fsa-text);}
.fsa-nav__link[aria-current="page"]::after{transform:scaleX(1);}
.fsa-nav__link:focus-visible{outline-offset:-4px;}

.fsa-progress{
  position:absolute;
  left:0;
  right:0;
  bottom:-1px;
  height:2px;
  background:linear-gradient(90deg,var(--fsa-accent),var(--fsa-summer));
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 90ms linear;
  pointer-events:none;
}

/* ==========================================================================
   页脚
   ========================================================================== */

.fsa-footer{
  margin-top:clamp(48px,7vw,96px);
  border-top:1px solid var(--fsa-line);
  background:linear-gradient(180deg,rgba(16,27,45,.88) 0%,rgba(7,12,22,1) 78%);
}

.fsa-footer__grid{
  display:grid;
  grid-template-columns:1.5fr 1fr 1fr;
  gap:clamp(26px,4vw,56px);
  padding-block:clamp(36px,5vw,64px);
}

.fsa-footer__col{display:flex;flex-direction:column;gap:16px;}

.fsa-footer__col--brand{gap:18px;}

.fsa-footer__title{
  margin:0;
  font-size:12px;
  font-weight:600;
  letter-spacing:.16em;
  text-transform:uppercase;
  color:var(--fsa-muted);
}

.fsa-footer__list{display:grid;gap:11px;}
.fsa-footer__list a{
  display:inline-block;
  color:var(--fsa-text);
  font-size:15px;
  transition:color var(--fsa-t-fast) ease,transform var(--fsa-t-fast) ease;
}
.fsa-footer__list a:hover{color:var(--fsa-accent);transform:translateX(3px);}

.fsa-footer__note{
  font-size:14.5px;
  line-height:1.7;
  color:var(--fsa-muted);
  max-width:38ch;
}

.fsa-footer__bottom{
  display:grid;
  gap:12px;
  padding-block:22px 34px;
  border-top:1px solid var(--fsa-line);
  font-size:13px;
  color:var(--fsa-muted);
}

.fsa-footer__legal,
.fsa-footer__contact{
  display:flex;
  flex-wrap:wrap;
  gap:8px 20px;
  align-items:center;
}

.fsa-footer__legal span:first-child{
  color:var(--fsa-text);
  font-weight:600;
  letter-spacing:.04em;
}

.fsa-footer__contact span{
  font-family:var(--fsa-font-mono);
  font-size:12.5px;
  letter-spacing:.01em;
}

.fsa-footer__fine{
  font-size:12.5px;
  line-height:1.7;
  color:rgba(159,176,200,.8);
  max-width:78ch;
}

/* ==========================================================================
   响应式
   ========================================================================== */

@media (max-width:1080px){
  .fsa-nav__list{gap:14px;}
  .fsa-nav__link{font-size:14.5px;}
}

@media (max-width:960px){
  .fsa-navtoggle{display:inline-flex;}

  .fsa-header__navinner{justify-content:space-between;}

  .fsa-nav{
    display:none;
    position:absolute;
    left:0;
    right:0;
    top:100%;
    max-height:min(72vh,540px);
    overflow-y:auto;
    padding:8px var(--fsa-gutter) 22px;
    background:var(--fsa-panel);
    border-top:1px solid var(--fsa-line);
    border-bottom:1px solid var(--fsa-line);
    box-shadow:0 34px 64px -34px rgba(0,0,0,.95);
  }
  .fsa-nav[data-open]{display:block;}

  .fsa-nav__list{flex-direction:column;align-items:stretch;gap:0;}
  .fsa-nav__link{
    width:100%;
    justify-content:space-between;
    padding:16px 2px;
    border-bottom:1px solid rgba(34,49,74,.55);
    font-size:17px;
  }
  .fsa-nav__link::after{display:none;}
  .fsa-nav__link:hover{transform:translateX(4px);}
  .fsa-nav__link[aria-current="page"]{color:var(--fsa-accent);}

  .fsa-footer__grid{grid-template-columns:1fr 1fr;}
  .fsa-footer__col--brand{grid-column:span 2;}

  .fsa-span-4,.fsa-span-6,.fsa-span-8{grid-column:span 6;}
}

@media (max-width:720px){
  :root{--fsa-gutter:18px;}

  body{font-size:16px;}

  .fsa-header__brandbar-inner{padding-block:10px;}
  .fsa-brand__desc{display:none;}
  .fsa-brand__mark{width:38px;height:38px;font-size:16px;}
  .fsa-brand__name{font-size:17px;}
  .fsa-header__meta{gap:10px;}
  .fsa-btn{padding:10px 16px;font-size:13px;}

  .fsa-footer__grid{grid-template-columns:1fr;}
  .fsa-footer__col--brand{grid-column:span 1;}
  .fsa-footer__note{max-width:none;}

  .fsa-span-4,.fsa-span-6,.fsa-span-8,.fsa-span-12{grid-column:span 12;}

  .fsa-section__head{align-items:flex-start;}
}

/* ==========================================================================
   动效偏好
   ========================================================================== */

@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}

  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }

  .js [data-reveal]{opacity:1;transform:none;}
  .fsa-card:hover,.fsa-card:focus-within{transform:none;}
  .fsa-btn:hover{transform:none;}
  .fsa-footer__list a:hover{transform:none;}
  .fsa-nav__link:hover{transform:none;}
  .fsa-progress{transition:none;}
}