/* ============================================================
   SHANGHAI ROBOT CHALLENGE — SRC Design System
   Brand: black carbon + SRC red + metallic silver
   Language: angular geometry, technical grids, precision lines
   ============================================================ */

/* ---------- TOKENS ---------- */
:root{
  /* brand — sampled from the official SRC logo */
  --red:#e10613;
  --red-bright:#ff2a34;
  --red-deep:#8e0106;
  --red-glow:rgba(225,6,19,.35);
  --red-soft:rgba(225,6,19,.10);

  /* metallic silver */
  --silver-1:#ffffff;
  --silver-2:#cdd4db;
  --silver-3:#98a0a9;
  --silver-4:#666e77;
  --metal:linear-gradient(176deg,#ffffff 0%,#e6ebf0 28%,#9aa2ab 58%,#f2f5f8 78%,#b9c1c9 100%);

  /* surfaces */
  --black:#050506;
  --carbon:#0a0a0d;
  --panel:#101015;
  --panel-2:#16161c;
  --panel-3:#1c1c23;

  /* lines */
  --line:rgba(190,205,225,.10);
  --line-2:rgba(190,205,225,.18);
  --line-3:rgba(190,205,225,.30);

  /* text */
  --fg:#eef1f5;
  --muted:#9aa2ad;
  --muted-2:#6b727c;

  /* type */
  --f-display:"Clash Display","Arial Narrow",sans-serif;
  --f-body:"Satoshi",ui-sans-serif,system-ui,-apple-system,sans-serif;
  --f-mono:ui-monospace,"SF Mono","Cascadia Code",Menlo,Consolas,monospace;

  /* motion */
  --e:cubic-bezier(.2,.8,.2,1);
  --e2:cubic-bezier(.65,0,.35,1);

  --maxw:1320px;
  --cut:14px;
  --nav-h:76px;
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:var(--nav-h)}
body{
  background:var(--black);color:var(--fg);
  font-family:var(--f-body);font-size:1rem;line-height:1.65;
  -webkit-font-smoothing:antialiased;overflow-x:hidden;
}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
::selection{background:var(--red);color:#fff}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block;height:auto}
button{font-family:inherit;color:inherit;background:none;border:none;cursor:pointer}
:focus-visible{outline:2px solid var(--red-bright);outline-offset:3px}

.wrap{max-width:var(--maxw);margin-inline:auto;padding-inline:clamp(1.1rem,3.5vw,2.75rem)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* ---------- TYPE ---------- */
h1,h2,h3,h4,h5{font-family:var(--f-display);font-weight:600;line-height:.98;letter-spacing:-.015em}
.metal{
  background:var(--metal);-webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent;color:transparent;
}
.eyebrow{
  font-family:var(--f-mono);font-size:.7rem;letter-spacing:.3em;text-transform:uppercase;
  color:var(--red);display:inline-flex;align-items:center;gap:.65rem;font-weight:500;
}
.eyebrow::before{content:"";width:22px;height:2px;background:var(--red);flex:none}
.eyebrow.c::after{content:"";width:22px;height:2px;background:var(--red);flex:none}
.tech{font-family:var(--f-mono);font-size:.68rem;letter-spacing:.16em;text-transform:uppercase;color:var(--muted-2)}
.tech .sep{color:var(--red);margin-inline:.45rem}

.sec{padding-block:clamp(4rem,8vw,7.5rem);position:relative}
.sec-head{max-width:820px;margin-bottom:clamp(2.2rem,4.5vw,3.6rem)}
.sec-head h2{font-size:clamp(2.1rem,5.4vw,4.2rem);text-transform:uppercase;margin:1.1rem 0 1.1rem;letter-spacing:-.02em}
.sec-head p{color:var(--muted);font-size:1.06rem;max-width:64ch}
.sec-head.c{margin-inline:auto;text-align:center}
.sec-head.c p{margin-inline:auto}

/* ---------- SHARED DECOR ---------- */
.grid-bg{position:absolute;inset:0;pointer-events:none;z-index:0;
  background-image:linear-gradient(var(--line) 1px,transparent 1px),linear-gradient(90deg,var(--line) 1px,transparent 1px);
  background-size:64px 64px;
  -webkit-mask-image:radial-gradient(120% 90% at 50% 0%,#000 10%,transparent 75%);
          mask-image:radial-gradient(120% 90% at 50% 0%,#000 10%,transparent 75%);}
.rule-red{height:1px;background:linear-gradient(90deg,transparent,var(--red),transparent);opacity:.55}
.sec > .wrap{position:relative;z-index:1}

/* cut-corner utility (angular panels) */
.cut{clip-path:polygon(0 0,calc(100% - var(--cut)) 0,100% var(--cut),100% 100%,var(--cut) 100%,0 calc(100% - var(--cut)))}
.cut-sm{--cut:9px;clip-path:polygon(0 0,calc(100% - 9px) 0,100% 9px,100% 100%,9px 100%,0 calc(100% - 9px))}

/* bordered angular panel: outer = border colour, inner = surface */
.pnl{background:var(--line-2);padding:1px;position:relative}
.pnl-in{background:var(--panel);height:100%;width:100%}

/* corner brackets */
.brk{position:relative}
.brk::before,.brk::after{content:"";position:absolute;width:14px;height:14px;border:2px solid var(--red);pointer-events:none}
.brk::before{top:0;left:0;border-right:0;border-bottom:0}
.brk::after{bottom:0;right:0;border-left:0;border-top:0}

/* ---------- BUTTONS ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.6rem;
  font-family:var(--f-mono);font-size:.76rem;font-weight:500;letter-spacing:.16em;text-transform:uppercase;
  padding:1rem 1.6rem;position:relative;transition:.28s var(--e);white-space:nowrap;
  clip-path:polygon(0 0,calc(100% - 10px) 0,100% 10px,100% 100%,10px 100%,0 calc(100% - 10px));
}
.btn .ar{transition:transform .28s var(--e)}
.btn:hover .ar{transform:translateX(4px)}
.btn-red{background:var(--red);color:#fff}
.btn-red:hover{background:var(--red-bright);box-shadow:0 0 26px var(--red-glow)}
.btn-ghost{background:transparent;color:var(--fg);box-shadow:inset 0 0 0 1px var(--line-3)}
.btn-ghost:hover{box-shadow:inset 0 0 0 1px var(--red);color:var(--red-bright)}
.btn-metal{background:var(--panel-2);color:var(--silver-2);box-shadow:inset 0 0 0 1px var(--line-2)}
.btn-metal:hover{color:#fff;box-shadow:inset 0 0 0 1px var(--silver-4)}
.btn-sm{padding:.7rem 1.1rem;font-size:.68rem}

/* ---------- NAV ---------- */
.nav{position:fixed;inset:0 0 auto 0;z-index:90;transition:background .35s,border-color .35s,backdrop-filter .35s;border-bottom:1px solid transparent}
.nav.on{background:rgba(8,8,11,.86);backdrop-filter:blur(16px);border-bottom:1px solid var(--line-2);box-shadow:0 10px 40px rgba(0,0,0,.5)}
.nav.on::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:1px;background:linear-gradient(90deg,transparent,var(--red),transparent);opacity:.7}
.nav-in{display:flex;align-items:center;justify-content:space-between;height:var(--nav-h);gap:1.5rem}
.brand{display:flex;align-items:center;gap:.75rem;flex:none}
.brand img{height:46px;width:auto}
.brand .bt{display:flex;flex-direction:column;line-height:1}
.brand .bt b{font-family:var(--f-display);font-size:.98rem;letter-spacing:.02em;text-transform:uppercase}
.brand .bt span{font-family:var(--f-mono);font-size:.56rem;letter-spacing:.28em;color:var(--muted-2);margin-top:.25rem}
.nav-links{display:flex;align-items:center;gap:1.45rem}
.nav-links .btn{margin-left:.6rem}
.nav-links a{font-family:var(--f-mono);font-size:.72rem;letter-spacing:.16em;text-transform:uppercase;color:var(--muted);position:relative;padding:.4rem 0;transition:color .25s}
.nav-links a::after{content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;background:var(--red);transform:scaleX(0);transform-origin:right;transition:transform .32s var(--e2)}
.nav-links a:hover{color:var(--fg)}
.nav-links a:hover::after,.nav-links a.act::after{transform:scaleX(1);transform-origin:left}
.nav-links a.act{color:var(--fg)}
/* keep button styling inside the nav (beats .nav-links a) */
.nav-links a.btn{color:#fff;padding:.72rem 1.15rem;font-size:.68rem}
.nav-links a.btn::after{display:none}
.nav-links a.btn:hover{color:#fff}
.nav-cta{flex:none}
.burger{display:none;width:46px;height:46px;align-items:center;justify-content:center;box-shadow:inset 0 0 0 1px var(--line-3)}
.burger i{display:block;width:19px;height:2px;background:var(--fg);position:relative;transition:.3s}
.burger i::before,.burger i::after{content:"";position:absolute;left:0;width:19px;height:2px;background:var(--fg);transition:.3s}
.burger i::before{top:-6px}.burger i::after{top:6px}
.burger.on i{background:transparent}
.burger.on i::before{top:0;transform:rotate(45deg);background:var(--red)}
.burger.on i::after{top:0;transform:rotate(-45deg);background:var(--red)}
@media (max-width:1180px){
  .nav-links{position:fixed;inset:var(--nav-h) 0 auto 0;flex-direction:column;align-items:stretch;gap:0;
    background:rgba(6,6,9,.98);backdrop-filter:blur(18px);border-bottom:1px solid var(--line-2);
    padding:.5rem clamp(1.1rem,3.5vw,2.75rem) 1.5rem;transform:translateY(-125%);transition:transform .42s var(--e2);max-height:calc(100vh - var(--nav-h));overflow:auto}
  .nav-links.open{transform:none}
  .nav-links a{padding:1.05rem 0;border-bottom:1px solid var(--line);font-size:.8rem}
  .nav-links a::after{display:none}
  .nav-links .btn{margin-top:1.1rem;width:100%}
  .burger{display:flex}
  .nav-cta{display:none}
}

/* ---------- HERO ---------- */
.hero{position:relative;min-height:100svh;display:flex;align-items:center;padding:calc(var(--nav-h) + 1rem) 0 7rem;overflow:hidden}
#hero-cv{position:absolute;inset:0;width:100%;height:100%;z-index:0}
.hero-veil{position:absolute;inset:0;z-index:1;pointer-events:none;
  background:radial-gradient(105% 80% at 50% 42%,transparent 0%,rgba(5,5,6,.55) 62%,var(--black) 100%),
             linear-gradient(180deg,rgba(5,5,6,.7) 0%,transparent 22%,transparent 62%,var(--black) 100%)}
.hero .wrap{position:relative;z-index:2;width:100%;text-align:center}
.hero-logo{width:min(300px,40vw);margin:0 auto clamp(1rem,2.2vw,1.6rem);filter:drop-shadow(0 18px 60px rgba(225,6,19,.28))}
.hero h1{font-size:clamp(2.3rem,7vw,6rem);text-transform:uppercase;letter-spacing:-.03em;line-height:.92;margin-bottom:1.1rem}
.hero h1 .r{color:var(--red)}
.hero-sub{max-width:60ch;margin:0 auto 1.9rem;color:var(--muted);font-size:clamp(1rem,1.35vw,1.15rem)}
.hero-cta{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}
.hero-strip{position:absolute;left:0;right:0;bottom:0;z-index:2;border-top:1px solid var(--line-2);background:rgba(8,8,11,.6);backdrop-filter:blur(8px)}
.hero-strip .wrap{display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;padding-block:1rem;text-align:left}
.hero-strip .hs{display:flex;flex-direction:column;gap:.3rem;min-width:120px}
.hero-strip .hs b{font-family:var(--f-display);font-size:1.02rem;letter-spacing:.01em}
@media (max-width:720px){.hero-strip .hs:nth-child(n+4){display:none}}
@media (max-width:460px){.hero-strip .hs:nth-child(n+3){display:none}}

/* ---------- REVEAL ---------- */
.rv{opacity:0;transform:translateY(24px);transition:opacity .75s var(--e),transform .75s var(--e)}
.rv.in{opacity:1;transform:none}
.rv[data-d="1"]{transition-delay:.07s}.rv[data-d="2"]{transition-delay:.14s}
.rv[data-d="3"]{transition-delay:.21s}.rv[data-d="4"]{transition-delay:.28s}
@media (prefers-reduced-motion:reduce){.rv{opacity:1;transform:none;transition:none}}

/* ---------- TICKER ---------- */
.ticker{border-block:1px solid var(--line-2);background:var(--carbon);overflow:hidden;padding-block:.85rem}
.ticker-tr{display:flex;gap:2.6rem;width:max-content;animation:tick 38s linear infinite}
.ticker:hover .ticker-tr{animation-play-state:paused}
@keyframes tick{to{transform:translateX(-50%)}}
@media (prefers-reduced-motion:reduce){.ticker-tr{animation:none}}
.ticker-it{display:flex;align-items:center;gap:.8rem;font-family:var(--f-mono);font-size:.72rem;letter-spacing:.2em;text-transform:uppercase;color:var(--muted);white-space:nowrap}
.ticker-it b{color:var(--fg);font-weight:500}
.ticker-it i{color:var(--red);font-style:normal}

/* ---------- INTRO / SPLIT ---------- */
.split{display:grid;grid-template-columns:1.05fr .95fr;gap:clamp(2rem,5vw,4.5rem);align-items:center}
@media (max-width:940px){.split{grid-template-columns:1fr}}
.split p{color:var(--muted);margin-bottom:1.1rem;font-size:1.05rem}
.split p b{color:var(--fg);font-weight:700}

/* ---------- STATS ---------- */
.stats{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line)}
@media (max-width:820px){.stats{grid-template-columns:repeat(2,1fr)}}
.stat{background:var(--carbon);padding:2rem 1.4rem;position:relative;overflow:hidden}
.stat::before{content:"";position:absolute;top:0;left:0;width:34px;height:2px;background:var(--red)}
.stat .n{font-family:var(--f-display);font-weight:600;font-size:clamp(2.3rem,4.6vw,3.6rem);line-height:1;letter-spacing:-.03em;font-variant-numeric:tabular-nums}
.stat .l{color:var(--muted);font-size:.9rem;margin-top:.55rem}
.stat .sub{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.14em;text-transform:uppercase;color:var(--muted-2);margin-top:.45rem}

/* ---------- CATEGORY CARDS ---------- */
.cats{display:grid;grid-template-columns:repeat(3,1fr);gap:1.15rem}
@media (max-width:940px){.cats{grid-template-columns:1fr}}
.cat{background:var(--line-2);padding:1px;transition:background .32s var(--e),transform .32s var(--e)}
.cat:hover{background:var(--red);transform:translateY(-5px)}
.cat-in{background:linear-gradient(165deg,var(--panel-2),var(--carbon));padding:2rem 1.75rem 1.75rem;height:100%;display:flex;flex-direction:column;position:relative;overflow:hidden}
.cat-in::after{content:"";position:absolute;inset:0;background:radial-gradient(90% 60% at 100% 0%,var(--red-soft),transparent 62%);opacity:0;transition:opacity .32s;pointer-events:none}
.cat:hover .cat-in::after{opacity:1}
.cat .ci{width:46px;height:46px;color:var(--red);margin-bottom:1.3rem}
.cat .cid{font-family:var(--f-mono);font-size:.62rem;letter-spacing:.2em;color:var(--muted-2);text-transform:uppercase}
.cat h3{font-size:1.55rem;text-transform:uppercase;margin:.6rem 0 .8rem;letter-spacing:-.01em}
.cat p{color:var(--muted);font-size:.95rem;flex:1}
.cat .cn{font-family:var(--f-mono);font-size:.66rem;letter-spacing:.14em;color:var(--silver-3);margin:1.2rem 0 .9rem;padding-top:.9rem;border-top:1px solid var(--line)}
.cat .cl{font-family:var(--f-mono);font-size:.7rem;letter-spacing:.16em;text-transform:uppercase;color:var(--red);display:inline-flex;gap:.5rem;align-items:center}

/* ---------- CHALLENGE CARDS ---------- */
.chals{display:grid;grid-template-columns:repeat(3,1fr);gap:1.1rem}
@media (max-width:1040px){.chals{grid-template-columns:repeat(2,1fr)}}
@media (max-width:660px){.chals{grid-template-columns:1fr}}
.chal{background:var(--line-2);padding:1px;transition:background .3s var(--e),transform .3s var(--e)}
.chal:hover{background:var(--red);transform:translateY(-4px)}
.chal-in{background:var(--panel);padding:1.4rem 1.35rem 1.3rem;height:100%;display:flex;flex-direction:column;position:relative;overflow:hidden}
.chal-in::before{content:"";position:absolute;top:0;left:0;right:0;height:1px;background:linear-gradient(90deg,var(--red),transparent 70%);opacity:.5;transition:opacity .3s}
.chal:hover .chal-in::before{opacity:1}
.chal-top{display:flex;align-items:center;justify-content:space-between;gap:.6rem;margin-bottom:1rem}
.chal-id{font-family:var(--f-mono);font-size:.7rem;letter-spacing:.2em;color:var(--red);font-weight:500}
.chal-new{font-family:var(--f-mono);font-size:.55rem;letter-spacing:.16em;text-transform:uppercase;color:#fff;background:var(--red);padding:.25rem .45rem}
.chal h3{font-size:1.2rem;text-transform:uppercase;letter-spacing:-.005em;margin-bottom:.75rem;min-height:2.35em;display:flex;align-items:flex-start}
.chal-tags{display:flex;flex-wrap:wrap;gap:.4rem;margin-bottom:.9rem}
.tag{font-family:var(--f-mono);font-size:.58rem;letter-spacing:.14em;text-transform:uppercase;padding:.32rem .55rem;box-shadow:inset 0 0 0 1px var(--line-2);color:var(--muted)}
.tag-auto{color:#7fd6ff;box-shadow:inset 0 0 0 1px rgba(127,214,255,.3)}
.tag-remote{color:#ffc46b;box-shadow:inset 0 0 0 1px rgba(255,196,107,.3)}
.tag-creative{color:#d79bff;box-shadow:inset 0 0 0 1px rgba(215,155,255,.3)}
.chal p{color:var(--muted);font-size:.88rem;line-height:1.55;flex:1}
.chal-meta{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.1em;color:var(--muted-2);text-transform:uppercase;margin-top:1rem;padding-top:.85rem;border-top:1px solid var(--line);line-height:1.6}
.chal-meta b{color:var(--silver-3);font-weight:500}
.chal-foot{display:flex;align-items:center;justify-content:space-between;gap:.7rem;margin-top:1rem}
.chal-foot a{font-family:var(--f-mono);font-size:.64rem;letter-spacing:.14em;text-transform:uppercase;display:inline-flex;align-items:center;gap:.35rem;transition:color .25s}
.chal-view{color:var(--fg)}
.chal-view:hover{color:var(--red-bright)}
.chal-dl{color:var(--muted-2)}
.chal-dl:hover{color:var(--silver-2)}

/* difficulty meter */
.dif{display:flex;align-items:center;gap:.45rem}
.dif-bars{display:flex;gap:3px}
.dif-bars i{width:14px;height:4px;background:var(--line-3);display:block}
.dif-l .dif-bars i:nth-child(1){background:#5ad18a}
.dif-m .dif-bars i:nth-child(-n+2){background:#ffb545}
.dif-h .dif-bars i{background:var(--red)}
.dif span{font-family:var(--f-mono);font-size:.58rem;letter-spacing:.14em;text-transform:uppercase;color:var(--muted)}

/* ---------- FILTERS ---------- */
.filters{border-block:1px solid var(--line-2);background:var(--carbon);position:sticky;top:var(--nav-h);z-index:40;backdrop-filter:blur(10px)}
.filters .wrap{display:flex;flex-wrap:wrap;gap:1.6rem;padding-block:1.1rem;align-items:center}
.fgrp{display:flex;align-items:center;gap:.55rem;flex-wrap:wrap}
.fgrp>span{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.18em;text-transform:uppercase;color:var(--muted-2);margin-right:.2rem}
.fchip{font-family:var(--f-mono);font-size:.64rem;letter-spacing:.13em;text-transform:uppercase;padding:.45rem .8rem;color:var(--muted);box-shadow:inset 0 0 0 1px var(--line-2);transition:.24s var(--e);
  clip-path:polygon(0 0,calc(100% - 7px) 0,100% 7px,100% 100%,7px 100%,0 calc(100% - 7px))}
.fchip:hover{color:var(--fg);box-shadow:inset 0 0 0 1px var(--line-3)}
.fchip.on{background:var(--red);color:#fff;box-shadow:none}
.fcount{margin-left:auto;font-family:var(--f-mono);font-size:.66rem;letter-spacing:.14em;color:var(--muted-2);text-transform:uppercase}
.fcount b{color:var(--red)}
.empty{text-align:center;padding:5rem 1rem;color:var(--muted)}

/* ---------- TIMELINE / JOURNEY ---------- */
.jrny{display:grid;grid-template-columns:repeat(6,1fr);gap:1px;background:var(--line)}
@media (max-width:1000px){.jrny{grid-template-columns:repeat(3,1fr)}}
@media (max-width:620px){.jrny{grid-template-columns:repeat(2,1fr)}}
.jn{background:var(--carbon);padding:1.9rem 1.2rem;position:relative;transition:background .3s}
.jn:hover{background:var(--panel-2)}
.jn .jnum{font-family:var(--f-mono);font-size:.68rem;letter-spacing:.2em;color:var(--red)}
.jn h4{font-size:1.05rem;text-transform:uppercase;margin:.75rem 0 .5rem}
.jn p{color:var(--muted);font-size:.85rem}

/* ---------- ACCORDION ---------- */
.acc{border-top:1px solid var(--line-2)}
.acc-i{border-bottom:1px solid var(--line-2)}
.acc-b{width:100%;display:flex;align-items:center;justify-content:space-between;gap:1.2rem;padding:1.45rem 0;text-align:left;transition:color .25s}
.acc-b:hover{color:var(--red-bright)}
.acc-n{font-family:var(--f-mono);font-size:.68rem;letter-spacing:.18em;color:var(--red);flex:none;width:2.4rem}
.acc-t{font-family:var(--f-display);font-size:clamp(1rem,1.6vw,1.22rem);text-transform:uppercase;flex:1;letter-spacing:-.005em}
.acc-ic{flex:none;width:30px;height:30px;position:relative;box-shadow:inset 0 0 0 1px var(--line-3);transition:.3s}
.acc-ic::before,.acc-ic::after{content:"";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);background:var(--fg);transition:.3s}
.acc-ic::before{width:11px;height:1.5px}
.acc-ic::after{width:1.5px;height:11px}
.acc-i.open .acc-ic{background:var(--red);box-shadow:none}
.acc-i.open .acc-ic::after{transform:translate(-50%,-50%) rotate(90deg);opacity:0}
.acc-body{max-height:0;overflow:hidden;transition:max-height .42s var(--e2)}
.acc-body-in{padding:0 0 1.5rem;color:var(--muted);max-width:78ch}
.acc-body-in p{margin-bottom:.8rem}
.acc-body-in ul{margin:.5rem 0 .9rem 1.1rem}
.acc-body-in li{margin-bottom:.4rem}
@media (prefers-reduced-motion:reduce){.acc-body{transition:none}}

/* ---------- DOC / PDF CARDS ---------- */
.docs{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}
@media (max-width:1000px){.docs{grid-template-columns:repeat(2,1fr)}}
@media (max-width:620px){.docs{grid-template-columns:1fr}}
.doc{background:var(--line-2);padding:1px;transition:background .3s var(--e)}
.doc:hover{background:var(--red)}
.doc-in{background:var(--panel);padding:1.3rem;height:100%;display:flex;gap:1rem;align-items:flex-start}
.doc-ic{flex:none;width:42px;height:52px;background:var(--panel-3);display:flex;align-items:center;justify-content:center;
  font-family:var(--f-mono);font-size:.56rem;letter-spacing:.08em;color:var(--red);font-weight:600;
  box-shadow:inset 0 0 0 1px var(--line-2);
  clip-path:polygon(0 0,calc(100% - 10px) 0,100% 10px,100% 100%,0 100%)}
.doc-c{flex:1;min-width:0}
.doc-c .dt{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.16em;color:var(--muted-2);text-transform:uppercase}
.doc-c h4{font-size:1rem;text-transform:uppercase;margin:.4rem 0 .7rem;line-height:1.15}
.doc-a{display:flex;gap:.55rem;flex-wrap:wrap}
.doc-a a{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.13em;text-transform:uppercase;padding:.42rem .7rem;box-shadow:inset 0 0 0 1px var(--line-2);color:var(--muted);transition:.24s}
.doc-a a:hover{color:#fff;background:var(--red);box-shadow:none}
.doc.soon .doc-in{opacity:.55}
.doc.soon .doc-ic{color:var(--muted-2)}
.pending{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.13em;text-transform:uppercase;color:var(--muted-2);padding:.42rem 0}

/* ---------- CHALLENGE DETAIL ---------- */
.chd-hero{padding-top:calc(var(--nav-h) + clamp(2.5rem,6vw,5rem));padding-bottom:clamp(2rem,4vw,3.5rem);position:relative;overflow:hidden;border-bottom:1px solid var(--line-2)}
.chd-hero::before{content:"";position:absolute;inset:0;background:radial-gradient(70% 100% at 85% 0%,var(--red-soft),transparent 60%);pointer-events:none}
.chd-back{font-family:var(--f-mono);font-size:.66rem;letter-spacing:.16em;text-transform:uppercase;color:var(--muted);display:inline-flex;gap:.5rem;margin-bottom:1.8rem;transition:color .25s}
.chd-back:hover{color:var(--red-bright)}
.chd-id{font-family:var(--f-mono);font-size:.82rem;letter-spacing:.28em;color:var(--red);display:block;margin-bottom:.7rem}
.chd-hero h1{font-size:clamp(2.2rem,6.5vw,5rem);text-transform:uppercase;letter-spacing:-.025em;margin-bottom:1.2rem}
.chd-tags{display:flex;gap:.5rem;flex-wrap:wrap;align-items:center}
.chd-spec{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);margin-top:clamp(2rem,4vw,3rem)}
@media (max-width:820px){.chd-spec{grid-template-columns:repeat(2,1fr)}}
.spc{background:var(--carbon);padding:1.4rem 1.2rem}
.spc .k{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.18em;text-transform:uppercase;color:var(--muted-2)}
.spc .v{font-family:var(--f-display);font-size:1.08rem;margin-top:.5rem;text-transform:uppercase;line-height:1.2}
.spc .v.sm{font-family:var(--f-body);font-size:.92rem;text-transform:none;color:var(--silver-2)}
.chd-grid{display:grid;grid-template-columns:1.5fr .8fr;gap:clamp(1.8rem,4vw,3.2rem);align-items:start}
@media (max-width:940px){.chd-grid{grid-template-columns:1fr}}
.chd-body h2{font-size:clamp(1.4rem,2.6vw,2rem);text-transform:uppercase;margin:0 0 1.1rem}
.chd-body h3{font-size:1.1rem;text-transform:uppercase;margin:2rem 0 .8rem;color:var(--silver-2)}
.chd-body p{color:var(--muted);margin-bottom:1rem;font-size:1.03rem}
.chd-body ul{margin:.6rem 0 1.2rem 1.15rem;color:var(--muted)}
.chd-body li{margin-bottom:.5rem}
.glance{display:grid;grid-template-columns:repeat(2,1fr);gap:1px;background:var(--line);margin:1.4rem 0 0}
.glance-3{grid-template-columns:repeat(3,1fr)}
.glance-4{grid-template-columns:repeat(4,1fr)}
@media (max-width:900px){.glance-3,.glance-4{grid-template-columns:repeat(2,1fr)}}
@media (max-width:560px){.glance-3,.glance-4{grid-template-columns:1fr}}
@media (max-width:520px){.glance{grid-template-columns:1fr}}
.gl{background:var(--carbon);padding:1.25rem}
.gl .k{font-family:var(--f-mono);font-size:.58rem;letter-spacing:.16em;text-transform:uppercase;color:var(--red)}
.gl .v{margin-top:.5rem;font-size:.95rem;color:var(--silver-2)}
.chd-side{position:sticky;top:calc(var(--nav-h) + 1.5rem)}
@media (max-width:940px){.chd-side{position:static}}
.rulebox{background:var(--line-2);padding:1px}
.rulebox-in{background:linear-gradient(170deg,var(--panel-2),var(--carbon));padding:1.7rem 1.5rem}
.rulebox h4{font-size:1.15rem;text-transform:uppercase;margin:.7rem 0 .7rem}
.rulebox p{color:var(--muted);font-size:.9rem;margin-bottom:1.3rem}
.rulebox .btn{width:100%;margin-bottom:.6rem}

/* ---------- CTA ---------- */
.cta{position:relative;overflow:hidden;border-block:1px solid var(--line-2);
  background:radial-gradient(80% 130% at 50% 100%,rgba(225,6,19,.16),transparent 60%),var(--carbon);
  padding-block:clamp(4rem,9vw,7rem);text-align:center}
.cta h2{font-size:clamp(2.2rem,6.5vw,5rem);text-transform:uppercase;letter-spacing:-.025em;margin-bottom:1.4rem}
.cta p{color:var(--muted);max-width:52ch;margin:0 auto 2.2rem;font-size:1.06rem}

/* ---------- FOOTER ---------- */
footer{background:var(--black);border-top:1px solid var(--line-2);padding-block:clamp(3rem,5vw,4.5rem) 1.8rem;position:relative;overflow:hidden}
.f-grid{display:grid;grid-template-columns:1.7fr 1fr 1fr 1.2fr;gap:2.2rem;margin-bottom:3rem;position:relative;z-index:1}
@media (max-width:900px){.f-grid{grid-template-columns:1fr 1fr}}
@media (max-width:560px){.f-grid{grid-template-columns:1fr}}
.f-brand img{width:150px;margin-bottom:1.2rem}
.f-brand p{color:var(--muted);font-size:.9rem;max-width:36ch}
.f-col h5{font-family:var(--f-mono);font-size:.62rem;letter-spacing:.22em;text-transform:uppercase;color:var(--red);margin-bottom:1.1rem}
.f-col a,.f-col span.fi{display:block;color:var(--muted);padding:.34rem 0;font-size:.9rem;transition:color .24s}
.f-col a:hover{color:var(--fg)}
.f-bot{display:flex;justify-content:space-between;gap:1rem;flex-wrap:wrap;padding-top:1.6rem;border-top:1px solid var(--line);
  font-family:var(--f-mono);font-size:.62rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted-2);position:relative;z-index:1}

/* ---------- PAGE HEADER (inner pages) ---------- */
.phead{padding-top:calc(var(--nav-h) + clamp(3rem,7vw,5.5rem));padding-bottom:clamp(2.2rem,5vw,3.8rem);position:relative;overflow:hidden;border-bottom:1px solid var(--line-2)}
.phead::before{content:"";position:absolute;inset:0;background:radial-gradient(60% 110% at 80% 0%,var(--red-soft),transparent 62%);pointer-events:none}
.phead h1{font-size:clamp(2.4rem,7vw,5.2rem);text-transform:uppercase;letter-spacing:-.028em;margin:1rem 0 1.1rem}
.phead p{color:var(--muted);max-width:66ch;font-size:1.06rem}

/* ---------- REGISTER TABLE ---------- */
.reg-wrap{overflow-x:auto;border:1px solid var(--line-2)}
.reg{width:100%;border-collapse:collapse;font-size:.88rem;min-width:760px}
.reg th{font-family:var(--f-mono);font-size:.6rem;letter-spacing:.18em;text-transform:uppercase;color:var(--muted-2);
  text-align:left;padding:.95rem 1rem;border-bottom:1px solid var(--line-2);background:var(--carbon);white-space:nowrap}
.reg td{padding:.9rem 1rem;border-bottom:1px solid var(--line);color:var(--muted);vertical-align:top}
.reg tr:last-child td{border-bottom:0}
.reg tbody tr{transition:background .22s}
.reg tbody tr:hover{background:var(--panel)}
.reg .rid{font-family:var(--f-mono);color:var(--red);white-space:nowrap;font-size:.78rem;letter-spacing:.06em}
.reg .rnm{color:var(--fg);font-family:var(--f-display);text-transform:uppercase;font-size:.98rem}
.reg .rdoc a{color:var(--silver-3);font-family:var(--f-mono);font-size:.68rem;letter-spacing:.1em;text-transform:uppercase;transition:color .22s}
.reg .rdoc a:hover{color:var(--red-bright)}
.reg .rdoc span{font-family:var(--f-mono);font-size:.64rem;letter-spacing:.1em;text-transform:uppercase;color:var(--muted-2)}