:root{
  --navy:#0e2238; --blue:#2774ae; --blue-dark:#1a527f; --gold:#e0a800; --gold-soft:#fff4cc;
  --bg:#f5f8fb; --paper:#fff; --ink:#1d2733; --muted:#5b6876; --line:#d9e2ec;
  --sans:"Helvetica Neue",Helvetica,Arial,sans-serif;
  --serif:Georgia,"Times New Roman",serif;
  --mono:"SF Mono",Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:1.05rem;line-height:1.7}
img{max-width:100%;height:auto;display:block}
a{color:var(--blue);text-underline-offset:3px}
a:hover{color:var(--blue-dark)}
.skip{position:absolute;left:-999px;top:0;background:#fff;padding:.5rem 1rem;z-index:10}
.skip:focus{left:0}
.wrap{max-width:62rem;margin:0 auto;padding:0 1.25rem}
.narrow{max-width:44rem}

header.site{background:var(--navy);color:#fff;border-bottom:3px solid var(--gold)}
header.site .wrap{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:.5rem 2rem;padding:.9rem 1.25rem}
.brand{font-family:var(--serif);font-size:1.5rem;letter-spacing:.02em;color:#fff;text-decoration:none}
.brand span{color:var(--gold)}
nav ul{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:.25rem 1.4rem}
nav a{font-size:.9rem;color:#cfe0f0;text-decoration:none;padding:.35rem 0;border-bottom:2px solid transparent}
nav a:hover,nav a[aria-current="page"]{color:#fff;border-bottom-color:var(--gold)}

.hero{background:linear-gradient(160deg,var(--navy) 0%,#17375a 100%);color:#fff;padding:4rem 0 3.5rem;text-align:center}
.hero h1{font-family:var(--serif);font-weight:normal;font-size:clamp(2.2rem,6vw,3.5rem);margin:0 0 .6rem}
.hero p{color:#cfe0f0;font-size:1.15rem;max-width:36rem;margin:0 auto}
.hero p.decay{font-family:var(--serif);font-size:clamp(1.3rem,4vw,2rem);color:var(--gold);margin:1.5rem auto 0;letter-spacing:.02em}

main{padding-bottom:3.5rem}
h1.page{font-family:var(--serif);font-weight:normal;font-size:clamp(1.9rem,5vw,2.7rem);line-height:1.2;margin:2.8rem 0 .4rem;color:var(--navy)}
.sub{color:var(--muted);font-size:1.15rem;margin:0 0 1.5rem}
h2{font-family:var(--serif);font-weight:normal;font-size:1.55rem;color:var(--blue-dark);margin:2.4rem 0 .6rem}
h3{font-size:1.1rem;margin:1.6rem 0 .3rem;color:var(--navy)}
.eq{font-family:var(--serif);background:var(--paper);border-left:4px solid var(--gold);padding:.7rem 1rem;margin:1rem 0;font-size:1.15rem}

.cards{display:grid;gap:1.25rem;grid-template-columns:repeat(2,1fr);margin:2rem 0}
@media (max-width:640px){.cards{grid-template-columns:1fr}}
.card{background:var(--paper);border:1px solid var(--line);border-top:4px solid var(--blue);border-radius:6px;padding:1.3rem;text-decoration:none;color:inherit;display:block;transition:box-shadow .15s,transform .15s}
.card:hover{box-shadow:0 6px 18px rgba(14,34,56,.12);transform:translateY(-2px)}
.card .tag{font-size:.78rem;letter-spacing:.1em;text-transform:uppercase;color:var(--blue);margin-bottom:.3rem}
.card h3{margin:0 0 .3rem;font-family:var(--serif);font-weight:normal;font-size:1.3rem;color:var(--navy)}
.card p{margin:0;font-size:.95rem;color:var(--muted)}

.questions{padding-left:1.2rem}
.questions li{margin-bottom:.8rem}
.sources{font-size:.92rem;color:var(--muted)}
.sources li{margin-bottom:.4rem}

.course{background:var(--paper);border:1px solid var(--line);border-radius:6px;padding:1.2rem 1.4rem;margin:1.5rem 0}
.course h2{margin-top:0}
.course .when{font-size:.85rem;letter-spacing:.08em;text-transform:uppercase;color:var(--blue);margin:0}
.dl{display:inline-block;margin:.4rem 0;padding:.55rem 1rem;background:var(--blue);color:#fff;text-decoration:none;border-radius:4px;font-size:.95rem}
.dl:hover{background:var(--blue-dark);color:#fff}
.dl small{display:block;font-size:.78rem;opacity:.85}
.links{list-style:none;padding:0;margin:0}
.links li{padding:.55rem 0;border-bottom:1px solid var(--line)}

.topics{list-style:none;padding:0;margin:1.5rem 0}
.topics li{background:var(--paper);border:1px solid var(--line);border-left:4px solid var(--gold);border-radius:4px;padding:.9rem 1.1rem;margin-bottom:.8rem}
.topics strong{display:block;color:var(--navy);font-size:1.05rem}
.topics span{color:var(--muted);font-size:.97rem}
.logo{width:min(17rem,55%);margin:0 0 1.5rem 2rem;float:right}
.clear{clear:both}

footer.site{background:var(--navy);color:#a9bdd1;font-size:.88rem;padding:1.8rem 0;border-top:3px solid var(--gold)}
footer.site a{color:#d9e7f5}
footer.site p{margin:.2rem 0}
@media (max-width:560px){
  .logo{float:none;margin:0 auto 1.5rem;width:70%}
  header.site .wrap{flex-direction:column;align-items:flex-start}
}
@media print{header.site,footer.site{display:none}body{background:#fff}}

/* ---- Hero animation ---- */
.hero.anim{padding:3rem 0 2.2rem}
.muon-stage{position:relative;margin:2rem auto 0;max-width:62rem;border-radius:10px;overflow:hidden;box-shadow:0 14px 40px rgba(0,0,0,.45);border:1px solid rgba(255,255,255,.12);background:#0a1626}
#muon-canvas{display:block;width:100%;height:clamp(300px,42vw,440px)}
#muon-toggle{position:absolute;right:.7rem;bottom:.7rem;background:rgba(14,34,56,.8);color:#fff;border:1px solid rgba(255,255,255,.35);border-radius:999px;font:inherit;font-size:.82rem;padding:.3rem .9rem;cursor:pointer}
#muon-toggle:hover,#muon-toggle:focus-visible{background:var(--blue);outline:none}
.muon-steps{list-style:none;counter-reset:s;margin:1.2rem auto 0;padding:0;max-width:62rem;display:grid;grid-template-columns:repeat(4,1fr);gap:.8rem;text-align:left}
.muon-steps li{counter-increment:s;font-size:.88rem;line-height:1.4;color:#a9bdd1;padding:.7rem .8rem .7rem 2.3rem;border:1px solid rgba(255,255,255,.14);border-radius:6px;position:relative;transition:all .3s}
.muon-steps li::before{content:counter(s);position:absolute;left:.7rem;top:.65rem;width:1.3rem;height:1.3rem;border-radius:50%;background:rgba(255,255,255,.14);color:#fff;font-size:.75rem;text-align:center;line-height:1.3rem}
.muon-steps li.on{color:#fff;border-color:var(--gold);background:rgba(224,168,0,.12)}
.muon-steps li.on::before{background:var(--gold);color:var(--navy)}
.hero .fact{font-size:.95rem;margin:1.2rem auto 0;color:#cfe0f0;max-width:44rem}
.hero .btn{display:inline-block;margin-top:1.1rem;background:var(--gold);color:var(--navy);padding:.65rem 1.3rem;border-radius:4px;text-decoration:none;font-weight:bold;font-size:.95rem}
.hero .btn:hover{background:#ffd24d;color:var(--navy)}
@media (max-width:760px){.muon-steps{grid-template-columns:1fr 1fr}#muon-canvas{height:320px}}
@media (max-width:420px){.muon-steps{grid-template-columns:1fr}}

/* ---- Page heroes ---- */
.pagehero{position:relative;overflow:hidden;background:linear-gradient(135deg,#091728 0%,var(--navy) 45%,#1b3f66 100%);color:#fff;padding:3.8rem 0 3.6rem;border-bottom:3px solid var(--gold)}
.pagehero .art{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.pagehero .inner{position:relative;max-width:62rem;margin:0 auto;padding:0 1.25rem;display:flex;align-items:center;justify-content:space-between;gap:2.5rem}
.pagehero .kicker{font-size:.8rem;letter-spacing:.18em;text-transform:uppercase;color:var(--gold);margin:0 0 .6rem}
.pagehero h1{font-family:var(--serif);font-weight:normal;font-size:clamp(2.2rem,5.6vw,3.6rem);line-height:1.12;margin:0 0 .7rem}
.pagehero .sub{font-size:1.15rem;line-height:1.55;color:#cfe0f0;max-width:34rem;margin:0}
.chips{display:flex;flex-wrap:wrap;gap:.5rem;margin:1.2rem 0 0;padding:0;list-style:none}
.chips li{background:rgba(255,255,255,.09);border:1px solid rgba(255,255,255,.22);border-radius:999px;padding:.25rem .85rem;font-size:.84rem;color:#e6f0fa}
.pagehero .hlogo{flex:0 0 auto;width:min(210px,40vw);border-radius:50%;box-shadow:0 14px 36px rgba(0,0,0,.5)}
.draw{stroke-dasharray:1;stroke-dashoffset:1;animation:draw 3.2s ease-out .3s forwards}.draw.d2{animation-delay:1.6s}.draw.d3{animation-delay:2.6s}
.tw{animation:tw 4s ease-in-out infinite alternate}.tw.b{animation-delay:-2s}
.spin{transform-box:view-box;transform-origin:0 0}.o1{animation:orb 38s linear infinite}.o2{animation:orb 24s linear infinite reverse}.o3{animation:orb 15s linear infinite}
.beam{animation:beam 4.8s ease-in-out infinite;opacity:.15}.beam.b2{animation-delay:.6s}.beam.b3{animation-delay:1.2s}.beam.b4{animation-delay:1.8s}
.nd{transform-box:fill-box;transform-origin:center;animation:nd 3.4s ease-in-out infinite alternate}.nd.b{animation-delay:-1.7s}
@keyframes draw{to{stroke-dashoffset:0}}
@keyframes tw{from{opacity:.25}to{opacity:.95}}
@keyframes orb{to{transform:rotate(360deg)}}
@keyframes beam{0%,100%{opacity:.12}40%{opacity:.7}}
@keyframes nd{from{transform:scale(.8);opacity:.6}to{transform:scale(1.25);opacity:1}}
@media (prefers-reduced-motion:reduce){.pagehero *{animation:none!important}.draw{stroke-dashoffset:0}}
@media (max-width:700px){.pagehero{padding:2.6rem 0 2.6rem}.pagehero .inner{flex-direction:column;align-items:flex-start;gap:1.4rem}.pagehero .art{opacity:.45}}

footer.site .credit{margin:.6rem 0 0;font-size:.8rem;letter-spacing:.05em;opacity:.9}