/* ============================================================
   PhysicsCalculator — shared site styles
   Deep-space / scientific-instrument theme
   ============================================================ */
:root{
  --void:#080b16;
  --void2:#0c1122;
  --ink:#eef1fa;
  --dim:#8a93b2;
  --faint:#5a6488;
  --line:#202845;
  --line2:#2c365c;
  --gold:#f0c674;
  --cyan:#62d6d3;
  --violet:#a99bf5;
  --rose:#f08ca0;
  --green:#7fd99a;
  --panel:rgba(16,21,40,.78);
  --panel2:rgba(11,15,30,.6);
  --glow:rgba(98,214,211,.16);
  --maxw:1180px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  background:var(--void);color:var(--ink);
  font-family:'Newsreader',serif;line-height:1.65;
  position:relative;min-height:100vh;overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
.bg{position:fixed;inset:0;z-index:-2;
  background:
    radial-gradient(ellipse 80% 50% at 18% -10%, rgba(169,155,245,.14), transparent 60%),
    radial-gradient(ellipse 70% 60% at 92% 8%, rgba(98,214,211,.10), transparent 55%),
    radial-gradient(ellipse 90% 70% at 50% 112%, rgba(240,140,160,.08), transparent 60%),
    var(--void);}
.stars{position:fixed;inset:0;z-index:-1;opacity:.4}
.grain{position:fixed;inset:0;z-index:-1;pointer-events:none;opacity:.03;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");}

a{color:var(--cyan);text-decoration:none;transition:color .15s}
a:hover{color:var(--gold)}

/* ===== top navigation ===== */
.nav{position:sticky;top:0;z-index:50;backdrop-filter:blur(14px);
  background:rgba(8,11,22,.72);border-bottom:1px solid var(--line);}
.nav-inner{max-width:var(--maxw);margin:0 auto;padding:14px 24px;display:flex;align-items:center;gap:26px}
.brand{display:flex;align-items:center;gap:11px;font-family:'Fraunces',serif;font-weight:700;
  font-size:20px;color:var(--ink);letter-spacing:-.01em}
.brand:hover{color:var(--ink)}
.brand .mark{width:30px;height:30px;border-radius:50%;flex:none;position:relative;
  background:radial-gradient(circle at 35% 30%, var(--gold), #b8821f 70%);
  box-shadow:0 0 16px rgba(240,198,116,.5);}
.brand .mark::after{content:"";position:absolute;inset:-6px;border:1.5px solid rgba(98,214,211,.55);
  border-radius:50%;transform:rotate(-18deg) scaleY(.42);}
.brand em{font-style:italic;font-weight:400;color:var(--gold)}
.nav-links{margin-left:auto;display:flex;gap:24px;align-items:center;
  font-family:'Spline Sans Mono',monospace;font-size:13px;letter-spacing:.02em}
.nav-links a{color:var(--dim)}
.nav-links a:hover,.nav-links a.active{color:var(--ink)}
.nav-cta{padding:8px 16px;border:1px solid var(--cyan);border-radius:8px;color:var(--cyan)!important}
.nav-cta:hover{background:var(--cyan);color:var(--void)!important}
.nav-burger{display:none;margin-left:auto;background:none;border:none;color:var(--ink);font-size:24px;cursor:pointer}
@media(max-width:760px){
  .nav-links{display:none;position:absolute;top:100%;left:0;right:0;flex-direction:column;
    gap:0;background:rgba(10,14,28,.97);border-bottom:1px solid var(--line);padding:8px 0}
  .nav-links.open{display:flex}
  .nav-links a{padding:13px 24px;width:100%}
  .nav-cta{margin:8px 24px;text-align:center}
  .nav-burger{display:block}
}

/* ===== layout ===== */
.container{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.narrow{max-width:760px}
section{position:relative}

/* ===== hero ===== */
.hero{text-align:center;padding:80px 24px 36px}
.eyebrow{font-family:'Spline Sans Mono',monospace;font-size:11.5px;letter-spacing:.42em;
  text-transform:uppercase;color:var(--cyan);opacity:.8;margin-bottom:18px}
h1.display{font-family:'Fraunces',serif;font-weight:800;font-size:clamp(40px,7.5vw,76px);
  line-height:.96;letter-spacing:-.02em;
  background:linear-gradient(118deg,var(--ink) 22%,var(--gold) 56%,var(--violet) 96%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;}
h1.display em{font-style:italic;font-weight:400}
.lede{color:var(--dim);max-width:600px;margin:20px auto 0;font-size:19px;font-style:italic}

.btn{display:inline-block;font-family:'Spline Sans Mono',monospace;font-size:13.5px;letter-spacing:.16em;
  text-transform:uppercase;font-weight:600;padding:15px 30px;border-radius:12px;cursor:pointer;transition:.22s;border:none}
.btn-primary{background:linear-gradient(118deg,var(--gold),var(--cyan));color:var(--void)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 14px 36px -10px rgba(98,214,211,.5);color:var(--void)}
.btn-ghost{border:1px solid var(--line2);color:var(--ink)}
.btn-ghost:hover{border-color:var(--cyan);color:var(--cyan)}
.btn-row{display:flex;gap:14px;justify-content:center;flex-wrap:wrap;margin-top:34px}

/* ===== panels & cards ===== */
.panel{background:var(--panel);border:1px solid var(--line);border-radius:18px;backdrop-filter:blur(16px);
  box-shadow:0 30px 70px -34px rgba(0,0,0,.85), inset 0 1px 0 rgba(255,255,255,.04);}

.section-head{text-align:center;margin:0 auto 38px;max-width:640px}
.section-head .k{font-family:'Spline Sans Mono',monospace;font-size:11px;letter-spacing:.3em;
  text-transform:uppercase;color:var(--violet);opacity:.8}
.section-head h2{font-family:'Fraunces',serif;font-weight:700;font-size:clamp(28px,4vw,40px);
  margin-top:12px;letter-spacing:-.01em}
.section-head p{color:var(--dim);margin-top:12px;font-size:17px}

.grid{display:grid;gap:20px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
@media(max-width:860px){.grid-3{grid-template-columns:1fr}.grid-2{grid-template-columns:1fr}}

.card{padding:26px;border:1px solid var(--line);border-radius:16px;background:var(--panel2);transition:.2s;display:block}
.card:hover{border-color:var(--line2);transform:translateY(-3px);
  box-shadow:0 24px 50px -28px rgba(0,0,0,.8)}
.card .ic{font-family:'STIX Two Math',serif;font-size:30px;color:var(--gold);font-style:italic}
.card h3{font-family:'Fraunces',serif;font-weight:600;font-size:21px;margin:14px 0 8px;color:var(--ink)}
.card p{color:var(--dim);font-size:15.5px}
.card .more{font-family:'Spline Sans Mono',monospace;font-size:12px;letter-spacing:.06em;
  color:var(--cyan);margin-top:14px;display:inline-block}

/* ===== article ===== */
.article{padding:48px 0 30px}
.article .meta{font-family:'Spline Sans Mono',monospace;font-size:12px;letter-spacing:.1em;
  text-transform:uppercase;color:var(--violet);opacity:.85}
.article h1{font-family:'Fraunces',serif;font-weight:800;font-size:clamp(32px,5vw,52px);
  line-height:1.05;letter-spacing:-.02em;margin:14px 0 10px}
.article .sub{color:var(--dim);font-size:19px;font-style:italic;margin-bottom:8px}
.prose{font-size:18px;color:#d8deef}
.prose h2{font-family:'Fraunces',serif;font-weight:700;font-size:28px;color:var(--ink);
  margin:42px 0 14px;letter-spacing:-.01em}
.prose h3{font-family:'Fraunces',serif;font-weight:600;font-size:21px;color:var(--ink);margin:30px 0 10px}
.prose p{margin:16px 0}
.prose ul,.prose ol{margin:16px 0 16px 26px}
.prose li{margin:8px 0}
.prose strong{color:var(--ink);font-weight:600}
.prose code{font-family:'Spline Sans Mono',monospace;font-size:.86em;color:var(--cyan);
  background:rgba(98,214,211,.09);padding:2px 7px;border-radius:5px}
.formula{font-family:'STIX Two Math','Newsreader',serif;font-size:30px;text-align:center;
  color:var(--gold);background:var(--panel2);border:1px solid var(--line);border-radius:14px;
  padding:26px 20px;margin:26px 0;overflow-x:auto}
.formula .where{display:block;font-size:14px;color:var(--dim);font-family:'Newsreader',serif;
  font-style:italic;margin-top:14px}
.callout{border-left:3px solid var(--cyan);background:var(--panel2);border-radius:0 12px 12px 0;
  padding:16px 20px;margin:26px 0;color:var(--dim);font-size:16px}
.callout strong{color:var(--cyan)}
.try-box{display:flex;align-items:center;justify-content:space-between;gap:18px;flex-wrap:wrap;
  margin:34px 0;padding:22px 26px;border:1px solid var(--line2);border-radius:14px;
  background:linear-gradient(118deg,rgba(240,198,116,.06),rgba(98,214,211,.06))}
.try-box .t{font-family:'Fraunces',serif;font-size:20px}
.try-box .t span{color:var(--dim);font-size:15px;font-style:italic;display:block;margin-top:3px}

/* math inline bits */
sub{font-size:.62em;vertical-align:sub}
sup{font-size:.62em;vertical-align:super}
.frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;margin:0 .15em}
.frac>.n{border-bottom:1.4px solid currentColor;padding:0 .4em 2px}
.frac>.d{padding:3px .4em 0}
.sqrt{white-space:nowrap}.sqrt>.r{font-size:1.1em}.sqrt>.b{border-top:1.4px solid currentColor;padding-top:2px}

/* ===== ad slots ===== */
.ad-slot{margin:30px auto;max-width:var(--maxw);padding:0 24px}
.ad-inner{border:1px dashed var(--line2);border-radius:12px;min-height:90px;
  display:flex;align-items:center;justify-content:center;background:var(--panel2);
  font-family:'Spline Sans Mono',monospace;font-size:11px;letter-spacing:.18em;
  text-transform:uppercase;color:var(--faint)}

/* ===== article list ===== */
.post-list{display:flex;flex-direction:column;gap:14px;margin-top:30px}
.post-row{display:flex;gap:18px;align-items:baseline;padding:20px 22px;border:1px solid var(--line);
  border-radius:14px;background:var(--panel2);transition:.18s}
.post-row:hover{border-color:var(--gold);transform:translateX(4px)}
.post-row .num{font-family:'Spline Sans Mono',monospace;color:var(--violet);font-size:13px;flex:none;opacity:.7}
.post-row h3{font-family:'Fraunces',serif;font-weight:600;font-size:20px;color:var(--ink)}
.post-row p{color:var(--dim);font-size:15px;margin-top:4px}

/* ===== footer ===== */
footer{border-top:1px solid var(--line);margin-top:70px;padding:48px 24px 40px;
  background:rgba(8,11,22,.5)}
.foot-inner{max-width:var(--maxw);margin:0 auto;display:grid;grid-template-columns:1.6fr 1fr 1fr;gap:40px}
@media(max-width:760px){.foot-inner{grid-template-columns:1fr;gap:30px}}
.foot-col h4{font-family:'Spline Sans Mono',monospace;font-size:11px;letter-spacing:.2em;
  text-transform:uppercase;color:var(--faint);margin-bottom:16px}
.foot-col a{display:block;color:var(--dim);margin:9px 0;font-size:15px}
.foot-col a:hover{color:var(--cyan)}
.foot-about{color:var(--dim);font-size:15px;max-width:340px;margin-top:14px}
.foot-bottom{max-width:var(--maxw);margin:36px auto 0;padding-top:24px;border-top:1px solid var(--line);
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;
  font-family:'Spline Sans Mono',monospace;font-size:12px;color:var(--faint)}

/* form (contact) */
.field{margin:18px 0}
.field label{display:block;font-family:'Spline Sans Mono',monospace;font-size:11px;letter-spacing:.14em;
  text-transform:uppercase;color:var(--faint);margin-bottom:8px}
.field input,.field textarea{width:100%;background:rgba(7,10,20,.7);border:1px solid var(--line);
  border-radius:10px;padding:13px 15px;color:var(--ink);font-family:'Newsreader',serif;font-size:16px}
.field input:focus,.field textarea:focus{outline:none;border-color:var(--cyan);box-shadow:0 0 0 3px var(--glow)}
.field textarea{min-height:140px;resize:vertical}