*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg:#0a0a14;--bg-card:rgba(255,255,255,0.04);--bg-card-hover:rgba(255,255,255,0.08);
  --border:rgba(255,255,255,0.08);--text:#e8e8f0;--text-dim:#8888a0;
  --accent:#7c3aed;--accent2:#22d3ee;--glow:0 0 40px rgba(124,58,237,0.3);
  --hot:#f472b6;--fun:#a78bfa;--classic:#34d399;
}
html{scroll-behavior:smooth}
body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,'Helvetica Neue',sans-serif;background:var(--bg);color:var(--text);min-height:100vh;line-height:1.7;overflow-x:hidden}

/* Animated starfield background */
.stars{position:fixed;top:0;left:0;width:100%;height:100%;z-index:0;pointer-events:none}
.stars::before{content:'';position:absolute;top:0;left:0;width:100%;height:100%;background-image:
  radial-gradient(2px 2px at 20% 30%,rgba(255,255,255,0.8),transparent),
  radial-gradient(1px 1px at 60% 70%,rgba(255,255,255,0.6),transparent),
  radial-gradient(1.5px 1.5px at 80% 20%,rgba(255,255,255,0.7),transparent),
  radial-gradient(1px 1px at 40% 80%,rgba(255,255,255,0.5),transparent),
  radial-gradient(2px 2px at 90% 50%,rgba(255,255,255,0.6),transparent),
  radial-gradient(1px 1px at 15% 60%,rgba(255,255,255,0.4),transparent),
  radial-gradient(1.5px 1.5px at 70% 40%,rgba(167,139,250,0.5),transparent),
  radial-gradient(1px 1px at 30% 15%,rgba(34,211,238,0.5),transparent);
  animation:twinkle 4s ease-in-out infinite alternate;
}
@keyframes twinkle{0%{opacity:0.6}100%{opacity:1}}

/* Nav */
nav{position:fixed;top:0;left:0;right:0;z-index:100;backdrop-filter:blur(20px);background:rgba(10,10,20,0.7);border-bottom:1px solid var(--border)}
.nav-inner{max-width:1100px;margin:0 auto;padding:16px 24px;display:flex;align-items:center;justify-content:space-between}
.logo{font-size:1.4rem;font-weight:800;letter-spacing:-0.02em}
.logo a{color:var(--text);text-decoration:none}
.logo span{color:var(--accent2)}
.nav-links{display:flex;gap:24px}
.nav-links a{color:var(--text-dim);font-size:0.9rem;text-decoration:none;transition:color .2s}
.nav-links a:hover{color:var(--text)}

/* Container */
.container{position:relative;z-index:1;max-width:800px;margin:0 auto;padding:0 24px}

/* Hero */
.hero{padding:130px 0 40px;text-align:center}
.hero h1{font-size:clamp(2.5rem,6vw,4.5rem);font-weight:900;letter-spacing:-0.03em;line-height:1.1;background:linear-gradient(135deg,#f472b6,#a78bfa,#22d3ee,#34d399);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:16px}
.hero p{font-size:clamp(1rem,2vw,1.2rem);color:var(--text-dim);max-width:600px;margin:0 auto}
.tool-hero{padding:120px 0 30px;text-align:center}
.tool-hero h1{font-size:clamp(2rem,5vw,3.5rem);font-weight:900;letter-spacing:-0.03em;line-height:1.1;background:linear-gradient(135deg,#f472b6 0%,#a78bfa 30%,#22d3ee 60%,#34d399 100%);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:16px}
.tool-hero p{color:var(--text-dim);max-width:600px;margin:0 auto;font-size:1.05rem}

/* Cards */
.tool-card{background:var(--bg-card);border:1px solid var(--border);border-radius:24px;padding:32px;margin:24px 0;transition:border-color .3s}
.tool-card:focus-within{border-color:var(--accent)}

/* Result */
.result-box{background:rgba(0,0,0,0.3);border:1px solid var(--border);border-radius:12px;padding:24px;text-align:center;margin:16px 0}
.result-big{font-size:clamp(1.5rem,4vw,2.2rem);font-weight:900;background:linear-gradient(135deg,var(--accent2),#a78bfa);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;font-variant-numeric:tabular-nums}
.result-unit{color:var(--text-dim);font-size:0.9rem;margin-top:6px}

/* Result pop-in animation */
.result-box{animation:popIn .4s ease-out}
@keyframes popIn{0%{transform:scale(0.95);opacity:0}100%{transform:scale(1);opacity:1}}

/* Inputs */
input[type="number"],input[type="text"],select{width:100%;padding:12px 16px;background:rgba(255,255,255,0.05);border:1px solid var(--border);border-radius:10px;color:var(--text);font-size:0.95rem;outline:none;transition:border-color .2s,box-shadow .3s;font-family:inherit}
input:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(124,58,237,0.15)}
select option{background:#1a1a2e}

/* Buttons */
.btn{padding:12px 24px;border:none;border-radius:10px;background:linear-gradient(135deg,var(--accent),#a78bfa);color:#fff;font-size:0.95rem;font-weight:600;cursor:pointer;transition:transform .2s,box-shadow .2s;font-family:inherit;position:relative;overflow:hidden}
.btn:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(124,58,237,0.4)}
.btn:active{transform:translateY(0) scale(0.98)}
.btn::after{content:'';position:absolute;top:50%;left:50%;width:0;height:0;border-radius:50%;background:rgba(255,255,255,0.3);transform:translate(-50%,-50%);transition:width .4s,height .4s}
.btn:active::after{width:300px;height:300px}

/* Share button */
.share-row{display:flex;gap:10px;justify-content:center;margin:16px 0}
.btn-share{padding:10px 20px;border:1px solid var(--border);border-radius:10px;background:transparent;color:var(--text-dim);font-size:0.85rem;cursor:pointer;transition:all .2s;font-family:inherit;display:flex;align-items:center;gap:6px}
.btn-share:hover{border-color:var(--accent2);color:var(--accent2);background:rgba(34,211,238,0.05)}

/* Form */
.form-row{margin-bottom:16px}
.form-row label{display:block;margin-bottom:6px;color:var(--text-dim);font-size:0.85rem}

/* Planet rows */
.planet-row{display:flex;justify-content:space-between;align-items:center;padding:12px 0;border-bottom:1px solid var(--border);transition:background .2s,padding-left .2s;border-radius:8px}
.planet-row:hover{background:rgba(124,58,237,0.08);padding-left:8px}
.planet-row:last-child{border-bottom:none}
.planet-name{font-weight:600;font-size:0.95rem}
.planet-value{color:var(--accent2);font-variant-numeric:tabular-nums;font-size:0.95rem}

/* Result number glow pulse */
.result-big{animation:numberPulse .6s ease-out}
@keyframes numberPulse{0%{opacity:0;transform:translateY(8px)}100%{opacity:1;transform:translateY(0)}}

/* Page load fade */
body{animation:pageIn .5s ease-out}
@keyframes pageIn{0%{opacity:0}100%{opacity:1}}

/* Card hover lift */
.related-card{transition:all .25s ease}
.next-challenge{transition:all .25s ease}

/* Science section */
.science{margin:24px 0}
.science p{color:var(--text-dim);font-size:0.95rem;line-height:1.8;margin-bottom:14px}

/* Related tools */
.related{margin:32px 0}
.related h2{font-size:1.1rem;margin-bottom:16px;color:var(--text)}
.related-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}
.related-card{background:var(--bg-card);border:1px solid var(--border);border-radius:16px;padding:16px;text-decoration:none;color:var(--text);transition:all .2s}
.related-card:hover{border-color:var(--accent);background:var(--bg-card-hover);transform:translateY(-2px)}
.related-card h4{font-size:0.95rem;margin-bottom:4px}
.related-card p{font-size:0.8rem;color:var(--text-dim)}

/* Ad slot */
.ad-slot{background:rgba(255,255,255,0.02);border:1px dashed var(--border);border-radius:8px;padding:20px;text-align:center;color:var(--text-dim);font-size:0.75rem;margin:24px 0}

/* Footer */
footer{border-top:1px solid var(--border);padding:40px 0;text-align:center;color:var(--text-dim);font-size:0.85rem}
footer a{color:var(--text-dim);text-decoration:none;margin:0 8px}
footer a:hover{color:var(--text)}

/* Daily cosmic snapshot */
.cosmic-snapshot{background:linear-gradient(135deg,rgba(124,58,237,0.15),rgba(34,211,238,0.08));border:1px solid rgba(124,58,237,0.3);border-radius:24px;padding:32px;margin:32px 0;text-align:center}
.cosmic-snapshot h3{font-size:1rem;color:var(--accent2);margin-bottom:16px;text-transform:uppercase;letter-spacing:0.1em}
.cosmic-snapshot .big{font-size:clamp(1.5rem,4vw,2.5rem);font-weight:900;background:linear-gradient(135deg,var(--accent2),#a78bfa);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;margin:8px 0}
.cosmic-snapshot .desc{color:var(--text-dim);font-size:0.9rem;margin-top:8px;max-width:500px;margin-left:auto;margin-right:auto}
.cosmic-canvas{width:100%;max-width:300px;height:160px;margin:16px auto;display:block}

@media(max-width:640px){
  .nav-links{display:none}
  .related-grid{grid-template-columns:1fr}
}