@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@200;300;400;500;600;700;800&family=Roboto+Mono:wght@300;400;500&display=swap');

:root {
  --sky: #f5faff;
  --cloud: #e8f4ff;
  --mist: #d8ecff;
  --blue-light: #a8d4ff;
  --blue: #2870d0;
  --blue-deep: #0a3a80;
  --plasma: #60a8ff;
  --energy: #00b4ff;
  --energy-dim: rgba(0,180,255,0.08);
  --energy-border: rgba(0,180,255,0.2);
  --white: #ffffff;
  --text: #3060a0;
  --text-muted: #6090c0;
  --text-dim: #aaccee;
  --border: rgba(40,112,208,0.15);
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
body{font-family:'Manrope',sans-serif;background:var(--sky);color:var(--text);min-height:100vh;overflow-x:hidden;}
#h-canvas{position:fixed;inset:0;z-index:0;pointer-events:none;}
body::before{content:'H';position:fixed;top:50%;right:-5%;transform:translateY(-50%);font-family:'Manrope',sans-serif;font-size:60vw;font-weight:800;opacity:0.025;z-index:1;pointer-events:none;color:var(--blue);}
.wrap{position:relative;z-index:2;max-width:1020px;margin:0 auto;padding:0 28px 90px;}

/* ── HERO ── */
.hero{padding:68px 0 54px;display:grid;grid-template-columns:1fr 260px;gap:44px;align-items:center;border-bottom:1px solid var(--border);margin-bottom:58px;}
.hero-tag{font-family:'Roboto Mono',monospace;font-size:0.58rem;letter-spacing:5px;text-transform:uppercase;color:var(--blue);opacity:0.5;margin-bottom:14px;}
.hero h1{font-size:clamp(4rem,12vw,8.5rem);font-weight:800;line-height:0.85;color:var(--blue-deep);letter-spacing:-3px;}
.hero h1 em{display:block;font-size:0.2em;font-style:normal;font-weight:300;letter-spacing:6px;color:var(--blue-light);margin-top:12px;font-family:'Roboto Mono',monospace;text-transform:uppercase;}
.hero-desc{font-size:0.96rem;line-height:1.85;color:var(--text-muted);font-weight:300;margin-top:18px;}

/* ── Periodic card ── */
.periodic-card{width:240px;height:240px;background:var(--white);border:1px solid var(--energy-border);border-radius:8px;padding:18px;display:flex;flex-direction:column;justify-content:space-between;position:relative;overflow:hidden;box-shadow:0 4px 30px rgba(0,180,255,0.08),0 20px 60px rgba(40,112,208,0.06);}
.periodic-card::before{content:'';position:absolute;inset:0;background:radial-gradient(ellipse at 40% 35%,rgba(0,180,255,0.06),transparent 60%);}
.pc-num{font-family:'Roboto Mono',monospace;font-size:0.85rem;color:var(--energy);opacity:0.7;}
.pc-symbol{font-family:'Manrope',sans-serif;font-size:5.5rem;font-weight:800;color:var(--blue-deep);line-height:1;text-align:center;}
.pc-name{font-size:0.8rem;font-weight:700;color:var(--blue);text-align:center;letter-spacing:3px;text-transform:uppercase;}
.pc-mass{font-family:'Roboto Mono',monospace;font-size:0.72rem;color:var(--text-dim);text-align:right;}

/* ── Stats ── */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(148px,1fr));border:1px solid var(--border);overflow:hidden;margin-bottom:58px;background:var(--white);border-radius:4px;}
.stat{padding:18px 14px;background:var(--white);border-right:1px solid var(--border);transition:background 0.2s;}
.stat:last-child{border-right:none;} .stat:hover{background:var(--energy-dim);}
.s-label{font-family:'Roboto Mono',monospace;font-size:0.52rem;letter-spacing:2px;text-transform:uppercase;color:var(--energy);opacity:0.7;margin-bottom:7px;}
.s-value{font-size:1.05rem;font-weight:700;color:var(--blue-deep);line-height:1.1;}
.s-unit{font-size:0.6rem;color:var(--text-dim);}

/* ── Sections ── */
.section{margin-bottom:56px;opacity:0;transform:translateY(18px);transition:opacity 0.65s,transform 0.65s;}
.section.visible{opacity:1;transform:none;}
.sh{display:flex;align-items:baseline;gap:14px;margin-bottom:20px;padding-bottom:12px;border-bottom:1px solid var(--border);}
.sn{font-family:'Roboto Mono',monospace;font-size:0.55rem;letter-spacing:3px;color:var(--energy);opacity:0.5;}
.section h2{font-size:1.5rem;font-weight:800;color:var(--blue-deep);letter-spacing:-0.5px;}
p{font-size:0.95rem;line-height:1.87;color:var(--text-muted);font-weight:300;margin-bottom:14px;}
strong{color:var(--blue-deep);font-weight:600;}

/* ── Isotopes ── */
.isotopes{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px;}
.iso-card{background:var(--white);border:1px solid var(--border);border-top:3px solid var(--energy);border-radius:4px;padding:20px;text-align:center;box-shadow:0 2px 12px rgba(40,112,208,0.06);}
.iso-symbol{font-family:'Roboto Mono',monospace;font-size:1.8rem;font-weight:700;color:var(--blue-deep);display:block;margin-bottom:4px;}
.iso-name{font-size:0.75rem;font-weight:700;color:var(--energy);text-transform:uppercase;letter-spacing:1px;margin-bottom:8px;}
.iso-card p{font-size:0.78rem;margin:0;line-height:1.55;text-align:left;}

/* ── Hydrogen colors ── */
.colors-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:10px;margin-top:18px;}
.color-card{background:var(--white);border:1px solid var(--border);padding:16px;border-radius:4px;transition:box-shadow 0.2s;}
.color-card:hover{box-shadow:0 4px 16px rgba(40,112,208,0.1);}
.color-dot{width:16px;height:16px;border-radius:50%;display:inline-block;margin-right:8px;vertical-align:middle;}
.color-card h3{font-size:0.82rem;font-weight:700;color:var(--blue-deep);margin-bottom:6px;}
.color-card p{font-size:0.78rem;margin:0;line-height:1.5;}

/* ── Uses ── */
.uses-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:10px;margin-top:18px;}
.use-card{background:var(--white);border:1px solid var(--border);border-left:3px solid var(--energy);padding:16px;border-radius:0 4px 4px 0;transition:border-left-color 0.2s,box-shadow 0.2s;}
.use-card:hover{border-left-color:var(--blue);box-shadow:0 4px 16px rgba(40,112,208,0.08);}
.use-card h3{font-size:0.8rem;font-weight:700;color:var(--blue-deep);text-transform:uppercase;letter-spacing:0.5px;margin-bottom:6px;}
.use-card p{font-size:0.78rem;margin:0;line-height:1.5;}

/* ── Discovery ── */
.disc-box{background:var(--white);border:1px solid var(--border);border-left:3px solid var(--blue);border-radius:0 4px 4px 0;padding:24px 26px;margin-top:18px;box-shadow:0 2px 16px rgba(40,112,208,0.05);}
.disc-box h3{font-size:0.82rem;font-weight:700;color:var(--blue-deep);text-transform:uppercase;letter-spacing:1px;margin-bottom:10px;}
.disc-box p{margin:0 0 10px;} .disc-box p:last-child{margin:0;}

.footer-band{margin-top:70px;border-top:1px solid var(--border);padding-top:20px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;}
.footer-band span{font-family:'Roboto Mono',monospace;font-size:0.52rem;letter-spacing:2px;color:var(--text-dim);text-transform:uppercase;}
@media(max-width:640px){.hero{grid-template-columns:1fr;} .periodic-card{margin:0 auto;} .isotopes{grid-template-columns:1fr;}}