:root{
  --bg:#F3F6F9; --surface:#FFFFFF; --ink:#14242E; --ink2:#5A7284;
  --line:#DCE5EC; --hero:#0C2230; --hero2:#123346; --energy:#22D3EE;
  --save:#0FA37A; --accent:#0E7490; --warn:#B45309;
}
*{margin:0;padding:0;box-sizing:border-box}
body{background:var(--bg);color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
h1,h2,h3,.display{font-family:"Space Grotesk",ui-sans-serif,system-ui,sans-serif;letter-spacing:-0.01em}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}

/* header */
header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;gap:18px;height:60px}
.brand{display:flex;align-items:center;gap:9px;font-family:"Space Grotesk",sans-serif;font-weight:700;font-size:17px;color:var(--ink)}
.brand svg{display:block}
.navlinks{margin-left:auto;display:flex;gap:4px;flex-wrap:wrap}
.navlinks a{padding:7px 11px;border-radius:8px;color:var(--ink2);font-size:14px;font-weight:500}
.navlinks a:hover{background:#EAF1F6;color:var(--ink);text-decoration:none}
.navlinks a.active{background:#E0F4F9;color:var(--accent)}

/* hero */
.hero{background:linear-gradient(160deg,var(--hero) 0%,var(--hero2) 100%);color:#EAF4F8;padding:64px 0 54px;position:relative;overflow:hidden}
.hero:after{content:"";position:absolute;left:0;right:0;bottom:0;height:5px;background:linear-gradient(90deg,var(--energy) 0%,var(--energy) 38%,rgba(34,211,238,.25) 38%,rgba(34,211,238,.25) 62%,rgba(34,211,238,.08) 62%)}
.hero h1{font-size:clamp(30px,4.4vw,46px);line-height:1.12;max-width:760px}
.hero .sub{margin-top:14px;max-width:640px;color:#A9C4D2;font-size:17px}
.hero .stats{display:flex;gap:34px;margin-top:26px;flex-wrap:wrap}
.hero .stat b{font-family:"Space Grotesk",sans-serif;font-size:26px;color:var(--energy);display:block;line-height:1.1}
.hero .stat span{font-size:13px;color:#8FB0C0}

/* sections */
section{padding:44px 0}
.sec-head{display:flex;align-items:baseline;gap:14px;margin-bottom:22px;flex-wrap:wrap}
.sec-head h2{font-size:24px}
.sec-head p{color:var(--ink2);font-size:15px}

/* tool cards */
.grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.toolcard{display:flex;flex-direction:column;gap:10px;background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:20px;transition:border-color .15s,transform .15s}
.toolcard:hover{border-color:var(--energy);transform:translateY(-2px);text-decoration:none}
.toolcard .ico{width:40px;height:40px;border-radius:10px;background:#E7F6FA;display:flex;align-items:center;justify-content:center}
.toolcard h3{font-size:16px;color:var(--ink)}
.toolcard p{font-size:13.5px;color:var(--ink2);flex:1}
.toolcard .go{font-size:13.5px;font-weight:600;color:var(--accent)}

/* tool panel */
.panel{background:var(--surface);border:1px solid var(--line);border-radius:14px;overflow:hidden}
.panel .pbar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 20px;border-bottom:1px solid var(--line);background:#F8FAFC}
.panel .pbar h3{font-size:16px}
.panel .pbar .tag{font-size:12px;color:var(--ink2);background:#EEF3F7;padding:3px 10px;border-radius:999px}
.panelbody{display:grid;grid-template-columns:1fr 1fr;gap:0}
.col{padding:24px}
.col.in{border-right:1px solid var(--line)}
.field{margin-bottom:16px}
.field label{display:block;font-size:13.5px;font-weight:600;margin-bottom:6px;color:var(--ink)}
.field .hint{font-size:12px;color:var(--ink2);margin-top:4px}
input[type=number],select{width:100%;padding:10px 12px;border:1px solid var(--line);border-radius:9px;font-size:16px;color:var(--ink);background:#fff;font-family:inherit}
input[type=number]:focus,select:focus{outline:2px solid rgba(34,211,238,.5);border-color:var(--energy)}
input[type=range]{width:100%;accent-color:var(--energy)}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.rangeval{display:flex;justify-content:space-between;font-size:12.5px;color:var(--ink2);margin-top:2px}
.result{display:flex;flex-direction:column;gap:14px}
.bignum{font-family:"Space Grotesk",sans-serif;font-size:42px;font-weight:700;line-height:1.05;color:var(--hero)}
.bignum small{font-size:16px;color:var(--ink2);font-weight:500}
.resultline{display:flex;justify-content:space-between;align-items:baseline;padding:10px 0;border-bottom:1px dashed var(--line);font-size:14.5px}
.resultline b{font-family:"Space Grotesk",sans-serif;font-size:17px}
.resultline .pos{color:var(--save)}
.track{height:12px;border-radius:999px;background:#E6EDF3;overflow:hidden;margin-top:4px}
.track i{display:block;height:100%;border-radius:999px;background:linear-gradient(90deg,#67E8F9,var(--energy));transition:width .35s ease}
.track.green i{background:linear-gradient(90deg,#6EE7B7,var(--save))}
.note{font-size:12.5px;color:var(--ink2);background:#F2F7FA;border:1px solid var(--line);border-radius:10px;padding:12px 14px}
.hintbar{margin-top:22px;padding-top:18px;border-top:1px solid var(--line);display:flex;align-items:center;gap:10px;font-size:13px;color:var(--ink2)}
.hintbar svg{flex:none}

/* faq */
.faq{margin-top:26px}
.faq details{border:1px solid var(--line);border-radius:10px;background:var(--surface);margin-bottom:10px;padding:0}
.faq summary{cursor:pointer;padding:14px 18px;font-weight:600;font-size:15px;list-style:none;display:flex;justify-content:space-between;align-items:center;gap:10px}
.faq summary::after{content:"+";font-size:18px;color:var(--accent);font-weight:600}
.faq details[open] summary::after{content:"–"}
.faq .ans{padding:0 18px 16px;font-size:14.5px;color:var(--ink2)}

/* page head for tool pages */
.pagehead{padding:40px 0 6px}
.pagehead h1{font-size:30px}
.pagehead p{color:var(--ink2);margin-top:6px;max-width:720px}
.pagebody{padding-top:26px}

/* intro text */
.intro{max-width:760px}
.intro p{color:var(--ink2);font-size:15px;margin-top:10px}
.intro p b{color:var(--ink)}

/* footer */
footer{background:var(--hero);color:#9FB8C6;padding:36px 0;margin-top:30px;font-size:13.5px}
footer .wrap{display:flex;justify-content:space-between;gap:18px;flex-wrap:wrap}
footer a{color:#CBE9F3}
footer .disc{max-width:620px;line-height:1.7}

@media (max-width:900px){
  .grid4{grid-template-columns:repeat(2,1fr)}
  .panelbody{grid-template-columns:1fr}
  .col.in{border-right:none;border-bottom:1px solid var(--line)}
  .hero .stats{gap:22px}
}
@media (max-width:560px){
  .grid4{grid-template-columns:1fr}
  .brand{flex:none}
  .navlinks a{padding:12px 8px;font-size:13px;min-height:44px;display:inline-flex;align-items:center}
  .navlinks{gap:0}
  .bignum{font-size:34px}
}