:root{--bg:#f7f9fb;--surface:#fff;--ink:#101820;--muted:#66727d;--line:#dfe6ea;--line-strong:#cfd9de;--accent:#0a7d78;--accent-soft:#e6f4f2;--warning-soft:#fff3df;--shadow:0 18px 50px rgba(16,24,32,.06);--r:22px;--shell:1180px}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);background:radial-gradient(circle at 82% 4%,rgba(10,125,120,.055),transparent 24rem),var(--bg);font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button,input,select{font:inherit}.shell{width:min(var(--shell),calc(100% - 40px));margin:auto}.site-header{position:sticky;top:0;z-index:20;border-bottom:1px solid rgba(223,230,234,.88);background:rgba(247,249,251,.88);backdrop-filter:blur(16px)}.header-inner{height:68px;display:grid;grid-template-columns:1fr auto 1fr;align-items:center}.brand{display:flex;align-items:center;gap:10px;width:max-content}.brand-mark{width:30px;height:30px;display:grid;place-items:center;border-radius:9px;background:var(--ink)}.brand-mark svg{width:21px;fill:none;stroke:#d6fffb;stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}.brand-name{font-weight:750;font-size:18px;letter-spacing:-.03em}.top-nav{display:flex;gap:28px;color:var(--muted);font-size:14px;font-weight:600}.status-pill{justify-self:end;display:flex;align-items:center;gap:8px;padding:7px 10px;border:1px solid var(--line);border-radius:999px;color:var(--muted);background:#ffffffb3;font-size:12px;font-weight:650}.status-dot{width:7px;height:7px;border-radius:50%;background:var(--accent);box-shadow:0 0 0 4px var(--accent-soft)}.hero{padding:64px 0 56px;border-bottom:1px solid var(--line)}.eyebrow{color:var(--accent);font-size:12px;font-weight:800;letter-spacing:.12em}.hero h1{margin:14px 0 18px;max-width:760px;font-size:clamp(38px,5.2vw,64px);line-height:1.02;letter-spacing:-.05em}.hero-copy{max-width:620px;margin:0;color:var(--muted);font-size:17px;line-height:1.6}.hero-actions{display:flex;gap:12px;margin-top:26px;flex-wrap:wrap}.button{display:inline-flex;min-height:44px;align-items:center;padding:0 17px;border-radius:11px;font-size:14px;font-weight:700}.button-primary{color:#fff;background:var(--ink)}.button-secondary{background:#ffffffb3;border:1px solid var(--line-strong)}.tool-strip-wrap{padding:68px 0;border-bottom:1px solid var(--line);background:#ffffff52}.section-heading{display:grid;grid-template-columns:1fr minmax(260px,470px);gap:60px;align-items:end;margin-bottom:28px}.section-heading h2,.about-card h2{margin:9px 0 0;font-size:clamp(28px,3vw,38px);line-height:1.12;letter-spacing:-.04em}.section-heading>p,.about-card>p{margin:0;color:var(--muted);line-height:1.65;font-size:15px}.tool-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.tool-tile{min-height:96px;padding:18px;display:flex;align-items:center;gap:14px;border-radius:14px;border:1px solid var(--line);background:#ffffffcc}.tool-tile.active{border-color:#0a7d7847;background:var(--accent-soft)}.tool-tile.muted{color:#7c8790}.tool-icon{width:38px;height:38px;display:grid;place-items:center;border-radius:10px;background:#fff;border:1px solid var(--line);font-size:20px}.tool-tile strong{display:block;font-size:14px}.tool-tile small{display:block;margin-top:5px;color:var(--muted);font-size:12px}.calculator-section{padding:92px 0}.calculator-grid{display:grid;grid-template-columns:1.03fr .97fr;gap:18px}.calc-panel,.result-panel{border:1px solid var(--line);border-radius:var(--r);background:#fff;box-shadow:var(--shadow);padding:26px}.panel-title,.result-head{display:flex;justify-content:space-between;gap:18px}.panel-title h3,.result-head h3{margin:0;font-size:20px}.panel-title p{margin:7px 0 0;color:var(--muted);font-size:13px}.text-button{border:0;background:none;color:var(--muted);cursor:pointer}.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px 16px;margin-top:26px}.field{display:flex;flex-direction:column;gap:8px}.field-wide{grid-column:1/-1}.field-label{display:flex;justify-content:space-between;color:#3f4b55;font-size:13px;font-weight:700}.field-hint{color:#8b969e;font-size:11px;font-weight:500}.input-group{min-height:48px;display:grid;grid-template-columns:1fr auto;overflow:hidden;border:1px solid var(--line-strong);border-radius:11px;background:#fff}.input-group:focus-within{border-color:#0a7d78b3;box-shadow:0 0 0 3px #0a7d781a}.input-group input,.input-group select{border:0;outline:0;background:transparent;color:var(--ink)}.input-group input{min-width:0;padding:0 14px;font-size:17px;font-weight:670}.input-group select,.unit-static{min-width:78px;padding:0 12px;display:grid;place-items:center;border-left:1px solid var(--line);color:var(--muted);background:#f8fafb;font-size:12px;font-weight:700}.preset-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin-top:22px;padding-top:18px;border-top:1px solid var(--line)}.preset-row>span{color:var(--muted);font-size:12px}.chip{padding:7px 10px;border:1px solid var(--line);border-radius:999px;background:#fff;cursor:pointer;font-size:11px;font-weight:700}.result-panel{background:linear-gradient(180deg,#e6f4f299,#fff0 150px),#fff}.result-kicker{display:block;margin-bottom:8px;color:var(--accent);font-size:11px;font-weight:800;letter-spacing:.12em}.icon-button{padding:8px 11px;border:1px solid var(--line);border-radius:10px;background:#ffffffc2;color:var(--muted);cursor:pointer}.bucket-visual{margin-top:28px;padding:18px;border-radius:14px;background:#f7f9fbe6;border:1px solid var(--line)}.bucket-meta,.bucket-caption{display:flex;justify-content:space-between}.bucket-meta{align-items:baseline;color:#48545d;font-size:12px;font-weight:650}.bucket-meta strong{font-size:18px;color:var(--ink)}.bucket-track{height:9px;overflow:hidden;margin:13px 0 10px;border-radius:999px;background:#dfe7ea}.bucket-fill{width:0;height:100%;border-radius:inherit;background:var(--accent);transition:width .25s}.bucket-caption{color:var(--muted);font-size:11px}.metrics{display:grid;grid-template-columns:1fr 1fr;margin-top:20px;border:1px solid var(--line);border-radius:14px;overflow:hidden}.metric{min-height:92px;padding:16px;display:flex;flex-direction:column;justify-content:space-between;border-bottom:1px solid var(--line)}.metric:nth-child(odd){border-right:1px solid var(--line)}.metric:nth-last-child(-n+2){border-bottom:0}.metric span{color:var(--muted);font-size:11px}.metric strong{font-size:18px}.engineering-note{margin-top:18px;padding:14px 15px;display:flex;gap:11px;border:1px solid #f0d3a7;border-radius:12px;background:var(--warning-soft);color:#68410e}.engineering-note.ok{border-color:#0a7d783d;background:var(--accent-soft);color:#155754}.note-icon{width:20px;height:20px;display:grid;place-items:center;border-radius:50%;background:#ffdca7;font-size:11px;font-weight:900}.engineering-note.ok .note-icon{background:#bee7e2}.engineering-note p{margin:0;font-size:12px;line-height:1.55}.formula-card{margin-top:18px;padding:22px 24px;display:grid;grid-template-columns:280px 1fr;gap:28px;align-items:center;border:1px solid var(--line);border-radius:14px;background:#ffffffb8}.formula-label{display:block;margin-bottom:6px;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.12em}.formula-card p{margin:0;color:var(--muted);font-size:13px;line-height:1.6}.about-section{padding:0 0 92px}.about-card{padding:38px;display:grid;grid-template-columns:.95fr 1.05fr;gap:60px;border-radius:var(--r);background:var(--ink);color:#f7fbfc}.about-card .eyebrow{color:#8be1d9}.about-card>p{color:#b9c4ca}.site-footer{border-top:1px solid var(--line);background:#fff}.footer-inner{min-height:112px;display:flex;align-items:center;justify-content:space-between}.footer-brand{display:flex;gap:10px}.footer-brand span,.footer-note{color:var(--muted);font-size:12px}@media(max-width:900px){.header-inner{grid-template-columns:1fr auto}.top-nav{display:none}.tool-strip{grid-template-columns:1fr 1fr}.section-heading{grid-template-columns:1fr;gap:16px}.calculator-grid{grid-template-columns:1fr}.formula-card,.about-card{grid-template-columns:1fr}}@media(max-width:620px){.shell{width:min(100% - 24px,var(--shell))}.hero{padding:52px 0 46px}.hero h1{font-size:40px}.tool-strip,.field-grid,.metrics{grid-template-columns:1fr}.field-wide{grid-column:auto}.metric,.metric:nth-child(odd),.metric:nth-last-child(-n+2){border-right:0;border-bottom:1px solid var(--line)}.metric:last-child{border-bottom:0}.about-card{padding:28px}.footer-inner{min-height:130px;flex-direction:column;align-items:flex-start;justify-content:center}.footer-brand{flex-direction:column;gap:4px}} 
.icon-button{
  min-width:74px;
  transition:background .16s ease,border-color .16s ease,color .16s ease,transform .08s ease;
}
.icon-button:hover{
  background:#fff;
  color:var(--ink);
  border-color:#b8c4ca;
}
.icon-button:active{
  transform:translateY(1px);
}
.icon-button.copied{
  color:#0b5e59;
  background:#dff3ef;
  border-color:#9fd8d1;
}

.input-group input::placeholder{
  color:#a8b2b9;
  font-weight:500;
  opacity:1;
}
.result-panel.is-empty .bucket-fill{
  width:0 !important;
}
.result-panel.is-empty .engineering-note{
  border-color:var(--line);
  background:#f7f9fb;
  color:var(--muted);
}
.result-panel.is-empty .engineering-note .note-icon{
  background:#e6ecef;
  color:#69757e;
}