/* AlphaCalcs - instrument-panel design system
   Palette: cool drafting paper, deep navy structure, one mint readout accent. */
:root{
  --canvas:#EDF1F5;
  --surface:#FFFFFF;
  --ink:#0E1A24;
  --ink-2:#334756;
  --muted:#65788A;
  --line:#DCE3EA;
  --line-2:#C6D1DC;
  --navy:#12325C;
  --navy-700:#0B2444;
  --mint:#3BE0A6;
  --amber:#E8A33D;
  --red:#C63D3D;
  --r:10px;
  --shadow:0 1px 2px rgba(14,26,36,.06),0 8px 24px -12px rgba(14,26,36,.18);
  --sans:"IBM Plex Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
[hidden]{display:none !important}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--canvas);color:var(--ink);font-family:var(--sans);font-size:16.5px;line-height:1.62;
  font-feature-settings:"tnum" off}
img,svg{max-width:100%}
a{color:var(--navy);text-decoration-color:var(--line-2);text-underline-offset:2px}
a:hover{text-decoration-color:currentColor}
h1,h2,h3,h4{line-height:1.2;letter-spacing:-.018em;margin:0 0 .5em}
h1{font-size:clamp(1.75rem,1.2rem + 2vw,2.5rem);font-weight:700}
h2{font-size:clamp(1.25rem,1.05rem + .8vw,1.6rem);font-weight:600;margin-top:2em}
h3{font-size:1.06rem;font-weight:600;margin-top:1.6em}
p{margin:0 0 1em}
.wrap{max-width:1180px;margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px}
.skip:focus{left:12px;top:12px;z-index:99;background:var(--navy);color:#fff;padding:10px 14px;border-radius:8px}
:focus-visible{outline:2.5px solid var(--navy);outline-offset:2px;border-radius:4px}

/* ---- header ---- */
.site-head{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.94);backdrop-filter:saturate(1.4) blur(8px);
  border-bottom:1px solid var(--line)}
.site-head__in{display:flex;align-items:center;gap:18px;height:62px}
.brand{display:flex;align-items:center;gap:9px;text-decoration:none;color:var(--ink);flex:none}
.brand__mark{display:grid;place-items:center;width:32px;height:32px;border-radius:9px;background:var(--navy);color:var(--mint)}
.brand__word{font-weight:700;letter-spacing:-.03em;font-size:1.16rem}
.brand__word em{font-style:normal;color:var(--navy)}
.nav{display:flex;gap:2px;margin-left:6px}
.nav a{padding:7px 11px;border-radius:7px;font-size:.94rem;font-weight:500;text-decoration:none;color:var(--ink-2)}
.nav a:hover{background:var(--canvas);color:var(--navy)}
.navtoggle{display:none;margin-left:auto;font:inherit;font-size:.9rem;padding:7px 12px;border:1px solid var(--line-2);
  background:#fff;border-radius:8px;cursor:pointer}
.findbox{position:relative;margin-left:auto;width:min(260px,32vw)}
.findbox input{width:100%;font:inherit;font-size:.92rem;padding:8px 12px;border:1px solid var(--line-2);border-radius:8px;
  background:var(--canvas)}
.findbox input:focus{background:#fff}
.findbox__list{position:absolute;top:calc(100% + 6px);right:0;width:320px;max-width:80vw;background:#fff;list-style:none;
  margin:0;padding:6px;border:1px solid var(--line-2);border-radius:10px;box-shadow:var(--shadow);max-height:60vh;overflow:auto}
.findbox__list a{display:block;padding:8px 10px;border-radius:7px;text-decoration:none;font-size:.92rem;color:var(--ink)}
.findbox__list a:hover,.findbox__list a:focus{background:var(--canvas)}
.findbox__list small{display:block;color:var(--muted);font-size:.78rem}

/* ---- hero ---- */
.hero{background:var(--navy-700);color:#E8EFF6;padding:56px 0 64px;
  background-image:linear-gradient(rgba(255,255,255,.045) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.045) 1px,transparent 1px);
  background-size:34px 34px}
.hero h1{color:#fff;max-width:16ch}
.hero p{color:#A9BFD4;max-width:52ch;font-size:1.05rem}
.hero__search{margin-top:26px;max-width:620px;position:relative}
.hero__search input{width:100%;font-family:var(--mono);font-size:1.05rem;padding:16px 18px;border-radius:12px;
  border:1px solid rgba(255,255,255,.18);background:#0A1B2E;color:#fff}
.hero__search input::placeholder{color:#5E7C99}
.hero__search input:focus{border-color:var(--mint)}
.hero__hits{list-style:none;margin:8px 0 0;padding:6px;background:#fff;border-radius:12px;box-shadow:var(--shadow);
  position:absolute;width:100%;z-index:5;max-height:52vh;overflow:auto}
.hero__hits a{display:block;padding:9px 12px;border-radius:8px;text-decoration:none;color:var(--ink)}
.hero__hits a:hover{background:var(--canvas)}
.hero__hits small{color:var(--muted);display:block;font-size:.79rem}
.chips{margin-top:14px;display:flex;flex-wrap:wrap;gap:8px}
.chips a{font-size:.85rem;padding:5px 11px;border-radius:99px;border:1px solid rgba(255,255,255,.2);color:#CBDCEC;
  text-decoration:none}
.chips a:hover{border-color:var(--mint);color:var(--mint)}

/* ---- layout ---- */
.section{padding:44px 0}
.eyebrow{font-family:var(--mono);font-size:.74rem;letter-spacing:.13em;text-transform:uppercase;color:var(--muted);
  margin:0 0 8px}
.cols{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:40px;align-items:start;padding:32px 0 56px}
.side{position:sticky;top:78px;display:grid;gap:20px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--shadow)}
.card--pad{padding:22px}
.side h3{margin:0 0 10px;font-size:.85rem;font-family:var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.side ul{list-style:none;margin:0;padding:0}
.side li+li{border-top:1px solid var(--line)}
.side a{display:block;padding:9px 0;text-decoration:none;font-size:.94rem;color:var(--ink-2)}
.side a:hover{color:var(--navy)}

/* ---- calculator ---- */
.calc{padding:24px}
.calc__grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:16px 18px;align-items:start}
.field{display:grid;grid-template-rows:auto 44px auto;align-content:start}
.field label{font-size:.86rem;font-weight:600;color:var(--ink-2);line-height:1.3;margin-bottom:6px;
  display:flex;align-items:flex-end;min-height:2.6em}
.field .hint{font-size:.76rem;color:var(--muted);line-height:1.35;margin-top:6px}
.field input,.field select{font:inherit;font-family:var(--mono);font-size:.98rem;line-height:1.4;height:44px;
  padding:0 12px;border:1px solid var(--line-2);border-radius:8px;background:#fff;width:100%;color:var(--ink);
  -webkit-appearance:none;-moz-appearance:none;appearance:none}
.field select{padding-right:38px;cursor:pointer;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8' fill='none' stroke='%2365788A' stroke-width='1.6' stroke-linecap='round'%3E%3Cpath d='M1 1.5 6 6.5 11 1.5'/%3E%3C/svg%3E");
  background-repeat:no-repeat;background-position:right 13px center}
.field input::-webkit-outer-spin-button,.field input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}
.field input[type=number]{-moz-appearance:textfield}
.field input[type=time],.field input[type=date]{-webkit-appearance:none;appearance:none;min-height:44px}
.field input:focus,.field select:focus{border-color:var(--navy);outline:none;box-shadow:0 0 0 3px rgba(18,50,92,.12)}
.field select:focus{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8' fill='none' stroke='%2312325C' stroke-width='1.8' stroke-linecap='round'%3E%3Cpath d='M1 1.5 6 6.5 11 1.5'/%3E%3C/svg%3E")}
.field.is-bad input{border-color:var(--red)}
.inline{display:flex;gap:8px;align-items:stretch}
.inline input{flex:1}
.inline select{width:auto;flex:none;min-width:96px}
.calc__actions{display:flex;gap:10px;margin-top:20px;flex-wrap:wrap}
.btn{font:inherit;font-weight:600;font-size:.95rem;padding:11px 22px;border-radius:8px;border:1px solid var(--navy);
  background:var(--navy);color:#fff;cursor:pointer}
.btn:hover{background:var(--navy-700)}
.btn--ghost{background:#fff;color:var(--ink-2);border-color:var(--line-2)}
.btn--ghost:hover{background:var(--canvas);color:var(--ink)}
.err{margin-top:14px;color:var(--red);font-size:.9rem;font-weight:500}

/* ---- the signature: instrument readout ---- */
.readout{margin-top:22px;background:var(--ink);border-radius:12px;padding:22px;color:#9FB6C6;position:relative;overflow:hidden}
.readout::after{content:"";position:absolute;inset:0;pointer-events:none;
  background:repeating-linear-gradient(180deg,rgba(255,255,255,.028) 0 1px,transparent 1px 3px)}
.readout__label{font-family:var(--mono);font-size:.72rem;letter-spacing:.16em;text-transform:uppercase;color:#6E8A9E}
.readout__value{font-family:var(--mono);font-weight:600;font-variant-numeric:tabular-nums;color:var(--mint);
  font-size:clamp(2rem,1.3rem + 3.2vw,3.1rem);line-height:1.1;margin:6px 0 0;letter-spacing:-.02em}
.readout__sub{font-size:.9rem;color:#8FA8BA;margin:6px 0 0}
.readout__rows{display:grid;grid-template-columns:1fr auto;gap:0;margin:18px 0 0;font-size:.92rem}
.readout__rows dt{padding:9px 0;border-top:1px solid rgba(255,255,255,.09);color:#8FA8BA}
.readout__rows dd{padding:9px 0;border-top:1px solid rgba(255,255,255,.09);margin:0;text-align:right;
  font-family:var(--mono);font-variant-numeric:tabular-nums;color:#E6F0F6}
.readout__bar{display:flex;height:9px;border-radius:99px;overflow:hidden;margin-top:16px;background:rgba(255,255,255,.1)}
.readout__bar i{display:block;height:100%}
.readout.is-new{animation:flick .34s ease-out}
@keyframes flick{0%{opacity:.35}40%{opacity:1}60%{opacity:.7}100%{opacity:1}}
@media (prefers-reduced-motion:reduce){.readout.is-new{animation:none}}

/* ---- keypad (scientific) ---- */
.pad{display:grid;grid-template-columns:repeat(5,1fr);gap:7px;margin-top:16px}
.pad button{font-family:var(--mono);font-size:.95rem;padding:13px 4px;border:1px solid var(--line-2);background:#fff;
  border-radius:8px;cursor:pointer}
.pad button:hover{background:var(--canvas)}
.pad .k-op{background:#F3F6F9;color:var(--navy);font-weight:600}
.pad .k-eq{background:var(--navy);color:#fff;border-color:var(--navy);grid-column:span 2}
.pad .k-cl{color:var(--red)}

.gparow{display:grid;gap:10px;grid-template-columns:1.5fr 1fr .8fr}
@media (max-width:560px){.gparow{grid-template-columns:1fr 1fr}}

/* ---- prose ---- */
.prose{max-width:70ch}
.prose ul,.prose ol{padding-left:1.2em;margin:0 0 1em}
.prose li{margin:.35em 0}
.prose table{width:100%;border-collapse:collapse;margin:1.2em 0;font-size:.94rem}
.prose th,.prose td{text-align:left;padding:9px 12px;border-bottom:1px solid var(--line)}
.prose th{font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:600}
.prose td:not(:first-child){font-family:var(--mono);font-variant-numeric:tabular-nums}
.prose blockquote{margin:1.2em 0;padding:2px 0 2px 16px;border-left:3px solid var(--mint);color:var(--ink-2)}
.guide-meta{font-family:var(--mono);font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin:0 0 20px}
.guide-lede{font-size:1.14rem;line-height:1.6;color:var(--ink-2);margin:0 0 8px}
.guide-hero{display:block;width:100%;height:auto;aspect-ratio:16/9;border-radius:12px;margin:20px 0 4px;
  border:1px solid var(--line)}
.explainer{margin:24px 0 0;padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:var(--r)}
.explainer svg{display:block;width:100%;height:auto}
.explainer figcaption{margin-top:12px;font-size:.88rem;color:var(--muted);line-height:1.5}
.guide-cta{margin:32px 0 0}
.guide-cta a{display:inline-block;background:var(--navy);color:#fff;text-decoration:none;font-weight:600;
  padding:12px 22px;border-radius:8px;font-size:.96rem}
.guide-cta a:hover{background:var(--navy-700)}
.guidetiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px;margin-top:24px}
.guidecard{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:22px;text-decoration:none;
  color:var(--ink);display:flex;flex-direction:column;gap:8px;transition:border-color .15s,transform .15s}
.guidecard:hover{border-color:var(--navy);transform:translateY(-2px)}
.guidecard b{font-size:1.08rem;line-height:1.3}
.guidecard span{font-size:.9rem;color:var(--muted);line-height:1.5}
.guidecard em{font-style:normal;font-family:var(--mono);font-size:.72rem;letter-spacing:.06em;text-transform:uppercase;color:var(--mint-ink,#1a8f66)}
.faq details{border-top:1px solid var(--line);padding:14px 0}
.faq details[open] summary{color:var(--navy)}
.faq summary{cursor:pointer;font-weight:600;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"+";font-family:var(--mono);color:var(--navy);margin-right:10px}
.faq details[open] summary::before{content:"\2212"}
.faq p{margin:.7em 0 0;color:var(--ink-2)}

/* ---- grids of calculators ---- */
.tiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:16px;margin-top:22px}
.tile{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:18px;text-decoration:none;
  color:var(--ink);display:block;transition:border-color .15s,transform .15s}
.tile:hover{border-color:var(--navy);transform:translateY(-2px)}
.tile b{display:block;font-size:1.02rem;margin-bottom:3px}
.tile span{font-size:.88rem;color:var(--muted);line-height:1.5;display:block}
.catgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px;margin-top:22px}
.catcard{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:22px}
.catcard h2{margin:0 0 6px;font-size:1.12rem}
.catcard p{color:var(--muted);font-size:.9rem;margin:0 0 12px}
.catcard ul{list-style:none;margin:0;padding:0}
.catcard li{border-top:1px solid var(--line)}
.catcard a{display:block;padding:8px 0;font-size:.93rem;text-decoration:none;color:var(--ink-2)}
.catcard a:hover{color:var(--navy)}
.listcols{columns:3 210px;column-gap:32px;margin-top:18px}
.listcols a{display:block;padding:7px 0;text-decoration:none;font-size:.95rem;border-bottom:1px solid var(--line);
  break-inside:avoid;color:var(--ink-2)}
.listcols a:hover{color:var(--navy)}

/* ---- crumbs, ads, consent ---- */
.crumbs{font-size:.82rem;color:var(--muted);padding:16px 0 0}
.crumbs a{color:var(--muted);text-decoration:none}
.crumbs a:hover{color:var(--navy)}
.crumbs__sep{margin:0 8px;color:var(--line-2)}
.ad{margin:26px 0;text-align:center}
.ad__tag{display:block;font-size:.66rem;letter-spacing:.16em;text-transform:uppercase;color:#94A5B4;margin-bottom:5px}
.ad__slot{background:repeating-linear-gradient(45deg,#E5EAF0 0 8px,#EDF1F5 8px 16px);border-radius:8px;
  display:grid;place-items:center}
.ad--sidebar{margin:0}
.consent{position:fixed;left:16px;right:16px;bottom:16px;z-index:60;background:#fff;border:1px solid var(--line-2);
  border-radius:12px;box-shadow:var(--shadow);padding:16px 18px;display:flex;gap:16px;align-items:center;
  flex-wrap:wrap;max-width:760px;margin:0 auto;font-size:.9rem}
.consent p{margin:0;flex:1 1 320px;color:var(--ink-2)}
.consent__btns{display:flex;gap:8px}

/* ---- footer ---- */
.site-foot{background:var(--ink);color:#9FB6C6;margin-top:40px;padding:44px 0 26px;font-size:.9rem}
.site-foot .brand__word{color:#fff}
.site-foot .brand__word em{color:var(--mint)}
.foot-grid{display:grid;grid-template-columns:1.4fr repeat(4,1fr);gap:28px}
.foot-brand p{margin-top:10px;max-width:34ch;color:#7E97A9}
.site-foot h3{color:#fff;font-size:.76rem;font-family:var(--mono);letter-spacing:.12em;text-transform:uppercase;margin:0 0 10px}
.site-foot ul{list-style:none;margin:0;padding:0}
.site-foot li{margin:0 0 7px}
.site-foot a{color:#9FB6C6;text-decoration:none}
.site-foot a:hover{color:var(--mint)}
.foot-note{margin:34px 0 0;padding-top:18px;border-top:1px solid rgba(255,255,255,.1);color:#6E8A9E;font-size:.82rem}

@media (max-width:920px){
  .cols{grid-template-columns:1fr}
  .side{position:static}
  .foot-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:760px){
  .navtoggle{display:block;order:3}
  .nav{display:none;order:5;width:100%;flex-direction:column;padding:8px 0 12px;border-top:1px solid var(--line)}
  .nav.is-open{display:flex}
  .site-head__in{flex-wrap:wrap;height:auto;padding-top:10px;padding-bottom:10px}
  .findbox{order:4;width:100%;margin:8px 0 0}
  .listcols{columns:1}
  .foot-grid{grid-template-columns:1fr}
}