/* Drafting-desk neutrals, an aluminium calculator body, signal-yellow accent. IBM Plex Sans + Mono. */
:root{
  --sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --bg:#f2f4f6;--surface:#fff;--ink:#15202b;--muted:#5b6772;--line:#d9dee3;--alu:#d5d9dd;
  --signal:#f2c200;--on-signal:#15202b;--lcd:#c8d4bb;--lcd-ink:#1c2a1d;--lcd-err:#8f1d1d;
  --k-num:#f6f7f8;--k-num-ink:#15202b;--k-op:#2b343c;--k-op-ink:#fff;--k-fn:#b9bfc5;--k-fn-ink:#15202b;--k-clr:#cf3b3b;
  --focus:#2f6fed;--ok-bg:#dff3e3;--ok-ink:#14532d;--bad-bg:#fbe0e0;--bad-ink:#7f1d1d;
}
:root[data-theme="dark"]{
  --bg:#12161a;--surface:#1a2026;--ink:#e6e9ec;--muted:#96a1ab;--line:#2a323a;--alu:#262d34;
  --lcd:#1c2a22;--lcd-ink:#b8e6c4;--lcd-err:#ff9b9b;
  --k-num:#3a434b;--k-num-ink:#f1f3f4;--k-op:#14181c;--k-op-ink:#e6e9ec;--k-fn:#2f373e;--k-fn-ink:#d8dde1;--k-clr:#b8383a;
  --focus:#7aa2ff;--ok-bg:#16351f;--ok-ink:#b7ecc4;--bad-bg:#43191b;--bad-ink:#ffc2c2;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:400 1rem/1.6 var(--sans)}
a{color:inherit;text-decoration-color:var(--signal);text-decoration-thickness:2px;text-underline-offset:3px}
a:hover{text-decoration-color:currentColor}
:focus-visible{outline:3px solid var(--focus);outline-offset:2px;border-radius:4px}
.wrap{max-width:1120px;margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-999px;top:8px;background:var(--ink);color:var(--bg);padding:8px 12px;border-radius:6px;z-index:100}
.skip:focus{left:8px}
h1,h2,h3{line-height:1.15;letter-spacing:-.015em;margin:0 0 .5em}
h1{font-size:clamp(2rem,4.6vw,3.2rem);font-weight:600;letter-spacing:-.025em}
h2{font-size:1.4rem;font-weight:600}
.lead{font-size:1.15rem;color:var(--muted);max-width:52ch;margin:.4em 0 0}
.muted{color:var(--muted)}.small{font-size:.85rem}

/* header */
.top{position:sticky;top:0;z-index:20;background:var(--bg);border-bottom:1px solid var(--line)}
.bar{display:flex;align-items:center;gap:8px;min-height:60px}
.brand{display:flex;align-items:center;gap:10px;font-weight:600;font-size:1.1rem;text-decoration:none}
.mark{width:26px;height:26px;fill:currentColor}.mark .y{fill:var(--signal)}
.nav{display:flex;gap:2px;margin-left:16px;flex:1}
.dd{position:relative}
.dd-btn{background:none;border:0;color:inherit;font:500 .98rem var(--sans);padding:8px 12px;border-radius:8px;cursor:pointer;display:flex;align-items:center;gap:8px}
.dd-btn::after{content:"";width:6px;height:6px;border-right:2px solid currentColor;border-bottom:2px solid currentColor;transform:rotate(45deg) translateY(-2px)}
.dd-btn:hover,.dd.open .dd-btn{background:var(--surface)}
.dd-panel{display:none;position:absolute;left:0;top:calc(100% + 6px);min-width:360px;max-height:75vh;overflow-y:auto;background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:6px 14px 12px}
.dd.open .dd-panel{display:block}
.dd-links{display:flex;gap:18px;padding-top:10px;font-size:.92rem}
.icon{width:40px;height:40px;display:inline-flex;align-items:center;justify-content:center;border:0;background:none;color:inherit;border-radius:8px;cursor:pointer}
.icon:hover{background:var(--surface)}
.burger{display:none;margin-left:auto}
@media(max-width:820px){
  .burger{display:inline-flex}
  .nav{display:none;position:absolute;left:0;right:0;top:100%;margin:0;flex-direction:column;background:var(--bg);border-bottom:1px solid var(--line);padding:8px 20px 16px}
  .nav.open{display:flex}
  .dd-btn{width:100%;justify-content:space-between;padding:12px 4px}
  .dd-panel{position:static;min-width:0;border:0;border-radius:0;padding:0 0 8px;background:none}
}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 16px;border-radius:8px;border:1px solid var(--line);background:var(--surface);color:var(--ink);font:500 .95rem/1.1 var(--sans);cursor:pointer;text-decoration:none}
.btn:hover{border-color:var(--muted)}
.btn.primary{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.btn.sm{padding:6px 10px;font-size:.85rem}
.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}

/* layout */
.hero{display:grid;gap:32px;padding:44px 0 28px;align-items:center}
@media(min-width:900px){.hero{grid-template-columns:minmax(0,1fr) 380px;gap:56px}}
.page-head{display:flex;justify-content:space-between;align-items:flex-start;gap:16px;padding:12px 0 22px}
.page-head h1{margin-bottom:0}
.crumbs{padding-top:18px;font-size:.88rem;color:var(--muted)}
.crumbs ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:6px}
.crumbs li+li::before{content:"/";margin-right:6px;color:var(--line)}
.cols{display:grid;grid-template-columns:minmax(0,1fr);gap:36px;margin-bottom:40px}
@media(min-width:960px){.cols.has-side{grid-template-columns:minmax(0,1fr) 320px}}
.block{margin-top:36px}.block:first-child{margin-top:0}
.prose{max-width:68ch}.prose h2{margin-top:1.6em}.prose p,.prose li{line-height:1.7}
.calc-wrap{padding-bottom:36px}

/* tool / article rows */
.grp{font-size:.95rem;font-weight:600;color:var(--muted);margin:18px 0 8px}
.rows{list-style:none;margin:0 0 20px;padding:0;border-top:1px solid var(--line)}
.rows a{display:grid;gap:2px;position:relative;padding:14px 8px 14px 22px;border-bottom:1px solid var(--line);text-decoration:none}
.rows a::before{content:"";position:absolute;left:4px;top:21px;width:8px;height:8px;border-radius:2px;background:var(--signal)}
.rows a:hover{background:var(--surface)}
.row-t{font-weight:600}.row-d{color:var(--muted);font-size:.95rem}.row-m{color:var(--muted);font-size:.85rem}
.dd-panel .rows a{padding:10px 6px 10px 20px}.dd-panel .rows a::before{top:17px}

/* ads */
.ad{margin:18px auto;text-align:center;overflow:hidden;max-width:100%}
.ad-label{display:block;font-size:11px;color:var(--muted);margin-bottom:4px}
.ad-1{max-width:1120px;padding:0 20px}
.cols .ad-2{margin:0;align-self:start}

/* calculator */
.calc-bar-l{display:flex;gap:8px;flex-wrap:wrap}
.calc-bar{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:10px}
.calc-body{display:grid;gap:16px;grid-template-columns:minmax(0,1fr)}
.device{background:var(--alu);border-radius:22px;padding:14px;width:100%;margin:0 auto;box-shadow:inset 0 1px 0 rgba(255,255,255,.35),0 1px 0 var(--line)}
.std .device{max-width:360px}.sci .device{max-width:520px}
.lcd{background:var(--lcd);color:var(--lcd-ink);border-radius:10px;padding:8px 14px 10px;font-family:var(--mono);box-shadow:inset 0 2px 5px rgba(0,0,0,.18)}
.lcd-flags{display:flex;gap:10px;min-height:18px;font-size:.72rem;font-weight:500;opacity:.7}
.lcd-expr,.lcd-res{text-align:right;white-space:nowrap;overflow-x:auto;scrollbar-width:none}
.lcd-expr::-webkit-scrollbar,.lcd-res::-webkit-scrollbar{display:none}
.lcd-expr{font-size:.95rem;min-height:1.6em;opacity:.8}
.lcd-res{font-size:2.1rem;font-weight:500;line-height:1.3}
.lcd-res.err{font-size:1.1rem;color:var(--lcd-err);padding:.5em 0}
.keys{display:grid;gap:8px;margin-top:10px}
.k4{grid-template-columns:repeat(4,1fr)}.k5{grid-template-columns:repeat(5,1fr)}.k6{grid-template-columns:repeat(6,1fr)}
.key{height:54px;border:0;border-radius:8px;font:600 1.3rem var(--sans);cursor:pointer;color:var(--k-num-ink);background:var(--k-num);box-shadow:0 3px 0 rgba(0,0,0,.28);user-select:none;touch-action:manipulation;padding:0}
.key:active{transform:translateY(3px);box-shadow:0 0 0 rgba(0,0,0,.28)}
.key.op{background:var(--k-op);color:var(--k-op-ink);font-size:1.5rem}
.key.fn{background:var(--k-fn);color:var(--k-fn-ink);font-size:1.1rem}
.k6 .key{height:44px;font-size:.95rem}
@media(min-width:720px){.k6 .key{height:48px;font-size:1.05rem}}
@media(min-width:960px){.k6 .key{height:50px;font-size:1.15rem}}
.k5 .key{font-size:1.3rem}.k5 .key.fn{font-size:1.05rem}.k5 .key.op{font-size:1.5rem}
.key.clr{background:var(--k-clr);color:#fff}
.key.eq{background:var(--signal);color:var(--on-signal);font-size:1.7rem}
.key.wide{grid-column:1/-1}
.hist{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:12px 14px;display:none;flex-direction:column;min-height:0}
.hist-open .hist{display:flex}
.hist-head{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:6px}
.hist-head h2{font-size:1.05rem;margin:0}.hist-actions{display:flex;gap:6px}
.hist-shared{display:flex;justify-content:space-between;align-items:center;gap:8px;background:var(--signal);color:var(--on-signal);border-radius:8px;padding:6px 10px;margin:6px 0;font-weight:500;font-size:.9rem}
.hist-shared .btn{padding:4px 8px}
.hist-list{list-style:none;margin:0;padding:0;overflow-y:auto;flex:1;min-height:0;max-height:300px}
.hist-list li{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:0 8px;padding:8px 0;border-bottom:1px solid var(--line)}
.h-expr{grid-column:1/-1;font:400 .8rem var(--mono);color:var(--muted);overflow-wrap:anywhere}
.h-use{font:500 1.1rem var(--mono);text-align:left;background:none;border:0;color:var(--ink);cursor:pointer;padding:0;overflow-wrap:anywhere}
.h-use:hover{text-decoration:underline;text-decoration-color:var(--signal);text-decoration-thickness:2px}
.h-copy{font:500 .8rem var(--sans);padding:4px 9px;border:1px solid var(--line);border-radius:6px;background:var(--bg);color:var(--ink);cursor:pointer}
.hist-empty,.hist-size{margin:8px 0 0;font-size:.85rem;color:var(--muted)}
.hist-empty[hidden],.hist-shared[hidden]{display:none}
@media(min-width:720px){
  .calc:not(.mini) .calc-body{align-items:stretch;justify-content:start}
  .std:not(.mini) .calc-body{grid-template-columns:360px minmax(0,1fr)}
  .sci:not(.mini) .calc-body{grid-template-columns:420px minmax(0,1fr)}
  .calc:not(.mini) .device{margin:0}
  .calc:not(.mini) .hist{display:flex;height:0;min-height:100%}
  .calc:not(.mini) #ch-hist-toggle{display:none}
  .calc:not(.mini) .calc-bar:not(:has(.js-share)){display:none}
  .calc:not(.mini) .hist-list{max-height:none}
}
.mini .hist-list{max-height:220px}
@media(min-width:960px){.sci:not(.mini) .calc-body{grid-template-columns:520px minmax(0,1fr)}}

/* converters */
.conv-bar{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;margin-bottom:12px}
.conv-bar-r{display:flex;gap:8px;align-items:center}
.region{display:flex;align-items:center;gap:10px;font-weight:500}.region select{width:auto;max-width:100%}
.conv-explain{margin:0 0 16px;padding:10px 14px;border-left:4px solid var(--signal);background:var(--surface);border-radius:0 8px 8px 0;font-size:.95rem;max-width:80ch}
.conv-body{display:grid;gap:18px;grid-template-columns:minmax(0,1fr)}
@media(min-width:960px){.conv-body{grid-template-columns:minmax(0,1fr) 300px;align-items:start}}
.conv-card{background:var(--alu);border-radius:20px;padding:18px;box-shadow:inset 0 1px 0 rgba(255,255,255,.35),0 1px 0 var(--line)}
.conv-grid{display:grid;gap:12px;grid-template-columns:minmax(0,1fr)}
@media(min-width:640px){.conv-grid{grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);align-items:end}}
.conv-field{display:grid;gap:8px;min-width:0}
.conv-field label,.conv-label{font-weight:600;font-size:.88rem;color:var(--muted)}
.conv-field input{font:500 1.7rem var(--mono);padding:10px 14px;background:var(--surface);border-radius:10px}
.conv-out{font:500 1.7rem var(--mono);padding:10px 14px;min-height:3.1rem;background:var(--lcd);color:var(--lcd-ink);border-radius:10px;box-shadow:inset 0 2px 5px rgba(0,0,0,.18);overflow-x:auto;white-space:nowrap}
.conv-field select{background:var(--surface);font-weight:500}
.conv-swap{width:46px;height:46px;border:0;border-radius:50%;background:var(--k-op);color:var(--k-op-ink);display:inline-flex;align-items:center;justify-content:center;cursor:pointer;box-shadow:0 3px 0 rgba(0,0,0,.28);justify-self:center}
.conv-swap:active{transform:translateY(3px);box-shadow:none}
@media(min-width:640px){.conv-swap{margin-bottom:2px}}
.conv-line{margin:14px 0 0;font:400 .92rem var(--mono);color:var(--ink);opacity:.8}
.conv-err{margin:12px 0 0;padding:8px 12px;border-radius:8px;background:var(--bad-bg);color:var(--bad-ink);font-weight:500}
.conv-err[hidden]{display:none}
.conv-actions{display:flex;flex-wrap:wrap;gap:12px;align-items:center;margin-top:14px}
.dp{display:flex;align-items:center;gap:8px;font-weight:500;font-size:.92rem}.dp select{width:auto;padding:7px 10px}
.conv-all{margin-top:22px}
.conv-all .list td{padding:8px}
.conv-all tr.is-from td{background:var(--surface)}.conv-all tr.is-to td{background:var(--lcd);color:var(--lcd-ink)}
.conv .hist-list{max-height:380px}
@media(min-width:720px){.conv .hist{display:flex}.conv #ch-hist-toggle{display:none}}

/* footer, toast, share */
.foot{border-top:1px solid var(--line);padding:28px 0 36px;margin-top:20px;color:var(--muted);font-size:.92rem}
.foot-grid{display:flex;flex-wrap:wrap;justify-content:space-between;gap:24px}
.foot-grid p{margin:.3em 0 0}.foot-links{display:flex;flex-wrap:wrap;gap:8px 20px;align-items:flex-start}
.copy{margin:20px 0 0;font-size:.85rem}
.foot-note{margin-top:-24px;padding:0 0 32px;color:var(--muted);font-size:.85rem}
.foot-note p{margin:0;max-width:80ch}
.toast{position:fixed;left:50%;bottom:24px;transform:translate(-50%,20px);background:var(--ink);color:var(--bg);padding:9px 16px;border-radius:8px;font-size:.9rem;opacity:0;pointer-events:none;transition:opacity .15s,transform .15s;z-index:60}
.toast.show{opacity:1;transform:translate(-50%,0)}
.share-ov{position:fixed;inset:0;background:rgba(10,14,18,.55);display:none;align-items:center;justify-content:center;padding:16px;z-index:50}
.share-ov.open{display:flex}
.share-box{background:var(--surface);color:var(--ink);border-radius:14px;padding:22px;width:100%;max-width:460px;position:relative}
.share-box h2{margin-bottom:12px}
.share-url{display:flex;gap:8px;margin:10px 0 14px}
.share-url input{flex:1;min-width:0}
.share-links{display:flex;flex-wrap:wrap;gap:8px}
.share-box .close{margin-top:16px}
input,select,textarea{font:inherit;color:var(--ink);background:var(--bg);border:1px solid var(--line);border-radius:8px;padding:10px 12px;width:100%}
.check{display:flex;align-items:center;gap:8px;font-weight:500}.check input{width:auto}

/* admin */
.admin{max-width:820px;margin:0 auto;padding:20px 0 48px}
.admin-head{display:flex;justify-content:space-between;align-items:center;gap:12px}
.admin-head h1{font-size:1.8rem}.admin-head form{margin:0}
.tabs{display:flex;flex-wrap:wrap;gap:4px;border-bottom:1px solid var(--line);margin:8px 0 22px}
.tabs a{padding:10px 14px;text-decoration:none;border-bottom:3px solid transparent;margin-bottom:-1px}
.tabs a[aria-current=page]{border-bottom-color:var(--signal);font-weight:600}
.form label{display:grid;gap:6px;margin-bottom:16px;font-weight:500}
.form label.check{display:flex}
.form .actions{margin-top:8px}
.mono{font-family:var(--mono);font-size:.85rem}
.flash{padding:10px 14px;border-radius:8px;background:var(--ok-bg);color:var(--ok-ink);margin:16px 0}
.flash.bad{background:var(--bad-bg);color:var(--bad-ink)}
.table-wrap{overflow-x:auto}
.list{width:100%;border-collapse:collapse;font-size:.95rem}
.list th,.list td{text-align:left;padding:10px 8px;border-bottom:1px solid var(--line);vertical-align:middle}
.act{display:flex;gap:6px;flex-wrap:wrap}.act form{margin:0}
.pill{display:inline-block;padding:2px 10px;border-radius:99px;font-size:.8rem;font-weight:500}
.pill.on{background:var(--ok-bg);color:var(--ok-ink)}.pill.off{background:var(--line);color:var(--muted)}
@media(prefers-reduced-motion:reduce){*{transition:none!important}}