/* WattDraw — an editorial data site. Warm paper, copper accent, numbers set in
   tabular figures so columns line up and a changing calculator does not jitter. */

@font-face{font-family:Inter;src:url(/fonts/inter-latin.woff2)format("woff2");font-weight:400 700;font-display:swap;font-style:normal}
@font-face{font-family:"Source Serif 4";src:url(/fonts/source-serif-4-latin.woff2)format("woff2");font-weight:400 700;font-display:swap;font-style:normal}

:root{
  /* Native controls -- range thumbs, select menus, number spinners, scrollbars --
     render light-on-dark without this, whatever the CSS variables say. */
  color-scheme: light dark;
  --bg:#FBFAF8; --surface:#FFF; --raised:#F5F2EC; --sunken:#EFEBE3;
  --text:#1B1A17; --muted:#57534B; --faint:#726D63;
  --line:#E3DED4; --line-strong:#CFC8BA;
  --accent:#A34E11; --accent-ink:#8A4210; --accent-bg:#FBF0E3;
  --good:#1F6F4A; --good-bg:#E9F4EE;
  --warn:#9A3412; --warn-bg:#FDEDE6;
  --shadow:0 1px 2px rgba(27,26,23,.05),0 8px 24px -12px rgba(27,26,23,.14);
  --sans:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  --serif:"Source Serif 4",ui-serif,Georgia,serif;
  --wrap:74rem; --measure:38rem; --r:10px;
}
@media (prefers-color-scheme:dark){:root:not([data-theme=light]){
  --bg:#14130F; --surface:#1C1B16; --raised:#22201A; --sunken:#100F0C;
  --text:#F0EDE6; --muted:#A9A399; --faint:#8C877E;
  --line:#2E2B24; --line-strong:#413D33;
  --accent:#E9A24A; --accent-ink:#F2BC77; --accent-bg:#2A2118;
  --good:#5FBF8E; --good-bg:#16241D;
  --warn:#F0906A; --warn-bg:#2B1912;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.6);
}}
[data-theme=dark]{
  --bg:#14130F; --surface:#1C1B16; --raised:#22201A; --sunken:#100F0C;
  --text:#F0EDE6; --muted:#A9A399; --faint:#8C877E;
  --line:#2E2B24; --line-strong:#413D33;
  --accent:#E9A24A; --accent-ink:#F2BC77; --accent-bg:#2A2118;
  --good:#5FBF8E; --good-bg:#16241D; --warn:#F0906A; --warn-bg:#2B1912;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.6);
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation-duration:.01ms!important;transition-duration:.01ms!important}}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--sans);
  font-size:1.0625rem;line-height:1.65;font-feature-settings:"cv05","ss03";
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
.tnum,table,.figure-value,.bar-value,input,output{font-variant-numeric:tabular-nums}
img,svg{max-width:100%;height:auto}
a{color:var(--accent-ink);text-underline-offset:.18em;text-decoration-thickness:.06em}
a:hover{color:var(--accent)}
:focus-visible{outline:2.5px solid var(--accent);outline-offset:2px;border-radius:3px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip{position:absolute;left:-9999px;top:0;background:var(--accent);color:#fff;padding:.7rem 1.1rem;z-index:100;border-radius:0 0 var(--r) 0}
.skip:focus{left:0}
.wrap{max-width:var(--wrap);margin-inline:auto;
  padding-inline:max(clamp(1rem,4vw,2rem),env(safe-area-inset-left),env(safe-area-inset-right))}

/* ------------------------------------------------------------------ header */
.site-head{border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--bg) 88%,transparent);
  backdrop-filter:saturate(1.4) blur(10px);position:sticky;top:0;z-index:40}
.head-inner{display:flex;align-items:center;justify-content:space-between;gap:1rem;min-height:3.75rem}
.brand{text-decoration:none;color:var(--text);display:inline-flex}
.logo{display:inline-flex;align-items:center;gap:.5rem;color:var(--text)}
.logo svg{color:var(--line-strong);flex:none}
.logo svg rect:last-child{fill:var(--accent)}
.logo-word{font-family:var(--serif);font-size:1.22rem;letter-spacing:-.015em;font-weight:400}
.logo-word b{font-weight:700}
.nav ul{display:flex;gap:.25rem;list-style:none;margin:0;padding:0}
.nav a{display:block;padding:.45rem .7rem;border-radius:7px;color:var(--muted);text-decoration:none;font-size:.945rem;font-weight:500}
.nav a:hover{background:var(--raised);color:var(--text)}
.nav-toggle{display:none;background:none;border:1px solid var(--line);border-radius:8px;width:2.5rem;height:2.5rem;cursor:pointer;color:var(--text);align-items:center;justify-content:center}
.burger,.burger::before,.burger::after{display:block;width:17px;height:2px;background:currentColor;border-radius:2px;content:""}
.burger{position:relative}
.burger::before{position:absolute;top:-5.5px}.burger::after{position:absolute;top:5.5px}
@media (max-width:820px){
  .nav-toggle{display:inline-flex}
  .nav ul{position:absolute;left:0;right:0;top:100%;flex-direction:column;gap:0;background:var(--surface);
    border-bottom:1px solid var(--line);padding:.5rem clamp(1rem,4vw,2rem) 1rem;display:none;box-shadow:var(--shadow)}
  .nav[data-open=true] ul{display:flex}
  .nav a{padding:.7rem .25rem;font-size:1.05rem;border-bottom:1px solid var(--line)}
}

/* -------------------------------------------------------------------- main */
main{padding-bottom:4rem}
.layout{display:grid;grid-template-columns:minmax(0,1fr);gap:3rem;padding-block:2rem 1rem}
.layout.has-aside{grid-template-columns:minmax(0,var(--measure)) 18rem;justify-content:center;gap:4rem}
@media (max-width:1120px){.layout.has-aside{grid-template-columns:minmax(0,var(--measure));justify-content:start}}
@media (max-width:980px){.layout.has-aside{grid-template-columns:minmax(0,1fr)}}
.rail{display:flex;flex-direction:column;gap:1.5rem;align-self:start;position:sticky;top:5rem}
@media (max-width:980px){.rail{position:static}}
.prose{max-width:var(--measure)}
main.wide .prose{max-width:none}
.crumbs{padding-top:1.25rem;font-size:.85rem;color:var(--faint)}
.crumbs ol{list-style:none;display:flex;flex-wrap:wrap;gap:.4rem;margin:0;padding:0}
.crumbs li+li::before{content:"/";margin-right:.4rem;color:var(--line-strong)}
.crumbs a{color:var(--muted);text-decoration:none}
.crumbs a:hover{text-decoration:underline}

h1,h2,h3,h4{font-family:var(--serif);line-height:1.15;letter-spacing:-.018em;margin:0 0 .5em;text-wrap:balance}
h1{font-size:clamp(2rem,1.3rem + 2.9vw,3.15rem);font-weight:600;margin-bottom:.35em}
h2{font-size:clamp(1.45rem,1.15rem + 1.2vw,1.95rem);font-weight:600;margin-top:2.4em;padding-top:.2em}
h3{font-size:1.24rem;font-weight:600;margin-top:1.9em}
.prose>p,.prose>ul,.prose>ol{margin:0 0 1.15em}
.prose li{margin-bottom:.4em}
.lead{font-size:1.2rem;line-height:1.55;color:var(--muted);text-wrap:pretty}
p{text-wrap:pretty}
code,kbd{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.9em;background:var(--raised);padding:.12em .38em;border-radius:5px}
hr{border:0;border-top:1px solid var(--line);margin:2.5rem 0}
blockquote{margin:1.5rem 0;padding-left:1.1rem;border-left:3px solid var(--accent);color:var(--muted);font-family:var(--serif);font-size:1.1rem}

/* -------------------------------------------------------------------- hero */
.hero{border-bottom:1px solid var(--line);background:
  radial-gradient(120% 100% at 88% -10%,var(--accent-bg) 0%,transparent 58%),var(--bg);
  padding-block:clamp(2.5rem,6vw,4.5rem)}
.hero h1{max-width:20ch}
.hero .lead{max-width:46ch;font-size:clamp(1.08rem,1rem + .4vw,1.3rem)}
.eyebrow{font-size:.78rem;letter-spacing:.1em;text-transform:uppercase;color:var(--accent);font-weight:650;margin:0 0 .9rem}

/* -------------------------------------------------------------- components */
.note{border-radius:var(--r);padding:1.05rem 1.2rem;margin:1.75rem 0;border:1px solid var(--line);background:var(--raised)}
.note-label{font-size:.72rem;letter-spacing:.09em;text-transform:uppercase;font-weight:700;margin:0 0 .3rem;color:var(--muted)}
.note-title{margin:0;font-weight:600}
.note-body{margin-top:.5rem;color:var(--muted)}
.note-body p{margin:0 0 .6em}.note-body p:last-child{margin:0}
.note-key{border-color:color-mix(in srgb,var(--accent) 32%,var(--line));background:var(--accent-bg)}
.note-key .note-label{color:var(--accent-ink)}
.note-save{border-color:color-mix(in srgb,var(--good) 30%,var(--line));background:var(--good-bg)}
.note-save .note-label{color:var(--good)}
.note-warn{border-color:color-mix(in srgb,var(--warn) 30%,var(--line));background:var(--warn-bg)}
.note-warn .note-label{color:var(--warn)}

.figure-card{border:1px solid var(--line);border-radius:var(--r);padding:1.4rem 1.5rem;background:var(--surface);box-shadow:var(--shadow);margin:1.75rem 0}
.figure-eyebrow{margin:0 0 .35rem;font-size:.8rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);font-weight:650}
.figure-value{margin:0;font-family:var(--serif);font-size:clamp(2.4rem,1.6rem + 3vw,3.5rem);line-height:1;font-weight:600;letter-spacing:-.03em}
.figure-unit{font-size:.36em;font-family:var(--sans);font-weight:500;color:var(--muted);margin-left:.4rem;letter-spacing:0}
.figure-sub{margin:.6rem 0 0;color:var(--muted)}
.figure-foot{margin:.75rem 0 0;font-size:.85rem;color:var(--faint);border-top:1px solid var(--line);padding-top:.7rem}

.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(9.5rem,1fr));gap:1px;margin:1.75rem 0;background:var(--line);border:1px solid var(--line);border-radius:var(--r);overflow:hidden}
.stat{background:var(--surface);padding:1rem 1.1rem}
.stat dt{font-size:.8rem;color:var(--muted);margin-bottom:.25rem}
.stat dd{margin:0;font-family:var(--serif);font-size:1.65rem;font-weight:600;line-height:1.1;letter-spacing:-.02em}
.stat-sub{margin:.3rem 0 0;font-size:.79rem;color:var(--faint);line-height:1.4}

.bar-row{margin:0 0 .85rem}
.bar-head{display:flex;justify-content:space-between;align-items:baseline;gap:1rem;margin-bottom:.3rem}
.bar-label{font-size:.94rem;font-weight:500}
.bar-sub{display:block;font-size:.78rem;color:var(--faint);font-weight:400}
.bar-value{font-size:.94rem;font-weight:600;white-space:nowrap}
.bar-track{height:9px;background:var(--sunken);border-radius:99px;overflow:hidden}
/* width, not transform: scaleX would distort the pill radius on a 9px bar, and
   only a few bars move, only in response to a direct input. */
.bar-fill{height:100%;border-radius:99px;transition:width .35s cubic-bezier(.2,.8,.2,1)}
.bar-accent{background:var(--accent)}
.bar-muted{background:var(--line-strong)}
.bar-good{background:var(--good)}
.bar-warn{background:var(--warn)}

.table-wrap{overflow-x:auto;margin:1.75rem 0;border:1px solid var(--line);border-radius:var(--r);background:var(--surface)}
table{border-collapse:collapse;width:100%;font-size:.94rem}
caption{text-align:left;padding:.9rem 1rem .2rem;color:var(--muted);font-size:.85rem}
th,td{padding:.62rem .85rem;text-align:left;border-bottom:1px solid var(--line)}
thead th{font-size:.76rem;letter-spacing:.05em;text-transform:uppercase;color:var(--muted);font-weight:650;white-space:nowrap;background:var(--raised)}
tbody tr:last-child th,tbody tr:last-child td{border-bottom:0}
tbody th{font-weight:550}
.num{text-align:right}
tbody tr:hover{background:var(--raised)}

.toc{border:1px solid var(--line);border-radius:var(--r);padding:1rem 1.2rem;background:var(--raised);margin:2rem 0}
.toc-title{margin:0 0 .5rem;font-size:.76rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:700}
.toc ol{margin:0;padding-left:1.15rem;font-size:.94rem}
.toc li{margin-bottom:.28rem}
.toc a{color:var(--muted);text-decoration:none}
.toc a:hover{color:var(--accent);text-decoration:underline}

.faq-item{border-bottom:1px solid var(--line)}
.faq-item summary{padding:.95rem 0;cursor:pointer;font-weight:600;list-style:none;display:flex;justify-content:space-between;gap:1rem;align-items:baseline}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";color:var(--accent);font-size:1.3rem;line-height:1;flex:none}
.faq-item[open] summary::after{content:"−"}
.faq-a{padding:0 0 1.1rem;color:var(--muted)}
.faq-a p{margin:0 0 .7em}.faq-a p:last-child{margin:0}

/* ------------------------------------------------------------ monetisation */
.ad{display:flex;align-items:center;justify-content:center;position:relative;
  border:1px dashed var(--line);border-radius:var(--r);background:var(--sunken);
  color:var(--faint);overflow:hidden;margin:2.25rem 0}
.ad-tag{font-size:.66rem;letter-spacing:.12em;text-transform:uppercase;color:var(--faint)}
.ad-in-article{min-height:280px}
.ad-sidebar{min-height:600px;margin:0}
.ad-leaderboard{min-height:110px}
@media (max-width:640px){.ad-in-article{min-height:250px}.ad-leaderboard{min-height:100px}}

.promo{border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:var(--r);
  padding:1.1rem 1.25rem;background:var(--surface);margin:2rem 0}
.promo-title{margin:0 0 .4rem;font-weight:650;font-family:var(--serif);font-size:1.1rem}
.promo-body{margin:0 0 .75rem;color:var(--muted);font-size:.95rem}
.promo-cta{font-weight:600;text-decoration:none;font-size:.95rem}
.promo-cta:hover{text-decoration:underline}
.buy{display:inline-flex;align-items:center;gap:.25rem;font-weight:600}
.buy-mark{font-size:.8em;opacity:.6}
.buy-note{color:var(--faint);font-size:.85rem;margin-left:.4rem}
.disclosure{font-size:.85rem;color:var(--muted);background:var(--raised);border:1px solid var(--line);
  border-radius:var(--r);padding:.8rem 1rem;margin:2rem 0}
.source-line{font-size:.85rem;color:var(--faint);margin:.6rem 0 0}

/* ------------------------------------------------------------------- forms */
.controls{display:grid;gap:1.1rem;border:1px solid var(--line);border-radius:var(--r);
  padding:1.3rem 1.4rem;background:var(--surface);box-shadow:var(--shadow);margin:1.75rem 0}
.field{display:grid;gap:.35rem}
.field label{font-size:.88rem;font-weight:600}
.field-hint{font-size:.8rem;color:var(--faint);line-height:1.45}
input[type=number],input[type=text],select{width:100%;padding:.6rem .7rem;border:1px solid var(--line-strong);
  border-radius:8px;background:var(--bg);color:var(--text);font:inherit;font-size:1rem}
/* A bare range input is ~16px tall, which is a poor touch target. The extra
   height is hit area, not visual weight -- the track stays the same size. */
input[type=range]{width:100%;accent-color:var(--accent);height:28px;background:transparent;cursor:pointer}
select{cursor:pointer}
.field-row{display:grid;grid-template-columns:1fr 1fr;gap:1rem}
@media (max-width:560px){.field-row{grid-template-columns:1fr}}
.checks{display:flex;flex-wrap:wrap;gap:.6rem}
.check{display:inline-flex;align-items:center;gap:.45rem;border:1px solid var(--line-strong);
  border-radius:99px;padding:.6rem .95rem;min-height:44px;cursor:pointer;font-size:.9rem;user-select:none;background:var(--bg)}
.check input{accent-color:var(--accent);margin:0}
.check:has(input:checked){border-color:var(--accent);background:var(--accent-bg);color:var(--accent-ink);font-weight:550}
.range-head{display:flex;justify-content:space-between;align-items:baseline;gap:.5rem}
.range-val{font-weight:650;font-size:.92rem}
.result{border:1px solid var(--line);border-radius:var(--r);padding:1.3rem 1.4rem;background:var(--raised);margin:1.5rem 0}
.js-only{display:none}
.has-js .js-only{display:block}
.has-js .no-js{display:none}

/* ------------------------------------------------------------------- cards */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(15.5rem,1fr));gap:1rem;margin:1.75rem 0;padding:0;list-style:none}
.card{border:1px solid var(--line);border-radius:var(--r);background:var(--surface);padding:1.1rem 1.2rem;
  display:flex;flex-direction:column;gap:.35rem;transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--accent);transform:translateY(-1px)}
.card a{text-decoration:none;color:var(--text);font-weight:600;font-family:var(--serif);font-size:1.08rem}
.card a::after{content:"";position:absolute;inset:0}
.card{position:relative}
.card-cost{font-size:.9rem;color:var(--accent-ink);font-weight:650}
.card-sub{font-size:.86rem;color:var(--muted);margin:0;line-height:1.5}
.cat-head{margin-top:2.5rem}

/* ------------------------------------------------------------------ footer */
.site-foot{border-top:1px solid var(--line);background:var(--raised);padding-block:2.5rem 2rem;margin-top:4rem}
.foot-grid{display:grid;grid-template-columns:1.6fr repeat(3,1fr);gap:2rem}
@media (max-width:820px){.foot-grid{grid-template-columns:1fr 1fr}}
@media (max-width:520px){.foot-grid{grid-template-columns:1fr}}
.foot-brand p{color:var(--muted);font-size:.9rem;margin:.75rem 0 0;max-width:34ch}
.foot-built{font-size:.82rem!important;color:var(--faint)!important}
.foot-title{font-size:.76rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:700;margin:0 0 .6rem}
.foot-col ul{list-style:none;margin:0;padding:0}
.foot-col li{margin-bottom:.4rem}
.foot-col a{color:var(--muted);text-decoration:none;font-size:.92rem}
.foot-col a:hover{color:var(--accent);text-decoration:underline}
.foot-legal{margin:2.5rem 0 0;padding-top:1.25rem;border-top:1px solid var(--line);font-size:.82rem;color:var(--faint);max-width:80ch}

/* --------------------------------------------------- page-specific pieces */
.hero-inner{max-width:52rem}
.prose-wide{max-width:none}
.compare{margin:1.5rem 0 1.75rem}
.result-note{margin:.9rem 0 0;font-size:.9rem;color:var(--muted);line-height:1.55}
.btn-reset{margin-top:.9rem;background:none;border:1px solid var(--line-strong);border-radius:8px;
  padding:.45rem .85rem;font:inherit;font-size:.86rem;color:var(--muted);cursor:pointer}
.btn-reset:hover{border-color:var(--accent);color:var(--accent)}
.rail-box{border:1px solid var(--line);border-radius:var(--r);padding:1rem 1.1rem;background:var(--surface)}
.rail-title{margin:0 0 .6rem;font-size:.76rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:700}
.rail-box .stat-grid{grid-template-columns:1fr 1fr;margin:0}
.rail-box .stat dd{font-size:1.2rem}
table.compact th,table.compact td{padding:.44rem .8rem;font-size:.9rem}
.result .stat-grid{margin:0 0 0}
.controls .field-hint{margin:0}
.up{color:var(--warn);font-weight:600}
.down{color:var(--good);font-weight:600}
.field-label{font-size:.88rem;font-weight:600;margin:0 0 .1rem}
.result-head{display:flex;gap:2rem;flex-wrap:wrap;padding-bottom:1rem;margin-bottom:1.1rem;border-bottom:1px solid var(--line)}
.result-label{margin:0 0 .15rem;font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);font-weight:650}
.result-big{margin:0;font-family:var(--serif);font-size:2rem;font-weight:600;line-height:1;letter-spacing:-.025em}
.lines{margin-bottom:1.25rem}
.tool table input[type=number]{width:5.5rem;padding:.3rem .45rem;font-size:.9rem;text-align:right}
.tool .table-wrap{margin:.5rem 0}
.byline{margin:1.25rem 0 0;font-size:.86rem;color:var(--faint)}
.byline a{color:var(--muted)}
.hero-home{padding-block:clamp(3rem,8vw,5.5rem)}
.hero-cta{display:flex;gap:.75rem;flex-wrap:wrap;margin-top:1.75rem}
.btn{display:inline-flex;align-items:center;padding:.65rem 1.15rem;border-radius:9px;border:1px solid var(--line-strong);
  text-decoration:none;font-weight:600;font-size:.98rem;color:var(--text);background:var(--surface);transition:transform .12s,border-color .12s}
.btn:hover{border-color:var(--accent);transform:translateY(-1px);color:var(--text)}
.btn-primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn-primary:hover{color:#fff;filter:brightness(1.06)}
[data-theme=dark] .btn-primary,:root:not([data-theme=light]) .btn-primary{color:#1B1409}
@media (prefers-color-scheme:light){:root:not([data-theme=dark]) .btn-primary{color:#fff}}
.cards-lg{grid-template-columns:repeat(auto-fit,minmax(17rem,1fr))}
.formula{background:var(--sunken);border:1px solid var(--line);border-radius:var(--r);padding:1rem 1.1rem;
  overflow-x:auto;font-size:.88rem;line-height:1.6;margin:1.5rem 0}
.formula code{background:none;padding:0}
.go-wrap{max-width:34rem;padding-block:5rem}
.go-wrap h1{font-size:clamp(1.6rem,1.2rem + 1.6vw,2.2rem)}
.go-note{font-size:.88rem;color:var(--muted);margin-top:1.5rem}
.steps{counter-reset:step;list-style:none;padding:0;margin:1.5rem 0}
.steps li{position:relative;padding:.75rem 0 .75rem 2.6rem;border-bottom:1px solid var(--line);line-height:1.6}
.steps li:last-child{border-bottom:0}
.steps li::before{counter-increment:step;content:counter(step);position:absolute;left:0;top:.85rem;
  width:1.7rem;height:1.7rem;border-radius:50%;background:var(--accent-bg);color:var(--accent-ink);
  display:grid;place-items:center;font-size:.82rem;font-weight:700;font-variant-numeric:tabular-nums}