/*
Theme Name: HeatMath
Theme URI: https://heatmath.com
Author: HeatMath
Description: Lightweight, fast theme for HeatMath home heating and cooling calculators.
Version: 1.0.0
Requires at least: 6.0
Requires PHP: 7.4
License: GPL-2.0-or-later
Text Domain: heatmath
*/

:root{
  --bg:#f3f6f8; --surface:#ffffff; --ink:#15212b; --muted:#56646f; --line:#d6dee4;
  --cold:#0f7c8c; --cold-ink:#0b5f6b; --cold-soft:#dcf0f2; --warm:#c2621b; --warm-soft:#fbe9dc; --good:#2e7d4f; --slot:#eef2f5;
  --display:"Bricolage Grotesque","IBM Plex Sans",system-ui,sans-serif;
  --body:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--body);font-size:17px;line-height:1.65}
img{max-width:100%;height:auto}
a{color:var(--cold-ink);text-underline-offset:2px}
a:hover{color:var(--warm)}
:focus-visible{outline:2px solid var(--cold);outline-offset:2px}
.container{max-width:1080px;margin:0 auto;padding-inline:18px}
.narrow{max-width:760px}
.skip-link{position:absolute;left:-9999px}
.skip-link:focus{left:12px;top:12px;background:var(--surface);padding:8px 12px;z-index:10}

/* Header */
.site-header{background:var(--surface);border-bottom:1px solid var(--line)}
.site-header .container{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:64px;flex-wrap:wrap}
.brand{font-family:var(--display);font-weight:800;font-size:1.3rem;letter-spacing:-.01em;color:var(--ink);text-decoration:none}
.brand span{color:var(--cold)}
.brand:hover{color:var(--ink)}
.primary-nav ul{list-style:none;margin:0;padding:0;display:flex;gap:4px 20px;flex-wrap:wrap}
.primary-nav a{color:var(--muted);text-decoration:none;font-size:.95rem;font-weight:500}
.primary-nav a:hover,.primary-nav .current-menu-item a{color:var(--ink)}
.nav-toggle{display:none}
@media (max-width:720px){
  .nav-toggle{display:inline-block;font:inherit;background:none;border:1px solid var(--line);border-radius:6px;padding:6px 10px;color:var(--ink)}
  .primary-nav{flex-basis:100%;display:none;padding-bottom:12px}
  .primary-nav.open{display:block}
  .primary-nav ul{flex-direction:column;gap:10px}
}

/* Type */
h1,h2,h3{font-family:var(--display);line-height:1.15;letter-spacing:-.015em;text-wrap:balance}
h1{font-size:clamp(2rem,4.6vw,3rem);font-weight:800;margin:.2em 0 .4em}
h2{font-size:1.6rem;font-weight:700;margin:1.8em 0 .5em}
h3{font-size:1.2rem;font-weight:600;margin:1.5em 0 .4em}
.eyebrow{font-family:var(--mono);font-size:.74rem;letter-spacing:.08em;text-transform:uppercase;color:var(--cold)}
.lede{font-size:1.12rem;color:var(--muted);max-width:62ch}
.meta{font-size:.85rem;color:var(--muted)}

/* Home */
.hero{padding-block:48px 28px}
.hero h1{max-width:18ch}
.section{padding-block:28px}
.section-head{display:flex;justify-content:space-between;align-items:baseline;gap:12px;flex-wrap:wrap;border-bottom:1px solid var(--line);padding-bottom:8px;margin-bottom:18px}
.section-head h2{margin:0;font-size:1.3rem}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px}
.tool-card{display:grid;gap:6px;background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:18px;text-decoration:none;color:var(--ink);transition:border-color .15s}
.tool-card:hover{border-color:var(--cold);color:var(--ink)}
.tool-card .unit{font-family:var(--mono);font-size:.72rem;color:var(--cold);text-transform:uppercase;letter-spacing:.07em}
.tool-card strong{font-family:var(--display);font-size:1.15rem;line-height:1.2}
.tool-card span.d{font-size:.9rem;color:var(--muted);line-height:1.45}
.post-list{display:grid;gap:0}
.post-item{display:grid;gap:4px;padding-block:16px;border-bottom:1px solid var(--line)}
.post-item a.t{font-family:var(--display);font-weight:600;font-size:1.2rem;color:var(--ink);text-decoration:none;line-height:1.25}
.post-item a.t:hover{color:var(--cold-ink)}
.post-item p{margin:0;color:var(--muted);font-size:.95rem}

/* Article */
.entry{padding-block:32px 24px}
.crumbs{font-size:.82rem;color:var(--muted);margin-bottom:6px}
.crumbs a{color:var(--muted)}
.entry-content{max-width:70ch}
.entry-content.wide{max-width:none}
.entry-content p,.entry-content li{max-width:70ch}
.entry-content ul,.entry-content ol{padding-left:1.3em}
.entry-content li{margin-bottom:.35em}
.entry-content table{border-collapse:collapse;width:100%;font-size:.93rem;margin:1.2em 0;background:var(--surface)}
.entry-content th,.entry-content td{border:1px solid var(--line);padding:8px 10px;text-align:left;vertical-align:top}
.entry-content th{background:var(--slot);font-weight:600}
.entry-content .table-wrap{overflow-x:auto}
.entry-content blockquote{margin:1.4em 0;padding:12px 16px;border-left:3px solid var(--cold);background:var(--surface)}
.entry-content .formula{font-family:var(--mono);font-size:.9rem;background:var(--surface);border:1px solid var(--line);border-left:3px solid var(--cold);padding:12px 14px;border-radius:4px;overflow-x:auto}
.entry-content .callout{background:var(--cold-soft);border-radius:8px;padding:14px 16px;margin:1.4em 0}
.entry-content .callout p{margin:.3em 0}
.byline{display:flex;gap:10px;flex-wrap:wrap;font-size:.85rem;color:var(--muted);margin-bottom:18px}
.author-box{margin-top:36px;padding:18px;border:1px solid var(--line);border-radius:10px;background:var(--surface);font-size:.93rem}
.author-box strong{font-family:var(--display)}
.related{margin-top:36px}
.related h2{font-size:1.2rem}

/* Footer */
.site-footer{margin-top:56px;border-top:1px solid var(--line);background:var(--surface);font-size:.88rem;color:var(--muted)}
.site-footer .container{display:grid;grid-template-columns:2fr 1fr 1fr;gap:24px;padding-block:32px}
.site-footer h3{font-size:.8rem;font-family:var(--mono);text-transform:uppercase;letter-spacing:.08em;color:var(--ink);margin:0 0 10px}
.site-footer ul{list-style:none;margin:0;padding:0;display:grid;gap:6px}
.site-footer a{color:var(--muted)}
.site-footer .legal{grid-column:1/-1;border-top:1px solid var(--line);padding-top:14px}
@media (max-width:720px){.site-footer .container{grid-template-columns:1fr}}

.pagination{display:flex;gap:10px;margin-top:24px}
.search-form{display:flex;gap:8px}
.search-form input{font:inherit;padding:8px 10px;border:1px solid var(--line);border-radius:6px;flex:1;background:var(--surface);color:var(--ink)}
.search-form button{font:inherit;padding:8px 14px;border:0;border-radius:6px;background:var(--cold);color:#fff;cursor:pointer}