:root{--ink: #17212b;--muted: #5a6673;--bg: #ffffff;--bg-soft: #f4f6f8;--border: #dbe1e7;--brand: #0e4d7a;--link: #0b62a4;--diy: #16713a;--diy-bg: #e7f5ec;--part: #8a5a00;--part-bg: #fdf3d7;--pro: #a34200;--pro-bg: #fdeadd;--emergency: #c11f2e;--emergency-bg: #fdecec;--radius: 10px;--content: 44rem}*,*:before,*:after{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;font-size:1rem;line-height:1.6;color:var(--ink);background:var(--bg)}img,svg{max-width:100%;height:auto}a{color:var(--link)}a:hover{text-decoration-thickness:2px}h1,h2,h3{line-height:1.2;margin:0 0 .5em;letter-spacing:-.01em}h1{font-size:1.9rem}h2{font-size:1.35rem;margin-top:2rem}h3{font-size:1.1rem}p{margin:0 0 1em}ol,ul{padding-left:1.4rem}.wrap{max-width:var(--content);margin-inline:auto;padding-inline:1rem}.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}.skip-link{position:absolute;left:-999px;top:0;background:var(--brand);color:#fff;padding:.5rem 1rem;z-index:100}.skip-link:focus{left:0}.site-header{border-bottom:1px solid var(--border);background:var(--bg)}.site-header .wrap{display:flex;align-items:center;gap:1rem;padding-block:.65rem}.wordmark{font-weight:800;font-size:1.15rem;text-decoration:none;color:var(--ink);white-space:nowrap}.wordmark span{color:var(--brand)}.site-header .code-search{flex:1;min-width:0;max-width:18rem;margin-left:auto}.site-footer{margin-top:3rem;border-top:1px solid var(--border);background:var(--bg-soft);font-size:.9rem;color:var(--muted)}.site-footer .wrap{padding-block:1.5rem}.footer-safety{font-weight:600;color:var(--emergency)}.footer-nav{display:flex;flex-wrap:wrap;gap:.25rem 1rem;padding:0;margin:0 0 1rem;list-style:none}.code-search{position:relative;margin:0}.code-search input{width:100%;font:inherit;padding:.55rem .8rem;border:1.5px solid var(--border);border-radius:var(--radius);background:var(--bg);color:var(--ink)}.code-search input:focus{outline:2px solid var(--brand);outline-offset:1px;border-color:var(--brand)}.code-search-hero input{font-size:1.1rem;padding:.8rem 1rem;border-width:2px}.code-search-results{position:absolute;top:calc(100% + 4px);left:0;right:0;z-index:50;margin:0;padding:.25rem;list-style:none;background:var(--bg);border:1px solid var(--border);border-radius:var(--radius);box-shadow:0 8px 24px #17212b24;max-height:19rem;overflow-y:auto}.code-search-results li{margin:0}.code-search-results a{display:block;padding:.5rem .65rem;text-decoration:none;color:var(--ink);border-radius:6px;font-size:.95rem}.code-search-results a:hover,.code-search-results a:focus{background:var(--bg-soft)}.code-search-results strong{color:var(--brand)}.code-search-empty{padding:.5rem .65rem;color:var(--muted);font-size:.9rem}.breadcrumb{font-size:.85rem;margin:1rem 0 1.25rem}.breadcrumb ol{display:flex;flex-wrap:wrap;gap:.35rem;padding:0;margin:0;list-style:none;color:var(--muted)}.breadcrumb li+li:before{content:"›";margin-right:.35rem;color:var(--muted)}.code-header{margin-bottom:1.25rem}.code-header h1{margin:0 0 .35rem}.code-context{display:block;font-size:1rem;font-weight:600;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}.code-display{display:block;font-size:clamp(2.6rem,11vw,4rem);font-weight:800;letter-spacing:-.02em;color:var(--ink)}.code-meaning{font-size:1.1rem;margin-bottom:.75rem}.badge{display:inline-block;font-size:.8rem;font-weight:700;padding:.15rem .6rem;border-radius:999px;white-space:nowrap}.badge-diy{color:var(--diy);background:var(--diy-bg)}.badge-part{color:var(--part);background:var(--part-bg)}.badge-pro{color:var(--pro);background:var(--pro-bg)}.badge-emergency{color:#fff;background:var(--emergency)}.emergency-banner{border:2px solid var(--emergency);border-left-width:8px;border-radius:var(--radius);background:var(--emergency-bg);padding:.9rem 1rem;margin:1.25rem 0}.emergency-banner p{margin:0}.emergency-banner p+p{margin-top:.5rem}.gas-reminder{font-weight:600;color:var(--emergency)}.triage-card{border:2px solid var(--border);border-radius:var(--radius);padding:1rem 1.1rem;margin:1.25rem 0;background:var(--bg-soft)}.triage-card[data-path=descale]{border-color:var(--diy)}.triage-card[data-path=part]{border-color:var(--part)}.triage-card[data-path=pro]{border-color:var(--pro)}.triage-kicker{font-size:.8rem;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:.25rem}.triage-card h2{margin:0 0 .5rem}.triage-cost{margin:0;font-size:.95rem}.ad-slot{display:flex;align-items:center;justify-content:center;background:var(--bg-soft);border:1px solid var(--border);border-radius:var(--radius);margin:1.5rem 0}.ad-slot-label{font-size:.7rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted)}.source-cite{background:var(--bg-soft);border:1px solid var(--border);border-radius:var(--radius);padding:.75rem 1rem;font-size:.95rem}.source-cite-check{color:var(--diy);font-weight:700;margin-right:.25rem}.steps li{margin-bottom:.5rem}.faq{border-bottom:1px solid var(--border);padding:.6rem 0}.faq summary{font-weight:600;cursor:pointer}.faq p{margin:.5rem 0 0}.table-wrap{overflow-x:auto;margin:1rem 0}.code-table{width:100%;border-collapse:collapse;font-size:.95rem}.code-table th,.code-table td{text-align:left;padding:.5rem .6rem;border-bottom:1px solid var(--border);vertical-align:top}.code-table th{font-size:.8rem;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}.code-table td:first-child a{font-weight:700;white-space:nowrap}.card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:.75rem;padding:0;margin:1rem 0;list-style:none}.card{border:1px solid var(--border);border-radius:var(--radius);padding:.85rem 1rem;background:var(--bg)}.card h3{margin:0 0 .25rem}.card p{margin:0;font-size:.88rem;color:var(--muted)}.card a{font-weight:600;text-decoration:none}.card a:hover{text-decoration:underline}.card .soon{font-size:.8rem;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.05em}.related-list{padding-left:1.2rem}.related-list li{margin-bottom:.4rem}.back-link{margin-top:2rem;font-size:.95rem}.hero{padding-block:2.25rem 1.5rem;text-align:left}.hero-kicker{font-size:.85rem;font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--brand);margin-bottom:.4rem}.hero h1{font-size:clamp(1.8rem,6vw,2.5rem)}.hero-sub{font-size:1.05rem;color:var(--muted);max-width:38rem}.verdict-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:.75rem;padding:0;margin:1rem 0;list-style:none}.verdict-grid .card{border-top:4px solid var(--border)}.verdict-grid .card-descale{border-top-color:var(--diy)}.verdict-grid .card-part{border-top-color:var(--part)}.verdict-grid .card-pro{border-top-color:var(--pro)}.prose h2{margin-top:1.75rem}.prose li{margin-bottom:.35rem}.page-meta{display:flex;flex-wrap:wrap;gap:.5rem 1rem;align-items:center;font-size:.9rem;color:var(--muted);margin-bottom:1.25rem}.affiliate-box{border:1.5px solid var(--part);border-radius:var(--radius);background:var(--part-bg);padding:.85rem 1rem;margin:1.25rem 0}.affiliate-box p{margin:0}.affiliate-note{font-size:.8rem;color:var(--muted);margin-top:.35rem}