/* North London Structural — global stylesheet
   Design system: structural graphite / steel blue / stone white / signal amber.
   Signature: engineering-drawing annotation eyebrows + dimension-grid hero. */

:root{
  --ink:#1B2933;         /* structural graphite */
  --steel:#375A73;       /* steel blue */
  --steel-deep:#24405A;
  --stone:#F4F6F5;       /* cool stone white */
  --line:#D8DEDC;
  --amber:#E89D1C;       /* signal amber CTA */
  --amber-dark:#C57F0A;
  --white:#FFFFFF;
  --text:#26333C;
  --muted:#5A6B75;
  --radius:10px;
  --shadow:0 10px 30px rgba(27,41,51,.10);
  --font-display:"Bitter",Georgia,serif;
  --font-body:"Source Sans 3","Segoe UI",Arial,sans-serif;
  --font-mono:"IBM Plex Mono","Courier New",monospace;
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation:none!important;transition:none!important}}
body{margin:0;font-family:var(--font-body);font-size:1.06rem;line-height:1.65;color:var(--text);background:var(--white)}
img{max-width:100%;height:auto;display:block}
a{color:var(--steel-deep)}
a:hover{color:var(--steel)}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--ink);line-height:1.2;margin:0 0 .6em}
h1{font-size:clamp(1.9rem,4.5vw,2.9rem);font-weight:700}
h2{font-size:clamp(1.5rem,3vw,2.05rem);font-weight:700}
h3{font-size:1.22rem;font-weight:600}
p{margin:0 0 1em}
ul,ol{padding-left:1.3em;margin:0 0 1.1em}
li{margin-bottom:.35em}
.container{max-width:1160px;margin:0 auto;padding:0 20px}
.container.narrow{max-width:860px}
.section{padding:64px 0}
.section.tight{padding:44px 0}
.section.alt{background:var(--stone)}
.visually-hidden{position:absolute!important;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip-link{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:10px 16px;z-index:200}
.skip-link:focus{left:8px;top:8px;color:#fff}
:focus-visible{outline:3px solid var(--amber);outline-offset:2px}

/* Signature: drawing-annotation eyebrow */
.eyebrow{font-family:var(--font-mono);font-size:.78rem;letter-spacing:.14em;text-transform:uppercase;color:var(--steel);margin:0 0 .7em;display:flex;align-items:center;gap:.7em}
.eyebrow::before{content:"";width:34px;height:1px;background:var(--steel);flex:none}

/* Buttons */
.btn{display:inline-block;padding:12px 22px;border-radius:8px;font-weight:700;text-decoration:none;border:2px solid transparent;cursor:pointer;font-size:1rem;font-family:var(--font-body);text-align:center}
.btn-lg{padding:15px 28px;font-size:1.08rem}
.btn-block{display:block;width:100%}
.btn-accent{background:var(--amber);color:var(--ink)}
.btn-accent:hover{background:var(--amber-dark);color:var(--ink)}
.btn-dark{background:var(--ink);color:#fff}
.btn-dark:hover{background:var(--steel-deep);color:#fff}
.btn-outline{border-color:var(--ink);color:var(--ink);background:transparent}
.btn-outline:hover{background:var(--ink);color:#fff}
.btn-outline-light{border-color:#fff;color:#fff;background:transparent}
.btn-outline-light:hover{background:#fff;color:var(--ink)}
.btn-ghost{background:transparent;border-color:var(--line);color:var(--text)}

/* Topbar + header */
.topbar{background:var(--ink);color:#dbe4e9;font-size:.9rem}
.topbar-inner{display:flex;justify-content:space-between;align-items:center;padding-top:7px;padding-bottom:7px;gap:12px}
.topbar-msg{opacity:.85}
.topbar-phone{color:#fff;font-weight:700;text-decoration:none}
.topbar-phone:hover{color:var(--amber)}
.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:100}
.header-inner{display:flex;align-items:center;gap:22px;padding-top:12px;padding-bottom:12px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink)}
.logo-mark{color:var(--steel-deep);flex:none}
.logo-text{font-family:var(--font-display);font-size:.98rem;line-height:1.15}
.logo-text strong{font-weight:700}
.main-nav{display:flex;gap:20px;margin-left:auto}
.main-nav a{text-decoration:none;color:var(--text);font-weight:600;padding:6px 2px;border-bottom:2px solid transparent}
.main-nav a:hover,.main-nav a.active{color:var(--ink);border-bottom-color:var(--amber)}
.header-ctas{display:flex;align-items:center;gap:10px}
.nav-toggle{display:none;background:none;border:2px solid var(--ink);border-radius:8px;width:44px;height:42px;position:relative;cursor:pointer}
.nav-toggle-bar,.nav-toggle-bar::before,.nav-toggle-bar::after{content:"";position:absolute;left:9px;right:9px;height:2.5px;background:var(--ink);transition:transform .2s}
.nav-toggle-bar{top:19px}
.nav-toggle-bar::before{top:-7px}
.nav-toggle-bar::after{top:7px}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar{background:transparent}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar::before{transform:translateY(7px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar::after{transform:translateY(-7px) rotate(-45deg)}

/* Hero — dimension-grid signature */
.hero{background:var(--ink);color:#e7edf0;position:relative;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.05) 1px,transparent 1px);background-size:56px 56px;pointer-events:none}
.hero-inner{position:relative;display:grid;grid-template-columns:1.15fr .85fr;gap:48px;padding:64px 0 72px;align-items:start}
.hero h1{color:#fff}
.hero .eyebrow{color:var(--amber)}
.hero .eyebrow::before{background:var(--amber)}
.hero-lede{font-size:1.16rem;max-width:56ch;color:#c9d5db}
.hero-ctas{display:flex;flex-wrap:wrap;gap:14px;margin:22px 0 18px}
.hero-points{list-style:none;padding:0;margin:0;color:#c9d5db;font-size:.98rem}
.hero-points li{padding-left:1.5em;position:relative;margin-bottom:.45em}
.hero-points li::before{content:"—";position:absolute;left:0;color:var(--amber)}
.hero-card{background:#fff;color:var(--text);border-radius:var(--radius);box-shadow:var(--shadow);padding:26px}
.hero-card h2{font-size:1.25rem}
.hero-card .card-note{font-size:.9rem;color:var(--muted)}

/* Forms */
.lead-form .ff{margin-bottom:14px}
.lead-form label{display:block;font-weight:600;font-size:.92rem;margin-bottom:4px;color:var(--ink)}
.lead-form input[type=text],.lead-form input[type=tel],.lead-form input[type=email],.lead-form select,.lead-form textarea{width:100%;padding:11px 12px;border:1.5px solid var(--line);border-radius:8px;font:inherit;background:#fff;color:var(--text)}
.lead-form input:focus,.lead-form select:focus,.lead-form textarea:focus{border-color:var(--steel);outline:2px solid rgba(55,90,115,.25)}
.lead-form .consent{display:flex;gap:10px;align-items:flex-start;font-size:.86rem;color:var(--muted)}
.lead-form .consent input{margin-top:4px;flex:none;width:18px;height:18px}
.lead-form .consent label{font-weight:400;margin:0;color:var(--muted)}
.form-note{font-size:.86rem;color:var(--muted);margin-top:10px;text-align:center}
.field-error{color:#A63A2B;font-size:.85rem;margin-top:4px;display:none}
.ff.invalid .field-error{display:block}
.ff.invalid input,.ff.invalid select{border-color:#A63A2B}

/* Cards + grids */
.grid{display:grid;gap:22px}
.grid.cols-3{grid-template-columns:repeat(3,1fr)}
.grid.cols-4{grid-template-columns:repeat(4,1fr)}
.grid.cols-2{grid-template-columns:repeat(2,1fr)}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;display:flex;flex-direction:column}
.card h3 a{text-decoration:none;color:var(--ink)}
.card h3 a:hover{color:var(--steel)}
.card p{color:var(--muted);font-size:.97rem;flex:1}
.card .card-link{font-weight:700;text-decoration:none;color:var(--steel-deep)}
.card .card-link:hover{color:var(--amber-dark)}
.card-ref{font-family:var(--font-mono);font-size:.72rem;color:var(--steel);letter-spacing:.1em;margin-bottom:10px}

/* Trust strip */
.trust-strip{background:var(--stone);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.trust-inner{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;padding:22px 0}
.trust-item{font-size:.93rem;color:var(--ink);display:flex;gap:10px;align-items:flex-start}
.trust-item svg{flex:none;color:var(--steel);margin-top:2px}

/* Process steps */
.steps{counter-reset:step;display:grid;gap:20px;grid-template-columns:repeat(4,1fr)}
.step{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:22px;position:relative}
.step::before{counter-increment:step;content:"0" counter(step);font-family:var(--font-mono);color:var(--amber-dark);font-size:.85rem;letter-spacing:.1em}
.step h3{margin-top:8px;font-size:1.08rem}
.step p{font-size:.94rem;color:var(--muted);margin:0}

/* Signs list */
.signs{list-style:none;padding:0;display:grid;grid-template-columns:repeat(2,1fr);gap:12px 26px}
.signs li{background:#fff;border:1px solid var(--line);border-left:4px solid var(--amber);border-radius:8px;padding:12px 16px;font-size:.98rem}

/* AI answer block */
.answer-block{background:var(--stone);border-left:4px solid var(--steel);border-radius:0 8px 8px 0;padding:18px 22px;margin:0 0 1.4em}
.answer-block p{margin:0;font-size:1.02rem}
.answer-block strong{color:var(--ink)}

/* Tables */
.table-wrap{overflow-x:auto;margin:0 0 1.4em}
table{border-collapse:collapse;width:100%;font-size:.96rem;background:#fff}
th,td{border:1px solid var(--line);padding:10px 13px;text-align:left;vertical-align:top}
th{background:var(--stone);font-family:var(--font-body);font-weight:700;color:var(--ink)}
caption{caption-side:top;text-align:left;font-weight:700;color:var(--ink);padding-bottom:8px}

/* FAQ */
.faq-item{border:1px solid var(--line);border-radius:8px;margin-bottom:10px;background:#fff}
.faq-item summary{cursor:pointer;padding:15px 18px;font-weight:700;color:var(--ink);list-style:none;position:relative;padding-right:44px}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";position:absolute;right:18px;top:50%;transform:translateY(-50%);font-size:1.4rem;color:var(--steel);font-weight:400}
.faq-item[open] summary::after{content:"–"}
.faq-a{padding:0 18px 15px;color:var(--muted)}
.faq-a p{margin:0}

/* Breadcrumbs */
.breadcrumbs{font-size:.86rem;padding:14px 0 0;color:var(--muted)}
.breadcrumbs a{color:var(--muted);text-decoration:none}
.breadcrumbs a:hover{color:var(--ink);text-decoration:underline}
.breadcrumbs .sep{margin:0 4px;opacity:.6}

/* Page hero (interior) */
.page-hero{padding:40px 0 30px}
.page-hero .lede{font-size:1.14rem;color:var(--muted);max-width:62ch}

/* Two-col article + aside */
.article-layout{display:grid;grid-template-columns:1fr 320px;gap:44px;align-items:start}
.aside-card{background:var(--stone);border:1px solid var(--line);border-radius:var(--radius);padding:22px;position:sticky;top:88px}
.aside-card h3{font-size:1.05rem}
.aside-card ul{list-style:none;padding:0;margin:0 0 14px}
.aside-card li{margin-bottom:8px;font-size:.94rem}
.toc{background:var(--stone);border:1px solid var(--line);border-radius:var(--radius);padding:18px 22px;margin:0 0 1.6em}
.toc h2{font-size:1rem;font-family:var(--font-mono);letter-spacing:.1em;text-transform:uppercase;color:var(--steel)}
.toc ol{margin:0;padding-left:1.2em;columns:2;gap:30px;font-size:.94rem}
.toc a{text-decoration:none}
.toc a:hover{text-decoration:underline}

/* CTA band */
.cta-band{background:linear-gradient(135deg,var(--steel-deep),var(--ink));color:#e7edf0}
.cta-band h2{color:#fff}
.cta-inner{display:flex;justify-content:space-between;align-items:center;gap:32px;flex-wrap:wrap}
.cta-actions{display:flex;gap:14px;flex-wrap:wrap}

/* Footer */
.site-footer{background:var(--ink);color:#b9c6cd;padding:52px 0 0;font-size:.94rem}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr 1.1fr;gap:34px;padding-bottom:36px}
.footer-logo{font-family:var(--font-display);font-size:1.2rem;color:#fff}
.site-footer h3{color:#fff;font-size:1rem;font-family:var(--font-body);text-transform:uppercase;letter-spacing:.08em}
.site-footer ul{list-style:none;padding:0;margin:0}
.site-footer li{margin-bottom:7px}
.site-footer a{color:#b9c6cd;text-decoration:none}
.site-footer a:hover{color:var(--amber)}
.footer-contact a{color:#fff;font-weight:700}
.footer-legal{border-top:1px solid rgba(255,255,255,.15);padding:20px 0 88px;font-size:.84rem}
.legal-links{display:flex;gap:18px;flex-wrap:wrap;list-style:none;padding:0}

/* Sticky mobile CTA */
.sticky-cta{position:fixed;bottom:0;left:0;right:0;display:none;z-index:150;box-shadow:0 -4px 16px rgba(0,0,0,.18)}
.sticky-cta a{flex:1;text-align:center;padding:15px 8px;font-weight:800;text-decoration:none;font-size:1rem}
.sticky-call{background:var(--amber);color:var(--ink)}
.sticky-form{background:var(--ink);color:#fff}

/* Consent banner */
.consent-banner{position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:2px solid var(--ink);padding:14px 20px;z-index:200;display:flex;gap:18px;align-items:center;justify-content:center;flex-wrap:wrap;font-size:.92rem;box-shadow:0 -6px 20px rgba(0,0,0,.12)}
.consent-banner p{margin:0}
.consent-actions{display:flex;gap:10px}

/* Tools */
.tool-panel{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow)}
.tool-result{background:var(--stone);border:1px solid var(--line);border-radius:var(--radius);padding:22px;margin-top:20px}
.tool-result .range{font-family:var(--font-display);font-size:1.7rem;color:var(--ink);font-weight:700}
.tool-disclaimer{font-size:.86rem;color:var(--muted);border-top:1px dashed var(--line);margin-top:16px;padding-top:12px}
.checklist{list-style:none;padding:0}
.checklist li{display:flex;gap:12px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:8px;padding:13px 16px;margin-bottom:10px}
.checklist input{width:20px;height:20px;flex:none;margin-top:3px}
.checklist label{cursor:pointer}
.severity{padding:14px 18px;border-radius:8px;font-weight:700;margin-top:14px}
.severity.low{background:#E7F1E7;color:#2C5530}
.severity.med{background:#FBF0DA;color:#8A5A00}
.severity.high{background:#F7E3DF;color:#8C2F1F}

/* Utility */
.mt-0{margin-top:0}.mb-0{margin-bottom:0}
.center{text-align:center}
.lede{font-size:1.13rem}
hr.rule{border:none;border-top:1px solid var(--line);margin:2.2em 0}

/* Responsive */
@media(max-width:960px){
  .hero-inner{grid-template-columns:1fr;gap:34px;padding:44px 0 56px}
  .grid.cols-4{grid-template-columns:repeat(2,1fr)}
  .grid.cols-3{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .trust-inner{grid-template-columns:repeat(2,1fr)}
  .article-layout{grid-template-columns:1fr}
  .aside-card{position:static}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:720px){
  .main-nav{display:none;position:absolute;top:100%;left:0;right:0;background:#fff;flex-direction:column;gap:0;border-bottom:1px solid var(--line);box-shadow:var(--shadow)}
  .main-nav.open{display:flex}
  .main-nav a{padding:14px 22px;border-bottom:1px solid var(--stone)}
  .nav-toggle{display:block}
  .header-call{display:none}
  .sticky-cta{display:flex}
  .topbar-msg{display:none}
  .topbar-inner{justify-content:center}
  .grid.cols-3,.grid.cols-2,.grid.cols-4{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .signs{grid-template-columns:1fr}
  .trust-inner{grid-template-columns:1fr}
  .toc ol{columns:1}
  .section{padding:46px 0}
  .footer-grid{grid-template-columns:1fr}
  .cta-inner{flex-direction:column;align-items:flex-start}
}
@media print{.topbar,.site-header,.sticky-cta,.consent-banner,.cta-band,.site-footer{display:none}}

/* ===== v1.1 visual system — figures, diagrams, before/after ===== */
.fig{margin:26px 0;background:#fff;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:0 4px 14px rgba(27,41,51,.05)}
.fig img{width:100%;height:auto;display:block}
.fig figcaption{font-family:var(--font-mono);font-size:.8rem;color:var(--muted);padding:10px 16px;border-top:1px solid var(--line);letter-spacing:.03em}
.fig.banner{margin:0;border-left:0;border-right:0;border-radius:0;box-shadow:none;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.fig.banner img{max-height:420px;object-fit:cover;object-position:left center}
.ba-grid{display:grid;grid-template-columns:1fr 1fr;gap:1px;background:var(--line)}
.ba-grid>div{background:#fff;position:relative}
.ba-grid img{width:100%;height:auto;display:block}
.ba-tag{position:absolute;top:10px;left:10px;background:var(--ink);color:#fff;font-family:var(--font-mono);font-size:.7rem;letter-spacing:.09em;text-transform:uppercase;padding:4px 9px;border-radius:5px;z-index:1}
.ba-disclaimer{font-weight:600;color:var(--ink)}
.fig .ba-disclaimer{color:var(--ink)}
@media (max-width:720px){.ba-grid{grid-template-columns:1fr}.fig{margin:20px 0}}
@media print{.fig{box-shadow:none}}