/* ============================================================
   GRINDING ADVISOR — engineering-authority design language
   §8 of ~/workspace/design-guidelines/GUIDELINES.md
   Cool steel neutrals + ONE machine-shop amber. Light canvas
   dominant. Hairline rules as the signature gesture. Sharp corners.
   ALL color lives in :root tokens; derivatives via color-mix().
   ============================================================ */
:root{
  /* ---- steel neutrals (cool) ---- */
  --paper:#fafbfc;            /* light canvas */
  --steel-050:#eef1f5;        /* alt section wash */
  --steel-100:#dde3ea;        /* hairline rules */
  --steel-300:#aeb9c6;        /* strong borders */
  --steel-500:#556274;        /* secondary text */
  --steel-700:#2c3642;        /* soft ink */
  --steel-900:#131a23;        /* ink / single dark band */
  /* ---- ONE amber accent: sparks / warning-plate energy ---- */
  --amber:#bd5d0e;
  --amber-deep:color-mix(in srgb,var(--amber) 80%,black);
  --amber-ink:color-mix(in srgb,var(--amber) 72%,black);
  --amber-wash:color-mix(in srgb,var(--amber) 7%,white);
  --amber-line:color-mix(in srgb,var(--amber) 38%,var(--steel-100));
  /* ---- functional tokens (not brand accents) ---- */
  --ok-bg:color-mix(in srgb,#16a34a 8%,white);
  --ok-ink:#166534;
  --ok-line:color-mix(in srgb,#16a34a 30%,white);
  --err-bg:color-mix(in srgb,#dc2626 6%,white);
  --err-ink:#991b1b;
  --err-line:color-mix(in srgb,#dc2626 28%,white);
  /* ---- type ---- */
  --font:"Archivo",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --maxw:1160px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;overflow-x:clip}
body{
  margin:0;font-family:var(--font);color:var(--steel-900);background:var(--paper);
  line-height:1.65;font-size:17px;overflow-x:clip;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;height:auto}
a{color:var(--amber-ink)}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.mono{font-family:var(--mono)}

/* ---------- header ---------- */
.site-header{
  position:sticky;top:0;z-index:50;background:var(--paper);
  border-bottom:1px solid var(--steel-100);
}
.header-inner{
  max-width:var(--maxw);margin:0 auto;padding:0 20px;
  display:flex;align-items:center;justify-content:space-between;
  min-height:66px;gap:12px;
}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--steel-900)}
.brand-mark{
  width:34px;height:34px;flex:0 0 34px;background:var(--steel-900);
  position:relative;
}
.brand-mark::before{ /* crosshair: engineering drawing mark */
  content:"";position:absolute;left:50%;top:6px;bottom:6px;width:1px;
  background:var(--paper);transform:translateX(-.5px);
}
.brand-mark::after{
  content:"";position:absolute;top:50%;left:6px;right:6px;height:1px;
  background:var(--amber);transform:translateY(-.5px);
}
.brand-name{font-weight:800;font-size:19px;letter-spacing:-.01em;line-height:1.1}
.brand-name small{
  display:block;font-family:var(--mono);font-weight:500;font-size:10px;
  color:var(--steel-500);letter-spacing:.14em;text-transform:uppercase;margin-top:3px;
}
.main-nav{display:none}
.nav-toggle{
  background:none;border:1px solid var(--steel-300);border-radius:0;
  min-width:44px;min-height:44px;padding:10px 12px;font-size:16px;cursor:pointer;
  color:var(--steel-900);font-family:var(--mono);
}
.mobile-menu{display:none;border-top:1px solid var(--steel-100);background:var(--paper);padding:6px 20px 20px}
.mobile-menu.open{display:block}
.mobile-menu a{
  display:block;padding:14px 0;color:var(--steel-900);text-decoration:none;
  border-bottom:1px solid var(--steel-100);font-weight:600;min-height:44px;
}
.mobile-menu .sub{padding-left:18px;font-weight:400;color:var(--steel-500);font-size:15px}

/* ---------- buttons: obviously buttons, sharp corners ---------- */
.btn{
  display:inline-block;background:var(--amber);color:var(--paper);text-decoration:none;
  padding:13px 24px;border-radius:0;font-weight:700;border:1px solid var(--amber-deep);
  cursor:pointer;font-size:16px;font-family:var(--font);min-height:48px;line-height:1.4;
}
.btn:hover{background:var(--amber-deep);color:var(--paper);border-color:var(--amber-deep)}
.btn-outline{background:transparent;color:var(--steel-900);border:1px solid var(--steel-900)}
.btn-outline:hover{background:var(--steel-900);color:var(--paper)}
.header-cta{padding:12px 16px;font-size:14px;min-height:44px;white-space:nowrap}

/* ---------- hero: typographic, light, whitespace-carried ---------- */
.hero{
  background:var(--paper);color:var(--steel-900);padding:64px 0 72px;
  border-bottom:1px solid var(--steel-100);
}
.hero-eyebrow{
  display:flex;align-items:center;gap:12px;margin:0 0 20px;
  font-family:var(--mono);font-size:12px;font-weight:600;
  letter-spacing:.16em;text-transform:uppercase;color:var(--amber-ink);
}
.hero-eyebrow::before{content:"";width:36px;height:2px;background:var(--amber);flex:0 0 36px}
.hero h1{
  font-size:clamp(34px,6vw,58px);line-height:1.08;margin:0 0 20px;
  letter-spacing:-.02em;font-weight:800;max-width:22ch;
}
.hero p.lede{font-size:19px;color:var(--steel-700);max-width:40em;margin:0 0 32px}
.hero p.lede strong{
  color:var(--steel-900);font-weight:700;
  border-left:3px solid var(--amber);padding-left:12px;
  display:inline-block;margin-top:6px;
}
.hero .cta-row{display:flex;gap:14px;flex-wrap:wrap}

/* ---------- sections ---------- */
.section{padding:60px 0}
.section.alt{background:var(--steel-050);border-top:1px solid var(--steel-100);border-bottom:1px solid var(--steel-100)}
.section h2{font-size:clamp(24px,3.4vw,32px);margin:0 0 10px;letter-spacing:-.015em;font-weight:800}
.section .sub{color:var(--steel-500);max-width:44em;margin:0 0 34px;font-size:18px}
.kicker{
  display:flex;align-items:center;gap:10px;margin:0 0 12px;
  font-family:var(--mono);font-size:12px;font-weight:600;
  letter-spacing:.16em;text-transform:uppercase;color:var(--amber-ink);
}
.kicker::before{content:"";width:24px;height:2px;background:var(--amber);flex:0 0 24px}

/* cards */
.grid{display:grid;gap:0;grid-template-columns:1fr;border-top:1px solid var(--steel-100);border-left:1px solid var(--steel-100)}
.card{
  border-right:1px solid var(--steel-100);border-bottom:1px solid var(--steel-100);
  border-radius:0;padding:28px;background:var(--paper);
  display:flex;flex-direction:column;gap:10px;
}
.card h3{margin:0;font-size:20px;font-weight:700;letter-spacing:-.01em}
.card h3 a{color:var(--steel-900);text-decoration:none}
.card h3 a:hover{color:var(--amber-ink)}
.card p{margin:0;color:var(--steel-500);font-size:16px}
.card .more{margin-top:auto;padding-top:10px;font-weight:700;color:var(--amber-ink);text-decoration:none;font-size:15px}
.card .more:hover{text-decoration:underline}
.steps{display:grid;gap:0;grid-template-columns:1fr;counter-reset:step;border-top:1px solid var(--steel-100);border-left:1px solid var(--steel-100)}
.step{border-right:1px solid var(--steel-100);border-bottom:1px solid var(--steel-100);border-radius:0;padding:28px;background:var(--paper)}
.step-num{
  width:40px;height:40px;border:1px solid var(--steel-900);border-radius:0;
  color:var(--steel-900);font-family:var(--mono);font-weight:600;font-size:15px;
  display:flex;align-items:center;justify-content:center;margin-bottom:14px;background:var(--paper);
}
.step h3{margin:0 0 8px;font-size:19px;font-weight:700}
.step p{margin:0;color:var(--steel-500)}

/* ---------- CTA band: the single dark band ---------- */
.cta-band{background:var(--steel-900);color:var(--paper);padding:64px 0;text-align:center;border-top:3px solid var(--amber)}
.cta-band h2{margin:0 0 12px;font-size:clamp(24px,3.4vw,32px);font-weight:800;letter-spacing:-.015em}
.cta-band p{margin:0 auto 28px;max-width:36em;color:color-mix(in srgb,var(--paper) 72%,var(--steel-900))}
.cta-band .btn{background:var(--amber);border-color:var(--amber-deep);color:var(--paper)}
.cta-band .btn:hover{background:var(--amber-deep)}
.cta-band .kicker{justify-content:center;color:var(--amber)}
.cta-band .kicker::before{background:var(--amber)}

/* ---------- article ---------- */
.article{padding:44px 0 70px}
.article .wrap{max-width:800px}
.article h1{font-size:clamp(30px,4.6vw,42px);line-height:1.15;margin:0 0 14px;letter-spacing:-.02em;font-weight:800}
.article .lede{font-size:19px;color:var(--steel-500);margin:0 0 34px;padding-bottom:26px;border-bottom:1px solid var(--steel-100)}
.article h2{font-size:25px;margin:42px 0 12px;font-weight:800;letter-spacing:-.01em}
.article h3{font-size:19px;margin:30px 0 8px;font-weight:700}
.article p{margin:0 0 16px}
.article ul,.article ol{margin:0 0 18px;padding-left:22px}
.article li{margin-bottom:8px}
.breadcrumb{font-family:var(--mono);font-size:13px;color:var(--steel-500);margin-bottom:20px}
.breadcrumb a{color:var(--steel-500);text-decoration:none}
.breadcrumb a:hover{color:var(--amber-ink)}
.callout{
  border-left:3px solid var(--amber);background:var(--amber-wash);
  padding:18px 22px;border-radius:0;margin:28px 0;
}
.callout p{margin:0;color:var(--steel-700)}
/* spec tables: the signature motif — grid lines + mono values, dark header */
.spec-table{width:100%;border-collapse:collapse;margin:24px 0;font-size:15px}
.spec-table th,.spec-table td{border:1px solid var(--steel-300);padding:11px 14px;text-align:left;vertical-align:top}
.spec-table th{background:var(--steel-900);color:var(--paper);font-weight:700;font-size:13px;letter-spacing:.04em;text-transform:uppercase;border-color:var(--steel-900)}
.spec-table td{font-family:var(--mono);font-size:14px;color:var(--steel-700);background:var(--paper)}
.spec-table td:first-child{font-family:var(--font);font-weight:600;color:var(--steel-900);font-size:15px}
.spec-note{font-size:14px;color:var(--steel-500)}
.checklist{list-style:none;padding:0}
.checklist li{padding-left:32px;position:relative;margin-bottom:10px}
.checklist li::before{content:"✓";position:absolute;left:2px;color:var(--amber-ink);font-weight:800}
.xlist{list-style:none;padding:0}
.xlist li{padding-left:32px;position:relative;margin-bottom:10px}
.xlist li::before{content:"✕";position:absolute;left:2px;color:var(--err-ink);font-weight:800}

/* ---------- forms ---------- */
.form-card{border:1px solid var(--steel-300);border-radius:0;padding:30px;background:var(--paper);max-width:720px;color:var(--steel-900)}
.field{margin-bottom:20px}
.field label{display:block;font-weight:700;margin-bottom:7px;font-size:15px;color:var(--steel-900)}
.field .hint{display:block;font-weight:400;color:var(--steel-500);font-size:14px;margin-top:5px}
.field input[type=text],.field input[type=email],.field input[type=tel],
.field select,.field textarea{
  width:100%;padding:12px 14px;border:1px solid var(--steel-300);border-radius:0;
  font-size:16px;font-family:var(--font);background:var(--paper);color:var(--steel-900);
  min-height:48px;
}
.field input:focus,.field select:focus,.field textarea:focus{
  outline:2px solid var(--amber);outline-offset:1px;border-color:var(--amber);
}
.field textarea{min-height:120px;resize:vertical}
.field-row{display:grid;gap:20px;grid-template-columns:1fr}
.form-status{margin-top:18px;padding:15px 20px;border-radius:0;display:none;font-size:15px}
.form-status.ok{display:block;background:var(--ok-bg);color:var(--ok-ink);border:1px solid var(--ok-line)}
.form-status.err{display:block;background:var(--err-bg);color:var(--err-ink);border:1px solid var(--err-line)}

/* ---------- footer: light steel, hairline top ---------- */
.site-footer{background:var(--steel-050);color:var(--steel-500);padding:56px 0 32px;border-top:1px solid var(--steel-100)}
.footer-grid{display:grid;gap:30px;grid-template-columns:1fr}
.site-footer h4{
  color:var(--steel-900);font-family:var(--mono);font-size:12px;font-weight:600;
  text-transform:uppercase;letter-spacing:.14em;margin:0 0 16px;
}
.site-footer ul{list-style:none;margin:0;padding:0}
.site-footer li{margin-bottom:10px}
.site-footer a{color:var(--steel-500);text-decoration:none;font-size:15px}
.site-footer a:hover{color:var(--amber-ink)}
.footer-note{margin-top:40px;padding-top:26px;border-top:1px solid var(--steel-100);font-size:13px;color:var(--steel-500)}
.footer-note p{margin:0 0 10px;max-width:70em}
.footer-note strong{color:var(--steel-700)}

/* ---------- search page ---------- */
.search-tabs{display:flex;gap:0;border:1px solid var(--steel-300);margin-bottom:24px}
.search-tabs button{
  flex:1;background:var(--paper);border:none;border-right:1px solid var(--steel-300);
  padding:13px 10px;font-family:var(--font);font-weight:700;font-size:15px;cursor:pointer;
  color:var(--steel-500);min-height:48px;border-radius:0;
}
.search-tabs button:last-child{border-right:none}
.search-tabs button.active{background:var(--steel-900);color:var(--paper)}

/* ---------- desktop ---------- */
@media(min-width:760px){
  .grid.cols-2{grid-template-columns:1fr 1fr}
  .grid.cols-3{grid-template-columns:1fr 1fr 1fr}
  .steps{grid-template-columns:1fr 1fr 1fr}
  .field-row{grid-template-columns:1fr 1fr}
  .footer-grid{grid-template-columns:1.4fr 1fr 1fr 1fr}
  .hero{padding:88px 0 96px}
  .section{padding:72px 0}
}
@media(min-width:960px){
  .main-nav{display:flex;align-items:center;gap:2px}
  .main-nav a,.main-nav .nav-label{
    color:var(--steel-900);text-decoration:none;font-weight:600;font-size:15px;
    padding:12px 13px;border-radius:0;background:none;border:none;cursor:pointer;font-family:var(--font);
    min-height:44px;
  }
  .main-nav a:hover,.main-nav .nav-label:hover{background:var(--steel-050)}
  .nav-item{position:relative}
  .nav-drop{
    display:none;position:absolute;top:100%;left:0;min-width:250px;background:var(--paper);
    border:1px solid var(--steel-300);border-radius:0;box-shadow:0 14px 34px color-mix(in srgb,var(--steel-900) 14%,transparent);padding:6px;z-index:60;
  }
  .nav-item:hover .nav-drop{display:block}
  .nav-drop a{display:block;padding:11px 14px;font-size:14px;min-height:44px}
  .nav-toggle{display:none}
  .mobile-menu{display:none!important}
}