/* ai4smartmfg.com — landing styles
   Inter Tight, near-black on white with a single muted-industrial-blue accent.
   Dieter Rams / Apple restraint. Left-aligned, asymmetric, generous whitespace. */

:root {
  /* Settled palette per brand brief */
  --ink: #1D1D1F;            /* Apple softened black */
  --ink-soft: #86868B;        /* secondary text / hairline */
  --bg: #FFFFFF;              /* primary background */
  --bg-alt: #F5F5F7;          /* light section background */
  --accent: #3B5566;          /* muted industrial blue — used sparingly */
  --rule: #E5E5E7;            /* very light hairline */

  --max-w: 1120px;
  --gutter: clamp(20px, 4vw, 56px);
  --section-y: clamp(80px, 12vw, 160px);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

body {
  font-family: 'Inter Tight', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  font-weight: 400;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--ink); }

.container { max-width: var(--max-w); margin: 0 auto; padding: 0 var(--gutter); }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,0.92);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--rule);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.wordmark {
  font-weight: 500;
  font-size: 17px;
  letter-spacing: -0.01em;
  color: var(--ink);
  display: inline-flex;
  align-items: baseline;
}
.wordmark .mark-prefix { color: var(--ink); font-weight: 500; }
.wordmark .mark-rest   { color: var(--ink); font-weight: 500; }
.wordmark:hover .mark-prefix { color: var(--accent); }

.nav { display: flex; align-items: center; gap: clamp(20px, 3vw, 40px); }
.nav a {
  color: var(--ink);
  font-size: 15px;
  font-weight: 400;
  letter-spacing: -0.005em;
}
.nav a:hover { color: var(--accent); }
.nav-toggle {
  display: none;
  background: none;
  border: 0;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--ink);
  margin: 5px 0;
}

/* ---------- Buttons (small radius, restrained) ---------- */
.btn {
  display: inline-block;
  padding: 12px 22px;
  background: var(--ink);
  color: #fff;
  border: 1px solid var(--ink);
  border-radius: 4px;
  font-weight: 500;
  font-size: 15px;
  letter-spacing: -0.005em;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
  cursor: pointer;
  font-family: inherit;
}
.btn:hover { background: #000; color: #fff; border-color: #000; }
.btn.btn-light {
  background: transparent;
  color: var(--ink);
  border-color: var(--ink);
}
.btn.btn-light:hover { background: var(--ink); color: #fff; }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 40px; }

/* ---------- Hero (left-aligned, asymmetric, generous whitespace) ---------- */
.hero {
  padding: clamp(96px, 14vw, 200px) 0 var(--section-y);
  background: var(--bg);
}
.hero .container { max-width: 980px; }   /* sit content left of center */
.hero h1 {
  font-size: clamp(40px, 6vw, 68px);
  line-height: 1.05;
  letter-spacing: -0.03em;
  font-weight: 500;                       /* Medium per brief */
  margin: 0 0 24px 0;
  max-width: 18ch;
  color: var(--ink);
}
.hero .tagline {
  font-size: clamp(20px, 2.2vw, 26px);
  font-weight: 400;
  color: var(--ink-soft);
  letter-spacing: -0.01em;
  margin: 0 0 36px 0;
  max-width: 28ch;
}

/* ---------- Sections ---------- */
section { padding: var(--section-y) 0; }
section.alt { background: var(--bg-alt); }

.eyebrow {
  font-size: 12px;
  font-weight: 500;
  color: var(--ink-soft);
  text-transform: uppercase;
  letter-spacing: 0.16em;
  margin: 0 0 24px 0;
}
h2 {
  font-size: clamp(28px, 3.8vw, 40px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 500;
  margin: 0 0 24px 0;
  max-width: 24ch;
  color: var(--ink);
}
h3 {
  font-size: 18px;
  line-height: 1.35;
  letter-spacing: -0.01em;
  font-weight: 500;
  margin: 0 0 10px 0;
  color: var(--ink);
}
p { margin: 0 0 16px 0; }
p.large {
  font-size: clamp(19px, 1.8vw, 22px);
  line-height: 1.5;
  color: var(--ink);
  max-width: 60ch;
  font-weight: 400;
}
p.muted { color: var(--ink-soft); }

/* ---------- Value-prop lead-in ---------- */
.leadin .container { max-width: 820px; }
.leadin p {
  font-size: clamp(22px, 2.3vw, 28px);
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--ink);
  font-weight: 400;
  margin: 0;
}
.leadin p .em { color: var(--ink); font-weight: 500; }

/* ---------- Two-column rail (heading | content) ---------- */
.rail {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: clamp(32px, 6vw, 96px);
  align-items: start;
}
.rail h2 { margin-top: 0; max-width: 16ch; }
.rail .rail-body { max-width: 60ch; }

/* ---------- Item lists (Problems We Solve, Principles) ---------- */
.list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.list li {
  padding: 22px 0;
  border-top: 1px solid var(--rule);
  font-size: 17px;
  line-height: 1.55;
  color: var(--ink);
}
.list li:last-child { border-bottom: 1px solid var(--rule); }
.list li .lbl {
  display: block;
  font-weight: 500;
  color: var(--ink);
  margin-bottom: 4px;
}
.list li .desc { color: var(--ink-soft); font-size: 16px; }

/* ---------- Confidentiality block (quiet emphasis) ---------- */
.trust .container { max-width: 820px; }
.trust .rule-top {
  border-top: 1px solid var(--ink);
  padding-top: 32px;
  width: 64px;
  margin-bottom: 24px;
}
.trust h2 { margin-bottom: 28px; }
.trust p.large { color: var(--ink); }
.trust .pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 56px;
}
.trust .pillars h3 { color: var(--ink); margin-bottom: 8px; }
.trust .pillars p { color: var(--ink-soft); font-size: 16px; line-height: 1.55; }

/* ---------- Founder strip ---------- */
.founder p { color: var(--ink-soft); }
.founder .name { color: var(--ink); font-weight: 500; }

/* ---------- Closing CTA ---------- */
.closing {
  background: var(--bg-alt);
  text-align: left;
}
.closing h2 { color: var(--ink); max-width: 22ch; }
.closing p { color: var(--ink-soft); max-width: 56ch; }

/* ---------- Footer ---------- */
.site-footer {
  padding: 40px 0 48px;
  border-top: 1px solid var(--rule);
  background: var(--bg);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 16px;
}
.site-footer .copy { display: flex; flex-direction: column; gap: 4px; }
.site-footer .copy p { font-size: 14px; color: var(--ink-soft); margin: 0; }
.site-footer .copy p.fineprint { font-size: 11px; color: var(--ink-soft); }
.site-footer .footer-links {
  display: flex;
  gap: 24px;
}
.site-footer .footer-links a {
  font-size: 14px;
  color: var(--ink-soft);
}
.site-footer .footer-links a:hover { color: var(--ink); }

/* ---------- Contact ---------- */
.contact-page section { padding-top: clamp(72px, 10vw, 140px); padding-bottom: var(--section-y); }
.contact-form {
  max-width: 620px;
  margin-top: 40px;
}
.form-row { margin-bottom: 22px; }
.form-row label {
  display: block;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 8px;
}
.form-row input,
.form-row textarea {
  width: 100%;
  padding: 12px 14px;
  font-family: inherit;
  font-size: 16px;
  color: var(--ink);
  background: #fff;
  border: 1px solid var(--rule);
  border-radius: 4px;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.form-row input:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 85, 102, 0.12);
}
.form-row textarea { min-height: 140px; resize: vertical; }
.form-note { font-size: 14px; color: var(--ink-soft); margin-top: 16px; }

/* ---------- Stub pages ---------- */
.stub section { padding: clamp(80px, 12vw, 160px) 0; }
.stub h1 {
  font-size: clamp(36px, 5vw, 56px);
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin: 0 0 24px 0;
  font-weight: 500;
}
.stub p.large { font-size: 20px; color: var(--ink-soft); max-width: 60ch; }

/* ---------- Responsive ---------- */
@media (max-width: 820px) {
  .rail { grid-template-columns: 1fr; gap: 24px; }
  .rail h2 { max-width: none; }
  .trust .pillars { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .nav a:not(.btn) { display: none; }
  .nav-toggle { display: block; }
  .nav.open a:not(.btn) {
    display: block;
    padding: 12px 0;
    border-top: 1px solid var(--rule);
    width: 100%;
    text-align: left;
  }
  .nav.open {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    padding: 0 var(--gutter) 16px;
    flex-direction: column;
    align-items: stretch;
    border-bottom: 1px solid var(--rule);
  }
  .footer-inner { flex-direction: column; align-items: flex-start; }
}