/* RadTower – shared styles
   Visual language inspired by Altaeros: white nav, blue accent (#1A8FBF),
   generous whitespace, tall hero, sans-serif typography. */

:root {
  --brand: #1A8FBF;
  --brand-dark: #0F6E96;
  --ink: #1a1a1a;
  --ink-soft: #4a4a4a;
  --line: #e5e7eb;
  --bg-soft: #f5f7fa;
  --max-w: 1200px;
  --radius: 999px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: var(--ink);
  background: #fff;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand); text-decoration: none; }
a:hover { color: var(--brand-dark); }

img, svg { max-width: 100%; display: block; }

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
  z-index: 100;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 22px;
  color: var(--brand);
  letter-spacing: -0.01em;
}
.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--brand);
  position: relative;
  flex-shrink: 0;
}
.brand-mark::after {
  content: '';
  position: absolute;
  inset: 6px;
  background: #fff;
  border-radius: 50%;
}
.brand-mark::before {
  content: '';
  position: absolute;
  inset: 11px;
  background: var(--brand);
  border-radius: 50%;
  z-index: 1;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}
.nav-links a {
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 15px;
}
.nav-links a.active,
.nav-links a:hover { color: var(--brand); }

.nav-toggle {
  display: none;
  background: transparent;
  border: 0;
  font-size: 24px;
  color: var(--ink);
  cursor: pointer;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 14px 28px;
  border-radius: var(--radius);
  font-weight: 700;
  font-size: 15px;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all 0.18s ease;
  text-align: center;
}
.btn-primary {
  background: var(--brand);
  color: #fff;
  border-color: var(--brand);
}
.btn-primary:hover {
  background: var(--brand-dark);
  border-color: var(--brand-dark);
  color: #fff;
}
.btn-outline {
  background: transparent;
  color: var(--ink);
  border-color: var(--ink);
}
.btn-outline:hover {
  background: var(--ink);
  color: #fff;
}
.btn[disabled] { opacity: 0.6; cursor: not-allowed; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(180deg, #eaf4fa 0%, #ffffff 100%);
  padding: 80px 0 60px;
  position: relative;
  overflow: hidden;
}
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}
.hero h1 {
  font-size: clamp(36px, 5vw, 60px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin: 0 0 20px;
  font-weight: 800;
}
.hero h1 .accent { color: var(--brand); }
.hero p.lead {
  font-size: 19px;
  color: var(--ink-soft);
  margin: 0 0 32px;
  max-width: 540px;
}
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }

.hero-image {
  position: relative;
  aspect-ratio: 4 / 3;
  background: linear-gradient(180deg, #cfe7f3 0%, #eaf4fa 60%, #f5f7fa 100%);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

/* ---------- Sections ---------- */
section.block {
  padding: 80px 0;
}
section.block.alt { background: var(--bg-soft); }

.section-head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px;
}
.section-head .eyebrow {
  color: var(--brand);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 12px;
}
.section-head h2 {
  font-size: clamp(28px, 3.5vw, 42px);
  margin: 0 0 16px;
  letter-spacing: -0.01em;
  font-weight: 800;
}
.section-head p {
  color: var(--ink-soft);
  font-size: 17px;
  margin: 0;
}

/* ---------- Feature grid ---------- */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 28px;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.feature:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.feature .icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: #eaf4fa;
  color: var(--brand);
  display: grid;
  place-items: center;
  margin-bottom: 16px;
  font-size: 22px;
}
.feature h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 700;
}
.feature p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 15px;
}

/* ---------- Stats ---------- */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat .num {
  font-size: 44px;
  font-weight: 800;
  color: var(--brand);
  letter-spacing: -0.02em;
}
.stat .lbl {
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 600;
}

/* ---------- CTA banner ---------- */
.cta-banner {
  background: linear-gradient(135deg, var(--brand) 0%, var(--brand-dark) 100%);
  color: #fff;
  padding: 64px 0;
  text-align: center;
}
.cta-banner h2 {
  font-size: clamp(26px, 3vw, 36px);
  margin: 0 0 12px;
  font-weight: 800;
}
.cta-banner p { margin: 0 0 24px; opacity: 0.9; font-size: 17px; }
.cta-banner .btn-primary {
  background: #fff;
  color: var(--brand-dark);
  border-color: #fff;
}
.cta-banner .btn-primary:hover { background: #eaf4fa; }

/* ---------- Forms ---------- */
.form-card {
  max-width: 720px;
  margin: 0 auto;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 40px;
  box-shadow: var(--shadow);
}
.form-row { margin-bottom: 22px; }
.form-row label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 14px;
  color: var(--ink);
}
.form-row .req { color: #d33; }
.form-row input[type=text],
.form-row input[type=email],
.form-row input[type=tel],
.form-row select,
.form-row textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font: inherit;
  background: #fff;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
  outline: none;
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(26, 143, 191, 0.15);
}
.form-row textarea { min-height: 140px; resize: vertical; }
.checkbox-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.checkbox-group label {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 500;
  font-size: 15px;
  color: var(--ink);
  cursor: pointer;
  margin: 0;
}
.checkbox-group input[type=checkbox] {
  width: 18px; height: 18px; accent-color: var(--brand);
}
.form-status {
  margin-top: 16px;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 14px;
  display: none;
}
.form-status.ok { display: block; background: #e8f5ed; color: #166534; border: 1px solid #bbe5c9; }
.form-status.err { display: block; background: #fdecec; color: #8a1c1c; border: 1px solid #f5c6c6; }

/* ---------- White paper layout ---------- */
.wp-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 56px;
  align-items: start;
}
.wp-cover {
  background: linear-gradient(160deg, #1A8FBF 0%, #0F6E96 100%);
  color: #fff;
  border-radius: 16px;
  padding: 48px 36px;
  box-shadow: var(--shadow);
  aspect-ratio: 3 / 4;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.wp-cover .eyebrow { font-size: 12px; letter-spacing: 0.18em; opacity: 0.8; text-transform: uppercase; }
.wp-cover h2 { font-size: 34px; line-height: 1.1; margin: 16px 0 0; font-weight: 800; }
.wp-cover .meta { font-size: 14px; opacity: 0.85; }
.wp-bullets { margin: 24px 0 0; padding: 0 0 0 18px; }
.wp-bullets li { margin-bottom: 8px; color: var(--ink-soft); }

/* ---------- Footer ---------- */
footer {
  background: #0a1620;
  color: #c8d6e0;
  padding: 48px 0 28px;
  font-size: 14px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 32px;
  margin-bottom: 32px;
}
footer h4 { color: #fff; margin: 0 0 12px; font-size: 14px; letter-spacing: 0.05em; text-transform: uppercase; }
footer ul { list-style: none; padding: 0; margin: 0; }
footer ul li { margin-bottom: 8px; }
footer a { color: #c8d6e0; }
footer a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid #1a2a36;
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  color: #6a7c8a;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero-grid, .wp-grid { grid-template-columns: 1fr; }
  .features { grid-template-columns: 1fr 1fr; }
  .stats { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: 72px; left: 0; right: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 16px 24px;
    gap: 12px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .features { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .form-card { padding: 24px; }
  .hero { padding: 48px 0 32px; }
}