:root {
  --bg: #ffffff;
  --bg-alt: #f3f5f8;
  --primary: #005caa;
  --primary-dark: #004276;
  --accent: #f9a825;
  --text: #1f2933;
  --muted: #6b7280;
  --border: #d1d5db;
  --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.12);
  --radius: 6px;
  --font-main: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family: var(--font-main);
  color: var(--text);
  background: var(--bg);
}

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

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(209, 213, 219, 0.7);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 0;
}

.logo {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.logo-main {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--primary-dark);
}

.logo-sub {
  font-size: 0.8rem;
  color: var(--muted);
}

.nav a {
  margin-left: 1.5rem;
  font-size: 0.95rem;
  color: var(--muted);
  font-weight: 500;
}

.nav a:hover {
  color: var(--primary-dark);
}

/* Hero */

.hero {
  background: radial-gradient(circle at top left, #e0f2fe 0, #ffffff 45%, #e5e7eb 100%);
  padding: 3.5rem 0 3rem;
}

.hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  gap: 2.5rem;
  align-items: center;
}

.hero-text h1 {
  font-size: 2.4rem;
  margin: 0 0 1rem;
  color: #0f172a;
}

.hero-text p {
  font-size: 1.05rem;
  color: var(--muted);
  max-width: 34rem;
}

.hero-cta {
  margin-top: 1.75rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.4rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
}

.btn.primary {
  background: var(--primary);
  color: #ffffff;
  box-shadow: var(--shadow-soft);
}

.btn.primary:hover {
  background: var(--primary-dark);
}

.btn.secondary {
  background: #ffffff;
  color: var(--primary-dark);
  border-color: var(--border);
}

.hero-image {
  display: flex;
  justify-content: center;
}

.device-frame {
  background: #ffffff;
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(148, 163, 184, 0.4);
}

/* Sections */

.section {
  padding: 3.5rem 0;
}

.section-alt {
  background: var(--bg-alt);
}

.section h2 {
  font-size: 1.8rem;
  margin: 0 0 0.75rem;
}

.section-intro {
  max-width: 40rem;
  color: var(--muted);
  margin-bottom: 2rem;
}

.two-column {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 2.5rem;
  align-items: flex-start;
}

/* Cards & lists */

.card {
  background: #ffffff;
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(148, 163, 184, 0.4);
}

.card h3 {
  margin-top: 0;
}

.feature-list,
.checklist,
.numbered {
  margin: 0.75rem 0 0;
  padding-left: 1.1rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.feature-list li + li,
.checklist li + li,
.numbered li + li {
  margin-top: 0.35rem;
}

.checklist li::marker {
  content: "• ";
  color: var(--primary);
}

.numbered {
  list-style: decimal;
}

/* Calculation tabs */

.calc-tabs {
  display: inline-flex;
  border-radius: 999px;
  background: #e5e7eb;
  padding: 0.25rem;
  margin-bottom: 1.5rem;
}

.calc-tab {
  border: none;
  background: transparent;
  padding: 0.45rem 1.1rem;
  border-radius: 999px;
  font-size: 0.9rem;
  cursor: pointer;
  color: var(--muted);
  font-weight: 500;
}

.calc-tab.active {
  background: #ffffff;
  color: var(--primary-dark);
  box-shadow: 0 2px 6px rgba(15, 23, 42, 0.15);
}

.calc-panels {
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: #ffffff;
  padding: 1.5rem;
  box-shadow: var(--shadow-soft);
}

.calc-panel {
  display: none;
}

.calc-panel.active {
  display: block;
}

/* Contact form */

.contact-form {
  max-width: 480px;
  margin-top: 1.5rem;
}

.form-row {
  display: flex;
  flex-direction: column;
  margin-bottom: 0.9rem;
}

.form-row label {
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.form-row input,
.form-row textarea {
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 0.55rem 0.6rem;
  font-size: 0.95rem;
  font-family: var(--font-main);
}

.form-row input:focus,
.form-row textarea:focus {
  outline: 2px solid rgba(37, 99, 235, 0.4);
  border-color: var(--primary);
}

.form-note {
  margin-top: 0.5rem;
  font-size: 0.8rem;
  color: var(--muted);
}

/* Footer */

.site-footer {
  border-top: 1px solid var(--border);
  background: #f9fafb;
  padding: 1.25rem 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

/* Responsive */

@media (max-width: 900px) {
  .hero-inner,
  .two-column {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero {
    padding-top: 2.5rem;
  }

  .hero-text h1 {
    font-size: 2rem;
  }

  .nav a {
    margin-left: 1rem;
    font-size: 0.9rem;
  }
}

@media (max-width: 640px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.4rem;
  }

  .nav {
    display: flex;
    flex-wrap: wrap;
  }

  .nav a {
    margin-left: 0;
    margin-right: 1rem;
    margin-bottom: 0.25rem;
  }

  .hero-inner {
    gap: 1.75rem;
  }

  .calc-panels {
    padding: 1.1rem;
  }
}