:root {
  --navy: #13294b;
  --navy-soft: #2a4170;
  --teal: #1f9e9b;
  --teal-dark: #167a78;
  --teal-tint: #e8f6f5;
  --ink: #1e2633;
  --muted: #5b6575;
  --line: #dde3ea;
  --bg: #ffffff;
  --bg-alt: #f6f8fb;
  --radius: 14px;
  --serif: "Source Serif 4", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
}

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

a { color: var(--teal-dark); }

h1, h2, h3 {
  font-family: var(--serif);
  color: var(--navy);
  line-height: 1.2;
  margin: 0 0 0.6em;
}

h1 { font-size: clamp(2rem, 4.5vw, 3.1rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); }
h3 { font-size: 1.25rem; }

.container { width: min(1120px, 100% - 32px); margin-inline: auto; }
.narrow { width: min(760px, 100% - 32px); }
.center { text-align: center; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.nav { display: flex; align-items: center; justify-content: space-between; gap: 16px; min-height: 64px; }

.brand {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--navy);
  text-decoration: none;
  line-height: 1.2;
}

.brand span {
  display: block;
  font-family: var(--sans);
  font-weight: 500;
  font-size: 0.75rem;
  color: var(--teal-dark);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

nav { display: flex; align-items: center; gap: 22px; }
nav a { color: var(--ink); text-decoration: none; font-weight: 500; font-size: 0.95rem; }
nav a:not(.btn):hover { color: var(--teal-dark); }

/* Buttons */
.btn {
  display: inline-block;
  background: var(--navy);
  color: #fff;
  border: 2px solid var(--navy);
  border-radius: 999px;
  padding: 12px 26px;
  font: 600 1rem var(--sans);
  text-decoration: none;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.btn:hover { background: var(--navy-soft); border-color: var(--navy-soft); }
.btn-small { padding: 8px 18px; font-size: 0.9rem; color: #fff !important; }
.btn-ghost { background: transparent; color: var(--navy); }
.btn-ghost:hover { background: var(--teal-tint); border-color: var(--navy); }

/* Hero */
.hero { padding: 64px 0 48px; background: linear-gradient(180deg, var(--teal-tint), var(--bg)); }
.hero-grid { display: grid; grid-template-columns: 1.25fr 1fr; gap: 48px; align-items: center; }
.eyebrow { color: var(--teal-dark); font-weight: 600; font-size: 0.9rem; letter-spacing: 0.03em; margin: 0 0 12px; }
.lead { font-size: 1.15rem; color: var(--muted); max-width: 36em; }
.cta-row { display: flex; flex-wrap: wrap; gap: 12px; margin: 28px 0 8px; }
.formula { color: var(--navy-soft); opacity: 0.75; font-size: 0.95rem; overflow-x: auto; }
.portrait { border-radius: 24px; box-shadow: 0 20px 50px rgba(19, 41, 75, 0.18); justify-self: end; }

/* Credentials */
.credentials { background: var(--navy); color: #fff; padding: 28px 0; }
.cred-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; text-align: center; }
.cred-grid strong { display: block; font-family: var(--serif); font-size: 1.5rem; }
.cred-grid span { color: #b9c6dd; font-size: 0.92rem; }

/* Sections */
.section { padding: 80px 0; }
.alt { background: var(--bg-alt); }
.section-lead { color: var(--muted); margin-top: -8px; margin-bottom: 32px; }

.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.card {
  background: #fff;
  border: 1px solid var(--line);
  border-top: 4px solid var(--teal);
  border-radius: var(--radius);
  padding: 28px;
}
.card ul { padding-left: 1.1em; margin: 0; color: var(--muted); }
.card li { margin-bottom: 4px; }
.tag {
  display: inline-block;
  background: var(--teal-tint);
  color: var(--teal-dark);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: 999px;
  padding: 2px 12px;
  margin: 0 0 12px;
}

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 32px; margin-top: 24px; }
.steps p { color: var(--muted); margin: 0; }

/* Pricing */
.price-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 40px 32px;
  max-width: 460px;
  margin: 24px auto 0;
  box-shadow: 0 10px 30px rgba(19, 41, 75, 0.06);
}
.price { font-family: var(--serif); font-size: 3.4rem; font-weight: 700; color: var(--navy); margin: 0; line-height: 1; }
.price span { font-family: var(--sans); font-size: 1.1rem; font-weight: 500; color: var(--muted); }
.checks { list-style: none; padding: 0; margin: 20px 0 28px; text-align: left; display: inline-block; }
.checks li { padding-left: 28px; position: relative; margin-bottom: 6px; }
.checks li::before { content: "\2713"; position: absolute; left: 0; color: var(--teal); font-weight: 700; }

/* FAQ */
details { border-bottom: 1px solid var(--line); padding: 16px 0; }
summary { cursor: pointer; font-weight: 600; color: var(--navy); list-style: none; display: flex; justify-content: space-between; gap: 16px; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--teal); font-size: 1.3rem; line-height: 1; }
details[open] summary::after { content: "\2212"; }
details p { color: var(--muted); margin: 10px 0 0; }

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1fr 1.1fr; gap: 48px; align-items: start; }
.contact-info p { margin: 0 0 16px; }
.muted { color: var(--muted); font-size: 0.95rem; margin-top: -10px !important; }

.contact-form {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  display: grid;
  gap: 14px;
}
.contact-form label { display: grid; gap: 6px; font-weight: 500; font-size: 0.95rem; }
.contact-form input,
.contact-form select,
.contact-form textarea {
  font: inherit;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  width: 100%;
}
.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus { outline: 2px solid var(--teal); outline-offset: 1px; border-color: var(--teal); }
.hp { position: absolute; left: -9999px; }

/* Footer */
.site-footer { background: var(--navy); color: #b9c6dd; padding: 28px 0; font-size: 0.9rem; }
.footer-grid { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 24px; }
.footer-grid p { margin: 0; }

/* Responsive */
@media (max-width: 860px) {
  .hero-grid, .contact-grid { grid-template-columns: 1fr; }
  .portrait { justify-self: center; max-width: 280px; order: -1; }
  .card-grid, .steps { grid-template-columns: 1fr; }
  .cred-grid { grid-template-columns: repeat(2, 1fr); }
  nav a:not(.btn) { display: none; }
  .section { padding: 56px 0; }
}

.formula .katex-display, .formula .katex-display > .katex { text-align: left; margin: 12px 0 0; }

/* WhatsApp */
.btn-whatsapp {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #fff;
  border: 2px solid #25d366;
  color: #128c4a;
  padding: 10px 20px;
  margin-bottom: 20px;
}
.btn-whatsapp:hover { background: #effcf4; border-color: #1ebe5b; }
.btn-whatsapp svg { width: 18px; height: 18px; flex: none; color: #25d366; }

.whatsapp-float {
  position: fixed;
  right: 20px;
  bottom: 20px;
  z-index: 20;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #25d366;
  color: #fff;
  display: grid;
  place-items: center;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
  transition: transform 0.15s;
}
.whatsapp-float:hover { transform: scale(1.06); }
.whatsapp-float svg { width: 30px; height: 30px; }

/* Form validation */
.contact-form input:user-invalid { border-color: #c0392b; outline-color: #c0392b; }

.badge {
  display: inline-block;
  background: var(--teal);
  color: #fff;
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.03em;
  border-radius: 999px;
  padding: 4px 14px;
  margin: 0 0 16px;
}

/* Videos */
.video-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px; }
.video-card h3 { margin-bottom: 4px; }
.video-card .tag { margin-top: 14px; }
.video-note { color: var(--muted); font-size: 0.92rem; margin: 0; }
.video-facade,
.video-frame {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 0;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--navy);
}
.video-facade { position: relative; padding: 0; cursor: pointer; }
.video-facade img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.2s; }
.video-facade:hover img { transform: scale(1.03); }
.play {
  position: absolute;
  inset: 0;
  margin: auto;
  width: 68px;
  height: 48px;
  border-radius: 12px;
  background: rgba(19, 41, 75, 0.85);
  transition: background 0.15s;
}
.play::after {
  content: "";
  position: absolute;
  left: 28px;
  top: 14px;
  border-style: solid;
  border-width: 10px 0 10px 16px;
  border-color: transparent transparent transparent #fff;
}
.video-facade:hover .play { background: #ff0033; }

@media (max-width: 860px) {
  .video-grid { grid-template-columns: 1fr; }
}