*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --blue: #0c9aff;
  --blue-dark: #0b8eeb;
  --blue-deeper: #00456d;
  --green: #75c423;
  --dark: #030812;
  --dark-light: #1a1f2e;
  --white: #ffffff;
  --gray: #c2c2c2;
  --gray-light: #f2f4f7;
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-heading: 'Antonio', 'Inter', sans-serif;
  --font-accent: 'Poppins', sans-serif;
  --radius: 100px;
  --radius-sm: 12px;
  --max-w: 1200px;
}

html {
  font-size: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  color: var(--dark);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-primary);
  font-weight: 700;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s ease;
  letter-spacing: -0.03em;
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
  font-size: 16px;
  padding: 14px 36px;
  box-shadow: 2px 4px 10px rgba(0,0,0,0.1);
}

.btn-primary:hover {
  background: #0891e6;
  transform: translateY(-1px);
  box-shadow: 2px 6px 16px rgba(0,0,0,0.15);
}

.btn-small {
  font-size: 13px;
  padding: 8px 20px;
}

.btn-green {
  background: var(--green);
  color: var(--white);
}

.btn-green:hover {
  background: #65b01e;
}

/* --- Topbar --- */
.topbar {
  background: var(--blue-dark);
  color: var(--white);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.topbar-title {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* --- Hero --- */
.hero {
  background: linear-gradient(135deg, var(--blue-dark) 0%, var(--blue-deeper) 100%);
  color: var(--white);
  padding: 60px 0 80px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.hero-content h1 {
  font-family: var(--font-heading);
  font-size: clamp(40px, 6vw, 80px);
  font-weight: 700;
  line-height: 0.9;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: clamp(18px, 2.5vw, 28px);
  font-weight: 600;
  opacity: 0.9;
  margin-bottom: 8px;
}

.hero-author {
  font-family: var(--font-accent);
  font-size: 18px;
  font-weight: 300;
  opacity: 0.8;
  margin-bottom: 32px;
}

.hero-media {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}

.video-wrapper {
  width: 100%;
  max-width: 280px;
}

.video-wrapper {
  max-width: 100%;
}

.video-vertical {
  aspect-ratio: 16 / 9;
  width: 100%;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: #000;
}

.video-wrapper iframe {
  display: block;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: 48px;
  align-items: start;
}

.about-cover img {
  border-radius: var(--radius-sm);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  width: 100%;
}

/* --- About --- */
.about {
  padding: 80px 0;
  background: var(--white);
}

.isbn {
  font-family: var(--font-heading);
  font-size: 22px;
  color: var(--blue-deeper);
  font-weight: 700;
  margin-bottom: 24px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

.about-text p {
  font-size: 16px;
  line-height: 1.8;
  color: #444;
  margin-bottom: 16px;
}

.about-signoff {
  font-style: italic;
  color: var(--blue-deeper);
  font-weight: 600;
  margin-top: 24px;
}

.about-cta {
  margin-top: 40px;
  text-align: center;
}

/* --- Author --- */
.author {
  padding: 80px 0;
  background: var(--gray-light);
}

.author-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 48px;
  align-items: start;
}

.author-image img {
  width: 100%;
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

.author-content h2 {
  font-family: var(--font-heading);
  font-size: 40px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  color: var(--dark);
}

.author-content p {
  font-size: 16px;
  line-height: 1.8;
  color: #444;
  margin-bottom: 14px;
}

/* --- Social --- */
.social {
  padding: 64px 0;
  background: var(--dark);
  color: var(--white);
  text-align: center;
}

.social h2 {
  font-family: var(--font-heading);
  font-size: 36px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.social-links a {
  transition: transform 0.2s ease;
}

.social-links a:hover {
  transform: translateY(-3px);
}

/* --- Contact --- */
.contact {
  padding: 64px 0;
  background: var(--white);
  text-align: center;
}

.contact h2 {
  font-family: var(--font-heading);
  font-size: 36px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
}

.contact-grid {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 16px;
  color: var(--dark);
  padding: 12px 24px;
  border-radius: var(--radius);
  background: var(--gray-light);
  transition: all 0.2s ease;
}

.contact-item:hover {
  background: var(--blue);
  color: var(--white);
}

.contact-icon {
  font-size: 20px;
}

/* --- Footer --- */
.footer {
  padding: 32px 0;
  background: var(--dark);
  color: var(--gray);
  text-align: center;
  font-size: 14px;
}

.footer a {
  color: var(--blue);
}

.footer a:hover {
  text-decoration: underline;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    order: 1;
  }

  .hero-media {
    order: 0;
  }

  .about-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .about-cover {
    max-width: 200px;
    margin: 0 auto;
  }

  .about-cover img {
    max-width: 200px;
  }

  .author-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .author-image {
    max-width: 250px;
    margin: 0 auto;
  }

  .btn-primary {
    font-size: 14px;
    padding: 12px 28px;
  }

  .topbar-title {
    font-size: 16px;
  }
}