/* Reset & base */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f9fafb;
  color: #333;
  line-height: 1.6;
  font-size: 16px;
}

a {
  color: #0077ff;
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: #0056b3;
}

/* Header & Nav */
header {
  background: #111;
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 6px rgba(0,0,0,0.3);
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
}

.logo img {
  height: 50px;
  width: auto;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 1.5rem;
}

.nav-links li a {
  font-weight: 600;
  padding: 0.5rem 0.75rem;
  border-radius: 4px;
}

.nav-links li a:hover,
.nav-links li a:focus {
  background: #0077ff;
  color: #fff;
}

/* Hero Section */
.hero {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  background: linear-gradient(135deg, #0077ff 0%, #00bfff 100%);
  color: white;
  padding: 4rem 2rem;
  gap: 2rem;
  max-width: 1200px;
  margin: 2rem auto;
  border-radius: 12px;
  box-shadow: 0 12px 30px rgba(0, 123, 255, 0.3);
}

.hero-content {
  flex: 1 1 400px;
  max-width: 600px;
}

.hero-content h1 {
  font-size: 3rem;
  margin-bottom: 0.5rem;
  font-weight: 900;
  letter-spacing: 2px;
}

.hero-content p {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  font-weight: 500;
  line-height: 1.4;
}

.cta-button {
  display: inline-block;
  background: #fff;
  color: #0077ff;
  padding: 0.75rem 2rem;
  font-weight: 700;
  border-radius: 40px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transition: background-color 0.3s ease, color 0.3s ease;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 1.5px;
}

.cta-button:hover,
.cta-button:focus {
  background-color: #0056b3;
  color: #fff;
  box-shadow: 0 6px 18px rgba(0,86,179,0.5);
}

.hero-image {
  flex: 1 1 350px;
  max-width: 400px;
  text-align: center;
}

.hero-image img {
  max-width: 100%;
  border-radius: 20px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

/* Sections */
section {
  max-width: 900px;
  margin: 3rem auto;
  padding: 0 1rem;
}

h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: #0077ff;
  border-bottom: 3px solid #00bfff;
  display: inline-block;
  padding-bottom: 0.25rem;
  font-weight: 700;
}

p {
  margin-bottom: 1rem;
  font-size: 1.1rem;
  color: #444;
}

strong {
  color: #0077ff;
}

/* Lists */
ul, ol {
  margin-left: 1.25rem;
  margin-bottom: 1.5rem;
  color: #555;
  font-size: 1.1rem;
  line-height: 1.5;
}

ul li, ol li {
  margin-bottom: 0.75rem;
}

ul.social-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
  padding-left: 0;
}

.social-links li a {
  background: #0077ff;
  color: #fff;
  padding: 0.6rem 1.2rem;
  border-radius: 30px;
  font-weight: 600;
  transition: background-color 0.3s ease;
}

.social-links li a:hover,
.social-links li a:focus {
  background: #0056b3;
}

/* Code style */
code {
  background: #eaeaea;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-family: 'Courier New', Courier, monospace;
  color: #d6336c;
  font-weight: 700;
}

/* Footer */
footer {
  background: #111;
  color: #bbb;
  text-align: center;
  padding: 2rem 1rem;
  font-size: 0.9rem;
  margin-top: 4rem;
  user-select: none;
}

footer a {
  color: #0077ff;
  text-decoration: underline;
}

footer a:hover,
footer a:focus {
  color: #00bfff;
}

/* Responsive */
@media (max-width: 768px) {
  .hero {
    flex-direction: column;
    text-align: center;
  }

  .hero-content, .hero-image {
    max-width: 100%;
  }

  nav {
    flex-direction: column;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin-top: 0.75rem;
  }
}