/* ===== Fuente base y estilo general ===== */
body {
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(180deg, #f9fbff 0%, #eef2f6 100%);
  color: #1b1b1b;
  margin: 0;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a {
  color: #0078d7;
  text-decoration: none;
  font-weight: 500;
}

a:hover {
  text-decoration: underline;
}

/* ===== Encabezado ===== */
header {
  background: linear-gradient(135deg, #1a2040 0%, #253b80 60%, #5a7cff 100%);
  color: #ffffff;
  text-align: center;
  padding: 4rem 1rem 3rem;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
  position: relative;
}

header h1 {
  font-size: 2.5rem;
  letter-spacing: 1px;
  margin-bottom: 0.7rem;
}

.subtitle {
  font-weight: 400;
  opacity: 0.9;
  font-size: 1.1rem;
  max-width: 650px;
  margin: 0 auto;
}

/* ===== Contenido general ===== */
main {
  max-width: 1000px;
  margin: 3rem auto;
  padding: 0 1rem;
}

/* ===== Secciones ===== */
section {
  background: #ffffff;
  border-radius: 20px;
  padding: 2.5rem;
  margin-bottom: 2.5rem;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.05);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

section:hover {
  transform: translateY(-3px);
  box-shadow: 0 14px 34px rgba(0, 0, 0, 0.07);
}

section h2 {
  color: #1f2a60;
  font-size: 1.6rem;
  margin-top: 0;
  margin-bottom: 1rem;
  position: relative;
}

section h2::after {
  content: '';
  display: block;
  width: 50px;
  height: 3px;
  background: linear-gradient(90deg, #00aaff, #0078ff);
  border-radius: 2px;
  margin-top: 0.4rem;
}

/* ===== Texto ===== */
section p {
  margin-bottom: 1rem;
  color: #2e2e2e;
}

/* ===== Listas ===== */
ul {
  list-style: none;
  padding-left: 0;
}

ul li {
  margin: 0.6rem 0;
  padding-left: 1.4rem;
  position: relative;
}

ul li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: #0078d7;
  font-weight: bold;
}

/* ===== Bloques de código ===== */
pre {
  background: #111523;
  color: #f1f1f1;
  padding: 1rem 1.5rem;
  border-radius: 12px;
  overflow-x: auto;
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 1.2rem 0;
  box-shadow: inset 0 0 12px rgba(0, 0, 0, 0.4);
}

code {
  font-family: 'Source Code Pro', monospace;
}

/* ===== Galería ===== */
.gallery {
  background: #ffffff;
}

.image-grid {
  width: 700px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.image-grid img {
  width: 100%;
  border-radius: 12px;
  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.1);
  transition: all 0.4s ease;
  opacity: 0.95;
}

.image-grid img:hover {
  transform: scale(1.04);
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.15);
  opacity: 1;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 2rem 1rem;
  background: #f0f3f7;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
  font-size: 0.95rem;
  color: #555;
}

footer a {
  color: #006edc;
}

footer a:hover {
  color: #004ea3;
}

/* ===== Responsividad ===== */
@media screen and (max-width: 768px) {
  header h1 {
    font-size: 2rem;
  }

  section {
    padding: 1.8rem;
  }

  .image-grid {
    grid-template-columns: 1fr;
    width: 100% !important;
  }
}