/* ==========================
   Reset & base
========================== */
*, *::before, *::after {
  box-sizing: border-box;
}

a:visited {
   color: inherit;
}

body {
  margin: 0;
  font-family: sans-serif;
  line-height: 1.5;
}

/* ==========================
   Header
========================== */
header {
  position: sticky;
  top: 0;
  background: #fff;
  padding: .8rem 1.2rem;
  border-bottom: 2px solid #ccc;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: .5px;
}

/* ==========================
   Botones
========================== */
.btn {
  padding: .55rem 1rem;
  border: 1px solid #444;
  background: #111;
  color: #fff;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}
.btn:hover {
  background: #333;
}

/* ==========================
   Layout principal
========================== */
main {
  padding: 2rem 1.5rem;
  max-width: 800px;
  margin: 0 auto;
}

h1, h2 {
  margin: .5rem 0;
}

p {
  margin: .75rem 0 1.5rem;
  color: #444;
}

/* ==========================
   Hero
========================== */
.hero {
  text-align: center;
  margin-top: 2rem;
}
.hero h2 {
  font-size: 2rem;
}
.hero p {
  font-size: 1.1rem;
  max-width: 55ch;
  margin-inline: auto;
}

/* ==========================
   Features
========================== */
.features {
  display: grid;
  gap: 1.2rem;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-top: 2.5rem;
}

.card {
  border: 1px solid #ddd;
  border-radius: 12px;
  padding: 1.2rem;
  background: #f9f9f9;
}
.card h3 {
  margin: 0 0 .5rem;
  font-size: 1.2rem;
}

/* ==========================
   Footer
========================== */
footer {
  border-top: 1px solid #ddd;
  padding: 1.2rem;
  text-align: center;
  font-size: .9rem;
  color: #555;
  margin-top: 3rem;
}