:root {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --border-color: #334155;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --accent: #38bdf8;
  --accent-hover: #0284c7;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: system-ui, -apple-system, sans-serif;
  margin: 0;
  padding: 0;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Navbar */
.navbar {
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
}
.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.brand-logo {
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--text-main);
  text-decoration: none;
}
.nav-menu {
  display: flex;
  gap: 20px;
}
.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}
.nav-link:hover { color: var(--accent); }

/* Hero */
.hero-section {
  text-align: center;
  padding: 50px 20px 30px;
}
.hero-section h1 {
  font-size: 2.2rem;
  margin-bottom: 10px;
}
.hero-section p {
  color: var(--text-muted);
  font-size: 1.1rem;
  margin-bottom: 30px;
}

/* Buscador */
.search-box input {
  width: 100%;
  max-width: 550px;
  padding: 14px 20px;
  border-radius: 30px;
  border: 1px solid var(--border-color);
  background-color: var(--card-bg);
  color: var(--text-main);
  font-size: 1rem;
  outline: none;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}
.search-box input:focus {
  border-color: var(--accent);
}

/* Grid de Tarjetas */
.main-content { margin-top: 20px; }
.section-title h2 { font-size: 1.4rem; margin-bottom: 20px; }

.promo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
  padding-bottom: 60px;
}

.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s, border-color 0.2s;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
}

.card-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 12px;
}
.badge {
  font-size: 0.75rem;
  font-weight: bold;
  padding: 4px 8px;
  border-radius: 6px;
  text-transform: uppercase;
}
.badge-finanzas { background: #1e3a8a; color: #93c5fd; }
.badge-energia { background: #4c1d95; color: #ddd6fe; }
.tag-hot { font-size: 0.75rem; color: #f59e0b; font-weight: bold; }

.card-body h3 { margin: 0 0 6px; font-size: 1.2rem; }
.reward { color: #4ade80; font-weight: bold; font-size: 1.1rem; margin: 0 0 10px; }
.description { color: var(--text-muted); font-size: 0.9rem; line-height: 1.4; margin-bottom: 20px; }

.btn-primary {
  display: block;
  text-align: center;
  background-color: var(--accent);
  color: #0f172a;
  font-weight: bold;
  text-decoration: none;
  padding: 10px 0;
  border-radius: 8px;
  transition: background 0.2s;
}
.btn-primary:hover { background-color: var(--accent-hover); color: white; }