/* =========================
   🌐 MODERN WEB SCHOOL UI
   ========================= */

/* RESET */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: #0f172a; /* tmavé pozadie */
  color: #e2e8f0;
  line-height: 1.6;
}

/* HEADER */
.header {
  text-align: center;
  padding: 60px 20px;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 800;
}

.header p {
  opacity: 0.9;
  margin-top: 10px;
}

/* NAVBAR */
.nav {
  position: sticky;
  top: 0;
  background: rgba(15, 23, 42, 0.9);
  backdrop-filter: blur(10px);
  display: flex;
  justify-content: center;
  gap: 20px;
  padding: 15px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
  z-index: 100;
}

.nav a {
  color: #e2e8f0;
  text-decoration: none;
  padding: 8px 14px;
  border-radius: 10px;
  transition: 0.2s ease;
}

.nav a:hover {
  background: #2563eb;
  color: white;
}

/* CONTAINER */
.container {
  max-width: 900px;
  margin: auto;
  padding: 40px 20px;
}

/* CARDS */
.card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 25px;
  margin-bottom: 20px;

  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
  transition: transform 0.2s ease, background 0.2s ease;
}

.card:hover {
  transform: translateY(-3px);
  background: rgba(255, 255, 255, 0.08);
}

.card h1, .card h2 {
  color: #f8fafc;
  margin-bottom: 10px;
}

/* TEXT */
p {
  color: #cbd5e1;
}

ul {
  margin-left: 20px;
  color: #cbd5e1;
}

/* CODE BLOCK */
pre {
  background: #020617;
  padding: 15px;
  border-radius: 12px;
  overflow-x: auto;
  border: 1px solid rgba(255,255,255,0.1);
  color: #38bdf8;
  margin: 10px 0;
}

/* BUTTON */
button {
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  color: white;
  border: none;
  padding: 12px 18px;
  border-radius: 12px;
  cursor: pointer;
  font-weight: 600;
  margin-top: 10px;
  transition: 0.2s ease;
}

button:hover {
  transform: scale(1.05);
  opacity: 0.9;
}

/* FOOTER */
.footer {
  text-align: center;
  padding: 30px;
  margin-top: 50px;
  color: #94a3b8;
  border-top: 1px solid rgba(255,255,255,0.1);
}

/* RESPONSIVE */
@media (max-width: 600px) {
  .header h1 {
    font-size: 1.8rem;
  }

  .nav {
    flex-wrap: wrap;
    gap: 10px;
  }
}