/* Font a základ */
body {
  font-family: 'Inter', sans-serif;
  margin: 0;
  padding: 0;
  background: #0f1724;
  color: #e0e0e0;
  line-height: 1.6;
}

/* Header */
header {
  background: #1f2937;
  padding: 2rem 1rem;
}

.header-container {
  max-width: 1100px;
  margin: auto;
  text-align: center;
}

.header-logo {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.header-logo img {
  height: 70px;
}

header h1 {
  margin: 0.2rem 0 1rem 0;
  font-weight: 700;
}

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

nav a {
  color: #e0e0e0;
  text-decoration: none;
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  transition: background 0.2s;
}

nav a:hover {
  background: #374151;
}

/* Tlačidlá */
.btn {
  padding: 0.6rem 1.2rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
}

.gradient-btn {
  background: linear-gradient(90deg, #4f46e5, #6366f1);
  color: #fff;
}

.gradient-btn:hover {
  opacity: 0.85;
}

.btn-secondary {
  padding: 0.5rem 1.2rem;
  border: 1px solid #555;
  color: #e0e0e0;
  background: transparent;
  border-radius: 8px;
}

.btn-secondary:hover {
  background: #374151;
}

/* Hero sekcia */
.section-hero {
  display: flex;
  flex-wrap: wrap-reverse;
  gap: 2rem;
  align-items: center;
  padding: 3rem 1rem;
  max-width: 1100px;
  margin: auto;
}

.hero-text {
  flex: 1 1 300px;
}

.hero-text h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.hero-text p {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
}

.hero-image img {
  max-width: 100%;
  border-radius: 16px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.5);
}

/* Sekcia cvičení */
.section-cards h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  text-align: center;
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}

.card {
  padding: 1.5rem;
  border-radius: 16px;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  color: #000000;
  display: flex;
  flex-direction: column;
  align-items: start;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 24px rgba(0,0,0,0.4);
}

.card-icon img {
  height: 40px;
  border-radius: 25px;
}

/* Farebné karty */
.card.vocab { background: #facc15; color: #111; }
.card.grammar { background: #f97316; }
.card.reading { background: #3b82f6; }
.card.listening { background: #10b981; }

/* Sekcia o stránke */
.section-about {
  margin: 4rem 0;
  padding: 0 1rem;
}

.section-about h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
}


.modal-content {
  background: #1f2937;
  padding: 2rem;
  max-width: 400px;
  width: 90%;
  border-radius: 16px;
}

/* Footer */
footer {
  padding: 2rem 1rem;
  text-align: center;
  background: #1f2937;
  font-size: 0.9rem;
}