/* =================== GLOBAL BOX-SIZING =================== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family: 'Trebuchet MS', sans-serif;
  margin: 0;
  background-color: #fdf7ef;
  background-image: url('https://www.transparenttextures.com/patterns/paper-fibers.png');
  background-repeat: repeat;
  color: #4a3b26;
}

header {
  background-color: #f0d5aa;
  padding: 2rem;
  text-align: center;
  border-bottom: 3px solid #bb935a;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.15);
}

header h1, header h2 {
  text-shadow: 1px 1px 2px rgba(0,0,0,0.2);
}

nav {
  background-color: #e0c193;
  padding: 1rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

nav a {
  background: linear-gradient(to bottom, #fff7ea, #e6cda3);
  padding: 0.6rem 1.2rem;
  border-radius: 8px;
  text-decoration: none;
  font-weight: bold;
  color: #4a3b26;
  border: 1px solid #b48a60;
  box-shadow: 3px 3px 5px rgba(0, 0, 0, 0.2),
              inset -1px -1px 0 rgba(255, 255, 255, 0.4);
  transition: all 0.2s ease-in-out;
}

nav a:hover {
  background: linear-gradient(to bottom, #f8eac6, #dec6a0);
  box-shadow: 2px 2px 4px rgba(0, 0, 0, 0.25),
              inset -1px -1px 0 rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
}

nav a:active {
  box-shadow: inset 2px 2px 4px rgba(0, 0, 0, 0.3);
  transform: translateY(1px);
}

main {
  max-width: 1000px;
  margin: 2rem auto;
  padding: 1rem;
  background-color: #fff;
  border: 4px solid #d8b47c;
  box-shadow: 0 0 15px rgba(0,0,0,0.15);
  border-radius: 15px;
}

img.responsive {
  width: 70%;
  height: auto;
  display: block;
  margin: 1rem auto;
  border: 2px solid #c9a673;
}

footer {
  background-color: #f0d5aa;
  text-align: center;
  padding: 1rem;
  border-top: 3px solid #bb935a;
  margin-top: 2rem;
}

@media (max-width: 768px) {
  nav {
    flex-direction: column;
    align-items: center;
  }

  nav a {
    width: 90%;
    text-align: center;
  }

  img.responsive {
    width: 90%;
  }
}

/* =================== UNIFORM LESSON BOXES =================== */
details {
  display: block;
  width: 100%;
  margin: 1.5rem 0;
  padding: 1rem;
  border: 2px solid #d8b47c;
  border-radius: 12px;
  background-color: #fffaf3;
  box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.1);
}

details > summary {
  display: block;
  width: 100%;
  font-size: 1.2rem;
  font-weight: bold;
  cursor: pointer;
  color: #4a3b26;
}

details > summary:hover {
  color: #bb935a;
}

/* (opcjonalnie) wewnętrzne elementy w summary pozostają inline */
details > summary * {
  display: inline;
}

/* Mobile tweaks */
@media (max-width: 600px) {
  main {
    padding: 0.5rem;
  }
  details {
    padding: 0.8rem;
    margin: 1rem 0;
  }
  details > summary {
    font-size: 1rem;
  }
}