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

body {
  font-family: "Segoe UI", Roboto, system-ui, sans-serif;
  background: #f6f7fb;
  color: #333;
  line-height: 1.6;
}

.container {
  max-width: 960px;
  margin: auto;
  padding: 1rem;
}

header {
  background-color: #d42000;
  color: white;
  padding: 1rem 0;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  position: relative;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  height: 60px;
  display: block;
}

.hamburger {
  display: none;
  flex-direction: column;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  width: 30px;
  height: 30px;
  justify-content: space-around;
}

.hamburger span {
  width: 100%;
  height: 3px;
  background-color: white;
  border-radius: 2px;
  transition: all 0.3s ease;
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(8px, 8px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(8px, -8px);
}

nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: 600;
}

nav a:hover {
  text-decoration: underline;
}

main section {
  background: white;
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: 0 2px 4px rgba(0,0,0,0.06);
}

section h1 {
  color: #555555;
  margin-bottom: 0.75rem;
}

section h2 {
  color: #555555;
  margin-bottom: 0.75rem;
}

section ul {
  margin-top: 0.5rem;
  padding-left: 3rem;
}

section ul li {
  margin-bottom: 0.25rem;
}

/* Collapsible sections */
.collapsible-section {
  margin-bottom: 1rem;
}

.collapsible-header {
  cursor: pointer;
  user-select: none;
  position: relative;
  padding-right: 2rem;
  font-weight: 600;
  color: #555555;
}

.collapsible-header::after {
  content: '+';
  position: absolute;
  right: 0;
  top: 0;
  font-size: 1.2em;
  font-weight: bold;
  transition: transform 0.3s ease;
}

.collapsible-header.active::after {
  transform: rotate(45deg);
}

.collapsible-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding-left: 3rem;
  margin-top: 0.75rem;
}

.collapsible-content.active {
  max-height: 2000px;
  transition: max-height 0.3s ease-in;
}

footer {
  text-align: center;
  padding: 0.5rem 0;
  font-size: 0.9rem;
  color: #555;
}

.download img {
  height: 50px;
  margin-right: 10px;
}

@media (max-width: 600px) {
  .hamburger {
    display: flex;
  }

  nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: #d42000;
    padding: 1rem;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
  }

  nav.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  nav ul {
    flex-direction: column;
    gap: 0.5rem;
  }

  nav li {
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  }

  nav li:last-child {
    border-bottom: none;
  }

  .logo {
    height: 48px;
  }

  .download img {
    height: 40px;
  }
}