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

body {
  font-family: 'Montserrat', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #333;
}

header {
  background-color: #fff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  padding: 20px;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 24px;
  font-weight: bold;
  color: #ff6b6b;
}

nav ul {
  list-style: none;
  display: flex;
}

nav ul li {
  margin-left: 20px;
}

nav ul li a {
  text-decoration: none;
  color: #333;
  transition: color 0.3s;
}

nav ul li a:hover {
  color: #ff6b6b;
}

main {
  padding: 40px 0;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

h1, h2 {
  margin-bottom: 20px;
}

.btn {
  display: inline-block;
  background-color: #ff6b6b;
  color: #fff;
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.btn:hover {
  background-color: #ff4f4f;
}

.form-group {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 5px;
}

select, input {
  width: 100%;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 16px;
}

.card-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.card {
  background-color: #fff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  padding: 20px;
  border-radius: 4px;
  text-align: center;
  cursor: pointer;
  transition: transform 0.3s;
  position: relative;
}

.card:hover {
  transform: translateY(-5px);
}

.card img {
  width: 100%;
  height: auto;
  border-radius: 4px;
  margin-bottom: 10px;
}

.card .amount {
  position: absolute;
  top: 10px;
  right: 10px;
  background-color: rgba(255, 255, 255, 0.8);
  padding: 5px 10px;
  border-radius: 4px;
  font-size: 14px;
  font-weight: bold;
}

.card .selected-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(255, 107, 107, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 24px;
  font-weight: bold;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.card.selected .selected-overlay {
  opacity: 1;
}

.section {
  padding: 60px 0;
}

.hidden {
  display: none;
}

footer {
  background-color: #333;
  color: #fff;
  padding: 20px;
  text-align: center;
}