* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f4f7fb;
  color: #222;
}

main {
  max-width: 900px;
  margin: 16px auto;
  padding: 16px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 14px 35px rgba(0, 0, 0, 0.08);
}

h1,
h2 {
  margin-top: 0;
}

.search-section,
.product-list-section,
.detail-section,
.session-section {
  margin-bottom: 24px;
}

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
}

input[type="search"],
input[type="number"],
input[type="date"] {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid #ccd4e0;
  border-radius: 10px;
  margin-bottom: 16px;
  font-size: 1rem;
}

.product-list {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.product-card {
  border: 1px solid #d3dde7;
  background: #f9fbff;
  padding: 16px;
  border-radius: 10px;
  text-align: left;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.2s ease;
  min-height: 60px;
}

.product-card:hover {
  background: #eef4ff;
  transform: translateY(-1px);
}

.detail-card {
  background: #fefefe;
  border: 1px solid #dfe7ef;
  border-radius: 12px;
  padding: 16px;
}

.hidden {
  display: none;
}

button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 52px;
  border: none;
  border-radius: 12px;
  padding: 14px 18px;
  background: #2563eb;
  color: white;
  font-size: 1rem;
  cursor: pointer;
}

.warning-button {
  background: #f97316;
  margin-bottom: 12px;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

button:hover:not(:disabled) {
  background: #1d4ed8;
}

.warning-button:hover:not(:disabled) {
  background: #ea580c;
}

.session-entries ul {
  list-style: none;
  margin: 0;
  padding-left: 0;
}

.session-entries li {
  background: #f1f5f9;
  margin-bottom: 8px;
  border-radius: 10px;
  padding: 12px 14px;
}

.empty {
  color: #555;
}

@media (max-width: 640px) {
  main {
    margin: 8px;
    border-radius: 0;
    box-shadow: none;
  }

  .product-list {
    grid-template-columns: 1fr;
  }

  button {
    font-size: 1.05rem;
  }

  .warning-button {
    margin-right: 0;
  }
}