body {
  font-family: Arial, sans-serif;
  background: #f5f6fa;
  margin: 0;
  padding: 0;
}
.container {
  width: 95%;
  max-width: 1100px;
  margin: 20px auto;
  background: white;
  padding: 20px;
  border-radius: 8px;
}
h1,h2,h3 {
  margin-top: 0;
}
nav a {
  margin-right: 12px;
  text-decoration: none;
  color: #2c3e50;
}
.btn {
  display: inline-block;
  padding: 6px 12px;
  background: #0984e3;
  color: white;
  border-radius: 5px;
  text-decoration: none;
  font-size: 14px;
}
.btn-danger { background: #d63031; }
.btn-green { background: #00b894; }
.btn-gray { background: gray; }

.table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 10px;
}
.table th, .table td {
  border: 1px solid #ddd;
  padding: 8px;
}
.table th { background: #ecf0f1; }

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.slot-box {
  border: 1px solid #ddd;
  padding: 8px;
  margin-bottom: 6px;
  border-radius: 5px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.session-header {
  padding: 6px;
  font-weight: bold;
  color: black;
  margin-top: 12px;
  border-radius: 4px;
}
.morning { background: #ffeaa7; }
.day { background: #81ecec; }
.daynight { background: #55efc4; }

.notice {
  padding: 8px;
  margin: 10px 0;
  background: #dfe6e9;
  border-left: 4px solid #0984e3;
}
.error {
  padding: 8px;
  margin: 10px 0;
  background: #fab1a0;
  border-left: 4px solid #d63031;
}