body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background: #eef2fa;
  margin: 0;
  padding: 0;
}
.container {
  max-width: 720px;
  margin: 32px auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 4px 24px rgba(60,80,120,0.13);
  padding: 28px 32px 32px 32px;
}
h1, h2, h3 {
  color: #354875;
  margin-top: 0;
}
nav {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}
.tab-btn {
  background: #dee6fa;
  color: #354875;
  border: none;
  padding: 10px 18px;
  border-radius: 5px 5px 0 0;
  font-size: 1em;
  cursor: pointer;
  transition: background 0.2s;
}
.tab-btn.active, .tab-btn:hover {
  background: #4a6ef5;
  color: #fff;
}
.tab-content {
  display: none;
}
.tab-content.active {
  display: block;
}
.section {
  margin-bottom: 24px;
}
input[type="text"], input[type="number"], input[type="date"], select {
  padding: 7px 9px;
  margin-right: 6px;
  border: 1px solid #a8b4cb;
  border-radius: 6px;
  font-size: 15px;
}
button {
  background: #4a6ef5;
  color: #fff;
  border: none;
  padding: 8px 16px;
  margin: 2px 0;
  border-radius: 6px;
  font-size: 15px;
  cursor: pointer;
  transition: background 0.2s;
}
button[title] {
  background: #e74c3c;
  padding: 8px 10px;
}
button:hover {
  background: #3957c3;
}
ul {
  list-style: none;
  padding-left: 0;
}
#studentList li,
#attendanceList li {
  display: flex;
  align-items: center;
  padding: 3px 0;
}
#studentList li span {
  flex: 1;
}
#studentList li button,
#attendanceList li button {
  background: #e74c3c;
  margin-left: 6px;
  padding: 2px 8px;
}
.attendance-checkbox {
  margin-right: 8px;
  accent-color: #4a6ef5;
  width: 18px;
  height: 18px;
}
#result {
  margin-top: 12px;
  font-size: 22px;
  color: #3957c3;
  min-height: 32px;
  font-weight: bold;
}
#history {
  margin-top: 20px;
}
#historyList {
  font-size: 14px;
  color: #444;
  max-height: 80px;
  overflow-y: auto;
}
#scoresForm {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 350px;
}
#scoresForm label {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
#scoresForm input[type="number"] {
  width: 80px;
}
#seatingChart {
  margin-top: 20px;
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
}
.table-box {
  background: #f3f6ff;
  border: 2px solid #4a6ef5;
  border-radius: 12px;
  min-width: 150px;
  min-height: 70px;
  padding: 10px 14px;
  margin-bottom: 10px;
  text-align: center;
  box-shadow: 0 2px 6px rgba(60,80,120,0.06);
  flex: 1 1 180px;
}
.table-box h4 {
  margin-top: 0;
  color: #3957c3;
  font-size: 1.1em;
}
.table-box ul {
  padding: 0;
  margin: 0;
}
.table-box li.high-performer {
  color: #166241;
  font-weight: bold;
}
.table-box li.low-performer {
  color: #c0392b;
}
@media (max-width: 800px) {
  .container { padding: 14px 3vw; }
  #seatingChart { flex-direction: column; }
}