:root {
  --bg: #f1f4f9;
  --card: #fff;
  --line: #e2e8f0;
  --text: #1e293b;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --danger: #dc2626;
  --radius: 10px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
}

.page {
  max-width: 1080px;
  margin: 0 auto;
  padding: 24px 18px 48px;
}

.page-title {
  margin: 0 0 6px;
  font-size: 26px;
}

.page-desc {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 14px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin-bottom: 18px;
}

.card h2 {
  margin: 0 0 14px;
  font-size: 17px;
  border-left: 4px solid var(--primary);
  padding-left: 10px;
}

.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 16px;
  align-items: flex-end;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.field label {
  font-size: 13px;
  color: var(--muted);
}

.field select,
.field input[type="text"] {
  min-width: 140px;
  padding: 8px 11px;
  border: 1px solid var(--line);
  border-radius: 8px;
  font-size: 14px;
  background: #fff;
}

.field select:disabled {
  background: #f8fafc;
  color: var(--muted);
}

.btn {
  padding: 8px 18px;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  cursor: pointer;
  font-weight: 600;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-primary:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn-sm {
  padding: 5px 12px;
  font-size: 13px;
}

.hint {
  font-size: 12px;
  color: var(--muted);
  margin-top: 10px;
}

.empty-hint {
  color: var(--muted);
  font-size: 14px;
  padding: 20px;
  text-align: center;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
}

.school-block {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 14px;
  background: #fafbfc;
}

.school-head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.school-head h3 {
  margin: 0;
  font-size: 18px;
}

.school-meta {
  font-size: 13px;
  color: var(--muted);
}

.grade-block {
  margin: 12px 0 12px 12px;
  padding: 12px 14px;
  border-left: 3px solid #94a3b8;
  background: #fff;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.grade-title {
  font-weight: 700;
  margin-bottom: 10px;
  font-size: 15px;
}

.class-block {
  margin: 10px 0 10px 10px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.class-title {
  font-weight: 600;
  margin-bottom: 8px;
}

.students-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin-top: 8px;
}

.students-table th,
.students-table td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
}

.students-table th {
  background: #f1f5f9;
  color: var(--muted);
  font-weight: 600;
}

.add-student-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: flex-end;
  margin-top: 10px;
}

.add-student-row .field input {
  min-width: 120px;
}

.err {
  color: var(--danger);
  font-size: 13px;
  margin-top: 6px;
}

.err.school-msg-success {
  color: #15803d;
}

@media (max-width: 640px) {
  .field select,
  .field input[type="text"] {
    min-width: 100%;
  }
}