body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  background-color: #f4f7f9;
  color: #333;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.container {
  background-color: #fff;
  border-radius: 8px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
  padding: 30px;
  width: 90%;
  max-width: 900px;
}

h1, h2 {
  color: #007bff;
  text-align: center;
  margin-bottom: 20px;
}

h2 {
  margin-top: 0;
}

.hidden {
  display: none;
}

/* Стили для формы входа */
#login-form {
  background-color: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  width: 300px;
  margin: 20px auto;
}

#login-form h2 {
  margin-top: 0;
}

#login-form label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

#login-form input[type="text"],
#login-form input[type="password"] {
  width: 100%;
  padding: 10px;
  margin-bottom: 15px;
  border: 1px solid #ddd;
  border-radius: 4px;
  box-sizing: border-box;
  font-size: 16px;
}

#login-form button {
  background-color: #007bff;
  color: white;
  padding: 10px 15px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
  width: 100%;
  transition: background-color 0.3s ease;
}

#login-form button:hover {
  background-color: #0056b3;
}

/* Общие стили для панелей */
#teacher-panel, #student-panel {
  margin-top: 20px;
}

#teacher-panel h2, #student-panel h2 {
  text-align: left;
  margin-bottom: 15px;
}

/* Стили для кнопок */
button {
  background-color: #28a745;
  color: white;
  padding: 10px 15px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
  transition: background-color 0.3s ease;
  margin-right: 10px;
}

button:hover {
  background-color: #1e7e34;
}

/* Стили для таблиц */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 20px;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
}

th, td {
  border: 1px solid #ddd;
  padding: 12px 15px;
  text-align: left;
}

th {
  background-color: #f0f0f0;
  font-weight: bold;
  text-align: center;
}

td {
  text-align: center;
}

tbody tr:nth-child(even) {
  background-color: #f9f9f9;
}

tbody tr:hover {
  background-color: #e0e0e0;
}

.edit-cell input {
  width: 60px;
  padding: 8px;
  text-align: center;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-sizing: border-box;
}

/* Стили для редактора оценок */
#student-grades-editor {
  margin-top: 10px;
  border: 1px solid #ccc;
  border-radius: 8px;
  padding: 20px;
  position: absolute;
  background-color: white;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  z-index: 10;
}

#student-grades-editor h3 {
  margin-top: 0;
  margin-bottom: 15px;
  color: #333;
}

#student-grades-editor label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

#student-grades-editor select {
  width: 100%;
  padding: 10px;
  margin-bottom: 15px;
  border: 1px solid #ddd;
  border-radius: 4px;
  box-sizing: border-box;
  font-size: 16px;
}

#student-grades-editor button {
  margin-top: 10px;
  margin-right: 0;
}

#session-grades {
  margin-bottom: 20px;
}

.subject-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.delete-subject-button {
  background: none;
  border: none;
  color: #dc3545;
  font-size: 16px;
  cursor: pointer;
  padding: 0;
}

.delete-subject-button:hover {
  color: #bd2130;
}

/* Стили для информации о студенте */
#student-info {
  background-color: #e8f0fe;
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 20px;
}

#student-info p {
  margin: 5px 0;
}

#student-info strong {
  font-weight: bold;
}

/* Стили для модального окна */
.modal {
  position: fixed;
  z-index: 1;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-content {
  background-color: #fefefe;
  padding: 30px;
  border-radius: 8px;
  border: 1px solid #888;
  width: 80%;
  max-width: 500px;
  position: relative;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.close-button {
  color: #aaa;
  float: right;
  font-size: 28px;
  font-weight: bold;
  cursor: pointer;
}

.close-button:hover,
.close-button:focus {
  color: black;
  text-decoration: none;
  cursor: pointer;
}

#add-student-modal label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

#add-student-modal input[type="text"],
#add-student-modal input[type="password"] {
  width: 100%;
  padding: 10px;
  margin-bottom: 15px;
  border: 1px solid #ddd;
  border-radius: 4px;
  box-sizing: border-box;
  font-size: 16px;
}

#add-student-modal button {
  margin-top: 15px;
  margin-right: 0;
}

#add-student-errors {
  color: #dc3545;
  margin-bottom: 10px;
}

#add-subject-dialog {
  position: absolute;
  top: 0;
  left: 100%;
  margin-left: 10px;
  background-color: white;
  padding: 20px;
  border: 1px solid #ccc;
  border-radius: 4px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  z-index: 11;
  display: none;
  flex-direction: column;
  gap: 10px;
  width: 300px;
}

#add-subject-dialog label {
  display: block;
  font-weight: bold;
}

#add-subject-dialog input[type="text"] {
  padding: 8px;
  border: 1px solid #ddd;
  border-radius: 4px;
}

#add-subject-dialog button {
  padding: 8px 12px;
  cursor: pointer;
  border: none;
  border-radius: 4px;
}

#add-subject-dialog button:first-of-type {
  background-color: #28a745;
  color: white;
}

#add-subject-dialog button:last-of-type {
  background-color: #f8f9fa;
  border: 1px solid #dee2e6;
}

#add-subject-dialog button {
  padding: 8px 12px;
  cursor: pointer;
  border: none;
  border-radius: 4px;
  margin-right: 5px;
}

#add-subject-dialog button:first-of-type {
  background-color: #28a745;
  color: white;
}

#add-subject-dialog button:nth-of-type(2) {
  background-color: #dc3545;
  color: white; 
  border: 1px solid #dc3545;
}

#add-subject-dialog div {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 10px;
}

#students-table table tr.student-row {
  transition: background-color 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
}

#students-table table tr.student-row:hover {
  background-color: #f0f8ff; /* Светлый цвет заливки при наведении */
  transform: scale(1.05); /* Небольшое увеличение масштаба */
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2); /* Небольшая тень для эффекта "поднятия" */
  cursor: pointer; /* Изменение курсора на "указатель" */
}