/* === Базові стилі === */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-danger: #dc2626;
  --color-danger-hover: #b91c1c;
  --color-success: #16a34a;
  --color-border: #e5e7eb;
  --color-bg: #f9fafb;
  --color-bg-header: #f3f4f6;
  --color-text: #1f2937;
  --color-text-light: #6b7280;

  /* Кольори типів занять */
  --color-lecture: #dbeafe;
  --color-practice: #dcfce7;
  --color-lab: #fef3c7;

  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --border-radius: 6px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
}

body {
  font-family: var(--font-family);
  font-size: 14px;
  color: var(--color-text);
  background: var(--color-bg);
}

/* === Шапка === */
.header {
  background: white;
  border-bottom: 1px solid var(--color-border);
  padding: 16px 24px;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header h1 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
}

.header h1 .version {
  font-size: 12px;
  font-weight: 400;
  color: var(--color-text-light);
  margin-left: 8px;
}

.controls {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

/* === Кнопки === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  background: white;
  color: var(--color-text);
  cursor: pointer;
  transition: all 0.15s ease;
}

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

.btn-primary {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

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

.btn-secondary {
  background: white;
  border-color: var(--color-border);
}

.btn-danger {
  background: white;
  border-color: var(--color-danger);
  color: var(--color-danger);
}

.btn-danger:hover {
  background: var(--color-danger);
  color: white;
}

/* Перемикач тижня */
.week-toggle {
  display: flex;
  gap: 0;
}

.btn-week {
  border-radius: 0;
  margin: 0;
}

.btn-week:first-child {
  border-radius: var(--border-radius) 0 0 var(--border-radius);
}

.btn-week:last-child {
  border-radius: 0 var(--border-radius) var(--border-radius) 0;
  margin-left: -1px;
}

.btn-week.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
  z-index: 1;
}

/* === Фільтри === */
.filters {
  display: flex;
  align-items: center;
  gap: 12px;
}

.filter-select {
  padding: 8px 12px;
  font-size: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  background: white;
  min-width: 180px;
  cursor: pointer;
}

.filter-select:focus {
  outline: none;
  border-color: var(--color-primary);
}

.actions {
  display: flex;
  gap: 8px;
  margin-left: auto;
}

/* === Контейнер розкладу === */
.main {
  padding: 24px;
}

.schedule-container {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  overflow: auto;
  max-height: calc(100vh - 140px);

  /* Firefox */
  scrollbar-width: auto;
  scrollbar-color: #6b7280 #d1d5db;
}

/* WebKit (Chrome, Safari, Edge) */
.schedule-container::-webkit-scrollbar {
  width: 16px;
  height: 16px;
}

.schedule-container::-webkit-scrollbar-track {
  background: #d1d5db;
}

.schedule-container::-webkit-scrollbar-thumb {
  background: #6b7280;
  border-radius: 8px;
  border: 3px solid #d1d5db;
}

.schedule-container::-webkit-scrollbar-thumb:hover {
  background: #4b5563;
}

.schedule-container::-webkit-scrollbar-corner {
  background: #d1d5db;
}

/* === Таблиця розкладу === */
.schedule-table {
  border-collapse: collapse;
}

/* Шапка таблиці */
.schedule-table thead {
  position: sticky;
  top: 0;
  z-index: 10;
}

.schedule-table th {
  background: var(--color-bg-header);
  padding: 10px 8px;
  font-weight: 600;
  text-align: center;
  border-bottom: 2px solid var(--color-border);
  border-right: 1px solid var(--color-border);
}

.th-day {
  width: 90px;
  min-width: 90px;
  position: sticky;
  left: 0;
  z-index: 11;
}

.th-period {
  width: 50px;
  min-width: 50px;
  position: sticky;
  left: 90px;
  z-index: 11;
}

.th-group {
  min-width: 160px;
  width: 160px;
}

/* Комірка дня */
.td-day {
  background: #e5e7eb;
  padding: 8px;
  font-weight: 600;
  font-size: 13px;
  text-align: center;
  vertical-align: middle;
  border-right: 1px solid var(--color-border);
  border-bottom: 2px solid #d1d5db;
  position: sticky;
  left: 0;
  z-index: 5;
}

/* Комірка номера пари */
.td-period {
  background: var(--color-bg-header);
  padding: 8px;
  font-weight: 700;
  font-size: 16px;
  text-align: center;
  vertical-align: middle;
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  left: 90px;
  z-index: 5;
}

/* Комірка розкладу */
.td-cell {
  min-width: 160px;
  width: 160px;
  min-height: 70px;
  height: 70px;
  padding: 4px;
  border-bottom: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
  cursor: pointer;
  transition: background 0.15s ease;
  vertical-align: top;
}

.td-cell:hover {
  background: var(--color-bg);
}

.td-cell.drag-over {
  background: #dbeafe;
  outline: 2px dashed var(--color-primary);
  outline-offset: -2px;
}

/* Роздільник днів */
.schedule-row.day-separator td {
  border-bottom: 2px solid #d1d5db;
}

.schedule-row.day-separator .td-period {
  border-bottom: 2px solid #d1d5db;
}

/* Картка заняття */
.lesson-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 6px 8px;
  font-size: 12px;
  cursor: grab;
  transition: box-shadow 0.15s ease;
  height: 100%;
}

.lesson-card:hover {
  box-shadow: var(--shadow);
}

.lesson-card.dragging {
  opacity: 0.5;
  cursor: grabbing;
}

.lesson-card.type-lecture {
  background: var(--color-lecture);
  border-color: #93c5fd;
}

.lesson-card.type-practice {
  background: var(--color-practice);
  border-color: #86efac;
}

.lesson-card.type-lab {
  background: var(--color-lab);
  border-color: #fcd34d;
}

.lesson-subject {
  font-weight: 600;
  margin-bottom: 2px;
  line-height: 1.2;
}

.lesson-teacher {
  color: var(--color-text-light);
  margin-bottom: 2px;
}

.lesson-meta {
  font-size: 11px;
  color: var(--color-text-light);
}

/* Підсвітка при фільтрі */
.lesson-card.highlighted {
  box-shadow: 0 0 0 2px var(--color-primary);
}

.lesson-card.dimmed {
  opacity: 0.4;
}

/* === Модальне вікно === */
.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal.hidden {
  display: none;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
}

.modal-content {
  position: relative;
  background: white;
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 440px;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--color-border);
}

.modal-header h2 {
  font-size: 18px;
  font-weight: 600;
}

.modal-close {
  background: none;
  border: none;
  font-size: 24px;
  color: var(--color-text-light);
  cursor: pointer;
  padding: 0;
  line-height: 1;
}

.modal-close:hover {
  color: var(--color-text);
}

.modal-form {
  padding: 20px;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-weight: 500;
  margin-bottom: 6px;
}

.form-input {
  width: 100%;
  padding: 10px 12px;
  font-size: 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.modal-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--color-border);
}

.modal-actions-right {
  display: flex;
  gap: 8px;
}

/* === Сповіщення (Toast) === */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #1f2937;
  color: white;
  padding: 12px 20px;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
  z-index: 2000;
  animation: toast-in 0.3s ease;
}

.toast.hidden {
  display: none;
}

.toast.success {
  background: var(--color-success);
}

.toast.error {
  background: var(--color-danger);
}

@keyframes toast-in {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* === Стан завантаження === */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  color: var(--color-text-light);
}

.loading::after {
  content: '';
  width: 24px;
  height: 24px;
  margin-left: 12px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}