/* Обновленный CSS для страницы урока в стиле Феномен (lesson-page.css) */

/* Брендовые цвета Феномен Шахматная школа */
:root {
  --fenomen-blue: #249efa; /* Голубой */
  --fenomen-yellow: #ffdb58; /* Желтый */
  --fenomen-darkgray: #202020; /* Темно-серый */
  --fenomen-lightgray: #eaeaea; /* Светло-серый */
  --fenomen-white: #ffffff;
  --fenomen-accent: #c52f2f; /* Акцентный красный для ходов */

  /* Дополнительные свойства */
  --header-height: 70px;
  --transition-speed: 0.3s;
  --border-radius: 8px;
  --sidebar-max-height: 500px; /* Для мобильного меню */
}

/* =================== БАЗОВЫЕ СТИЛИ =================== */
body {
  font-family: "Cera Round Pro", "Roboto", sans-serif;
  color: var(--fenomen-darkgray);
  background-color: var(--fenomen-white);
  line-height: 1.6;
}

/* Стилизация выделения текста */
::selection {
  background-color: rgba(36, 158, 250, 0.2);
}

/* =================== СТРУКТУРА УРОКА =================== */
.lesson-container {
  display: flex;
  margin: 1.5rem auto 2rem;
  max-width: 1400px;
  padding: 0 1.5rem;
  align-items: flex-start;
  gap: 1.5rem;
}

.lesson-section {
  margin-bottom: 1rem;
  position: relative;
}

.subsection {
  margin-bottom: 0.75rem;
}

/* =================== БОКОВАЯ НАВИГАЦИЯ =================== */
.lesson-sidebar {
  width: 260px;
  flex-shrink: 0;
  background-color: var(--fenomen-white);
  border-radius: var(--border-radius);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  margin-right: 1.5rem;
  position: sticky;
  top: calc(var(--header-height) + 10px);
  align-self: flex-start;
  max-height: calc(100vh - 100px);
  max-height: calc(100dvh - 100px);
  overflow-y: auto;
  transition: top var(--transition-speed) ease;
  padding-bottom: 1rem;
  border: 1px solid var(--fenomen-lightgray);
  z-index: 100;
}

.sidebar-header {
  padding: 1rem;
  border-bottom: 1px solid var(--fenomen-lightgray);
  background-color: var(--fenomen-blue);
  color: var(--fenomen-white);
  border-radius: var(--border-radius) var(--border-radius) 0 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sidebar-header h3 {
  margin-bottom: 0;
  font-size: 1.1rem;
  font-weight: bold;
}

.sidebar-toggle-mobile {
  display: none;
  background: none;
  border: none;
  width: 30px;
  height: 30px;
  cursor: pointer;
  position: relative;
  z-index: 1001;
}

.sidebar-toggle-mobile span {
  display: block;
  width: 18px;
  height: 2px;
  background-color: var(--fenomen-white);
  margin: 4px auto;
  transition: transform 0.3s, opacity 0.3s;
}

/* Анимация гамбургер-меню */
.sidebar-toggle-mobile.active span:nth-child(1) {
  transform: rotate(-45deg) translate(-4px, 4px);
}

.sidebar-toggle-mobile.active span:nth-child(2) {
  opacity: 0;
}

.sidebar-toggle-mobile.active span:nth-child(3) {
  transform: rotate(45deg) translate(-4px, -4px);
}

/* Стили для навигации в сайдбаре */
.sidebar-navigation {
  padding: 1rem;
}

.sidebar-navigation ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
}

.sidebar-navigation ul ul {
  padding-left: 1.2rem;
  margin-top: 0.25rem;
  margin-bottom: 0.5rem;
  position: relative;
}

.sidebar-navigation ul ul::before {
  content: "";
  position: absolute;
  left: 0.3rem;
  top: 0;
  bottom: 0;
  width: 1px;
  background-color: var(--fenomen-lightgray);
}

.sidebar-navigation li {
  margin-bottom: 0.25rem;
}

.sidebar-navigation a {
  display: block;
  padding: 0.4rem 0.5rem;
  color: var(--fenomen-darkgray);
  font-size: 0.9rem;
  border-radius: 4px;
  transition: all var(--transition-speed) ease;
  text-decoration: none;
}

.sidebar-navigation a:hover {
  background-color: rgba(36, 158, 250, 0.1);
  color: var(--fenomen-blue);
}

.sidebar-navigation a.active {
  background-color: var(--fenomen-blue);
  color: var(--fenomen-white);
  font-weight: 500;
}

/* Стили для субменю на мобильных */
.submenu-item {
  padding-left: 20px;
  position: relative;
}

.submenu-item a {
  color: #555;
  font-size: 0.9em;
}

.submenu-item::before {
  content: "→";
  position: absolute;
  left: 5px;
  top: 8px;
  color: #777;
  font-size: 0.8em;
}

/* =================== ОСНОВНОЙ КОНТЕНТ =================== */
.lesson-content {
  flex: 1;
  background-color: var(--fenomen-white);
  border-radius: var(--border-radius);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
  padding: 1.5rem;
  border: 1px solid var(--fenomen-lightgray);
}

.lesson-header {
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--fenomen-lightgray);
  padding-bottom: 1rem;
}

/* Хлебные крошки */
.breadcrumbs {
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  color: #777;
}

.breadcrumbs a {
  color: #777;
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--fenomen-blue);
}

/* Основной заголовок */
h1 {
  font-size: 2.25rem;
  margin-bottom: 0.75rem;
  font-weight: bold;
  color: var(--fenomen-darkgray);
}

/* Метаданные урока */
.lesson-meta-header {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: #777;
}

.author {
  display: flex;
  align-items: center;
}

.date {
  color: #777;
}

/* Вводный текст */
.introduction-text {
  font-size: 1.15rem;
  color: var(--fenomen-darkgray);
  border-left: 3px solid var(--fenomen-blue);
  padding-left: 1rem;
  margin-bottom: 1.5rem;
}

/* Заголовки разделов */
h2 {
  font-size: 1.6rem;
  margin-bottom: 0.75rem;
  color: var(--fenomen-darkgray);
  font-weight: bold;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 50px;
  height: 3px;
  background-color: var(--fenomen-blue);
}

h3 {
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
  color: var(--fenomen-darkgray);
  font-weight: bold;
}

/* Параграфы */
p {
  margin-bottom: 0.75rem;
}

/* =================== ШАХМАТНЫЕ ДИАГРАММЫ =================== */
.chess-diagram {
  position: relative;
  width: 100%;
  max-width: 700px;
  margin: 1rem auto;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  background-color: var(--fenomen-lightgray);
}

.chess-diagram iframe {
  width: 100%;
  height: 500px;
  border: none;
  display: block;
}

/* Описания диаграмм и примеров */
.diagram-caption,
.example-description {
  text-align: center;
  font-size: 0.95rem;
  color: var(--fenomen-darkgray);
  margin-top: 0.5rem;
  margin-bottom: 0.75rem;
  padding: 0 1rem;
}

/* =================== ШАХМАТНЫЕ ХОДЫ =================== */
/* Стили для шахматных ходов и последовательностей */
.chess-move {
  font-weight: 700;
  color: var(--fenomen-accent);
  font-family: "Roboto Mono", monospace;
  padding: 0 3px;
  background-color: rgba(255, 245, 224, 0.6);
  border-radius: 3px;
  display: inline-block;
  margin: 0 2px;
}

.move-sequence {
  background-color: #f8f3e8;
  padding: 8px 12px;
  border-left: 3px solid var(--fenomen-accent);
  margin: 15px 0;
  border-radius: 0 4px 4px 0;
  font-family: "Roboto Mono", monospace;
  line-height: 1.6;
}

.move-description {
  margin-top: 8px;
  font-style: italic;
  color: #555;
  font-size: 0.95em;
}

/* Стили для важных заметок */
.important-note {
  background-color: #f0f7ff;
  border-left: 4px solid #3498db;
  padding: 12px 15px;
  margin: 20px 0;
  border-radius: 0 4px 4px 0;
}

.important-note h4 {
  margin-top: 0;
  color: #3498db;
}

/* =================== КОМПОНЕНТЫ УРОКА =================== */
/* Видео-контейнер */
.video-container {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: var(--border-radius);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  margin-bottom: 1.5rem;
}

.video-container iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

.video-caption {
  text-align: center;
  font-size: 0.9rem;
  color: #555;
  margin-top: 0.5rem;
}

/* Стилизация для нумерованных списков */
.numbered-list {
  counter-reset: item;
  list-style-type: none;
  padding-left: 0;
  margin: 1rem 0;
}

.numbered-list li {
  counter-increment: item;
  margin-bottom: 0.5rem;
  position: relative;
  padding-left: 2rem;
}

.numbered-list li::before {
  content: counter(item);
  background-color: var(--fenomen-blue);
  color: var(--fenomen-white);
  font-weight: 500;
  font-size: 0.8rem;
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  text-align: center;
  line-height: 1.5rem;
  position: absolute;
  left: 0;
  top: 0.15rem;
}

/* Исключаем вложенные <li> внутри <ul> из CSS нумерации */
.numbered-list ul li {
  counter-increment: none;
  padding-left: 0;
}

.numbered-list ul li::before {
  display: none;
}

.inline-link {
  color: var(--fenomen-blue);
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px dashed rgba(36, 158, 250, 0.7);
  padding-bottom: 1px;
  transition: color var(--transition-speed) ease, border-color var(--transition-speed) ease,
    background-color var(--transition-speed) ease;
}

.inline-link:hover,
.inline-link:focus {
  color: #1e7fc9;
  border-bottom-color: currentColor;
  background-color: rgba(36, 158, 250, 0.08);
}

.inline-link:focus-visible {
  outline: 2px solid rgba(36, 158, 250, 0.35);
  outline-offset: 2px;
}

/* Итоговый блок */
.summary-box {
  background-color: var(--fenomen-lightgray);
  border-radius: var(--border-radius);
  padding: 1.25rem;
  margin: 1rem 0;
  position: relative;
  overflow: hidden;
}

.summary-box::after {
  content: "";
  position: absolute;
  top: -30px;
  right: -30px;
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background-color: var(--fenomen-yellow);
  opacity: 0.2;
}

.summary-box p {
  font-weight: 500;
  margin-bottom: 0.5rem;
}

/* Домашнее задание */
.homework-container {
  background-color: var(--fenomen-lightgray);
  border-radius: var(--border-radius);
  padding: 1.25rem;
  margin: 1rem 0;
}

.homework-intro {
  margin-bottom: 1rem;
}

.homework-links {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.homework-link {
  display: flex;
  align-items: center;
  padding: 0.75rem;
  background-color: var(--fenomen-white);
  border-radius: var(--border-radius);
  text-decoration: none;
  color: var(--fenomen-darkgray);
  font-weight: 500;
  transition: all var(--transition-speed) ease;
}

.homework-link:hover {
  background-color: rgba(36, 158, 250, 0.05);
  transform: translateY(-2px);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.homework-link i {
  margin-right: 0.75rem;
  color: var(--fenomen-blue);
}

/* Форма обратной связи */
.lesson-feedback {
  margin-top: 2rem;
  margin-bottom: 1.5rem;
}

.feedback-form {
  background-color: var(--fenomen-lightgray);
  padding: 1.25rem;
  border-radius: var(--border-radius);
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.3rem;
  font-weight: 500;
}

.form-group textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid #ddd;
  border-radius: var(--border-radius);
  resize: vertical;
  font-family: inherit;
}

.form-group textarea:focus {
  border-color: var(--fenomen-blue);
  outline: none;
  box-shadow: 0 0 0 2px rgba(36, 158, 250, 0.2);
}

/* Кнопки "Поделиться" */
.lesson-share {
  margin-top: 2rem;
}

.share-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.share-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.5rem 1rem;
  border-radius: 50px;
  text-decoration: none;
  font-size: 0.9rem;
  transition: all var(--transition-speed) ease;
}

.share-button.vk {
  background-color: #4c75a3;
  color: white;
}

.share-button.telegram {
  background-color: #0088cc;
  color: white;
}

.share-button.whatsapp {
  background-color: #25d366;
  color: white;
}

.share-button i {
  margin-right: 0.5rem;
}

.share-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

/* Кнопки */
.btn {
  display: inline-block;
  padding: 0.6rem 1.5rem;
  background-color: var(--fenomen-blue);
  color: var(--fenomen-white);
  font-weight: 500;
  border: none;
  border-radius: 50px;
  cursor: pointer;
  transition: all var(--transition-speed) ease;
  text-decoration: none;
  text-align: center;
}

.btn:hover {
  background-color: #1e8ae0;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

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

.btn-secondary {
  background-color: var(--fenomen-white);
  color: var(--fenomen-blue);
  border: 1px solid var(--fenomen-blue);
}

.btn-secondary:hover {
  background-color: var(--fenomen-blue);
  color: var(--fenomen-white);
}

.btn-small {
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
}

/* Брендовые декоративные элементы */
.brand-element {
  position: absolute;
  z-index: 0;
  opacity: 0.3;
}

.brand-circle {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background-color: var(--fenomen-yellow);
}

.brand-cross {
  width: 60px;
  height: 60px;
  background: linear-gradient(var(--fenomen-blue), var(--fenomen-blue)) center
      center/10px 100% no-repeat,
    linear-gradient(var(--fenomen-blue), var(--fenomen-blue)) center center/100%
      10px no-repeat;
  transform: rotate(45deg);
}

/* =================== АДАПТИВНОСТЬ =================== */
@media (max-width: 992px) {
  .lesson-container {
    flex-direction: column;
  }

  .lesson-sidebar {
    width: 100%;
    margin-right: 0;
    margin-bottom: 1.5rem;
    position: sticky;
    top: var(--header-height);
    z-index: 100;
    max-height: none;
    border-radius: var(--border-radius);
  }

  .sidebar-toggle-mobile {
    display: block;
  }

  .sidebar-navigation {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background-color: var(--fenomen-white);
    border-bottom-left-radius: var(--border-radius);
    border-bottom-right-radius: var(--border-radius);
    border: 1px solid var(--fenomen-lightgray);
    border-top: none;
    padding: 0;
  }

  .sidebar-navigation.active {
    max-height: var(--sidebar-max-height);
    overflow-y: auto;
    padding: 1rem;
  }

  h1 {
    font-size: 1.75rem;
  }

  h2 {
    font-size: 1.4rem;
  }

  h3 {
    font-size: 1.2rem;
  }

  .chess-diagram iframe {
    height: 350px;
  }

  .chess-diagram {
    max-width: 600px;
  }

  .window-visualization {
    flex-direction: column;
    gap: 15px;
  }
}

@media (max-width: 768px) {
  .lesson-container {
    padding: 0 1rem;
  }

  .lesson-content {
    padding: 1rem;
  }

  .lesson-meta-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .chess-diagram iframe {
    height: 300px;
  }

  .chess-diagram {
    max-width: 450px;
  }

  .king-position {
    width: 100px;
    height: 100px;
  }

  .king-icon {
    font-size: 32px;
  }

  .share-buttons {
    flex-direction: column;
    align-items: stretch;
  }
}

@media (max-width: 576px) {
  h1 {
    font-size: 1.5rem;
  }

  .introduction-text {
    font-size: 1rem;
  }

  .chess-diagram iframe {
    height: 250px;
  }

  .chess-move {
    padding: 0 2px;
    margin: 0 1px;
  }

  .move-sequence {
    padding: 6px 10px;
  }

  .important-note {
    padding: 10px 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
}