:root {
  --primary-dark: #1a365d;
  --primary: #2c5282;
  --primary-light: #4299e1;
  --accent: #e53e3e;
  --text-light: #f7fafc;
  --text-dark: #2d3748;
  --background: #fff;
  --border: #cbd5e0;
  --shadow: rgba(0, 0, 0, 0.1);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

/****ul-li marker styles*****/
.section-content ul li {
  list-style-type: none;
  position: relative;
  padding-left: 0.75rem;
  margin-bottom: 0.5rem;
}

.section-content ul li::marker {
  content: "▶";
  color: var(--primary);
  font-size: 0.72em;
  margin-right: 0.5rem;
}

.section-content ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65em;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 8px solid var(--b1);
  transition: border-left-color 0.3s ease;
}

.venue-content ul li {
  list-style-type: none;
  position: relative;
  padding-left: 0.75rem;
  margin-bottom: 0.5rem;
}

.venue-content ul li::marker {
  content: "▶";
  color: var(--primary);
  font-size: 0.72em;
  margin-right: 0.5rem;
}

.venue-content ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65em;
  transform: translateY(-50%);
  width: 0;
  height: 0;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 8px solid var(--b1);
  transition: border-left-color 0.3s ease;
}

/**************************/

body {
  color: var(--text-dark);
  background-color: var(--background);
  line-height: 1.6;
  height: 100%;
}

/* Header */
header {
  top: 0;
  left: 0;
  width: 100%;
  background-color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 2px 10px var(--shadow);
  z-index: 1000;
}

.header-container {
  display: flex;
  align-items: center;
  opacity: 0;
  padding: 20px 30px;
  animation-delay: 0.6s;
  transform: translateY(-20px);
  transition: all 0.8s ease-in-out;
  justify-content: space-between;
}

.conference-logo {
  opacity: 1;
  width: 25%;
  transition: all 0.3s ease-in-out;
}

.conference-logo:hover {
  cursor: pointer;
  opacity: 0.8;
}

/* Правая часть хедера */
.header-right {
  display: flex;
  align-items: center;
  gap: 20px;
}

.lang-switcher {
  display: flex;
  align-items: center;
  white-space: nowrap;
  gap: 16px;
}

.lang-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-weight: 700;
  letter-spacing: 2.5px;
  color: var(--primary-dark);
  /* Темный цвет для доступных кнопок */
  transition: all 0.3s ease;
  font-size: 1.4rem;
  /* Нормальный размер */
  padding: 5px 8px;
  opacity: 1;
  /* Полная непрозрачность */
}

.lang-btn.active {
  color: #a0aec0;
  font-size: 0.85rem;
  opacity: 0.7;
  cursor: default;
  pointer-events: none;
}

.lang-btn:hover {
  color: var(--primary-light);
  opacity: 0.9;
}

.lang-btn.active:hover {
  color: #a0aec0;
  background-color: transparent;
}

.lang-separator {
  color: #e2e8f0;
  font-size: 0.9rem;
}

/* Кнопка бургер-меню */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--primary-dark);
  padding: 5px;
  transition: color 0.3s;
}

.mobile-menu-btn:hover {
  color: var(--primary-light);
}

/* Чекбокс для управления меню */
#nav-toggle {
  display: none;
}

/* Hero Section */
.hero {
  position: relative;
  height: 70vh;
  overflow: hidden;
  opacity: 0;
  transition: opacity 1.5s ease;
  animation-delay: 0.6s;
}

.slider {
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
  width: 100%;
  height: 115%;
  z-index: 1;
  transition: opacity 0.5s ease-in-out;
}

.slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  transition: opacity 1s ease-in-out;
  background-size: cover;
  background-position: center;
}

.slide.active {
  opacity: 1;
}

.slide::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(95deg, rgba(0, 0, 0, 0.6) 0%);
}

.hero-content {
  position: relative;
  z-index: 2;
  opacity: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  height: 100%;
  color: var(--text-light);
  transform: translateX(-40px);
  transition: all 0.8s ease-in-out;
  animation-delay: 0.6s;
  padding: 0 30px;
}

.hero-content h1 {
  font-size: 2.2rem;
  margin-bottom: 15px;
  font-weight: 600;
  font-family: Verdana, Geneva, Tahoma, sans-serif;
}

.date-location {
  max-width: 600px;
  font-size: 1.2rem;
  font-style: italic;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

/* Main Content */
main {
  padding: 60px 0;
}

section {
  margin-bottom: 3.5rem;
}

.section-header {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin-bottom: 20px;
}

.section-title {
  font-size: 1.8rem;
  font-weight: 600;
  color: var(--primary-dark);
}

.section-line {
  height: 0.05rem;
  background-color: var(--primary);
  width: 100%;
}

.section-content p {
  padding: 0;
  margin: 0;
  font-size: 1.2rem;
  line-height: 1.8;
  color: var(--text-dark);
}

.section-content h3 {
  font-style: italic;
  font-weight: 500;
  font: 1.2rem;
  color: var(--primary-dark);
}

.section-content ul {
  padding-left: 20px;
  margin-bottom: 15px;
}

.section-content li {
  margin-bottom: 8px;
}

/* Calendar */
.calendar-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 600px;
}

.calendar-list:hover {
  cursor: pointer;
}

.calendar-item {
  display: flex;
  align-items: baseline;
  padding: 12px 0;
  border-bottom: 1px solid var(--border-color, #eaeaea);
  transition: border-color 0.2s ease;
}

.calendar-item:hover {
  border-bottom-color: var(--primary, #007bff);
}

.calendar-date {
  font-weight: 600;
  min-width: 140px;
  color: var(--text-dark, #333);
  font-size: 0.95em;
  flex-shrink: 0;
  letter-spacing: 0.5px;
}

.calendar-date::after {
  content: "";
  margin: 0 12px;
  color: var(--text-light, #666);
  font-weight: 400;
}

.calendar-event {
  flex: 1;
  color: var(--text-dark, #333);
  line-height: 1.5;
}

.submission-top-block {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 30px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.submission-text-content {
  flex: 1;
  min-width: 300px;
}

.submission-text-content p {
  margin-bottom: 15px;
}

.submission-text-content p:last-child {
  margin-bottom: 0;
}

.submission-btn-wrapper {
  flex: 0 0 auto;
  align-self: flex-start;
}

.submit-paper-btn {
  display: inline-block;
  padding: 12px 28px;
  background-color: var(--primary);
  color: white;
  text-decoration: none;
  border: none;
  border-radius: 6px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  text-align: center;
  white-space: nowrap;
}

.submit-paper-btn:hover {
  background-color: #4875ac;
  color: white;
  transform: translateY(-2px);
}

/* Disabled состояние */
.submit-paper-btn:disabled,
.submit-paper-btn.disabled {
  background-color: #a0aec0;
  cursor: not-allowed;
  opacity: 0.8;
}

.submit-paper-btn:disabled:hover,
.submit-paper-btn.disabled:hover {
  background-color: #a0aec0;
  transform: none;
  box-shadow: none;
}

/* Альтернативный вариант с атрибутом disabled в HTML */
.submit-paper-btn[disabled] {
  background-color: #a0aec0;
  cursor: not-allowed;
  opacity: 0.8;
}

.submit-paper-btn[disabled]:hover {
  background-color: #a0aec0;
  transform: none;
  box-shadow: none;
}

.publication-logo {
  width: 220px;
  height: auto;
  object-fit: contain;
  flex-shrink: 0;
  opacity: 1;
}

.publication-logo:hover {
  opacity: 0.8;
  cursor: pointer;
  transition: all 0.3s ease-in-out;
}

/********VENUE********/

.venue-container {
  display: flex;
  gap: 40px;
  align-items: flex-start;
  flex-wrap: wrap;
}

.venue-map {
  flex: 1;
  width: 100%;
  height: 400px;
  border-radius: 8px;
  position: relative;
  overflow: hidden;
}

.venue-map iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.venue-content {
  flex: 1;
  min-width: 300px;
}

.venue-list {
  margin: 15px 0;
  padding-left: 1.5rem;
}

.venue-address {
  margin-top: 20px;
  padding: 15px;
  background-color: #f7fafc;
  border-left: 4px solid var(--primary);
  border-radius: 4px;
}

.venue-address strong {
  color: var(--primary-dark);
}

/* Адаптивность для мобильных устройств */
@media (max-width: 900px) {
  .venue-container {
    flex-direction: column;
    gap: 30px;
  }

  .venue-map {
    width: 100%;
    min-height: 350px;
    order: 2; /* Карта будет внизу на мобильных */
  }

  .venue-address {
    padding: 8px;
    font-size: 0.85rem;
  }

  .venue-content {
    width: 100%;
    order: 1; /* Контент будет сверху на мобильных */
  }
}

@media (max-width: 768px) {
  /* .venue-map {
    height: 300px;
  } */

  .section-content p {
    font-size: 1rem; /* Увеличиваем читаемость на мобильных */
  }

  .venue-list li {
    font-size: 1rem;
    margin-bottom: 10px;
  }
}

@media (max-width: 480px) {
  .venue-map {
    min-height: 250px;
  }

  .venue-address {
    padding: 12px;
    font-size: 0.95rem;
  }
}

/********/
.qr-contact {
  width: 140px;
  height: auto;
  object-fit: contain;
  flex-shrink: 0;
  border: 2px solid var(--border);
  border-radius: 8px;
  padding: 8px;
  background: white;
}

.web-contact-section {
  gap: 1rem;
  padding-left: 0.5rem;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.contact-icon {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary);
  color: var(--text-light);
  border-radius: 50%;
  flex-shrink: 0;
  transition: all 0.3s ease;
}

.contact-icon:hover {
  background: var(--primary-light);
  cursor: pointer;
  transform: scale(1.05);
}

.contact-label:hover {
  transition: color 0.3s ease;
  color: var(--primary-light);
}

.contact-icon svg {
  width: 20px;
  height: 20px;
  fill: var(--text-light);
}

.contact-details {
  flex: 1;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--text-dark);
  text-decoration: none;
  font-size: 1.1rem;
  transition: color 0.3s ease;
  padding: 0.5rem 0;
}

.contact-link:hover {
  color: var(--primary);
}

.contact-label {
  font-weight: 600;
  color: var(--primary-dark);
  white-space: nowrap;
}

.contact-container {
  display: flex;
  align-items: flex-start;
  gap: 2rem;
  flex-wrap: nowrap;
}

/* Footer */
footer {
  background-color: var(--primary-dark);
  color: var(--text-light);
  padding: 40px 0;
}

@media (max-width: 1200px) {
  main.container {
    padding: 0 40px 20px 40px;
  }
}

@media (max-width: 900px) {
  .hero {
    height: 52vh;
  }

  .hero-content h1 {
    font-size: 1.6rem;
  }

  main.container {
    padding: 0 40px 20px 40px;
  }

  .date-location {
    font-size: 1.1rem;
  }

  .conference-logo {
    width: 35%;
  }

  .publication-logo {
    width: 140px;
    align-self: center;
  }

  .header-right {
    gap: 15px;
  }

  .contact-container {
    gap: 1.5rem;
  }

  .qr-contact {
    width: 90px;
    padding: 5px;
  }

  .web-contact-section {
    gap: 0.6rem;
    flex-direction: row;
  }

  .contact-item {
    gap: 0.6rem;
  }

  .contact-icon {
    width: 26px;
    height: 26px;
  }

  .contact-icon svg {
    width: 13px;
    height: 13px;
  }

  .contact-link {
    font-size: 0.9rem;
    gap: 0.4rem;
  }

  .contact-label {
    font-size: 0.85rem;
  }
}

@media (max-width: 768px) {
  .header-container {
    padding: 15px 30px 15px 30px;
  }

  .header-container .container {
    padding: 0;
  }

  .hero {
    height: 62vh;
  }

  .conference-logo {
    width: 45%;
  }

  .publication-logo {
    width: 160px;
  }

  .lang-btn {
    padding: 4px 8px;
    letter-spacing: 0.5px;
    font-size: 0.8rem;
  }

  .sub-organizer-name a {
    line-height: 1;
    font-size: 0.8rem;
  }

  .lang-btn.active {
    padding: 4px 8px;
    font-size: 0.67rem;
  }

  .date-location {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .section-content p {
    font-size: 0.8rem;
  }

  .section-content h3 {
    font-size: 0.85rem;
    color: var(--primary);
  }

  .section-content li {
    font-size: 0.9rem;
  }
  .section-content ul li {
    font-size: 0.8rem;
  }

  .calendar-event {
    font-size: 0.9rem;
  }

  .calendar-item {
    flex-wrap: wrap;
  }

  .calendar-date::after {
    content: "-";
    margin: 0;
  }

  .submission-top-block {
    flex-direction: column;
    gap: 20px;
  }

  .submission-text-content {
    min-width: 100%;
    width: 100%;
  }

  .submission-btn-wrapper {
    width: 100%;
  }

  .submit-paper-btn {
    width: 100%;
    padding: 8px 10px;
  }
  .web-contact-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }

  .qr-contact {
    width: 80px;
    height: 80px;
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 5px;
    flex-shrink: 0;
  }

  .web-contact-section {
    gap: 0.5rem;
  }

  .contact-item {
    gap: 0.5rem;
  }

  .contact-icon {
    width: 24px;
    height: 24px;
  }

  .contact-icon svg {
    width: 12px;
    height: 12px;
  }

  .contact-link {
    font-size: 0.85rem;
    gap: 0.3rem;
  }

  .contact-label {
    font-size: 0.8rem;
    white-space: normal;
    min-width: auto;
  }

  .sub-organizer-item a img {
    max-width: 80%;
  }
}

@media (max-width: 480px) {
  .header-container {
    padding: 15px 20px 15px 20px;
  }

  .hero-content.container {
    padding: 10px;
  }

  .conference-logo {
    width: 60%;
  }

  .publication-logo {
    width: 100%;
    padding: 0 0 0 15px;
    max-width: 180px;
  }
  /* .springer-proceedings-wrapper {
    flex-wrap: wrap;
  } */
  /* .hero-content h1 {
    font-size: 0.4rem;
  } */

  .hero {
    height: 64vh;
  }

  /* .date-location {
    font-size: 0.4rem;
  } */

  .section-title {
    font-size: 1rem;
  }

  .lang-switcher {
    gap: 1px;
  }

  .lang-separator {
    font-size: 0.6rem;
  }

  /* .hero-content {
        height: auto;
      } */

  .lang-btn {
    padding: 3px 3px;
    letter-spacing: 1px;
    font-size: 0.9rem;
  }

  .lang-btn.active {
    color: #a0aec0;
    font-size: 0.7rem;
    opacity: 0.7;
    cursor: default;
    pointer-events: none;
  }

  .calendar-date {
    font-size: 0.7rem;
  }

  .calendar-event {
    font-size: 0.7rem;
  }

  .submission-header {
    gap: 10px;
  }

  .submit-paper-btn {
    padding: 12px 20px;
    font-size: 0.95rem;
  }

  .web-contact-container {
    flex-direction: column;
  }

  .contact-item {
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
  }

  .contact-icon {
    width: 25px;
    height: 25px;
  }

  .contact-icon svg {
    width: 12px;
    height: 12px;
  }

  .contact-link {
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.9rem;
  }

  .contact-label {
    min-width: auto;
    font-size: 0.85rem;
  }

  .qr-contact {
    width: 100px;
    height: auto;
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 5px;
    align-self: center;
  }

  .contact-details {
    width: 100%;
  }

  .web-contact-section {
    flex-direction: column;
    gap: 0.9rem;
    margin-top: 15px;
    gap: 0.8rem;
    padding-left: 0;
  }
}

@media (max-width: 320px) {
  main.container {
    padding: 0 20px 20px 20px;
  }
  .header-container {
    padding: 15px 20px 15px 20px;
  }

  .conference-logo {
    width: 40%;
  }

  .hero-content h1 {
    font-size: 1rem;
  }

  .date-location {
    font-size: 0.9rem;
  }

  .lang-btn {
    padding: 5px 5px;
    font-size: 0.7rem;
  }

  .lang-switcher {
    gap: 1px;
  }

  .lang-separator {
    font-size: 1rem;
  }

  .contact-link {
    font-size: 0.85rem;
  }

  .contact-label {
    font-size: 0.8rem;
  }

  .qr-contact {
    width: 90px;
  }

  .springer-proceedings-wrapper {
    flex-direction: column;
    gap: 15px;
  }
}

/* Плавная прокрутка */
html {
  scroll-behavior: smooth;
}

a {
  text-decoration: none;
  color: var(--primary);
  font-weight: 500;
  overflow-wrap: break-word;
  word-wrap: break-word;
  transition: color 0.3s;
}

a:hover {
  color: var(--primary-light);
}

/************Анимации для секций**************/
.section-animate {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease-in-out 0.15s; /* 0.2s - одинаковая задержка для всех */
}

.section-animate.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Применяем к секциям */
#purpose,
#organizers,
#themes,
#language,
#calendar,
#committees,
#submission,
#registration,
#proceedings,
#venue,
#history,
#contacts {
  scroll-margin-top: 100px; /* Отступ для якорных ссылок с фиксированной навигацией */
}

/**********************



/********ANIMATIOMS******/
.hero.loaded {
  opacity: 1;
}

.header-container.header-loaded {
  opacity: 1;
  transform: translateY(0);
}

.hero-content.hero-content-loaded {
  opacity: 1;
  transform: translateY(0);
}

.slider.slider-loaded {
  opacity: 1;
}