:root {
  --primary-color: #040c80;
  --secondary-color: #2c3e50;
  --accent-color: #f39c12;
  --light-bg: #f8f9fa;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.6;
}

.primary-text {
  color: var(--primary-color);
}

h2 {
  text-transform: uppercase;
}

.navbar {
  transition: all 0.3s ease;
  padding: 1rem 0;
}

.nav-tabs {
  border: none;
}

/* Tab styling for diagram section */
.tab-container .nav-tabs {
  border-bottom: 2px solid #e9ecef;
  margin-bottom: 0;
}

.tab-container .nav-tabs .nav-link {
  border: none;
  background: transparent;
  color: #6c757d;
  font-weight: 600;
  padding: 12px 24px;
  margin-right: 10px;
  border-radius: 8px 8px 0 0;
  transition: all 0.3s ease;
  position: relative;
}

.tab-container .nav-tabs .nav-link:hover {
  color: #dc3545;
  background-color: rgba(220, 53, 69, 0.1);
  border-color: transparent;
}

.tab-container .nav-tabs .nav-link.active {
  background-color: #dc3545;
  color: white;
  border-color: #dc3545;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(220, 53, 69, 0.3);
}

.tab-container .nav-tabs .nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: #dc3545;
}

.tab-container .tab-content {
  background: white;
  border: 1px solid #e9ecef;
  border-radius: 0 8px 8px 8px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.accordion-button {
  font-weight: 600;
  font-size: 16px;
  background-color: #fff8e1;
  color: #c8102e;
  border-left: 4px solid #c8102e;
  padding-left: 1rem;
  position: relative;
}

.accordion-button::after {
  content: "\f078"; /* FontAwesome icon: chevron-down */
  font-family: "Font Awesome 5 Free";
  font-weight: 900;
  position: absolute;
  right: 20px;
  transition: transform 0.2s ease-in-out;
  color: #c8102e;
}

.accordion-button:not(.collapsed)::after {
  transform: rotate(180deg);
}

.accordion-button:not(.collapsed) {
  background-color: #ffe9e9;
  color: #a40000;
  box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.125);
}

.accordion-body {
  background-color: #fff;
  border-left: 4px solid #c8102e;
  padding-left: 1.25rem;
  font-size: 15px;
  color: #333;
}

.accordion-item {
  margin-bottom: 10px;
  border: none;
  border-radius: 0;
  overflow: hidden;
}

.navbar .nav-link {
  position: relative;
  font-size: 1.2vw;
  transition: all 0.3s ease;
  color: #000 !important;
  font-weight: 600;
  padding: 0.5rem 1rem !important;
  margin: 0 0.2rem;
  border-radius: 5px;
}

#video {
  position: relative;
}

.nav-link {
  border: none !important;
}

.nav-link.active {
  background-color: rgba(133, 30, 30, 1);
  color: #fff !important;
  border-radius: 5px;
}

.navbar .nav-link:hover {
  transform: translateY(-2px);
}

#conference-diagram {
  position: relative;
}

.navbar-brand img {
  width: 100px;
  display: none;
  transform: scale(0.8);
  transition: all 0.3s ease;
}

.navbar.scrolled .navbar-brand img {
  display: block;
  transform: scale(1);
}

.navbar .nav-link.active {
  background-color: rgba(255, 255, 255, 0.2);
  color: #fff3cd !important;
  border-radius: 5px;
}

.navbar .nav-link.active::after {
  display: none;
  content: "";
  position: absolute;
  bottom: -5px;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  height: 2px;
  background-color: #fff3cd;
  border-radius: 1px;
}

/* Dropdown Menu Styling */
.navbar .dropdown-menu {
  background: #1e3a5f; /* Xanh biển đậm */
  backdrop-filter: blur(10px);
  border: none;
  border-radius: 8px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.25);
  min-width: 220px;
  opacity: 0;
  transform: translateY(-10px);
  transition: all 0.3s ease;
  padding: 0.5rem 0;
}

.navbar .dropdown:hover .dropdown-menu,
.navbar .dropdown-menu.show {
  opacity: 1;
  transform: translateY(0);
}

.navbar .dropdown-item {
  color: white; /* Chữ trắng */
  padding: 0.8rem 1.2rem;
  font-weight: 500;
  transition: all 0.3s ease;
  border-radius: 0;
  margin: 0;
  position: relative;
  border-bottom: 3px double #dc3545; /* Border kép màu đỏ */
}

.navbar .dropdown-item:last-child {
  border-bottom: none;
}

.navbar .dropdown-item:hover {
  background-color: rgba(220, 53, 69, 0.2);
  color: #fff3cd !important;
  transform: translateX(5px);
}

.navbar .dropdown-item:active {
  background-color: #dc3545;
  color: white !important;
}

.navbar .dropdown-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 0;
  background-color: #dc3545;
  transition: height 0.3s ease;
}

.navbar .dropdown-item:hover::before {
  height: 60%;
}

.navbar .dropdown-toggle::after {
  transition: transform 0.3s ease;
  margin-left: 0.5em;
}

.navbar .dropdown-toggle[aria-expanded="true"]::after {
  transform: rotate(180deg);
}

/* Hover effect for dropdown parent */
.navbar .dropdown:hover > .nav-link {
  /* color: #fff3cd !important; */
  display: block;
  height: 40px;
}

.nav-item.dropdown {
  display: block;
  min-height: 40px;
}

.navbar.scrolled {
  background-color: rgba(255, 255, 255, 0.95) !important;
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
  padding: 0.5rem 0;
}

.navbar.scrolled .nav-link {
  color: var(--secondary-color) !important;
}

.navbar.scrolled .nav-link:hover {
  color: var(--primary-color) !important;
}

.navbar.scrolled .nav-link.active {
  background-color: var(--primary-color);
  color: white !important;
  border-radius: 50px;
}

.navbar.scrolled .nav-link.active::after {
  background-color: white;
}

/* Dropdown styling when scrolled */
.navbar.scrolled .dropdown-menu {
  background: #1e3a5f;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.navbar.scrolled .dropdown-item {
  color: white;
}

.navbar.scrolled .dropdown-item:hover {
  background-color: rgba(220, 53, 69, 0.2);
  color: #fff3cd !important;
}

/* Mobile Responsive for Dropdown */
@media (max-width: 991.98px) {
  .navbar .dropdown-menu {
    position: static !important;
    float: none;
    width: auto;
    margin-top: 0;
    background-color: #1e3a5f; /* Giữ nền xanh biển đậm */
    border: none;
    box-shadow: inset 0 2px 8px rgba(0, 0, 0, 0.2);
    backdrop-filter: none;
    opacity: 1;
    transform: none;
    border-radius: 0;
    padding: 0;
    border-left: 4px solid #dc3545; /* Border trái màu đỏ */
  }

  .navbar .dropdown-item {
    color: white !important;
    padding: 0.8rem 1.5rem;
    margin: 0;
    border-radius: 0;
    border-bottom: 2px double #dc3545; /* Border kép dưới */
    font-size: 0.95rem;
  }

  .navbar .dropdown-item:last-child {
    border-bottom: none;
  }

  .navbar .dropdown-item:hover,
  .navbar .dropdown-item:focus {
    background-color: rgba(220, 53, 69, 0.3);
    color: #fff3cd !important;
    transform: none;
  }

  .navbar .dropdown-item::before {
    display: none;
  }

  /* Styling cho collapsed navbar */
  .navbar-collapse {
    background-color: rgba(30, 58, 95, 0.95);
    border-radius: 8px;
    margin-top: 1rem;
    padding: 1rem;
  }

  .navbar .nav-link {
    color: white !important;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    margin: 0;
    padding: 0.8rem 1rem !important;
  }

  .navbar .nav-link:hover {
    background-color: rgba(220, 53, 69, 0.2);
  }
}

.hero-section {
  background: url("images/hero-bg.jpg");
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  /* min-height: 100vh; */
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

#map iframe {
  position: relative;
  z-index: 999;
  display: block;
  margin: auto;
}

.hero-section::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("../img/Bo HNKH-05.jpg");
  background-size: cover;
}

.hero-content {
  position: relative;
  z-index: 2;
}

.btn-primary {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
  padding: 12px 30px;
  font-weight: 600;
  border-radius: 50px;
  transition: all 0.3s ease;
}

.btn-primary:hover {
  background-color: var(--secondary-color);
  border-color: var(--secondary-color);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.btn-outline-light:hover {
  background-color: white;
  color: var(--primary-color);
  transform: translateY(-2px);
}

.service-card {
  background: white;
  border-radius: 15px;
  padding: 2rem;
  box-shadow: 0 5px 25px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  height: 100%;
}

.service-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
}

.service-icon {
  width: 80px;
  height: 80px;
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--accent-color)
  );
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1.5rem;
  font-size: 2rem;
  color: white;
}

.section-title {
  position: relative;
  margin-bottom: 3rem;
}

.section-title::after {
  content: "";
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--accent-color)
  );
  border-radius: 2px;
}

.portfolio-item {
  position: relative;
  overflow: hidden;
  border-radius: 15px;
  cursor: pointer;
}

.portfolio-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(
    135deg,
    rgba(255, 107, 53, 0.9),
    rgba(243, 156, 18, 0.9)
  );
  opacity: 0;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

.portfolio-item:hover .portfolio-overlay {
  opacity: 1;
}

.stats-section {
  background: var(--secondary-color);
  color: white;
  padding: 4rem 0;
}

.stat-number {
  font-size: 3rem;
  font-weight: bold;
  color: var(--accent-color);
}

.contact-form {
  background: white;
  border-radius: 15px;
  padding: 2rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.form-control {
  border-radius: 10px;
  border: 2px solid #e9ecef;
  padding: 12px 15px;
  transition: all 0.3s ease;
}

.form-control:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 0.2rem rgba(255, 107, 53, 0.25);
}

.footer {
  background: var(--secondary-color);
  color: white;
  padding: 3rem 0 1rem;
}

.social-links a {
  display: inline-block;
  width: 40px;
  height: 40px;
  background: var(--primary-color);
  color: white;
  text-align: center;
  line-height: 40px;
  border-radius: 50%;
  margin: 0 5px;
  transition: all 0.3s ease;
}

.social-links a:hover {
  background: var(--accent-color);
  transform: translateY(-3px);
}

.info-card {
  background: white;
  border-radius: 10px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
  transition: all 0.3s ease;
  border: 1px solid #e9ecef;
}

.info-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.floating-btn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 60px;
  height: 60px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
  transition: all 0.3s ease;
  z-index: 1000;
  text-decoration: none;
}

.floating-btn:hover {
  background: var(--accent-color);
  color: white;
  transform: scale(1.1);
}

@media (max-width: 768px) {
  .hero-section {
    text-align: center;
  }

  .stat-number {
    font-size: 2rem;
  }
}

.portfolio-item img {
  transition: all 0.3s ease;
  width: 100%;
  height: 250px;
  object-fit: cover;
}

.hero-section img {
  object-fit: contain;
  z-index: 999;
  position: relative;
  top: 0px;
}

.about-section img {
  max-height: 400px;
  object-fit: cover;
}

/* schedule */
.schedule-section {
  border-bottom: 2px solid #8b4513;
  overflow: hidden;
}

.schedule-item {
  display: flex;
  min-height: 50px;
  transition: all 0.3s ease;
  cursor: pointer;
  position: relative;
}

.schedule-item:hover {
  background-color: none;
}

.main-event .content {
  color: #fff;
  text-align: left;
}
.schedule-item.expandable::after {
  content: "▼";
  position: absolute;
  right: 15px;
  top: 50%;
  transform: translateY(-50%);
  color: #c41e3a;
  font-size: 12px;
  transition: transform 0.3s ease;
}

.schedule-item.expanded::after {
  transform: translateY(-50%) rotate(180deg);
}

.time-slot {
  background-color: #f5f3ed;
  padding: 12px 15px;
  font-weight: bold;
  color: #8b4513;
  min-width: 140px;
  display: flex;
  align-items: center;
  border-right: 2px solid #8b4513;
}

.content {
  flex: 1;
  padding: 12px 15px;
  display: flex;
  align-items: center;
  color: #333;
  padding-right: 40px;
}

.content::before {
  content: "►";
  color: #c41e3a;
  margin-right: 8px;
  font-size: 14px;
}

.main-event {
  background-color: #c41e3a;
  color: white;
  font-weight: bold;
  text-align: center;
  font-size: 16px;
  padding: 20px;
  line-height: 1.6;
}

.main-event .time-slot {
  background-color: #c41e3a;
  color: white;
  border: none;
  padding: 0px;
  /* border-right: 2px solid #a01729; */
}

.plenary-session {
  color: #2c5aa0;
  font-weight: bold;
}

.specialized-sessions {
  color: #2c5aa0;
  font-weight: bold;
}

.break-time {
  background-color: #f5f3ed;
  font-style: italic;
}

.meeting-rooms {
  margin-top: 0;
}

.room-item {
  background-color: #f8f6f0;
}

.room-item:nth-child(even) {
  background-color: #f5f3ed;
}

.room-number {
  background-color: #f5f3ed;
  font-weight: bold;
  color: #8b4513;
}

.room-item:nth-child(even) .room-number {
  background-color: #f0ede6;
}

.room-topic {
  color: #2c5aa0;
}

/* Accordion Details Styles */
.details {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease-out, padding 0.3s ease;
  background-color: #fff;
  border-top: 1px solid #ddd;
}

.details.expanded {
  max-height: 2000px;
  padding: 20px;
}

.details-content {
  color: #333;
  line-height: 1.6;
  text-align: left;
  position: relative;
}

.details h3 {
  color: #c41e3a;
  margin-bottom: 15px;
  font-size: 18px;
  border-bottom: 2px solid #c41e3a;
  padding-bottom: 5px;
}

.session-info {
  margin-bottom: 15px;
}

.session-info h5 {
  font-size: 1rem;
  font-weight: bold;
}

.session-info h4 {
  color: #2c5aa0;
  margin-bottom: 8px;
  font-size: 16px;
}

.session-info p {
  margin-bottom: 5px;
  padding-left: 15px;
}

.speaker {
  font-weight: bold;
  color: #8b4513;
}

.topic-list {
  list-style: none;
  padding-left: 20px;
}

.topic-list li {
  margin-bottom: 8px;
  position: relative;
}

.topic-list li::before {
  content: "•";
  color: #c41e3a;
  position: absolute;
  left: -15px;
}

@media (max-width: 768px) {
  .container {
    margin: 10px;
  }

  #map iframe {
    width: 100%;
    height: 300px;
  }

  .navbar .nav-link {
    font-size: 14px;
  }
  .navbar.scrolled .nav-link {
    color: #fff !important;
  }
  #navbarNav > ul > li > ul > li:nth-child(1) > a {
    font-size: 14px;
  }
  .hero-section::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("../img/fd3c7d0f7349fa17a358.jpg");
    background-size: cover;
  }

  .title {
    font-size: 22px;
    padding: 15px;
  }

  .schedule-item {
    flex-direction: column;
  }

  .schedule-item.expandable::after {
    top: 25%;
  }
  .time-slot {
    min-width: auto;
    border-right: none;
    border-bottom: 1px solid #8b4513;
  }

  .content {
    padding-top: 8px;
    padding-right: 40px;
  }

  .main-event {
    font-size: 14px;
    padding: 15px;
  }

  .details.expanded {
    padding: 15px;
  }
}

.fade-in {
  animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.pulse {
  animation: pulse 0.3s ease;
}

@keyframes pulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.02);
  }
  100% {
    transform: scale(1);
  }
}
/* end schedule */