/* Global Styles */
:root {
  --ieee-blue: #00629B;
  --ieee-dark-blue: #002855;
  --text-color: #333;
  --light-gray: #f4f4f4;
  --white: #ffffff;
  --accent-color: #00b5e2;
  /* A lighter blue for accents */
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Roboto', 'Open Sans', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--white);
}

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

.container {
  max-width: 1200px;
  /* Increased from 1100px for wider layout */
  margin: 0 auto;
  padding: 0 20px;
}

/* Header & Navigation */
header {
  background-color: var(--white);
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
  /* Reduced from 90px */
  padding: 0 20px;
  /* Restored horizontal padding */
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 15px;
  flex: 0 0 auto;
  /* Don't take extra space */
  margin-right: auto;
  /* Push content to the right if needed, but flex grow on links handles it */
}

.logo-img {
  height: 60px;
  width: auto;
}

.nav-brand {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--ieee-dark-blue);
}

.nav-links {
  flex: 1;
  /* Take up remaining space */
  display: flex;
  justify-content: flex-end;
  /* Align links to the right */
  gap: 30px;
  padding-right: 30px;
  /* Space between links and button */
}

.nav-actions {
  flex: 0 0 auto;
  /* Only take necessary space */
  display: flex;
  justify-content: flex-end;
}

.nav-links li a {
  font-weight: 500;
  color: var(--ieee-dark-blue);
  transition: color 0.3s ease;
  font-size: 1.05rem;
}

.nav-links li a:hover {
  color: var(--ieee-blue);
}

.mobile-nav-btn {
  display: none;
  /* Hidden on desktop */
}

.hamburger {
  display: none;
  cursor: pointer;
}

.bar {
  display: block;
  width: 25px;
  height: 3px;
  margin: 5px auto;
  -webkit-transition: all 0.3s ease-in-out;
  transition: all 0.3s ease-in-out;
  background-color: var(--ieee-dark-blue);
}

/* Hero Section */
.hero {
  background: linear-gradient(rgba(0, 20, 50, 0.85), rgba(0, 80, 140, 0.85)), url('../logos/mbu-university.webp');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  /* Parallax effect */
  color: var(--white);
  min-height: 85vh;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 40px 20px;
  position: relative;
}

.hero-content {
  max-width: 900px;
  z-index: 2;
}

.hero-content h1 {
  font-size: 3rem;
  margin-bottom: 10px;
  line-height: 1.2;
  font-weight: 700;
  text-shadow: 0 4px 8px rgba(0, 0, 0, 0.5);
}

.hero-content h2 {
  font-size: 1.8rem;
  font-weight: 400;
  margin-bottom: 20px;
  color: #e0e0e0;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.hero-content h3 {
  font-size: 1.2rem;
  margin-bottom: 30px;
  font-weight: 300;
  font-style: italic;
}

.hero-content .date-location {
  font-size: 1.5rem;
  /* Increased from 1.3rem */
  margin-bottom: 40px;
  font-weight: bold;
  background: rgba(255, 255, 255, 0.1);
  padding: 20px 40px;
  /* Increased padding */
  border-radius: 10px;
  /* Reduced from 50px */
  display: inline-block;
  backdrop-filter: blur(5px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.btn {
  display: inline-block;
  padding: 15px 35px;
  background-color: var(--accent-color);
  color: var(--white);
  border-radius: 5px;
  font-weight: bold;
  transition: background-color 0.3s ease;
  font-size: 1.1rem;
}

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

/* Sections */
.section-padding {
  padding: 80px 0;
}

.bg-light {
  background-color: var(--light-gray);
}

h2.section-title {
  text-align: center;
  font-size: 2.2rem;
  color: var(--ieee-dark-blue);
  margin-bottom: 50px;
  position: relative;
}

h2.section-title::after {
  content: '';
  display: block;
  width: 80px;
  height: 4px;
  background-color: var(--excel-blue);
  /* Typo, meant ieee-blue? */
  background-color: var(--ieee-blue);
  margin: 15px auto 0;
}

/* About */
.about-text {
  max-width: 100%;
  /* Fill the container */
  margin: 0 auto;
  text-align: justify;
  font-size: 1.1rem;
}

.about-text p {
  margin-bottom: 20px;
}

.objectives-list {
  margin-top: 20px;
  padding-left: 20px;
}

.objectives-list li {
  list-style-type: disc;
  margin-bottom: 10px;
}

/* Important Dates */
.dates-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 20px;
  max-width: 100%;
  /* Allow to fill the larger container */
  margin: 0 auto;
}

.date-card {
  background: var(--white);
  padding: 20px;
  border-left: 6px solid var(--ieee-blue);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
  transition: transform 0.3s ease;
  width: calc(25% - 20px);
  /* Force 4 columns */
  min-width: 220px;
  /* Integrity check */
  text-align: center;
}

.date-card:hover {
  transform: translateY(-5px);
}

.date-card h3 {
  font-size: 1.1rem;
  color: var(--ieee-dark-blue);
  margin-bottom: 10px;
}

.date-card p {
  font-weight: bold;
  color: var(--text-color);
  font-size: 1.1rem;
}

/* Sponsors */
.sponsors-grid {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 60px;
  margin-top: 40px;
}

.sponsor-logo {
  max-height: 100px;
  max-width: 250px;
  object-fit: contain;
  /* filter: grayscale(100%);  Removed generic grayscale, keep logos original */
  transition: transform 0.3s;
}

.sponsor-logo:hover {
  transform: scale(1.05);
}

/* Sponsor Strip */
.logo-strip {
  background-color: var(--white);
  padding: 20px 0;
  border-bottom: 1px solid #eee;
  overflow: hidden;
}

.marquee-content {
  display: flex;
  justify-content: space-around;
  align-items: center;
  gap: 40px;
  flex-wrap: wrap;
}

.marquee-content img {
  height: 70px;
  width: auto;
  object-fit: contain;
  transition: transform 0.3s;
}

.marquee-content img:hover {
  transform: scale(1.05);
}

/* Organizer & Co-Sponsor Sections (Bottom) */
.organizer-block {
  margin-bottom: 40px;
  text-align: center;
}

.organizer-header {
  background-color: #e0f2f1;
  /* Light teal/cyan similar to screenshot */
  color: #00695c;
  /* Darker teal text */
  padding: 15px;
  border-radius: 50px;
  /* Pill shape */
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 30px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.organizer-logos {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 30px;
}

.organizer-logos .sponsor-card {
  background: white;
  padding: 20px;
  border: 1px solid #eee;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 200px;
}

.organizer-logos img {
  max-height: 80px;
  max-width: 100%;
  object-fit: contain;
}

/* Org Logos in Header */
.header-logos {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

/* Call for Papers Page */
.track-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 40px;
  max-width: 900px;
  margin: 0 auto;
}

.track-item {
  background: var(--white);
  padding: 30px;
  border-radius: 8px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
  border-top: 4px solid var(--ieee-blue);
}

.track-item h3 {
  color: var(--ieee-blue);
  margin-bottom: 15px;
  font-size: 1.5rem;
}

.track-item p {
  margin-bottom: 15px;
  font-style: italic;
  color: #555;
}

.track-item ul {
  padding-left: 20px;
  list-style-type: disc;
}

.track-item ul li {
  margin-bottom: 8px;
}

/* Committee Page */
.committee-section {
  margin-bottom: 50px;
}

.committee-section h3 {
  color: var(--ieee-dark-blue);
  border-bottom: 2px solid #e0e0e0;
  padding-bottom: 15px;
  margin-bottom: 25px;
  font-size: 1.6rem;
}

.committee-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 25px;
}

.committee-member {
  background: var(--white);
  padding: 20px;
  border-radius: 8px;
  border: 1px solid #eee;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
  transition: box-shadow 0.3s;
}

.committee-member:hover {
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.committee-member strong {
  display: block;
  font-size: 1.15rem;
  color: var(--ieee-dark-blue);
  margin-bottom: 5px;
}

.committee-member span {
  display: block;
  color: #555;
  font-size: 1rem;
}

/* Footer */
footer {
  background-color: var(--ieee-dark-blue);
  color: var(--white);
  padding: 30px 0;
  text-align: center;
}

.footer-logo {
  margin-top: 10px;
  font-weight: bold;
  font-size: 1.2rem;
}

.footer-links {
  margin: 20px 0;
}

.footer-links a {
  margin: 0 15px;
  font-size: 0.95rem;
  color: #ccc;
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--white);
  text-decoration: underline;
}

/* Registration Fees Table */
.registration-fees {
  max-width: 900px;
  margin: 0 auto;
}

.table-responsive {
  overflow-x: auto;
}

.fees-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--white);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
  border-radius: 8px;
  overflow: hidden;
  table-layout: fixed;
}

.fees-table thead {
  background-color: var(--ieee-dark-blue);
  color: var(--white);
}

.fees-table th {
  padding: 12px 8px;
  text-align: center;
  font-weight: 600;
  font-size: 0.9rem;
  border: 1px solid #1a4a7a;
  white-space: nowrap;
}

.fees-table th:first-child {
  text-align: left;
  width: 40%;
}

.fees-table th:not(:first-child) {
  width: 15%;
}

.fees-table td {
  padding: 12px 8px;
  text-align: center;
  border: 1px solid #e0e0e0;
  font-size: 0.95rem;
}

.fees-table td:first-child {
  text-align: left;
  font-weight: 500;
  color: var(--ieee-dark-blue);
  background-color: #f8f9fa;
}

.fees-table tbody tr:hover {
  background-color: #f0f7ff;
}

.fees-table tbody tr:nth-child(even) td:not(:first-child) {
  background-color: #fafafa;
}

.fees-table tbody tr:nth-child(even):hover td {
  background-color: #f0f7ff;
}

/* Mobile Responsive */
@media (max-width: 900px) {
  .header-logos {
    display: none;
    /* Hide extra logos on mobile header, keep main */
  }
}

@media (max-width: 768px) {
  .nav-actions {
    display: none;
    /* Hide desktop button */
  }

  .mobile-nav-btn {
    display: inline-block;
    /* Show on mobile */
    margin-top: 10px;
  }

  .hamburger {
    display: block;
  }

  .hamburger.active .bar:nth-child(2) {
    opacity: 0;
  }

  .hamburger.active .bar:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }

  .hamburger.active .bar:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }

  .nav-links {
    position: fixed;
    left: -100%;
    top: 90px;
    gap: 0;
    flex-direction: column;
    background-color: var(--white);
    width: 100%;
    text-align: center;
    transition: 0.3s;
    box-shadow: 0 10px 10px rgba(0, 0, 0, 0.1);
    padding: 20px 0;
  }

  .nav-links.active {
    left: 0;
  }

  .nav-links li {
    margin: 20px 0;
  }

  .hero-content h1 {
    font-size: 2rem;
  }

  .date-card {
    width: calc(50% - 20px);
    /* 2 columns on tablet */
  }
}

@media (max-width: 600px) {
  .date-card {
    width: 100%;
    /* 1 column on mobile */
  }

  /* Stack hero buttons on narrow screens */
  .hero-content .btn {
    display: block;
    width: 80%;
    /* Reduced from 100% */
    margin: 10px auto;
    /* Center buttons */
    margin-left: auto !important;
  }

  /* Registration fees table mobile scroll */
  .table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    margin: 0 -10px;
    padding: 0 10px;
  }

  .fees-table {
    min-width: 650px;
  }

  .fees-table th,
  .fees-table td {
    padding: 10px 6px;
    font-size: 0.85rem;
  }

  .registration-fees::after {
    content: '← Scroll horizontally →';
    display: block;
    text-align: center;
    font-size: 0.8rem;
    color: #888;
    margin-top: 10px;
  }
}