/* ============================================
   Color Scheme: Professional Blue & Teal
   Primary: #1e3a8a (Professional Blue)
   Secondary: #14b8a6 (Teal)
   ============================================ */

:root {
    --primary-color: #1e3a8a;
    --secondary-color: #14b8a6;
    --dark-bg: #0f172a;
    --light-bg: #f8fafc;
    --text-dark: #1e293b;
    --text-light: #64748b;
    --white: #ffffff;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-lg: rgba(0, 0, 0, 0.15);
}

/* ============================================
   Typography
   ============================================ */
body {
    font-family: 'Open Sans', sans-serif;
    color: var(--text-dark);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Poppins', sans-serif;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1.2;
}

.section-heading {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.section-heading::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

/* ============================================
   Navigation
   ============================================ */
.navbar {
    background: var(--dark-bg) !important;
    padding: 1rem 0;
    transition: all 0.3s ease;
    box-shadow: 0 2px 10px var(--shadow);
}

.navbar.scrolled {
    padding: 0.5rem 0;
    box-shadow: 0 4px 20px var(--shadow-lg);
}

.navbar-brand {
    font-family: 'Poppins', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white) !important;
    letter-spacing: 1px;
}

.navbar-nav .nav-link {
    color: var(--white) !important;
    font-weight: 500;
    margin: 0 0.5rem;
    transition: all 0.3s ease;
    position: relative;
}

.navbar-nav .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--secondary-color);
    transition: width 0.3s ease;
}

.navbar-nav .nav-link:hover::after,
.navbar-nav .nav-link.active::after {
    width: 80%;
}

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

.navbar-nav .btn-contact {
    background: var(--secondary-color);
    border-radius: 25px;
    padding: 0.5rem 1.5rem !important;
    margin-left: 1rem;
}

.navbar-nav .btn-contact::after {
    display: none;
}

.navbar-nav .btn-contact:hover {
    background: var(--primary-color);
    color: var(--white) !important;
    transform: translateY(-2px);
}

/* ============================================
   Hero Section
   ============================================ */
.hero-section {
    position: relative;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--dark-bg) 100%);
    background-image: url('/assets/images/banner-bg.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    min-height: 100vh;
    display: flex;
    align-items: center;
    color: var(--white);
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(30, 58, 138, 0.9) 0%, rgba(15, 23, 42, 0.95) 100%);
    z-index: 1;
}

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

.hero-title {
    font-size: 2rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 1.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--white);
    margin-bottom: 2rem;
    opacity: 0.95;
}

.hero-buttons .btn {
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 30px;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.hero-buttons .btn-primary {
    background: var(--secondary-color);
    border: none;
    color: var(--white);
}

.hero-buttons .btn-primary:hover {
    background: var(--white);
    color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(20, 184, 166, 0.3);
}

.hero-buttons .btn-secondary {
    background: transparent;
    border: 2px solid var(--white);
    color: var(--white);
}

.hero-buttons .btn-secondary:hover {
    background: var(--white);
    color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(255, 255, 255, 0.3);
}

.conference-emblem {
    position: relative;
    width: 200px;
    height: 200px;
    margin: 0 auto;
    background: linear-gradient(135deg, #fff 0%, #fff 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: float 3s ease-in-out infinite;
}

.conference-emblem i {
    position: absolute;
    color: var(--primary-color);
    font-size: 3rem;
}

.conference-emblem .fa-shield-alt {
    z-index: 3;
}

.conference-emblem .fa-book {
    z-index: 2;
    font-size: 2rem;
    top: 30%;
}

.conference-emblem .fa-torch {
    z-index: 4;
    color: #fbbf24;
    font-size: 2.5rem;
    top: -10%;
}

.springer-logo img{
    width: 200px;
}
@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-20px);
    }
}

.carousel-indicators-custom {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
    z-index: 3;
}

.carousel-indicators-custom .indicator {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
    cursor: pointer;
    transition: all 0.3s ease;
}

.carousel-indicators-custom .indicator.active {
    background: var(--secondary-color);
    width: 30px;
    border-radius: 6px;
}

/* ============================================
   About Section
   ============================================ */
#about {
    padding: 100px 0;
}

.about-image img {
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--shadow);
    transition: transform 0.3s ease;
    width: 100%;
    height: auto;
}

.about-image img:hover {
    transform: scale(1.05);
}

#about .section-heading {
    margin-bottom: 1.5rem;
}

#about p {
    font-size: 1.1rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

#about .lead {
    font-size: 1.2rem;
    color: var(--text-dark);
    font-weight: 500;
}

/* ============================================
   Call For Papers Section
   ============================================ */
#call-for-papers {
    padding: 100px 0;
}

.topic-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
    height: 100%;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.topic-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px var(--shadow-lg);
}

.topic-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.topic-icon i {
    color: var(--white);
    font-size: 1.5rem;
}

.topic-card h4 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.topic-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.topic-list li {
    padding: 0.5rem 0;
    color: var(--text-light);
    font-size: 0.95rem;
    display: flex;
    align-items: flex-start;
}

.topic-list li i {
    color: var(--secondary-color);
    margin-right: 0.75rem;
    margin-top: 0.25rem;
    font-size: 0.8rem;
}

/* ============================================
   Important Dates Section
   ============================================ */
.dates-section {
    position: relative;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--dark-bg) 100%);
    background-image: url('/assets/images/dates-bg.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    padding: 100px 0;
    overflow: hidden;
}

.dates-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(30, 58, 138, 0.9) 0%, rgba(15, 23, 42, 0.95) 100%);
    z-index: 1;
}

.dates-section .container {
    position: relative;
    z-index: 2;
}

.dates-section .section-heading::after {
    background: linear-gradient(90deg, var(--white), var(--secondary-color));
}

.date-card {
    background: rgba(255, 255, 255, 0.95);
    padding: 2rem;
    border-radius: 15px;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
    height: 100%;
}

.date-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.3);
    background: var(--white);
}

.date-card h5 {
    color: var(--primary-color);
    font-size: 1.1rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.date-text {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--secondary-color);
    margin: 0;
}

/* ============================================
   Paper Submission Section
   ============================================ */
#submission {
    padding: 100px 0;
}

.guidelines-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.guidelines-list li {
    padding: 0.75rem 0;
    color: var(--text-dark);
    font-size: 1rem;
    display: flex;
    align-items: flex-start;
}

.guidelines-list li i {
    color: var(--secondary-color);
    margin-right: 1rem;
    margin-top: 0.25rem;
    font-size: 0.9rem;
}

.template-links .btn {
    border-radius: 25px;
    padding: 0.5rem 1.5rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.template-links .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px var(--shadow);
}

.springer-image img {
    max-width: 250px;
    border-radius: 10px;
    box-shadow: 0 5px 15px var(--shadow);
}

.submission-form {
    background: var(--light-bg);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
}

.submission-form .form-label {
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.submission-form .form-control {
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    padding: 0.75rem;
    transition: all 0.3s ease;
}

.submission-form .form-control:focus {
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 0.2rem rgba(20, 184, 166, 0.25);
}

.submission-form .btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    padding: 0.75rem 2rem;
    font-weight: 600;
    border-radius: 25px;
    transition: all 0.3s ease;
}

.submission-form .btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(20, 184, 166, 0.3);
}

/* ============================================
   Speakers Section
   ============================================ */
#speakers {
    padding: 100px 0;
}

.speaker-card {
    text-align: center;
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
    transition: all 0.3s ease;
    height: 100%;
}

.speaker-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px var(--shadow-lg);
}

.speaker-image {
    width: 200px;
    height: 200px;
    margin: 0 auto;
    border-radius: 50%;
    overflow: hidden;
    border: 5px solid var(--secondary-color);
    box-shadow: 0 10px 30px var(--shadow);
}

.speaker-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.speaker-card h5 {
    color: var(--primary-color);
    font-weight: 600;
}

/* ============================================
   Organizing Committee Section
   ============================================ */
#committee {
    padding: 100px 0;
}

.committee-list {
    background: var(--light-bg);
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
}

.committee-item {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid #e2e8f0;
}

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

.committee-item h5 {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
}

.committee-item h5 i {
    color: var(--secondary-color);
    margin-right: 0.75rem;
    font-size: 1rem;
}

.committee-item p {
    color: var(--text-light);
    margin: 0;
    line-height: 1.8;
}

.committee-contact {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 10px;
    border-left: 4px solid var(--secondary-color);
}

.committee-contact a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.committee-contact a:hover {
    text-decoration: underline;
}

/* ============================================
   Registration Section
   ============================================ */
#registration {
    padding: 100px 0;
}

.fee-table-wrapper {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
    overflow-x: auto;
}

.fee-table-wrapper table {
    margin: 0;
}

.fee-table-wrapper table thead {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
}

.fee-table-wrapper table thead th {
    border: none;
    padding: 1rem;
    font-weight: 600;
    text-align: center;
}

.fee-table-wrapper table tbody td {
    padding: 1rem;
    text-align: center;
    border-color: #e2e8f0;
    color: var(--text-dark);
}

.fee-table-wrapper table tbody tr:hover {
    background: var(--light-bg);
}

.fee-includes {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
    margin-top: 2rem;
}

.fee-includes h5 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.fee-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.fee-list li {
    padding: 0.5rem 0;
    color: var(--text-light);
    display: flex;
    align-items: flex-start;
}

.fee-list li i {
    color: var(--secondary-color);
    margin-right: 0.75rem;
    margin-top: 0.25rem;
}

.payment-list {
    list-style: none;
    padding: 0;
    margin: 0;
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--shadow);
}

.payment-list li {
    padding: 0.75rem 0;
    color: var(--text-dark);
    font-size: 1rem;
    display: flex;
    align-items: flex-start;
    border-bottom: 1px solid #e2e8f0;
}

.payment-list li:last-child {
    border-bottom: none;
}

.payment-list li i {
    color: var(--secondary-color);
    margin-right: 1rem;
    margin-top: 0.25rem;
    font-size: 0.9rem;
}

.payment-instructions {
    background: var(--light-bg);
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 1.5rem;
    border-left: 4px solid var(--secondary-color);
}

.payment-instructions h5 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.payment-instructions a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
}

.payment-instructions a:hover {
    text-decoration: underline;
}

/* ============================================
   Footer
   ============================================ */
.footer-section {
    background: var(--dark-bg);
    color: var(--white);
    padding: 60px 0 30px;
}

.footer-heading {
    font-family: 'Poppins', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 0.75rem;
}

.footer-heading::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: var(--secondary-color);
    border-radius: 2px;
}

.footer-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-list li {
    padding: 0.75rem 0;
    color: rgba(255, 255, 255, 0.8);
    display: flex;
    align-items: flex-start;
}

.footer-list li i {
    color: var(--secondary-color);
    margin-right: 1rem;
    margin-top: 0.25rem;
    font-size: 1.1rem;
    width: 20px;
}

.footer-list li a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: all 0.3s ease;
}

.footer-list li a:hover {
    color: var(--secondary-color);
}

.footer-address {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.8;
    font-style: normal;
}

.map-container {
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
}

.map-container iframe {
    border-radius: 10px;
}

.copyright {
    color: rgba(255, 255, 255, 0.6);
    margin: 0;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* ============================================
   Responsive Design
   ============================================ */

/* Tablet */
@media (max-width: 992px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .section-heading {
        font-size: 2rem;
    }
    
    .conference-emblem {
        width: 150px;
        height: 150px;
        margin-top: 2rem;
    }
    
    .conference-emblem i {
        font-size: 2rem;
    }

    .hero-section {
        background-attachment: scroll;
    }
}

/* Mobile */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-buttons .btn {
        display: block;
        width: 100%;
        margin-bottom: 1rem;
    }
    
    .hero-section .row {
        text-align: center;
    }

    .hero-buttons {
        justify-content: center;
    }

    .section-heading {
        font-size: 1.75rem;
    }
    
    .navbar-nav .btn-contact {
        margin-left: 0;
        margin-top: 0.5rem;
    }
    
    .topic-card,
    .date-card,
    .speaker-card {
        margin-bottom: 1.5rem;
    }
    
    .conference-emblem {
        width: 120px;
        height: 120px;
    }
    
    .conference-emblem i {
        font-size: 1.5rem;
    }
    
    .speaker-image {
        width: 150px;
        height: 150px;
    }
    
    .fee-table-wrapper {
        overflow-x: auto;
    }
    
    .submission-form {
        padding: 1.5rem;
    }
    
    .committee-list {
        padding: 1.5rem;
    }
    
    #about,
    #call-for-papers,
    .dates-section,
    #submission,
    #speakers,
    #committee,
    #registration {
        padding: 60px 0;
    }

    #about .row {
        text-align: center;
    }

    #about p {
        text-align: left;
    }
}

/* Small Mobile */
@media (max-width: 576px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .section-heading {
        font-size: 1.5rem;
    }
    
    .topic-card,
    .date-card {
        padding: 1.5rem;
    }
    
    .footer-heading {
        font-size: 1.25rem;
    }
}

/* Smooth Scroll */
html {
    scroll-behavior: smooth;
}

/* Section Spacing */
section {
    scroll-margin-top: 80px;
}