/* CSS Custom Properties for consistent theming */
:root {
    --primary-color: #731b05;
    --secondary-color: #6c757d;
    --success-color: #731b05;
    --info-color: #731b05;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --white: #ffffff;
    
    --primary-gradient: linear-gradient(135deg, #731b05 0%, #731b05 100%);
    --hero-gradient: linear-gradient(135deg, rgba(115, 27, 5, 0.9) 0%, rgba(115, 27, 5, 0.9) 100%);
    
    --font-family-base: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-size-base: 1rem;
    --line-height-base: 1.6;
    
    --border-radius: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 1rem;
    
    --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --box-shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
    
    --transition: all 0.3s ease;
}

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

body {
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--dark-color);
    background-color: var(--white);
}

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

.header-logo {
    height: 90px;   /* bigger main TCE logo */
    width: auto;
}

.main-logo {
    max-height: 110px;  /* extra size for main logo */
}

.inst-logo {
    height: 80px;   /* increase size of other logos */
    width: auto;
    object-fit: contain;
}


/* Navigation Styles */
.navbar {
    background: var(--white) !important;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    padding: 1rem 0;
}

.navbar .nav-link {
    color: var(--dark-color) !important;
    font-weight: 450;
    padding: 0.5rem 1rem !important;
    transition: var(--transition);
    position: relative;
}

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

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

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

/* Hero Section */
.hero-section {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
    color: white;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url('attached_assets/TCE-Main-Building_1756395954885.webp');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    z-index: 1;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    z-index: 2;
}

.hero-content {
    position: relative;
    z-index: 3;
    padding: 2rem 0;
}

.hero-college-name {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    letter-spacing: 2px;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    opacity: 0.9;
}

.hero-location {
    font-size: 1.25rem;
    margin-bottom: 3rem;
    opacity: 0.8;
}

.conference-main-title {
    margin: 3rem 0;
    padding: 2rem;
    background: rgba(0, 0, 0, 0.3);
    border-radius: var(--border-radius-xl);
    backdrop-filter: blur(10px);
}

.main-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    opacity: 0.9;
}

.event-details {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin: 2rem 0;
    flex-wrap: wrap;
}

.event-date, .event-location {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 500;
    background: rgba(255, 255, 255, 0.1);
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius-lg);
    backdrop-filter: blur(10px);
}

.event-date i, .event-location i {
    font-size: 1.5rem;
}

/* Countdown Timer */
.countdown-timer {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    max-width: 600px;
    margin: 3rem auto;
}

.countdown-item {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-lg);
    padding: 2rem 1rem;
    text-align: center;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: var(--transition);
}

.countdown-item:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.2);
}

.countdown-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--white);
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.countdown-label {
    font-size: 1rem;
    font-weight: 500;
    color: var(--light-color);
    text-transform: lowercase;
}

/* Hero Actions */
.hero-actions {
    margin-top: 3rem;
}

.btn {
    padding: 1rem 2rem;
    font-weight: 600;
    border-radius: var(--border-radius-lg);
    transition: var(--transition);
    text-decoration: none;
    display: inline-block;
    margin: 0.5rem;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--box-shadow-lg);
}

/* Section Styles */
section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 3rem;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: var(--primary-gradient);
    border-radius: 2px;
}

/* About Section */
.about-content {
    font-size: 1.1rem;
    line-height: 1.8;
    text-align: justify;
}

.about-content .lead {
    font-size: 1.1rem;
    line-height: 1.8;
    text-align: justify;
    margin-bottom: 2rem;
}

/* Highlights Section */
.highlight-card {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    text-align: center;
    border: 1px solid rgba(0, 0, 0, 0.1);
    transition: var(--transition);
    height: 100%;
}

.highlight-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--box-shadow-lg);
    border-color: var(--primary-color);
}

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

.highlight-card h4 {
    color: var(--dark-color);
    margin-bottom: 1rem;
    font-weight: 600;
}

/* Call for Papers Section */
.topic-card {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius);
    padding: 1rem;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: var(--transition);
    font-weight: 500;
    margin-bottom: 1rem;
}

.topic-card:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-3px);
}

/* Speakers Section */
.speaker-card {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.speaker-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

.speaker-image {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    border: 5px solid var(--light-color);
}

/* Important Dates Section */
.date-card {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    height: 100%;
}

.date-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

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

.date-highlight {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-top: 1rem;
}

/* Guidelines Section */
.guidelines-content {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--box-shadow);
}

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

.guidelines-list li {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.guidelines-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--success-color);
    font-weight: bold;
    font-size: 1.2rem;
}

/* Paper Submissions Section */
.submission-step {
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: var(--transition);
    height: 100%;
}

.submission-step:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-3px);
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--white);
    color: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1rem;
}

/* Publication & Proceedings Section */
.publication-item, .proceedings-item {
    margin-bottom: 2rem;
}

.publication-number, .proceedings-number {
    width: 60px;
    height: 60px;
    background: var(--primary-gradient);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1rem;
}

/* Registration Section */
.registration-table {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--box-shadow);
}

.registration-row {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--light-color);
    transition: var(--transition);
}

.registration-row:hover {
    background: var(--light-color);
}

.registration-row:last-child {
    border-bottom: none;
}

.category-number {
    width: 40px;
    height: 40px;
    background: var(--primary-gradient);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin-right: 1rem;
}

.category-name {
    font-weight: 500;
    font-size: 1.1rem;
}

.category-fee {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary-color);
}

.registration-notes {
    background: var(--light-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    border-left: 4px solid var(--warning-color);
}

.payment-info {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--box-shadow);
}

.payment-info h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Committee Section Styles */
.committee-card {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    text-align: center;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    height: 100%;
    border-left: 4px solid var(--primary-color);
}

.committee-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

.committee-role {
    color: var(--primary-color);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.committee-name {
    color: var(--dark-color);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.committee-title {
    color: var(--secondary-color);
    font-size: 1rem;
    margin-bottom: 0;
    line-height: 1.4;
}

.committee-section {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--box-shadow);
    border-left: 4px solid var(--success-color);
}

.committee-section-title {
    color: var(--success-color);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.committee-member {
    background: var(--light-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1rem;
    transition: var(--transition);
}

.committee-member:hover {
    background: rgba(13, 110, 253, 0.05);
    transform: translateX(5px);
}

.committee-member h6 {
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.committee-member p {
    color: var(--secondary-color);
    margin-bottom: 0;
    font-size: 0.95rem;
    line-height: 1.4;
}

.committee-group {
    background: var(--white);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    height: 100%;
    border-top: 3px solid var(--primary-color);
}

.committee-group:hover {
    transform: translateY(-3px);
    box-shadow: var(--box-shadow-lg);
}

.committee-group-title {
    color: var(--primary-color);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--light-color);
}

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

.committee-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--light-color);
    color: var(--dark-color);
    font-size: 0.9rem;
    line-height: 1.4;
    transition: var(--transition);
}

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

.committee-list li:hover {
    color: var(--primary-color);
    padding-left: 0.5rem;
}

/* Brochure Modal Styles */
.modal-xl {
    max-width: 1200px;
}

.brochure-carousel {
    position: relative;
    background: var(--dark-color);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.brochure-carousel img {
    max-height: 80vh;
    object-fit: contain;
    background: var(--white);
}

.carousel-navigation {
    position: absolute;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 1rem;
    background: rgba(0, 0, 0, 0.8);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-lg);
    backdrop-filter: blur(10px);
}

.carousel-btn {
    background: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
    cursor: pointer;
}

.carousel-btn:hover:not(:disabled) {
    background: var(--primary-color);
    transform: translateY(-2px);
}

.carousel-btn:disabled {
    background: var(--secondary-color);
    cursor: not-allowed;
    opacity: 0.6;
}

.page-indicator {
    color: var(--white);
    font-weight: 600;
    font-size: 0.9rem;
    min-width: 60px;
    text-align: center;
}

.modal-header {
    background: var(--primary-gradient);
    color: var(--white);
    border-bottom: none;
}

.modal-header .btn-close {
    filter: invert(1);
}

.modal-footer {
    background: #731b05 !important; /* maroon */
    border-top: 1px solid #ffffff;
}
footer {
    background: #731b05 !important; /* maroon */
    color: #ffffff;
}

/* Responsive Design */
@media (max-width: 1200px) {
    .hero-college-name {
        font-size: 3rem;
    }
    
    .main-title {
        font-size: 2.5rem;
    }
    
    .subtitle {
        font-size: 1.25rem;
    }
}

@media (max-width: 992px) {
    .countdown-timer {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .hero-college-name {
        font-size: 2.5rem;
    }
    
    .main-title {
        font-size: 2rem;
    }
    
    .subtitle {
        font-size: 1.1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .event-details {
        gap: 1.5rem;
    }
    
    .institutional-logos {
        gap: 0.5rem;
    }
    
    .inst-logo {
        height: 40px;
    }
}

@media (max-width: 768px) {
    .hero-college-name {
        font-size: 2rem;
    }
    
    .main-title {
        font-size: 1.75rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .countdown-timer {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }
    
    .countdown-number {
        font-size: 2rem;
    }
    
    .conference-main-title {
        padding: 1.5rem;
    }
    
    .btn {
        padding: 0.75rem 1.5rem;
        margin-bottom: 1rem;
    }
    
    .registration-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
        text-align: center;
    }
    
    .category-number {
        margin: 0 auto 0.5rem;
    }
    
    .event-details {
        flex-direction: column;
        gap: 1rem;
    }
    
    .institutional-logos {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .inst-logo {
        height: 35px;
    }
    
    .header-logo.main-logo {
        max-height: 60px;
    }
}

@media (max-width: 576px) {
    .hero-college-name {
        font-size: 1.75rem;
    }
    
    .main-title {
        font-size: 1.5rem;
    }
    
    .countdown-timer {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.75rem;
    }
    
    .countdown-item {
        padding: 1rem 0.5rem;
    }
    
    .countdown-number {
        font-size: 1.5rem;
    }
    
    .countdown-label {
        font-size: 0.875rem;
    }
    
    section {
        padding: 3rem 0;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .topic-card {
        padding: 0.75rem;
        font-size: 0.9rem;
    }
    
    .top-header {
        padding: 0.5rem 0;
    }
    
    .institutional-logos {
        gap: 0.25rem;
    }
    
    .inst-logo {
        height: 30px;
    }
    
    .header-logo.main-logo {
        max-height: 50px;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .hero-actions,
    .btn {
        display: none !important;
    }
    
    .hero-section {
        min-height: auto;
        padding: 2rem 0;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .section-title {
        font-size: 18pt;
        color: black !important;
    }
    
    .hero-college-name {
        font-size: 24pt;
        color: black !important;
    }
}

/* Accessibility Improvements */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for better accessibility */
.btn:focus,
.nav-link:focus {
    outline: 2px solid var(--warning-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .hero-background {
        background: #731b05;
    }
    
    .topic-card,
    .submission-step {
        border: 2px solid white;
    }
    
    .committee-group,
    .committee-card {
        border: 2px solid var(--dark-color);
    }
}

.custom-bg {
    background-color: #731b05;  /* Change to any color */
}

.custom-btn {
  background-color: #731b05; /* same as section bg */
  color: #fff;
  border: none;
  transition: 0.3s;
}

.custom-btn:hover {
  background-color: #731b05; /* slightly lighter shade for hover */
  color: #fff;
}

.custom-footer {
    background: #731b05;  /* maroon */
    color: #fff;
}