/* Modern Design System for I3CEET-2027 (IEEE Style) */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
    /* Primary Color Palette (Deep Blue/IEEE vibe) */
    --primary: #9b0000; /* blue-800 */
    --primary-light: #ba6060; /* blue-500 */
    --accent: #ab3333; /* blue-600 */
    --accent-hover: #9b0000; /* blue-700 */
    
    /* Neutral Colors */
    --bg: #fffcfc;
    --section-bg: #f9fafb; /* gray-50 */
    --text: #111827; /* gray-900 */
    --text-muted: #4b5563; /* gray-600 */
    --border: #e5e7eb; /* gray-200 */
    
    /* Shadows & Transitions */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

*, ::before, ::after {
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    margin: 0;
    overflow-x: hidden;
}

/* Container */
.container {
    width: 100%;
    margin-right: auto;
    margin-left: auto;
    padding-right: 1.5rem;
    padding-left: 1.5rem;
    max-width: 1280px;
}

@media (max-width: 640px) {
    .container {
        padding-right: 1rem;
        padding-left: 1rem;
    }
}

/* Utilities */
.text-center { text-align: center; }
.my-12 { margin-top: 3rem; margin-bottom: 3rem; }
.py-16 { padding-top: 4rem; padding-bottom: 4rem; }
.flex { display: flex; }
.grid { display: grid; }
.gap-8 { gap: 2rem; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-weight: 600;
    border-radius: 9999px;
    transition: var(--transition);
    cursor: pointer;
    text-decoration: none;
    font-size: 0.95rem;
}

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

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background-color: transparent;
    color: var(--accent);
    border: 2px solid var(--accent);
}

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

/* Header */
.modern-header {
    background-color: var(--bg);
    padding: 6rem 0;
    position: relative;
    border-bottom: 1px solid var(--border);
}

.hero-content {
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}

.conference-title {
    font-size: clamp(2rem, 8vw, 4rem);
    font-weight: 800;
    color: #1e3a8a; /* blue-900 */
    margin-bottom: 1rem;
    letter-spacing: -0.025em;
    line-height: 1.1;
}

.conference-subtitle {
    font-size: clamp(1rem, 4vw, 1.5rem);
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    font-weight: 500;
}

.quick-info {
    display: flex;
    justify-content: center;
    gap: 1.5rem 2.5rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text);
    font-weight: 600;
    font-size: clamp(0.9rem, 3vw, 1.1rem);
}

.info-item i {
    color: var(--accent);
    font-size: 1.25rem;
}

/* Navigation */
.modern-nav {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo-img {
    height: 48px;
    width: auto;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

.nav-links a {
    text-decoration: none;
    color: #374151; /* gray-700 */
    font-weight: 600;
    font-size: 0.95rem;
    transition: var(--transition);
}

.nav-links a:hover, .nav-links a.active {
    color: var(--accent);
}

/* Ticker Styles */
#news-ticker-container {
    background-color: var(--accent);
    color: white;
    padding: 0.6rem 0;
    overflow: hidden;
    position: relative;
    z-index: 60;
}

.ticker-content {
    display: inline-block;
    white-space: nowrap;
    padding-left: 100%;
    animation: ticker 25s linear infinite;
}

.ticker-item {
    display: inline-block;
    margin-right: 4rem;
    font-weight: 500;
}

@keyframes ticker {
    0% { transform: translateX(0); }
    100% { transform: translateX(-100%); }
}

/* Sections & Sidebar */
.main-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    margin-bottom: 4rem;
}

.section-card {
    background-color: white;
    padding: 2.5rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
}

.section-title {
    font-size: clamp(1.5rem, 5vw, 2.25rem);
    font-weight: 700;
    color: #1e3a8a;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 4px;
    background-color: var(--accent);
    border-radius: 2px;
}

/* Responsive Table Wrapper */
.table-wrapper {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    margin-bottom: 1rem;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
}

/* Important Dates Table/List */
.date-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.date-card {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background-color: var(--section-bg);
    border-radius: 0.75rem;
    border-left: 4px solid var(--accent);
    transition: var(--transition);
}

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

.date-card .label {
    font-weight: 700;
    color: var(--text);
}

.date-card .value {
    color: var(--accent);
    font-weight: 700;
}

/* Gallery */
.full-width-gallery {
    background-color: var(--section-bg);
    padding: 5rem 0;
    overflow: hidden;
}

.gallery-track {
    display: flex;
    width: max-content;
    animation: scroll 40s linear infinite;
    gap: 1.5rem;
}

.gallery-item {
    width: clamp(250px, 40vw, 350px);
    height: clamp(180px, 30vw, 250px);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.gallery-item:hover img {
    transform: scale(1.1);
}

@keyframes scroll {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

/* Footer */
footer {
    background-color: #111827; /* gray-900 */
    color: white;
    padding: 5rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 4rem;
    margin-bottom: 4rem;
}

.footer-section h4 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    border-bottom: 2px solid #374151;
    padding-bottom: 0.5rem;
    display: inline-block;
}

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

.footer-section ul li {
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: #9ca3af; /* gray-400 */
}

.footer-section a {
    color: #9ca3af;
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: white;
}

/* Committee Card (Left Border Accent) */
.committee-card {
    background-color: white;
    padding: 1.5rem;
    border-radius: 0.5rem;
    border: 1px solid var(--border);
    border-left: 4px solid var(--accent);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.committee-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.committee-name {
    font-size: 1.15rem;
    font-weight: 700;
    color: #1e3a8a;
    display: block;
}

.committee-inst {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Registration Table */
.reg-table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    background-color: white;
    box-shadow: var(--shadow-sm);
    border-radius: 0.5rem;
    overflow: hidden;
}

.reg-table th, .reg-table td {
    padding: 1.25rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.reg-table th {
    background-color: #f3f4f6;
    color: #1e3a8a;
    font-weight: 800;
}

/* Responsive */
@media (max-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .section-card {
        padding: 1.5rem;
    }
}

@media (max-width: 768px) {
    .modern-header {
        padding: 4rem 0;
    }
    
    .nav-links {
        display: none; /* Hide on mobile by default */
    }
    
    .mobile-menu-toggle {
        display: block !important;
        font-size: 1.5rem;
        cursor: pointer;
    }

    .nav-actions {
        display: none; /* Hide button on mobile to save space */
    }
}

/* Mobile Nav Enhancement */
#nav-links.mobile-active {
    display: flex !important;
    animation: slideIn 0.3s ease-out forwards;
}

@keyframes slideIn {
    from { transform: translateX(100%); }
    to { transform: translateX(0); }
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 2.5rem;
    right: 2.5rem;
    width: 3.5rem;
    height: 3.5rem;
    background-color: var(--accent);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: var(--accent-hover);
    transform: translateY(-5px);
}

.back-to-top i {
    font-size: 1.25rem;
}