/* 
   =============================================
   Next-Generation Communication Seminar Styles
   =============================================
*/

:root {
    /* Color Palette */
    --clr-bg-deep: #0a0e17;
    --clr-bg-dark: #121826;
    --clr-glass: rgba(255, 255, 255, 0.05);
    --clr-glass-border: rgba(255, 255, 255, 0.1);
    
    --clr-primary: #00f0ff;
    --clr-secondary: #7000ff;
    --clr-accent: #ff0055;
    
    --clr-text: #f0f4f8;
    --clr-text-muted: #a0aec0;
    
    /* Typography */
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Inter', sans-serif;
    
    /* Spacing & Sizes */
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 2rem;
    --spacing-xl: 4rem;
    --border-radius: 16px;
    
    /* Transitions */
    --transition-smooth: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    min-height: 100vh;
    width: 100%;
    font-family: var(--font-body);
    background-color: var(--clr-bg-deep);
    color: var(--clr-text);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

a {
    text-decoration: none;
    color: var(--clr-primary);
    transition: var(--transition-smooth);
}

ul {
    list-style: none;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.text-center {
    text-align: center;
}

.mt-2 { margin-top: 1rem; }
.mt-4 { margin-top: 2rem; }
.bg-dark { background-color: var(--clr-bg-dark); }
.bg-dark-deep { background-color: var(--clr-bg-deep); }

/* Utility Components */
.grad-text {
    background: linear-gradient(90deg, var(--clr-primary), var(--clr-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.grad-bg {
    background: linear-gradient(135deg, var(--clr-primary), var(--clr-secondary));
}

.glass {
    background: var(--clr-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--clr-glass-border);
}

.glass-card {
    background: var(--clr-glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--clr-glass-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-family: var(--font-heading);
    cursor: pointer;
    border: none;
    outline: none;
    transition: var(--transition-smooth);
}

.btn-primary {
    background: var(--clr-primary);
    color: var(--clr-bg-deep);
    box-shadow: 0 0 15px rgba(0, 240, 255, 0.4);
}

.btn-primary:hover {
    background: #fff;
    color: var(--clr-bg-deep);
    box-shadow: 0 0 25px rgba(255, 255, 255, 0.6);
}

.btn-outline {
    background: transparent;
    color: var(--clr-text);
    border: 1px solid var(--clr-glass-border);
}

.btn-outline:hover {
    background: var(--clr-glass);
    border-color: var(--clr-primary);
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* Header */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 1rem 0;
    transition: var(--transition-smooth);
}

.header.scrolled {
    padding: 0.5rem 0;
    background: rgba(10, 14, 23, 0.85);
    border-bottom: 1px solid var(--clr-glass-border);
}

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

.logo h1 {
    font-size: 1.8rem;
    margin-bottom: 0;
    color: #fff;
}

.logo span {
    color: var(--clr-primary);
}

.logo-sub {
    font-size: 0.7rem;
    color: var(--clr-text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.nav-menu ul {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--clr-text-muted);
    font-weight: 500;
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.nav-link:hover {
    color: var(--clr-primary);
}

.hamburger {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #fff;
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8rem 0 4rem;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image: url('../BITS1.jpeg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    z-index: -2;
}

.hero::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: -1;
}

.hero-bg {
    display: none;
}

.blob {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.4;
    animation: float 10s infinite ease-in-out alternate;
}

.blob-1 {
    width: 400px; height: 400px;
    background: var(--clr-primary);
    top: -100px; left: -100px;
}

.blob-2 {
    width: 500px; height: 500px;
    background: var(--clr-secondary);
    bottom: -150px; right: -150px;
    animation-delay: 2s;
}

.blob-3 {
    width: 300px; height: 300px;
    background: var(--clr-accent);
    top: 40%; left: 40%;
    animation-delay: 4s;
    opacity: 0.2;
}

.badge {
    display: inline-block;
    padding: 0.4rem 1rem;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    color: #fff;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    margin-bottom: 0.5rem;
    color: #ffffff;
    text-shadow: 0 2px 15px rgba(0, 0, 0, 0.55);
}

.hero-subtitle {
    font-size: clamp(1.5rem, 3vw, 2.5rem);
    margin-bottom: 2rem;
    color: rgba(255, 255, 255, 0.9);
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--clr-text-muted);
    max-width: 600px;
    margin: 0 auto 3rem;
}

.hero-info {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    text-align: left;
}

.info-item i {
    font-size: 2rem;
    color: var(--clr-primary);
}

.info-item strong {
    display: block;
    font-size: 1.1rem;
    color: #fff;
}

.info-item span {
    font-size: 0.85rem;
    color: var(--clr-text-muted);
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Sections Base */
.section {
    padding: 6rem 0;
    position: relative;
    z-index: 1;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.section-header {
    margin-bottom: 4rem;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.section-header p {
    color: var(--clr-text-muted);
    font-size: 1.1rem;
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: #fff;
    margin-bottom: 1.5rem;
}

.about-text p {
    color: var(--clr-text-muted);
    margin-bottom: 1rem;
}

.check-list li {
    margin-bottom: 0.8rem;
    display: flex;
    align-items: flex-start;
    gap: 0.8rem;
    color: var(--clr-text-muted);
}

.check-list i {
    color: var(--clr-primary);
    margin-top: 0.3rem;
}

.about-visual {
    position: relative;
    height: 100%;
    min-height: 400px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: linear-gradient(145deg, rgba(255,255,255,0.02), rgba(0,240,255,0.05));
}

.visual-placeholder {
    font-size: 8rem;
    color: rgba(255, 255, 255, 0.1);
    animation: pulse 4s infinite;
}

.stats-card {
    position: absolute;
    bottom: -20px;
    right: -20px;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    max-width: 250px;
}

.stats-card h4 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
    color: var(--clr-primary);
}

.stats-card p {
    font-size: 0.85rem;
    color: var(--clr-text-muted);
}

/* Topics Section */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.topic-card {
    transition: var(--transition-smooth);
}

.hover-lift:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(0, 240, 255, 0.15);
    border-color: rgba(0, 240, 255, 0.3);
}

.topic-icon {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.topic-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

.topic-card ul {
    border-top: 1px solid var(--clr-glass-border);
    padding-top: 1rem;
}

.topic-card li {
    margin-bottom: 0.5rem;
    color: var(--clr-text-muted);
    font-size: 0.95rem;
    position: relative;
    padding-left: 1.5rem;
}

.topic-card li::before {
    content: "•";
    color: var(--clr-primary);
    position: absolute;
    left: 0;
    font-size: 1.2rem;
    line-height: 1;
}

/* Highlights Section */
.features-wrapper {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.feature-item {
    display: flex;
    gap: 1.5rem;
    background: var(--clr-glass);
    padding: 2rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--clr-glass-border);
}

.feature-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: rgba(112, 0, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--clr-secondary);
    flex-shrink: 0;
}

.feature-content h4 {
    font-size: 1.2rem;
    color: #fff;
}

.feature-content p {
    color: var(--clr-text-muted);
}

/* Speakers Section */
.speakers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.speaker-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.speaker-pic {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    margin-bottom: 1.5rem;
    background: var(--clr-bg-deep);
    border: 2px solid var(--clr-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
    box-shadow: 0 0 20px rgba(0, 240, 255, 0.2);
}

.user-placeholder::before {
    content: attr(data-name);
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--clr-glass-border);
}

.speaker-info h3 {
    font-size: 1.2rem;
    margin-bottom: 0.2rem;
}

.speaker-info .role {
    color: var(--clr-primary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1rem;
}

.speaker-abstract {
    font-size: 0.9rem;
    color: var(--clr-text-muted);
    border-top: 1px solid var(--clr-glass-border);
    padding-top: 1rem;
}

.speaker-abstract strong {
    color: #fff;
}

/* Schedule section */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    width: 2px;
    background: var(--clr-glass-border);
    top: 0;
    bottom: 0;
    left: 20px;
}

.timeline-item {
    position: relative;
    margin-bottom: 2rem;
    padding-left: 60px;
}

.timeline-dot {
    position: absolute;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    left: 13px;
    top: 24px;
    box-shadow: 0 0 10px var(--clr-primary);
}

.timeline-content {
    padding: 1.5rem;
}

.session-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.session-num {
    background: rgba(0, 240, 255, 0.1);
    color: var(--clr-primary);
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.session-header h3 {
    font-size: 1.1rem;
    margin-bottom: 0;
}

.timeline-content p {
    color: var(--clr-text-muted);
    font-size: 0.95rem;
    margin-top: 0.5rem;
}

.outcomes-box p {
    color: var(--clr-text-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* Footer */
.footer {
    padding: 4rem 0 2rem;
    border-top: 1px solid var(--clr-glass-border);
}

.footer-logo {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.footer-logo span {
    color: var(--clr-primary);
}

.footer p {
    color: var(--clr-text-muted);
    font-size: 0.9rem;
}

.footer-links {
    margin: 2rem 0;
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

.footer-references small {
    color: rgba(255, 255, 255, 0.3);
}

.copyright {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--clr-glass-border);
}

/* Animations */
@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(30px, -50px) scale(1.1); }
    100% { transform: translate(-20px, 20px) scale(0.9); }
}

@keyframes pulse {
    0%, 100% { opacity: 0.05; transform: scale(1); }
    50% { opacity: 0.15; transform: scale(1.05); }
}

/* Simple Intersection Observer Classes */
.fade-in, .fade-in-up, .fade-in-left, .fade-in-right {
    opacity: 0;
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
    will-change: opacity, transform;
}

.fade-in { transform: translateY(0); }
.fade-in-up { transform: translateY(30px); }
.fade-in-left { transform: translateX(-30px); }
.fade-in-right { transform: translateX(30px); }

.fade-in.is-visible, 
.fade-in-up.is-visible,
.fade-in-left.is-visible,
.fade-in-right.is-visible {
    opacity: 1;
    transform: translate(0);
}

.delay-1 { transition-delay: 0.2s; }
.delay-2 { transition-delay: 0.4s; }
.delay-3 { transition-delay: 0.6s; }
.delay-4 { transition-delay: 0.8s; }
.delay-5 { transition-delay: 1.0s; }

/* Responsive Media Queries */
@media screen and (max-width: 900px) {
    .about-grid {
        grid-template-columns: 1fr;
    }
    
    .stats-card {
        right: 0;
        bottom: 0;
    }
    
    .hero-info {
        flex-direction: column;
        gap: 1rem;
        align-items: center;
    }
    
    .hero-actions {
        flex-direction: column;
        gap: 1rem;
    }
}

@media screen and (max-width: 768px) {
    .hamburger {
        display: block;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 60px;
        flex-direction: column;
        background: rgba(10, 14, 23, 0.95);
        backdrop-filter: blur(10px);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.1);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-menu ul {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .header-cta {
        display: none; /* Hide button on mobile to save space */
    }
    
    .session-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.3rem;
    }
}