:root {
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --secondary: #0ea5e9;
    --accent: #f8fafc;
    --text: #0f172a;
    --text-light: #64748b;
    --bg: #ffffff;
    --bg-light: #f1f5f9;
    --border: #e2e8f0;
    --header-height: 80px;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--header-height);
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--text);
    line-height: 1.6;
    background-color: var(--bg);
    overflow-x: hidden;
}

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

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 6rem 0;
}

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

.bg-accent {
    background-color: var(--primary);
    color: white;
}

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

.mx-auto {
    margin-left: auto;
    margin-right: auto;
}

.w-100 {
    width: 100%;
}

.mt-2 {
    margin-top: 0.5rem;
}

.mt-4 {
    margin-top: 1.5rem;
}

.text-muted {
    color: var(--text-light);
}

.badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 500;
    backdrop-filter: blur(10px);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 6px -1px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-secondary {
    background: white;
    color: var(--text);
}

.btn-secondary:hover {
    background: var(--bg-light);
    transform: translateY(-2px);
}

.bg-accent .btn-primary {
    background: white;
    color: var(--primary);
}

.bg-accent .btn-primary:hover {
    background: var(--bg-light);
}

/* Typography Headings */
h1,
h2,
h3,
h4,
h5,
h6 {
    line-height: 1.2;
    font-weight: 700;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.bg-accent .section-title {
    color: white;
}

.title-underline {
    width: 60px;
    height: 4px;
    background: var(--primary);
    border-radius: 2px;
    margin-bottom: 3rem;
}

.bg-accent .title-underline {
    background: white;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--border);
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-sm);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-menu {
    display: flex;
    gap: 1.5rem;
}

.nav-menu a {
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--text);
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: var(--primary);
}

.lang-switcher select {
    padding: 0.3rem 0.5rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: white;
    cursor: pointer;
    font-weight: 500;
}

.mobile-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    margin: 5px 0;
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding-top: var(--header-height);
    overflow: hidden;
}

.hero-slider {
    position: absolute;
    inset: 0;
    z-index: 0;
}

.hero-slider .slide {
    position: absolute;
    inset: 0;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transform: scale(1.08);
    transition: opacity 1.2s ease-in-out, transform 9s ease-out;
}

.hero-slider .slide.active {
    opacity: 1;
    transform: scale(1);
}

/* Slide Progress Bar */
.slider-progress {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: rgba(255, 255, 255, 0.15);
    z-index: 10;
}

.slider-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--primary), #60a5fa, #38bdf8);
    transition: width linear;
}

/* Slide Counter */
.slide-counter {
    position: absolute;
    bottom: 2.8rem;
    right: 3rem;
    color: rgba(255, 255, 255, 0.85);
    font-size: 0.8rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    z-index: 10;
    display: flex;
    align-items: baseline;
    gap: 0.25rem;
}

.slide-counter .current {
    font-size: 2rem;
    font-weight: 800;
    color: white;
    line-height: 1;
}

/* Slider Dots */
.slider-indicators {
    position: absolute;
    bottom: 2.8rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 0.5rem;
    z-index: 5;
    align-items: center;
}

.slider-dot {
    width: 8px;
    height: 8px;
    border-radius: 4px;
    background: rgba(255, 255, 255, 0.4);
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: none;
    padding: 0;
}

.slider-dot.active {
    background: white;
    width: 30px;
    box-shadow: 0 0 14px rgba(255, 255, 255, 0.7);
}

/* Slider Nav */
.slider-nav {
    position: absolute;
    top: 50%;
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 0 1.5rem;
    transform: translateY(-50%);
    z-index: 10;
    pointer-events: none;
}

.nav-btn {
    width: 58px;
    height: 58px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1.5px solid rgba(255, 255, 255, 0.25);
    pointer-events: auto;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.25);
}

.nav-btn:hover {
    background: rgba(255, 255, 255, 0.22);
    border-color: rgba(255, 255, 255, 0.55);
    transform: scale(1.1);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
}

.nav-btn svg {
    width: 22px;
    height: 22px;
}

@media (max-width: 768px) {
    .slider-nav {
        display: none;
    }
    .slide-counter {
        display: none;
    }
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(
        135deg,
        rgba(10, 18, 50, 0.88) 0%,
        rgba(10, 18, 50, 0.55) 55%,
        rgba(10, 18, 50, 0.2) 100%
    );
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    color: white;
    max-width: 800px;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    margin: 1.5rem 0;
    font-weight: 800;
    letter-spacing: -0.02em;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 2rem;
    max-width: 600px;
    text-shadow: 0 1px 8px rgba(0, 0, 0, 0.25);
}

.hero-location {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
}

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

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

.about-text p {
    margin-bottom: 1.5rem;
    color: var(--text-light);
    font-size: 1.1rem;
}

.about-subtitle {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
}

.feature-list {
    margin-bottom: 2rem;
}

.feature-list li {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
    font-weight: 500;
}

.icon-check {
    color: var(--primary);
    flex-shrink: 0;
}

.payment-info {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 0.5rem;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    border-left: 4px solid var(--secondary);
}

.icon-info {
    color: var(--secondary);
    flex-shrink: 0;
}

.image-wrapper {
    position: relative;
}

.rounded-img {
    border-radius: 1rem;
    width: 100%;
    height: auto;
    object-fit: cover;
}

.experience-badge {
    position: absolute;
    bottom: -2rem;
    left: -2rem;
    background: white;
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
}

.experience-badge .years {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.experience-badge .text {
    font-size: 0.875rem;
    color: var(--text-light);
    font-weight: 600;
}

/* Cards Grid */
.grid {
    display: grid;
    gap: 2rem;
}

.cards-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

.card {
    background: white;
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

.committee-card.chairman {
    border: 2px solid var(--primary);
}

.avatar-placeholder {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--primary-dark);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1.5rem;
}

.member-name {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.member-role {
    color: var(--primary);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.member-uni {
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Lecturers */
.lecturers-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
}

.lecturer-card {
    background: white;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
}

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

.lecturer-img {
    height: 250px;
    background: var(--bg-light);
}

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

.lecturer-info {
    padding: 1.5rem;
    text-align: center;
}

.lecturer-title {
    color: var(--text-light);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

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

.timeline::before {
    content: '';
    position: absolute;
    left: 80px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    position: relative;
}

.timeline-date {
    width: 60px;
    flex-shrink: 0;
    text-align: right;
    padding-top: 0.5rem;
}

.timeline-date .day {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1;
    color: var(--primary);
}

.timeline-date .month {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    color: var(--text-light);
}

.timeline-content {
    background: white;
    padding: 1.5rem;
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    flex-grow: 1;
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: -26px;
    top: 1.5rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--primary);
    border: 4px solid var(--bg-light);
}

.timeline-content .time {
    font-weight: 600;
    color: var(--secondary);
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
}

/* ── Media Section ── */
.media-tabs-wrap {
    display: flex;
    justify-content: center;
    margin-bottom: 2.5rem;
}

.media-tabs {
    display: inline-flex;
    gap: 0.375rem;
    background: white;
    border-radius: 14px;
    padding: 0.375rem;
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.09);
}

.media-tab {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.65rem 1.6rem;
    border-radius: 10px;
    border: none;
    background: transparent;
    color: var(--text-light);
    font-size: 0.925rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.22s ease, color 0.22s ease, box-shadow 0.22s ease;
    white-space: nowrap;
    line-height: 1;
}

.media-tab.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.28);
}

.media-tab:not(.active):hover {
    background: var(--bg-light);
    color: var(--text);
}

.media-pane {
    display: none;
}

.media-pane.active {
    display: block;
}

/* Videos grid */
.videos-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.video-card {
    border-radius: 14px;
    overflow: hidden;
    background: white;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.07);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 14px 40px rgba(0, 0, 0, 0.13);
}

.video-thumb {
    background: #000;
    aspect-ratio: 16 / 9;
    overflow: hidden;
}

.video-thumb video {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: contain;
    background: #000;
}

.video-info {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    padding: 0.85rem 1rem;
    border-top: 1px solid var(--border);
}

.video-play-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.video-title {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text);
    line-height: 1.4;
    margin: 0;
}

.media-empty {
    text-align: center;
    padding: 5rem 2rem;
    color: var(--text-light);
    opacity: 0.4;
}

.media-empty p {
    margin-top: 1rem;
    font-size: 1rem;
}

/* Gallery */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.gallery-item {
    position: relative;
    border-radius: 1rem;
    overflow: hidden;
    aspect-ratio: 4/3;
    cursor: pointer;
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.gallery-overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.8), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
    display: flex;
    align-items: flex-end;
    padding: 1.5rem;
}

.gallery-item:hover .gallery-overlay {
    opacity: 1;
}

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

.gallery-caption {
    color: white;
    font-weight: 500;
    transform: translateY(20px);
    transition: transform 0.3s ease;
}

.gallery-item:hover .gallery-caption {
    transform: translateY(0);
}

/* Registration */
.register-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.contact-card {
    background: rgba(255, 255, 255, 0.1);
    padding: 1.5rem;
    border-radius: 0.5rem;
    backdrop-filter: blur(5px);
}

.contact-card .price {
    font-size: 1.5rem;
    margin-top: 0.5rem;
    background: white;
    color: var(--text);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text);
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    font-family: inherit;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Contacts */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    text-align: center;
}

.contact-item .icon-wrapper {
    width: 64px;
    height: 64px;
    background: var(--bg-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: var(--primary);
}

.contact-item h3 {
    margin-bottom: 0.5rem;
}

.contact-item p {
    color: var(--text-light);
}

/* Footer */
.footer {
    background: var(--text);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.footer-info h3 {
    margin-bottom: 1rem;
}

.footer-info p {
    color: #94a3b8;
    max-width: 600px;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    text-align: center;
    color: #94a3b8;
    font-size: 0.875rem;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate {
    animation: fadeIn 0.8s ease forwards;
}

/* Responsive */
@media (max-width: 992px) {

    .about-grid,
    .register-container {
        grid-template-columns: 1fr;
    }

    .experience-badge {
        left: 2rem;
    }

    .contact-grid {
        grid-template-columns: 1fr;
    }

    .videos-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 2rem;
        box-shadow: var(--shadow);
        clip-path: circle(0 at 100% 0);
        transition: clip-path 0.4s ease-in-out;
    }

    .nav-menu.active {
        clip-path: circle(150% at 100% 0);
    }

    .mobile-toggle {
        display: block;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-actions {
        flex-direction: column;
    }

    .videos-grid {
        grid-template-columns: 1fr;
    }

    .media-tab {
        padding: 0.6rem 1.1rem;
        font-size: 0.85rem;
    }
}