:root {
    --primary-bg: #f8fafc;
    --secondary-bg: #ffffff;
    --primary-text: #0f172a;
    --secondary-text: #475569;
    --accent-color: #4f46e5;
    --accent-hover: #4338ca;
    --border-color: #e2e8f0;
    --box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --rounded-lg: 0.75rem;
    --transition-duration: 0.3s;
    --animation-duration: 0.6s;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    line-height: 1.7;
    overflow-x: hidden;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.header {
    background-color: var(--secondary-bg);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    border-bottom: 1px solid var(--border-color);
}

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

.navbar .nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.navbar .nav-links a {
    color: var(--primary-text);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    padding-bottom: 5px;
}

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

.navbar .nav-links a:hover::after {
    width: 100%;
}

.hero {
    padding: 120px 0;
    background-color: var(--primary-bg);
    position: relative;
    overflow: hidden;
    display: flex; 
    align-items: center;
    justify-content: center;
    min-height: 80vh; 
}

#particles-js {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 1; 
}

.hero-overlay {
    position: relative; 
    z-index: 2; 
    width: 100%;
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.hero-content {
   max-width: 750px;
}

.hero h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--primary-text);
}

.hero h1 .highlight {
    color: var(--accent-color);
}

.hero p {
    font-size: 1.1rem;
    margin-bottom: 2.5rem;
    color: var(--secondary-text);
}

.btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: #fff;
    padding: 14px 28px;
    border-radius: var(--rounded-lg);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color var(--transition-duration) ease, transform 0.2s ease;
    border: none;
}

.btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-3px);
}

.section {
    padding: 80px 0;
    position: relative;
}

/* KODE BARU DITAMBAHKAN DI SINI */
/* Memberi ruang di atas section agar tidak tertutup header sticky */
#about, #speakers, #schedule, #packages {
  scroll-margin-top: 100px;
}

.section-light {
    background-color: #f1f5f9;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.section-subtitle {
    text-align: center;
    font-size: 1.1rem;
    color: var(--secondary-text);
    margin-bottom: 4rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.schedule-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.schedule-card {
    background: var(--secondary-bg);
    border-left: 5px solid var(--accent-color);
    padding: 1.5rem 2rem;
    border-radius: var(--rounded-lg);
    box-shadow: var(--box-shadow);
    text-align: center;
    transition: transform var(--transition-duration) ease, box-shadow var(--transition-duration) ease;
}

.schedule-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 20px -5px rgb(0 0 0 / 0.15), 0 5px 8px -6px rgb(0 0 0 / 0.15);
}

.schedule-card .session-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
    margin-bottom: 0.5rem;
}

.schedule-card .session-time {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: 0.5rem;
}

.schedule-card .session-date {
    font-size: 1rem;
    color: var(--secondary-text);
}


.packages-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    align-items: stretch;
}

.package-card {
    background-color: var(--secondary-bg);
    padding: 2.5rem;
    border-radius: var(--rounded-lg);
    box-shadow: var(--box-shadow);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: transform var(--transition-duration) ease;
}

.package-card:hover {
    transform: scale(1.03);
}

.package-card.featured {
    border-color: var(--accent-color);
    border-width: 2px;
}

.package-card h3 {
    font-size: 1.75rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 1rem;
}

.package-card .price {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-color);
    text-align: center;
    margin-bottom: 2rem;
}

.package-card ul {
    list-style: none;
    margin-bottom: 2rem;
    flex-grow: 1;
}

.package-card ul li {
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    color: var(--secondary-text);
}

.package-card ul li::before {
    content: '✓';
    color: var(--accent-color);
    font-weight: 700;
    margin-right: 12px;
    margin-top: 2px;
}

.footer {
    background-color: #0f172a;
    color: #94a3b8;
    text-align: center;
    padding: 2rem 0;
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity var(--animation-duration) ease-out, transform var(--animation-duration) ease-out;
}

.animate-on-scroll.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.navbar .logo {
    display: flex;
    align-items: center;
    gap: 15px; 
}

.navbar .logo img {
    height: 60px; 
    width: auto;
}

.package-button-container {
    margin-top: auto; 
    padding-top: 1rem; 
    text-align: center; 
}

@media (max-width: 768px) {
    .navbar .nav-links {
        display: none;
    }
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .packages-grid {
        grid-template-columns: 1fr;
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    .package-card {
        width: 90%;
        max-width: 400px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .navbar .logo {
        gap: 10px; 
    }

    .navbar .logo img {
        height: 35px; 
    }

    .footer .container {
        max-width: none;
    }
}