:root {
    --primary-color: #6842ff; /* Vibrant purple */
    --primary-rgb: 104, 66, 255;
    --secondary-color: #2c2c54; /* Deep blue/purple */
    --accent-color: #ff6b6b; /* Coral accent */
    --light-bg: #f8f9fa;
    --dark-text: #212529;
    --muted-text: #6c757d;
    --card-shadow: 0 8px 25px rgba(0, 0, 0, 0.07);
    --card-hover-shadow: 0 12px 35px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
}

body {
    font-family: 'Poppins', 'Noto Sans KR', sans-serif;
    color: var(--dark-text);
    line-height: 1.7;
    background-color: #ffffff;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    color: var(--secondary-color);
    letter-spacing: -0.5px; /* Subtle tightening */
}

.section-padding {
    padding: 80px 0;
}

.section-title {
    font-size: 2.5rem; /* Slightly larger */
    font-weight: 700;
    margin-bottom: 50px;
    position: relative;
    padding-bottom: 15px;
}

.section-title::after {
    content: '';
    position: absolute;
    display: block;
    width: 60px;
    height: 4px;
    background: var(--primary-color);
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    border-radius: 2px;
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--primary-color);
    font-weight: 500;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* --- Navbar Refinements --- */
.navbar {
    padding: 1rem 0;
    background-color: rgba(255, 255, 255, 0.95); /* Slightly transparent */
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.6rem;
    color: var(--primary-color);
}

.navbar .nav-link {
    font-weight: 500;
    color: var(--secondary-color);
    transition: color 0.3s ease;
    margin: 0 0.5rem;
    padding: 0.5rem 0.8rem;
    border-radius: 8px;
}

.navbar .nav-link:hover,
.navbar .nav-link.active {
    color: var(--primary-color);
    background-color: rgba(var(--primary-rgb), 0.08); /* Subtle background on hover */
}

.navbar-toggler {
    border: none;
}

.navbar-toggler:focus {
    box-shadow: none;
}

/* --- Hero Section Refinements --- */
.hero-section {
    /* Existing styles */
    background: linear-gradient(rgba(var(--primary-rgb), 0.1), rgba(var(--secondary-color), 0.1)), url('../images/hero-bg-placeholder.jpg') no-repeat center center;
    background-size: cover;
    color: var(--dark-text); /* Adjust text color for better readability on potential image */
    padding: 120px 0; /* More padding */
}

.hero-section h1 {
    font-size: 3.5rem; /* Larger heading */
    font-weight: 700;
    color: var(--secondary-color); /* Ensure contrast */
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-section .lead {
    font-size: 1.2rem;
    color: var(--muted-text);
    max-width: 600px;
    margin: 0 auto 40px auto;
}

/* --- Button Refinements --- */
.custom-btn {
    background: linear-gradient(135deg, var(--primary-color), #8a61ff);
    color: white;
    border: none;
    padding: 12px 30px;
    font-weight: 500;
    border-radius: 50px; /* Pill shape */
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(var(--primary-rgb), 0.3);
    display: inline-block;
}

.custom-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(var(--primary-rgb), 0.4);
    color: white;
}

.custom-btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 10px 28px;
    font-weight: 500;
    border-radius: 50px;
    transition: all 0.3s ease;
}

.custom-btn-outline:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

/* --- Card Refinements --- */
.card {
    border: none;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    overflow: hidden; /* Ensure content fits */
}

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

.card-img-top {
    aspect-ratio: 16 / 10; /* Consistent image ratio */
    object-fit: cover;
}

.card-title {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.card-text {
    color: var(--muted-text);
    font-size: 0.95rem;
}

/* --- Specific Section Styles --- */
#about {
    background-color: var(--light-bg);
}

#schedule .timeline {
    position: relative;
    padding: 20px 0;
}

#schedule .timeline::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    width: 3px;
    background: rgba(var(--primary-rgb), 0.2);
    left: 50%;
    margin-left: -1.5px;
    border-radius: 2px;
}

#schedule .timeline-item {
    margin-bottom: 40px;
    position: relative;
}
#schedule .timeline-item::after {
    content: "";
    display: table;
    clear: both;
}

#schedule .timeline-badge {
    color: #fff;
    width: 50px;
    height: 50px;
    line-height: 50px;
    font-size: 1.4em;
    text-align: center;
    position: absolute;
    top: 16px;
    left: 50%;
    margin-left: -25px;
    background-color: var(--primary-color);
    z-index: 100;
    border-radius: 50%;
    display: flex; /* Center icon */
    align-items: center; /* Center icon */
    justify-content: center; /* Center icon */
    box-shadow: 0 0 0 4px white, inset 0 2px 0 rgba(0, 0, 0, 0.08), 0 3px 0 4px rgba(0, 0, 0, 0.05);
}

#schedule .timeline-panel {
    width: 45%;
    float: left;
    border: 1px solid #e0e0e0;
    border-radius: var(--border-radius);
    padding: 25px;
    position: relative;
    background: #fff;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
}

#schedule .timeline-item:nth-child(odd) .timeline-panel {
    float: right;
}

#schedule .timeline-panel::before {
    content: ' ';
    display: inline-block;
    position: absolute;
    width: 0;
    height: 0;
    border-style: solid;
    top: 26px;
}

#schedule .timeline-item:nth-child(even) .timeline-panel::before {
    right: -15px;
    border-width: 15px 0 15px 15px;
    border-color: transparent transparent transparent #e0e0e0;
}
#schedule .timeline-item:nth-child(odd) .timeline-panel::before {
    left: -15px;
    border-width: 15px 15px 15px 0;
    border-color: transparent #e0e0e0 transparent transparent;
}

#schedule .timeline-heading h4 {
    margin-top: 0;
    color: var(--secondary-color);
    font-weight: 600;
    font-size: 1.2rem;
}
#schedule .timeline-heading .text-muted {
    font-size: 0.9rem;
}

/* Speaker/Host Card Specifics */
.speaker-card .card-img-top, .host-card .card-img-top {
    border-bottom: 4px solid var(--primary-color);
    border-radius: var(--border-radius) var(--border-radius) 0 0;
}

.speaker-card .card-body, .host-card .card-body {
    padding: 25px;
}

/* Call to Action Section */
#cta {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 60px 0;
    text-align: center;
}
#cta h2 {
    color: white;
    font-weight: 700;
    margin-bottom: 15px;
}
#cta p {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 30px;
}
#cta .custom-btn {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 4px 15px rgba(0,0,0, 0.2);
}
#cta .custom-btn:hover {
    background: #f1f1f1;
    color: var(--primary-color);
    box-shadow: 0 8px 25px rgba(0,0,0, 0.3);
}

/* --- Footer Refinements --- */
.footer {
    background-color: var(--secondary-color);
    color: rgba(255, 255, 255, 0.8);
    padding: 50px 0 30px;
    font-size: 0.95rem;
}

.footer a {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer a:hover {
    color: white;
}

.footer .social-icons a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.4rem;
    margin: 0 10px;
    transition: color 0.3s ease, transform 0.3s ease;
}

.footer .social-icons a:hover {
    color: white;
    transform: translateY(-2px);
}

.footer h5 {
    color: white;
    font-weight: 600;
    margin-bottom: 15px;
}

.footer .list-unstyled li {
    margin-bottom: 8px;
}

/* --- Testimonial Card Styles --- */
.testimonial-card {
    border: none;
    border-radius: 15px;
    background-color: var(--light-bg);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.testimonial-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.12);
}

.testimonial-card .card-body {
    padding: 2rem;
}

.testimonial-card .blockquote {
    margin-bottom: 0;
}

.testimonial-card .blockquote p {
    font-size: 1.05rem;
    color: var(--dark-text);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.testimonial-card .blockquote-footer {
    font-size: 0.9rem;
    color: var(--muted-text);
}

.testimonial-card .blockquote-footer cite {
    font-style: normal;
    color: var(--primary-color);
    font-weight: 500;
}

/* --- Admin Page Styles --- */
.admin-card .card-header {
    border-bottom: 1px solid #dee2e6;
}

.admin-table {
    border-collapse: collapse; /* Optional: removes space between borders */
    width: 100%;
    font-size: 0.9rem; /* Slightly smaller font for table */
}

.admin-table th,
.admin-table td {
    padding: 0.75rem; /* Adjust padding */
    vertical-align: middle;
    border-top: 1px solid #dee2e6;
    white-space: nowrap; /* Prevent text wrapping, enables horizontal scroll */
}

.admin-table td:not(:first-child):not(:nth-child(2)) {
    /* Allow wrapping for longer text fields if needed, adjust selector as necessary */
     white-space: normal;
     min-width: 150px; /* Give some minimum width to text fields */
}

.admin-table-header th {
    background-color: #f8f9fa; /* Light grey background for header */
    font-weight: 600;
    border-top: none; /* Remove top border for header */
    border-bottom: 2px solid #dee2e6; /* Stronger bottom border for header */
    white-space: nowrap; /* Ensure headers don't wrap */
}

/* Ensure responsive wrapper allows scrolling */
.table-responsive {
    overflow-x: auto;
}

/* Keep last row bottom border */
.admin-table tbody tr:last-child td {
    border-bottom: none;
}

/* --- Responsive Refinements --- */
@media (max-width: 767.98px) {
    .hero-section h1 {
        font-size: 2.5rem;
    }
    .hero-section .lead {
        font-size: 1.1rem;
    }
    .section-title {
        font-size: 2rem;
    }
    #schedule .timeline::before {
        left: 25px; /* Adjust timeline line */
    }
    #schedule .timeline-item:nth-child(even) .timeline-panel,
    #schedule .timeline-item:nth-child(odd) .timeline-panel {
        width: calc(100% - 75px); /* Adjust panel width */
        float: right;
    }
    #schedule .timeline-badge {
        left: 25px;
        margin-left: 0;
    }
     #schedule .timeline-item:nth-child(even) .timeline-panel::before,
     #schedule .timeline-item:nth-child(odd) .timeline-panel::before {
        border-width: 15px 15px 15px 0;
        border-color: transparent #e0e0e0 transparent transparent;
        left: -15px;
        right: auto;
    }
}