:root {
    --primary: #1d4ed8;
    --primary-dark: #1e40af;
    --secondary: #f97316;
    --background: #ffffff;
    --background-alt: #f1f5f9;
    --text: #1f2937;
    --text-light: #475569;
    --border: #e2e8f0;
    --shadow: 0 20px 40px rgba(15, 23, 42, 0.1);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: 'Roboto', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text);
    background-color: var(--background);

    /*background-image: url("back.jpeg");
    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-position: center;
    */

    overflow-x: hidden;
}

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

a:hover,
a:focus {
    color: var(--primary);
}

.container {
    width: min(1240px, 92vw);
    margin: 0 auto;
}

[data-animate] {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate].is-visible {
    opacity: 1;
    transform: translateY(0);
}

.navbar {
    position: sticky;
    top: 0;
    width: 100%;
    background: rgba(60, 200, 255, 0.95);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    backdrop-filter: blur(8px);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    gap: 1.25rem;
}

.brand {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.brand-mark {
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-size: 0.75rem;
}

.brand-text {
    font-size: 0.95rem;
    font-weight: 500;
}

.nav-links {
    display: flex;
    gap: 1.25rem;
    align-items: center;
    font-size: 0.95rem;
    flex-wrap: wrap;
    justify-content: flex-end;
}

.nav-links a {
    font-weight: 500;
    padding: 0.25rem 0;
    border-bottom: 2px solid transparent;
}

.nav-links a:hover,
.nav-links a:focus {
    border-color: var(--primary);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--text);
}

.hero {
    padding: 6rem 0 4rem;
    color: #fff;

    /* Transparent overlay + background image */
    background:
        linear-gradient(
            rgba(0, 0, 0, 0.55),   /* top transparency */
            rgba(0, 0, 0, 0.55)    /* bottom transparency */
        ),
        url("back.jpeg");

    background-size: cover;
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-position: center;
}

.hero-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2.5rem;
    align-items: center;
}

.hero-text h1 {
    font-size: clamp(2.3rem, 4vw, 3.2rem);
    margin: 0.75rem 0 1rem;
    color: rgba(25, 255, 255, .75);
}

.hero-text .lead {
    max-width: 42ch;
    line-height: 1.6;
    color: rgba(255, 255, 255, 1);
}

.eyebrow {
    font-weight: 500;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.75);
}

.hero-cta {
    display: flex;
    gap: 1rem;
    margin: 1.5rem 0 2.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.6rem;
    border-radius: 999px;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    cursor: pointer;
    border: none;
}

.btn.primary {
    background: var(--secondary);
    color: #fff;
    box-shadow: 0 10px 25px rgba(249, 115, 22, 0.35);
}

.btn.primary:hover,
.btn.primary:focus {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(249, 115, 22, 0.4);
}

.btn.secondary {
    background: rgba(255, 255, 255, 0.18);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.4);
}

.btn.secondary:hover,
.btn.secondary:focus {
    background: rgba(255, 255, 255, 0.28);
}

.btn.ghost {
    background: transparent;
    border: 1px solid currentColor;
    color: inherit;
}

.btn.ghost:hover,
.btn.ghost:focus {
    background: rgba(255, 255, 255, 0.12);
}

.countdown {
    display: grid;
    grid-template-columns: repeat(4, minmax(60px, 1fr));
    gap: 0.75rem;
}

.countdown-segment {
    background: rgba(15, 23, 42, 0.35);
    border-radius: 0.85rem;
    padding: 0.9rem 0.4rem;
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
}

.countdown-value {
    display: block;
    font-size: 1.8rem;
    font-weight: 700;
}

.countdown-label {
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.7);
}

.hero-card {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1.25rem;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    box-shadow: var(--shadow);
}

.hero-card-title {
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: rgba(255, 255, 255, 0.65);
    margin: 0;
}

.hero-logos {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1.5rem;
    align-items: center;
}

.hero-logos img {
    max-height: 112px;
    max-width: 320px;
    background: rgba(255, 255, 255, 0.92);
    border-radius: 0.85rem;
    padding: 0.6rem 0.9rem;
    box-shadow: 0 14px 25px rgba(15, 23, 42, 0.25);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
    object-fit: contain;
}

.hero-logos img:hover,
.hero-logos img:focus {
    transform: translateY(-4px);
    box-shadow: 0 16px 34px rgba(15, 23, 42, 0.35);
}

.section {
    padding: 5rem 0;
}

.section.light {
    background: var(--background-alt);
}

.section-header {
    text-align: center;
    max-width: 650px;
    margin: 0 auto 3rem;
}

.section-eyebrow {
    display: inline-block;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-size: 0.8rem;
    color: var(--secondary);
    margin-bottom: 0.6rem;
}

.section-header h2 {
    margin: 0.5rem 0;
    font-size: clamp(2rem, 3vw, 2.5rem);
}

.section-header p {
    color: var(--text-light);
    line-height: 1.6;
}

.card {
    background: #fff;
    border-radius: 1.25rem;
    padding: 2rem;
    border: 1px solid var(--border);
    box-shadow: 0 10px 35px rgba(15, 23, 42, 0.08);
}

.card h3 {
    margin-top: 0;
}

.about-grid {
    display: grid;
    gap: 2rem;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.about-card {
    position: relative;
    overflow: hidden;
    padding-top: 2.75rem;
    border: none;
    background: linear-gradient(135deg, rgba(29, 78, 216, 0.08), rgba(15, 23, 42, 0.05));
    box-shadow: 0 25px 45px rgba(15, 23, 42, 0.12);
    backdrop-filter: blur(6px);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    display: flex;
    flex-direction: column;
}

.about-card::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top right, rgba(30, 64, 175, 0.18), transparent 55%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.about-card:hover,
.about-card:focus-within {
    transform: translateY(-6px);
    box-shadow: 0 30px 55px rgba(15, 23, 42, 0.16);
}

.about-card:hover::after,
.about-card:focus-within::after {
    opacity: 1;
}
.card li{
    margin-bottom: 10px;
}

.objectives ul {
    margin: 0;
    padding-left: 1.25rem;
    line-height: 1.7;
    letter-spacing: 0.01em;
}

.objectives li::marker {
    color: var(--primary);
    font-weight: 600;
}

.accordion details {
    border: 1px solid var(--border);
    border-radius: 1rem;
    padding: 1rem 1.25rem;
    background: #fff;
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.05);
}

.accordion details+details {
    margin-top: 1rem;
}

.accordion summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    cursor: pointer;
    font-weight: 600;
    font-size: 1.05rem;
    list-style: none;
}

.accordion summary::-webkit-details-marker {
    display: none;
}

.accordion summary::marker {
    display: none;
}
.accordion summary::after {
    content: '▼';
    font-size: 0.9rem;
    transition: transform 0.3s ease;
}

.accordion details[open] summary::after {
    transform: rotate(180deg);
}

.details-content {
    margin-top: 1rem;
    color: var(--text-light);
    line-height: 1.7;
}

.subthemes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.subtheme-card {
    background: var(--background-alt);
    border-radius: 1rem;
    padding: 1.25rem;
    border: 1px solid var(--border);
}

.subtheme-card h4 {
    margin: 0 0 0.75rem;
}

.subtheme-card ul {
    margin: 0;
    padding-left: 1.1rem;
}

.timeline {
    position: relative;
    display: flex;
    flex-direction: column;
    gap: 2.75rem;
    align-items: center;
}

.timeline-item {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: center;
    gap: 2.5rem;
    width: min(900px, 100%);
}

.timeline-panel {
    background: #fff;
    border-radius: 1.25rem;
    padding: 1.75rem;
    border: 1px solid rgba(29, 78, 216, 0.18);
    box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
    display: grid;
    gap: 0.6rem;
}

.timeline-panel h3 {
    margin: 0;
}

.timeline-panel p {
    margin: 0;
    color: var(--text-light);
}

.timeline-marker {
    position: relative;
    grid-column: 2;
    justify-self: center;
    display: flex;
    align-items: center;
    justify-content: center;
}

.timeline-marker::before {
    content: '';
    position: absolute;
    width: 2px;
    background: linear-gradient(180deg, rgba(29, 78, 216, 0.35), rgba(15, 23, 42, 0.08));
    top: -100%;
    bottom: -100%;
}

.timeline-item:first-child .timeline-marker::before {
    top: 50%;
}

.timeline-item:last-child .timeline-marker::before {
    bottom: 50%;
}

.timeline-date {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 108px;
    height: 108px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    text-transform: uppercase;
    box-shadow: 0 20px 38px rgba(29, 78, 216, 0.35);
    padding: 0.6rem;
    text-align: center;
    line-height: 1.1;
}

.timeline-date-day {
    font-size: 1.7rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    white-space: nowrap;
}

.timeline-date-month {
    font-size: 0.95rem;
    letter-spacing: 0.2em;
}

.timeline-date-year {
    font-size: 0.8rem;
    opacity: 0.85;
}

.timeline-item:nth-child(odd) .timeline-panel {
    grid-column: 1;
    justify-self: end;
    text-align: right;
}

.timeline-item:nth-child(even) .timeline-panel {
    grid-column: 3;
    justify-self: start;
    text-align: left;
}

.registration-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
}

.fee-table {
    display: grid;
    gap: 0.75rem;
}

.venue-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    align-items: stretch;
}

.venue-card {
    flex: 1 1 320px;
    display: flex;
}

.map {
    flex: 1;
    border-radius: 1.25rem;
    overflow: hidden;
    border: 1px solid var(--border);
    box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
    background: #fff;
}

.map iframe {
    display: block;
    width: 100%;
    height: 100%;
    min-height: 360px;
    border: 0;
}

.venue-card.info-card .card {
    width: 100%;
    display: grid;
    gap: 1rem;
}

.travel-list {
    margin: 0;
    padding-left: 1.1rem;
    line-height: 1.75;
    letter-spacing: 0.01em;
}

.travel-note {
    margin: 0;
    color: var(--text-light);
}

.attraction-gallery {
    margin-top: 3rem;
    display: grid;
    gap: 1.5rem;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.attraction-card {
    position: relative;
    min-height: 280px;
    padding: 1.75rem;
    border-radius: 1.5rem;
    background-image: linear-gradient(180deg, rgba(15, 23, 42, 0.55), rgba(15, 23, 42, 0.45)), var(--bg-image);
    background-size: cover;
    background-position: center;
    color: #fff;
    display: flex;
    align-items: flex-start;
    justify-content: flex-start;
    box-shadow: 0 25px 45px rgba(15, 23, 42, 0.28);
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.attraction-card::before {
    content: '';
    position: absolute;
    inset: 0;
    mix-blend-mode: multiply;
}

.attraction-card:hover,
.attraction-card:focus-within {
    transform: translateY(-6px);
    box-shadow: 0 30px 55px rgba(15, 23, 42, 0.4);
}

.attraction-content {
    position: relative;
    z-index: 1;
    display: grid;
    gap: 0.75rem;
}

.attraction-content h3 {
    margin: 0;
    font-size: 1.3rem;
    letter-spacing: -0.01em;
}

.attraction-content ul {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 0.45rem;
}

.attraction-content li {
    line-height: 1.6;
    letter-spacing: 0.01em;
}

.attraction-content strong {
    font-weight: 700;
}

.payment-box {
    background: var(--background-alt);
    border-radius: 1rem;
    padding: 1.25rem;
    border: 1px solid var(--border);
    display: grid;
    gap: 0.5rem;
}

.register-cta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.committee-list {
    margin: 0;
    padding-left: 1.1rem;
    line-height: 1.8;
}

.committee-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin: 0;
    padding-left: 1rem;
}

.sponsorship-grid {
    display: grid;
    gap: 1.5rem;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.sponsorship-card {
    border-top: 4px solid var(--primary);
    text-align: center;
}

.sponsorship-card h3 {
    margin: 0 0 0.5rem;
}

.price {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary);
}

.sponsorship-card ul {
    list-style: none;
    padding: 0;
    margin: 1rem 0 0;
    color: var(--text-light);
    line-height: 1.7;
}

.center {
    text-align: center;
    margin-top: 2.5rem;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    align-items: start;
}

.contact-card p {
    line-height: 1.6;
    color: var(--text-light);
}

.contact-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.contact-form {
    display: grid;
    gap: 1rem;
}

.form-row {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-row label {
    font-weight: 600;
}

.form-row input,
.form-row textarea {
    background: var(--background-alt);
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: 0.75rem 0.9rem;
    font-size: 1rem;
    font-family: inherit;
}

.form-row input:focus,
.form-row textarea:focus {
    outline: 2px solid rgba(29, 78, 216, 0.35);
    border-color: var(--primary);
}

.form-note {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-light);
}

.footer {
    background: #0f172a;
    color: rgba(255, 255, 255, 0.72);
    padding: 1.5rem 0;
}

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

.back-to-top {
    color: rgba(255, 255, 255, 0.72);
    background: rgba(255, 255, 255, 0.1);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s ease;
}

.back-to-top:hover,
.back-to-top:focus {
    background: rgba(255, 255, 255, 0.25);
}

@media (max-width: 1200px) {
    .nav-toggle {
        display: block;
    }

    .nav-links {
        position: absolute;
        top: 100%;
        right: 1rem;

        background: rgba(255, 255, 255, 0.97);
        flex-direction: column;
        align-items: flex-start;
        padding: 1rem 1.5rem;
        border: 1px solid var(--border);
        border-radius: 0.85rem;
        margin: 0;
        box-shadow: 0 20px 40px rgba(15, 23, 42, 0.12);
        transform: scale(0.9);
        transform-origin: top right;
        opacity: 0;
        visibility: hidden;
        width: min(320px, calc(100vw - 2rem));
        pointer-events: none;
        transition: opacity 0.2s ease,
            transform 0.2s ease;
    }

    .nav-links.show {
        opacity: 1;
        visibility: visible;
        transform: scale(1);
        pointer-events: auto;
    }

    .timeline {
        gap: 2rem;
    }

    .timeline::before {
        left: 12px;
    }

    .timeline-item {
        grid-template-columns: 30px 1fr;
    }
}

@media (max-width: 900px) {
    .venue-grid {
        flex-direction: column;
    }

    .map iframe {
        min-height: 280px;
    }
}

@media (max-width: 640px) {
    .timeline-item {
        grid-template-columns: minmax(0, 1fr);
        gap: 2rem;
        text-align: left;
    }

    .timeline-panel {
        justify-self: center;
        text-align: left !important;
        width: 100%;
    }

    .timeline-marker {
        order: -1;
    }

    .timeline-marker::before {
        display: none;
    }

    .hero {
        padding-top: 5rem;
    }

    .hero-cta {
        flex-direction: column;
        align-items: flex-start;
    }

    .countdown {
        grid-template-columns: repeat(2, minmax(60px, 1fr));
    }

    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }

    .timeline-date {
        width: 92px;
        height: 92px;
    }

    .attraction-card {
        min-height: 220px;
    }

}