/* utilities */
.flex-box {
    display: flex;
    justify-content: center;
    align-items: center;
}

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



html {
    scroll-behavior: smooth;
}

* {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    text-decoration: none;
    word-break: keep-all;
    list-style: none;
    vertical-align: baseline;
    box-sizing: border-box;
}

:root {
    --color-blue: #181e59;
    --color-blue-light: #576bb3;
    --color-blue-light-trans: #576bb385;
    --color-blue-dark: #0d1031;
    --color-light: #95faeb;
    --color-white: #f3f3ff;
    --color-sky: #a4aff9;
    --color-background: #0D0C1D;
    --color-surface: rgba(30, 28, 58, 0.5);
    --color-border: rgba(255, 255, 255, 0.1);
    --color-primary-accent: #6A11CB;
    --color-secondary-accent: #2575FC;
    --color-highlight: #A4EBF3;
    --color-text-muted: #ccc;
    --transition-value: all .2s ease-out;

}

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

body {
    color: #fff;
    background-color: var(--color-background);
    font-family: "Noto Sans KR", system-ui, -apple-system, 'Segoe UI', Roboto, 'Open Sans', 'Helvetica Neue', sans-serif;
    font-style: normal;
}

.section {
    padding: 80px 16px;
    background: var(--color-background);
}

.container {
    max-width: 1080px;
    margin: 0 auto;
}

/* row for use with columns */
.row {
    display: flex;
    justify-content: space-between;
}

/* Gradient text */
.text-gradient {
    background: linear-gradient(90deg, var(--color-highlight), var(--color-secondary-accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

.text-gradient-dark {
    background: linear-gradient(90deg, var(--color-sky), var(--color-blue));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}

/* section title */
.section-title {
    position: relative;
    margin-top: 1rem;
    margin-bottom: 3rem;
    font-family: "Roboto", sans-serif;
    font-size: 3rem;
    font-weight: bold;
    text-transform: uppercase;
    text-align: center;
}



/* paddings */
.pb-1 {
    padding-bottom: 8px;
}

/* Navigation */
.nav-desk {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    position: fixed;
    left: 0;
    top: 0;
    z-index: 9999;
    width: 100%;
    height: 70px;
    padding: 0 24px;
    background: var(--color-surface);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    transition: var(--transition-value);
}

.nav-desk__logo {
    width: 32px;
    transition: var(--transition-value);
}

.nav-desk__logo:hover {
    opacity: .7;
}

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

.nav-desk__list li a {
    color: #fff;
    transition: var(--transition-value);
}

.nav-desk li a:hover {
    opacity: .7;
}

/* Navbar: Dropdown */
.dropdown {
    position: relative;
}

.dropdown-content {
    display: none;
    position: absolute;
    min-width: 100px;
    background-color: var(--color-surface);
    backdrop-filter: blur(10px);
    z-index: 10;
    padding: 12px;
    border-radius: 8px;
    border: 1px solid var(--color-border);
}

.dropdown-content a {
    padding: 12px;
    text-decoration: none;
    display: block;
    text-align: center;
}

.dropdown:hover .dropdown-content {
    display: block;
}

.go-to-reg {
    display: inline-block;
    padding: 10px 28px;
    border-radius: 50px;
    background: linear-gradient(90deg, var(--color-primary-accent), var(--color-secondary-accent));
    text-decoration: none;
    text-transform: uppercase;
    cursor: pointer;
    color: #fff;
    font-size: 16px;
    font-weight: bold;
    transition: var(--transition-value);
    box-shadow: 0 5px 15px rgba(37, 117, 252, 0.3);
    border: none;
}

.go-to-reg.big {
    padding: 12px 48px;
    font-size: 24px;
}

.go-to-reg:hover,
.go-to-reg:active {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(37, 117, 252, 0.5);
}

.mob-go-to-buy {
    display: inline-block;
    padding: 8px 16px;

    border: 1px solid #fff;
    border-radius: 10px;
    width: 100%;
    text-align: center;
    background-color: var(--color-blue);
    text-transform: uppercase;
}

/* burger menu */
.mobile-nav-fixed {
    position: fixed;
    top: 10px;
    right: 10px;
    z-index: 20;
}

.mobile-nav {
    display: none;
    background: var(--color-surface);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--color-border);
    padding: 10px;
    border-radius: 1rem;
}

/* Mobile menu */
.mobile-menu {
    position: fixed;
    z-index: 10;
    top: 0;
    left: 0;
    width: 100%;
    max-width: 200px;
    height: 100%;
    padding: 20px;
    background: var(--color-surface);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-right: 1px solid var(--color-border);
    transform: translateX(-100%);
    transition: var(--transition-value);
}

.mobile-menu li {
    padding: 10px 0;
    list-style-type: none;
}

.mobile-menu li a {
    color: #fff;
}

.mobile-menu.active {
    transform: translateX(0);
}

.accordion-menu-trigger::after {
    content: '\25BE';
    color: #fff;
    font-weight: bold;
    margin-left: 5px;
    font-size: 130%;
}

.accordion-menu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
}

.accordion-menu li {
    padding-left: 15px;
    list-style-type: none;
}

/* Humber icon start */
.mobile-menu-btn {
    width: 30px;
    height: 30px;
    position: relative;
    z-index: 20;
    overflow: hidden;
}

.mobile-menu-btn span {
    width: 30px;
    height: 2px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: #fff;
    transition: var(--transition-value);
}

.mobile-menu-btn span:nth-of-type(2) {
    top: calc(50% - 8px);
}

.mobile-menu-btn span:nth-of-type(3) {
    top: calc(50% + 8px);
}

/* Change burger when open menu */
.mobile-menu-btn.active span:nth-of-type(1) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-of-type(2) {
    top: 50%;
    transform: translate(-50%, 0%) rotate(45deg);
}

.mobile-menu-btn.active span:nth-of-type(3) {
    top: 50%;
    transform: translate(-50%, 0%) rotate(-45deg);
}


/* Change language button */
.lang-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
}


/* Header */
.header {
    position: relative;
    margin-top: 60px;
    height: calc(100vh - 60px);
    overflow: hidden;
}

/* overlay */
.video-overlay {
    position: absolute;
    inset: 0;
    background: rgba(13, 12, 29, 0.3);
    z-index: -1;
    transition: background-color 0.3s;
}

.bg-video {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: top;
    z-index: -2;
    pointer-events: none;
}

.header__meta {
    width: fit-content;
    margin-bottom: 5px;
    font-size: 1.8rem;
    font-weight: 500;
    color: var(--color-light);
}

.header__title {
    padding: 0 1rem;
    margin-bottom: 30px;
    font-family: "Roboto", sans-serif;
    font-size: 8rem;
    font-weight: 900;
}

.header__title p {
    line-height: 1;
}

.header__subtitle {
    padding: 0 1rem;
    font-family: "Roboto", sans-serif;
    font-size: 3rem;
    margin-bottom: 3rem;
}

.forum-info {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px 2rem;

    padding: 0 1rem;
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 3rem;

}

.forum-info__item i {
    color: #fff;
    margin-right: 8px;
}

.forum-info__line {
    display: flex;
    gap: 2rem;
    align-items: flex-start;
    margin-bottom: 2rem;
}

.forum-info__title {
    min-width: 160px;
    padding: 5px 20px;
    border-radius: 35px;
    background-color: #a7e1e7;
    color: #2c3849;
    font-weight: 600;
    text-align: center;
}

.forum-info__content .reg-btn {
    display: inline-block;
    position: relative;
    border-bottom: 2px solid var(--color-sky);
    color: var(--color-sky);
    transition: var(--transition-value);
}

.forum-info__content a:hover,
.forum-info__content a:active {
    color: #fff;
    border-color: #fff;
}

.oraganizator__title {
    font-size: 1.8rem;
    text-align: center;
}

.oraganizator__logo {
    margin-top: 60px;
}

.oraganizator__logo img {
    width: 220px;
    transition: var(--transition-value);
}

.oraganizator__logo img:hover {
    opacity: .8;
}


/* Speakers */
.speaker {
    background-color: var(--color-background);
}

.speaker__list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 40px;
}

.speaker__item {
    width: 220px;
    background: var(--color-surface);
    padding: 16px;
    border-radius: 8px;
    border: 1px solid var(--color-border);
    text-align: center;
}

.speaker__item img {
    display: block;
    width: 100%;
    margin-bottom: 1rem;
    transition: transform .2s ease-out;
}

.speaker__item img:hover {
    transform: scale(1.05);
}

.speaker__name {
    font-size: 1.5rem;
    letter-spacing: 5px;
    font-weight: 600;
}

.speaker__name.no-letter-space {
    letter-spacing: normal;
}

.speaker__position {
    font-size: 1rem;
}


/* Registration button positioning */
.registration {
    background-color: var(--color-blue-light-trans);
    background-image: url(../img/headerImg1.jpg);
    background-blend-mode: screen;
    background-position: bottom;
}

.button-box {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.registerButton {
    display: block;
    padding: 10px 24px;
    color: #fff;
    font-size: 20px;
    font-weight: 500;
    border-radius: 10px;
    border: 1px solid #fff;

    transition: var(--transition-value);
    cursor: pointer;

}

.registerButton:hover,
.registerButton:active {
    color: #202020;
    background-color: #fff;
}


/* Sponsorship, partnership */
.inner-section {
    padding-bottom: 0;
}

.company_log {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
}

.company_log img {
    display: block;
    width: 180px;
    height: 80px;
    padding: 12px;
    /* border: 1px solid var(--color-sky); */
    border-radius: 12px;
    object-fit: contain;
    background-color: #fff;
    transition: transform .2s ease-out;
}

.company_log img:hover {
    transform: scale(1.05);
}

.support {
    background-color: var(--color-white);
}


/* Timetable */
.timetable {
    padding-left: 0;
    padding-right: 0;
}

.timetable__comment {
    text-align: right;
    padding-right: 8px;
}

.timetable__table {
    width: 100%;
}

.timetable__table,
.timetable__table th,
.timetable__table td {
    border-collapse: collapse;
    padding: 16px;
    vertical-align: middle;
}

.timetable__table th {
    background-color: var(--color-light);
    color: var(--color-blue-dark);
}

.timetable__table tr {
    border-top: 1px solid #808080;
    border-bottom: 1px solid #808080;
}

.timetable__table th:not(:last-child),
.timetable__table td:not(:last-child) {
    border-right: 1px solid #808080;
}

.timetable__header_time {
    min-width: 140px;
}

.timetable_middle {
    background-color: #35366f;
    text-align: center;
}

.timetable__table b {
    display: inline-block;
    margin-bottom: 6px;
    color: var(--color-sky);
}



/* Footer */
.footer {
    padding: 40px 20px;
    background: #000000;
    font-size: 0.9rem;
    color: #dcdcdc;
}

.footer__email {
    color: inherit;
}

.footer__logo {
    display: block;
}

.footer__logo img {
    width: 200px;
}


/* Go to top button */
.top {
    display: none;
    /* or flex */
    justify-content: center;
    align-items: center;
    position: fixed;
    z-index: 9999;
    right: 10px;
    bottom: 10px;
    width: 50px;
    height: 50px;
    border-radius: 1rem;

    background: var(--color-surface);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--color-border);

    cursor: pointer;
}

.top svg {
    display: block;
    width: 35px;
    height: 35px;
}



/* TABLET */
@media (width <=1024px) {

    /* Menu */
    .mobile-nav {
        display: flex;
        justify-content: flex-end;
    }

    .nav-desk {
        display: none;
    }

    /* Header */
    .header {
        margin-top: 0;
        height: 100vh;
    }

    .header__meta {
        font-size: 1rem;
    }

    .header__title {
        font-size: 4rem;
    }

    .header__subtitle {
        font-size: 2rem;
        margin-bottom: 7rem;
    }

    .forum-info {
        font-size: 1rem;
    }

    .forum-info__title {
        min-width: 100px;
        padding: 5px 10px;
    }

    .oraganizator__title {
        font-size: 1rem;
    }

    .oraganizator__logo img {
        width: 160px;
    }

    .speaker__item {
        width: 200px;
    }

}


/* MOBILE */
@media (width <=480px) {
    .section {
        padding-top: 60px;
        padding-bottom: 60px;
    }
    .inner-section {
        padding-bottom: 0;
    }

    .row {
        flex-direction: column;
        gap: 2rem;
    }

    /* Mobile menu */
    .mobile-nav {
        display: flex;
        justify-content: flex-end;
    }

    .section-title {
        font-size: 2rem;
        margin-bottom: 1.2rem;
    }

    /* Header */
    .header {
        height: 600px;
    }

    .header__title {
        font-size: 3rem;
    }

    .header__subtitle {
        font-size: 1.5rem;
        margin-bottom: 2rem;
    }

    .forum-info__line {
        flex-direction: column;
        gap: 8px;
    }

    .oraganizator__logo {
        margin-top: 30px;
    }

    .go-to-reg.big {
        font-size: 18px;
    }

    /* Speakers */
    .speaker__list {
        gap: 8px;
    }

    .speaker__item {
        padding: 8px;
        width: 45%;
        max-width: 180px;
    }

    .speaker__name {
        font-size: 1.2rem;
        letter-spacing: normal;
    }

    .speaker__position {
        font-size: 0.8rem;
    }
 


    /* Sponsorship, partnership */
    .company_log img {
        width: calc(50% - 8px);
    }

    /* Timetable */
    .timetable {
        font-size: 12px;
    }

    .timetable__table,
    .timetable__table th,
    .timetable__table td {
        padding: 8px 5px;
    }

    /* Registration */
    .registerButton {
        font-size: 1rem;
    }

}

/* Timeline */
.program {
    background-color: var(--color-background);
}

.timeline {
    position: relative;
    margin-top: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 100px;
    transform: translateX(-50%);
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(var(--color-primary-accent), var(--color-secondary-accent));
    border-radius: 2px;
}

.timeline-item,
.timeline-break {
    position: relative;
    padding: 20px 0 20px 140px;
    margin-bottom: 20px;
}

.timeline-time {
    position: absolute;
    left: 0;
    top: 20px;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-text-muted);
    width: 90px;
    text-align: center;
}

.timeline-content {
    background: var(--color-surface);
    padding: 24px;
    border-radius: 8px;
    border: 1px solid var(--color-border);
    font-size: 1rem;
}

.timeline-content h3 {
    font-family: 'Sora', sans-serif;
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--color-highlight);
}

.timeline-break .timeline-content h3 {
    margin-bottom: 0;
}

.timeline-content .speaker_name {
    margin-top: 10px;
    color: var(--color-text-muted);
    font-style: italic;
}

.timeline-session-title {
    position: relative;
    z-index: 5;
    text-align: center;
    padding: 15px;
    background: var(--color-primary-accent);
    margin: 30px 0;
    border-radius: 8px;
    font-size: 1.3rem;
    font-weight: 700;
    color: #fff;
}

@media (width <=768px) {
    .timeline::before {
        left: 20px;
        transform: none;
    }

    .timeline-item,
    .timeline-break {
        padding-left: 50px;
    }

    .timeline-time {
        position: static;
        width: auto;
        margin-bottom: 10px;
        text-align: left;
        font-size: 1rem;
    }
}

@media (width <=480px) {
    .timeline-content {
        font-size: 0.8rem;
    }
    .timeline-content h3 {
        font-size: 1.2rem;
    }

    .timeline-item,
    .timeline-break {
        margin-bottom: 0;
    }
}

/* Animation on Scroll */
.animated-item {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.animated-item.is-visible {
    opacity: 1;
    transform: translateY(0);
}