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

:root {
    --navy: #2c3349;
    --blue: #5ea8d6;
    --green: #97e15a;
    --yellow: #f7ce40;
    --pale-blue: #eef8ff;
    --pale-green: #f3fde9;
    --pale-yellow: #fff8dc;
    --line: #dfe7ed;
    --text: #1f2633;
    --muted: #5e6875;
    --card-shadow: 0 8px 24px rgba(44, 51, 73, 0.06);
    scroll-behavior: smooth;
    scroll-padding-top: 88px;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #f7fafc;
    color: var(--text);
    line-height: 1.6;
}

.container {
    width: 90%;
    max-width: 1000px;
    margin: auto;
    min-width: 0;
}

.site-nav {
    position: sticky;
    top: 0;
    z-index: 10;
    background: white;
    border-bottom: 1px solid var(--line);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 90%;
    max-width: 1100px;
    min-height: 64px;
    margin: auto;
    gap: 20px;
}

.home-link {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 6px 10px;
    border-radius: 8px;
    color: var(--navy);
    font-weight: bold;
    text-decoration: none;
    transition: all 0.3s ease;
}

.home-link img {
    width: 38px;
    height: 38px;
    transition: transform 0.3s ease;
}

.home-link:hover {
    background: #7dd0ee1a;
    color: var(--navy);
}

.home-link:hover img {
    transform: scale(1.05);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 22px;
    font-size: 0.95rem;
    font-weight: bold;
    min-width: 0;
}

.nav-links a {
    position: relative;
    padding: 6px 10px;
    border-radius: 8px;
    color: var(--navy);
    text-decoration: none;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.nav-links a::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #7dd0ee 0%, #91e07e 100%);
    transform: translateX(-50%);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    background: #7dd0ee1a;
    color: var(--navy);
}

.nav-links a:hover::after {
    width: 80%;
}

header {
    background: linear-gradient(180deg, #ffffff 0%, var(--pale-blue) 100%);
    text-align: center;
    padding: 54px 0 46px;
    border-bottom: 1px solid var(--line);
}

.logo-full {
    max-width: 350px;
    width: 100%;
    height: auto;
    margin-bottom: 20px;
}

h1 {
    max-width: 820px;
    margin: 0 auto;
    color: var(--navy);
    font-size: 2.3rem;
    line-height: 1.18;
    font-weight: 700;
}

h2 {
    color: var(--navy);
    font-size: 1.35rem;
    line-height: 1.25;
    margin-bottom: 10px;
    font-weight: 700;
}

main {
    padding: 40px 0;
}

.intro,
.logistics,
.schedule,
.people-section {
    background: white;
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 25px;
    box-shadow: var(--card-shadow);
    min-width: 0;
}

.intro h2,
.logistics h2,
.schedule h2,
.people-section h2 {
    margin-bottom: 15px;
}

.intro p+p {
    margin-top: 14px;
}

#about,
#logistics,
#program,
#people {
    scroll-margin-top: 88px;
}

.program-list {
    border-top: 4px solid var(--green);
}

/* Main schedule rows */
.session {
    display: grid;
    grid-template-columns: 110px 30px minmax(0, 1fr);
    gap: 10px 12px;
    padding: 16px 0;
    border-bottom: 1px solid #e8eef2;
    align-items: start;
    min-width: 0;
}

.session:last-child {
    border-bottom: none;
}

.break-session {
    margin: 8px -14px;
    padding: 16px 14px;
    background: var(--pale-yellow);
    border: 1px solid #efd680;
    border-radius: 6px;
}

.time {
    color: var(--navy);
    font-weight: bold;
    white-space: nowrap;
    min-width: 0;
}

.event {
    color: var(--navy);
    font-weight: bold;
    min-width: 0;
    overflow-wrap: anywhere;
    line-height: 1.35;
}

.session-arrow,
.session-arrow-spacer {
    width: 30px;
    height: 30px;
    align-self: start;
    justify-self: start;
    margin-top: 0;
}

.session-arrow {
    border: none;
    background: none;
    display: grid;
    place-items: center;
    cursor: pointer;
    padding: 0;
    color: var(--blue);
}

.session-arrow svg {
    width: 18px;
    height: 18px;
    stroke: currentColor;
    stroke-width: 2.5;
    fill: none;
    transition: transform 0.35s ease;
}

.session.open .session-arrow svg {
    transform: rotate(90deg);
}

.session-arrow-spacer {
    display: block;
    opacity: 0;
    pointer-events: none;
}

.session-description {
    grid-column: 2 / 4;
    min-width: 0;
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    transform: translateY(-8px);
    padding-top: 0;
    color: var(--muted);
    font-size: 0.95rem;
    transition:
        max-height 0.45s ease,
        opacity 0.25s ease,
        transform 0.35s ease;
    white-space: normal;
    overflow-wrap: anywhere;
    line-height: 1.5;
}

.session.open .session-description {
    opacity: 1;
    transform: translateY(0);
    padding-top: 10px;
}

.session-description[hidden] {
    display: none !important;
}

.keynote-details,
.speaker-details {
    color: var(--text);
    width: 100%;
    max-width: 88ch;
    justify-self: start;
}

.keynote-speaker,
.speaker-lead {
    margin-bottom: 14px;
    color: var(--navy);
    font-size: inherit;
    line-height: 1.45;
}

.keynote-section + .keynote-section,
.speaker-section {
    margin-top: 18px;
}

.keynote-section h3,
.speaker-section h3 {
    margin-bottom: 7px;
    color: var(--navy);
    font-size: 0.86rem;
    line-height: 1.3;
    letter-spacing: 0.045em;
    text-transform: uppercase;
}

.keynote-section p + p,
.speaker-section p + p {
    margin-top: 10px;
}

.keynote-details a {
    color: #247baa;
    font-weight: 600;
    text-underline-offset: 2px;
}

.keynote-details a:hover {
    color: var(--navy);
}

.keynote-website {
    color: var(--navy);
}

.sub-session {
    display: grid;
    grid-template-columns: 110px minmax(0, 1fr);
    column-gap: 20px;
    row-gap: 6px;
    align-items: start;
    padding-left: 28px;
    padding-right: 20px;
    border-left: 2px solid var(--blue);
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    transform: translateY(-12px);
    transition:
        max-height 0.45s ease,
        opacity 0.25s ease,
        transform 0.35s ease;
}

.sub-session.open-sub {
    opacity: 1;
    transform: translateY(0);
    padding-top: 12px;
    padding-bottom: 12px;
}

.sub-session .time {
    grid-column: 1;
    grid-row: 1;
    font-size: 0.95rem;
    font-weight: normal;
}

.sub-session .event {
    grid-column: 2;
    grid-row: 1;
    color: var(--navy);
    font-size: 0.95rem;
    font-weight: 600;
    line-height: 1.5;
}

.sub-session .description {
    grid-column: 2;
    grid-row: 2;
    color: var(--muted);
    font-size: 0.95rem;
    line-height: 1.5;
}

.sub-break {
    display: grid;
    grid-template-columns: 110px minmax(0, 1fr);
    column-gap: 20px;

    align-items: start;

    padding-left: 28px;
    padding-right: 20px;

    border-left: 2px solid var(--blue);

    overflow: hidden;

    max-height: 0;
    opacity: 0;
    transform: translateY(-12px);

    transition:
        max-height .45s ease,
        opacity .25s ease,
        transform .35s ease;
}

.sub-break.open-sub {
    opacity: 1;
    transform: translateY(0);
    padding-top: 12px;
    padding-bottom: 12px;
}

.sub-break .event {
    grid-column: 2;
    width: 100%;

    color: var(--text);

    font-size: 0.95rem;
    font-weight: normal;

    white-space: normal;

}

.sub-break .time {
    grid-column: 1;
    font-size: 0.95rem;
    font-weight: normal;
}

.sub-break .event strong {
    color: var(--navy);
    font-weight: 600;
}

.sub-lightning {
    display: grid;

    /* Time | Presenter | Large Topic Area */
    grid-template-columns: 110px minmax(500px, 1fr);

    column-gap: 20px;

    align-items: start;

    padding-left: 28px;
    padding-right: 20px;

    border-left: 2px solid var(--blue);

    overflow: hidden;

    max-height: 0;
    opacity: 0;
    transform: translateY(-12px);

    transition:
        max-height .5s ease,
        opacity .25s ease,
        transform .35s ease;
}


.sub-lightning.open-sub {
    opacity: 1;
    transform: translateY(0);

    padding-top: 12px;
    padding-bottom: 12px;
}


.sub-lightning .time {
    grid-column: 1;
    white-space: nowrap;
    font-size: 0.95rem;
    font-weight: normal;
}


.sub-lightning .sub-info .talk-line {
    grid-column: 2;

    min-width: 0px;
    max-width: none;

    white-space: normal;
    overflow-wrap: break-word;

    font-size: 0.95rem;
    line-height: 1.5;
}

/* People section */
.people-section h2 {
    text-align: center;
    font-size: 2rem;
}

.people-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 22px;
    justify-items: center;
}

.person-card {
    position: relative;
    width: 100%;
    max-width: 240px;
    aspect-ratio: 1 / 1.18;
    overflow: hidden;
    border-radius: 10px;
    background: #edf4f7;
    color: white;
    box-shadow: 0 8px 22px rgba(44, 51, 73, 0.18);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.person-card:hover {
    transform: scale(1.05);
    box-shadow: 0 12px 30px rgba(44, 51, 73, 0.24);
}

.person-card img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.person-overlay {
    position: absolute;
    right: 0;
    bottom: 0;
    left: 0;
    padding: 10px 12px;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
    text-align: center;
}

.person-overlay h4 {
    margin: 0 0 2px;
    color: white;
    font-size: 1.05rem;
    line-height: 1.2;
    font-weight: 700;
}

.person-overlay p {
    margin: 0;
    color: #edf4f7;
    font-size: 0.82rem;
    line-height: 1.25;
}

footer {
    text-align: center;
    padding: 30px;
    border-top: 1px solid var(--line);
    color: var(--muted);
    margin-top: 20px;
}

/* Back to top */
.to-top {
    position: fixed;
    right: 24px;
    bottom: 24px;
    z-index: 20;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    background: white;
    color: var(--navy);
    border: 1px solid var(--line);
    border-radius: 8px;
    box-shadow: 0 8px 24px rgba(44, 51, 73, 0.16);
    font-size: 0.95rem;
    font-weight: bold;
    text-decoration: none;
    opacity: 0;
    pointer-events: none;
    transform: translateY(12px);
    transition: all 0.3s ease;
}

.to-top.is-visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

.to-top span:first-child {
    color: #247baa;
    font-size: 1.05rem;
    line-height: 1;
}

.to-top:hover {
    background: #7dd0ee1a;
    color: var(--navy);
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(44, 51, 73, 0.2);
}

.to-top:active {
    transform: translateY(0);
}



@media (max-width: 900px) {
    .info-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .sub-session,
    .sub-lightning,
    .sub-break {
        grid-template-columns: 90px minmax(0, 1fr);
    }

    .sub-session.no-time,
    .sub-lightning.no-time,
    .sub-break.no-time {
        grid-template-columns: 0 minmax(0, 1fr);
    }
}

@media (max-width: 700px) {
    :root {
        scroll-padding-top: 132px;
    }

    .nav-inner {
        flex-direction: column;
        align-items: flex-start;
        padding: 12px 0;
        gap: 10px;
    }

    .nav-links {
        width: 100%;
        gap: 12px;
        overflow-x: auto;
        padding-bottom: 2px;
        font-size: 0.88rem;
    }

    .logo-full {
        max-width: 250px;
    }

    h1 {
        font-size: 1.65rem;
    }

    .session {
        grid-template-columns: 1fr auto;
        gap: 6px 10px;
    }

    .time {
        grid-column: 1;
        grid-row: 1;
    }

    .session-arrow,
    .session-arrow-spacer {
        grid-column: 2;
        grid-row: 1;
        justify-self: end;
    }

    .event {
        grid-column: 1 / -1;
        grid-row: 2;
    }

    .session-description {
        grid-column: 1 / -1;
        grid-row: 3;
    }

    .sub-session,
    .sub-lightning {
        grid-template-columns: 1fr;
        gap: 4px;
        padding-left: 12px;
    }

    .sub-session.no-time,
    .sub-lightning.no-time {
        grid-template-columns: 1fr;
    }

    .sub-session .time,
    .sub-lightning .time {
        grid-column: 1;
    }

    .sub-session .event,
    .sub-lightning .event,
    .sub-lightning .description {
        grid-column: 1;
    }

    .sub-session .event {
        grid-row: 2;
    }

    .sub-session .description {
        grid-column: 1;
        grid-row: 3;
    }

    .sub-session.no-time .time {
        display: none;
    }

    .sub-session.no-time .event {
        grid-row: 1;
    }

    .sub-session.no-time .description {
        grid-row: 2;
    }

    .sub-break {
        grid-template-columns: 1fr;
        padding-left: 12px;
        padding-right: 12px;
    }

    .sub-break .description {
        display: none;
    }

    .sub-break .event {
        grid-column: 1;
    }



    .break-session {
        margin: 8px 0;
        padding: 16px 14px;
    }

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

    #about,
    #logistics,
    #program,
    #people {
        scroll-margin-top: 132px;
    }

    .to-top {
        right: 16px;
        bottom: 16px;
        padding: 9px 12px;
        font-size: 0.88rem;
    }
}