:root {
    --bg: #040713;
    --bg-alt: #060918;
    --bg-highlight: #0d1024;
    --card: rgba(12, 16, 40, 0.9);
    --accent: #8cf1ff;
    --accent-soft: rgba(140, 241, 255, 0.12);
    --accent-strong: #ffb3ff;
    --text: #f5f7ff;
    --text-muted: #b2b6d0;
    --border-subtle: rgba(255, 255, 255, 0.08);
    --radius-lg: 1.25rem;
    --radius-xl: 1.75rem;
    --shadow-soft: 0 18px 40px rgba(0, 0, 0, 0.55);
    --shadow-subtle: 0 8px 18px rgba(0, 0, 0, 0.4);
    --container-width: 1120px;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    background: radial-gradient(circle at top, #151a3a 0, #040713 55%);
    color: var(--text);
    font-family: "DM Sans", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

/* Background stars */
.bg-stars {
    position: fixed;
    inset: 0;
    pointer-events: none;
    background-image:
        radial-gradient(2px 2px at 20% 20%, rgba(255, 255, 255, 0.5), transparent),
        radial-gradient(1.5px 1.5px at 80% 30%, rgba(140, 241, 255, 0.7), transparent),
        radial-gradient(1.2px 1.2px at 60% 70%, rgba(255, 179, 255, 0.6), transparent),
        radial-gradient(1px 1px at 10% 80%, rgba(255, 255, 255, 0.5), transparent);
    opacity: 0.5;
    z-index: -1;
}

/* Layout helpers */
.container {
    width: 100%;
    max-width: var(--container-width);
    padding-inline: 1.5rem;
    margin-inline: auto;
}

.section {
    padding: 4.5rem 0;
}

.section-alt {
    background: radial-gradient(circle at top, rgba(60, 80, 180, 0.16), transparent),
        linear-gradient(to bottom, rgba(11, 15, 50, 0.94), rgba(4, 6, 18, 0.98));
}

.section-highlight {
    background: radial-gradient(circle at top, rgba(140, 241, 255, 0.16), rgba(6, 9, 24, 0.98));
}

.section-inner {
    position: relative;
}

.section-header {
    max-width: 640px;
    margin-bottom: 2.5rem;
}

.section-header h2 {
    font-family: "Space Grotesk", system-ui, sans-serif;
    font-size: 2rem;
    letter-spacing: 0.04em;
    margin-bottom: 0.75rem;
}

.section-header p {
    margin: 0;
    color: var(--text-muted);
}

#about .section-header,
#program .section-header,
#location .section-header {
    max-width: none;
}

/* Header / nav */
.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    backdrop-filter: blur(14px);
    background: linear-gradient(to bottom, rgba(4, 7, 20, 0.95), rgba(4, 7, 20, 0.7));
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding-block: 0.9rem;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    text-decoration: none;
    color: var(--text);
}

.logo-mark {
    width: 2rem;
    height: 2rem;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    background: radial-gradient(circle at 30% 30%, #ffb3ff, #8cf1ff);
    box-shadow: 0 0 16px rgba(140, 241, 255, 0.5);
}

.logo-text {
    font-family: "Space Grotesk", system-ui, sans-serif;
    font-weight: 600;
    font-size: 0.98rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.logo-sub {
    display: block;
    font-size: 0.72rem;
    font-weight: 400;
    opacity: 0.8;
}

.site-nav ul {
    list-style: none;
    display: flex;
    gap: 1.25rem;
    padding: 0;
    margin: 0;
}

.site-nav a {
    text-decoration: none;
    font-size: 0.9rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--text-muted);
    padding: 0.4rem 0;
    border-bottom: 2px solid transparent;
    transition: color 0.15s ease, border-color 0.15s ease;
}

.site-nav a:hover,
.site-nav a:focus-visible {
    color: var(--accent);
    border-color: rgba(140, 241, 255, 0.5);
}

.header-cta {
    text-decoration: none;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: 0.5rem 0.9rem;
    border-radius: 999px;
    border: 1px solid rgba(140, 241, 255, 0.5);
    color: var(--accent);
    background: radial-gradient(circle at top left, rgba(140, 241, 255, 0.18), transparent);
}

/* Mobile nav */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    padding: 0.35rem;
    cursor: pointer;
}

.nav-toggle-bar {
    width: 20px;
    height: 2px;
    background: var(--text);
    display: block;
    margin: 4px 0;
    border-radius: 999px;
}

/* Hero */
.hero {
    padding: 4rem 0 4.5rem;
}

.eyebrow {
    margin: 0 0 0.65rem;
    font-size: 1.05rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--accent);
}

.hero-inner {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1.1fr);
    gap: 3rem;
    align-items: center;
}

.hero-content h1 {
    font-family: "Space Grotesk", system-ui, sans-serif;
    font-size: clamp(2.15rem, 3.7vw, 2.85rem);
    margin: 0 0 0.9rem;
}

.hero-tagline {
    margin: 0 0 1.4rem;
    color: var(--text-muted);
    font-size: 1.02rem;
}

.hero-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-bottom: 1.4rem;
}

.hero-chip {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: 0.4rem 0.7rem;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    background: radial-gradient(circle at top, rgba(140, 241, 255, 0.16), rgba(4, 7, 20, 0.96));
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 0.8rem;
}

.hero-deadline {
    margin: 0;
    font-size: 0.92rem;
    color: var(--text-muted);
}

/* Buttons */
.btn {
    border-radius: 999px;
    padding: 0.8rem 1.4rem;
    border: none;
    cursor: pointer;
    font-size: 0.92rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease, color 0.12s ease;
}

.btn-primary {
    background: radial-gradient(circle at top left, var(--accent-strong), var(--accent));
    color: #050614;
    box-shadow: var(--shadow-soft);
    font-weight: 600;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 20px 46px rgba(0, 0, 0, 0.7);
}

.btn-ghost {
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--text);
    background: rgba(15, 18, 40, 0.8);
}

.btn-ghost:hover {
    background: rgba(25, 30, 70, 0.95);
}

.btn-block {
    width: 100%;
}

.btn-lg {
    padding: 1.05rem 2.25rem;
    font-size: 1rem;
}

.about-faq-cta {
    margin-top: 2.75rem;
    display: flex;
    justify-content: center;
}

.btn.disabled {
    opacity: 0.6;
    cursor: default;
}

/* Hero visual: orbits */
.hero-visual {
    display: flex;
    justify-content: center;
}

.orbit-card {
    position: relative;
    width: 270px;
    aspect-ratio: 4 / 5;
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.12);
    background:
        radial-gradient(circle at top, rgba(140, 241, 255, 0.15), transparent),
        radial-gradient(circle at bottom, rgba(255, 179, 255, 0.2), rgba(4, 7, 20, 0.96));
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

.orbit {
    position: absolute;
    border-radius: 50%;
    border: 1px dashed rgba(255, 255, 255, 0.25);
}

.orbit-1 {
    width: 75%;
    height: 45%;
    top: 17%;
    left: 12%;
    transform: rotate(15deg);
}

.orbit-2 {
    width: 100%;
    height: 62%;
    top: 7%;
    left: 2%;
    transform: rotate(-18deg);
    border-style: solid;
    border-color: rgba(140, 241, 255, 0.2);
}

.orbit-3 {
    width: 130%;
    height: 80%;
    top: 0%;
    left: -15%;
    transform: rotate(20deg);
    border-style: dotted;
    border-color: rgba(255, 179, 255, 0.3);
}

.planet {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, #ffffff, #8cf1ff);
    box-shadow: 0 0 32px rgba(140, 241, 255, 0.7);
}

.planet-main {
    width: 70px;
    height: 70px;
    top: 22%;
    left: 50%;
    transform: translateX(-50%);
}

.planet-small {
    width: 26px;
    height: 26px;
    bottom: 30%;
    left: 22%;
    background: radial-gradient(circle at 30% 30%, #fff6df, #ffb3ff);
    box-shadow: 0 0 26px rgba(255, 179, 255, 0.7);
}

.planet-tiny {
    width: 16px;
    height: 16px;
    bottom: 22%;
    right: 18%;
    background: radial-gradient(circle at 30% 30%, #f7fbff, #8cf1ff);
    box-shadow: 0 0 18px rgba(140, 241, 255, 0.7);
}

.orbit-caption {
    position: absolute;
    left: 50%;
    bottom: 1.15rem;
    transform: translateX(-50%);
    font-size: 0.8rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--text-muted);
}

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

.feature-card {
    padding: 1.4rem 1.3rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.02), rgba(140, 241, 255, 0.06));
    box-shadow: var(--shadow-subtle);
}

.feature-card h3 {
    margin-top: 0;
    margin-bottom: 0.6rem;
    font-size: 1.08rem;
    font-family: "Space Grotesk", system-ui, sans-serif;
}

.feature-card p {
    margin: 0;
    color: var(--text-muted);
}

/* Program */
.program-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    gap: 2.5rem;
}

.timeline {
    list-style: none;
    margin: 1rem 0 0;
    padding: 0;
    border-left: 1px solid rgba(255, 255, 255, 0.18);
    padding-left: 1.4rem;
}

.timeline li {
    margin-bottom: 1.3rem;
    position: relative;
}

.timeline li::before {
    content: "";
    position: absolute;
    left: -1.1rem;
    top: 0.35rem;
    width: 0.6rem;
    height: 0.6rem;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, var(--accent), var(--accent-strong));
    box-shadow: 0 0 14px rgba(140, 241, 255, 0.7);
}

.timeline-day {
    display: inline-block;
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 0.2rem;
}

.timeline h4 {
    margin: 0;
    font-size: 1rem;
}

.timeline p {
    margin: 0.2rem 0 0;
    color: var(--text-muted);
    font-size: 0.94rem;
}

.program-details h3 {
    margin-top: 0;
    margin-bottom: 0.7rem;
}

.pill-list {
    list-style: none;
    padding: 0;
    margin: 0 0 1.5rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.pill-list li {
    font-size: 0.8rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 0.35rem 0.7rem;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.18);
    background: rgba(7, 11, 32, 0.96);
}

.detail-list {
    list-style: none;
    padding: 0;
    margin: 0.4rem 0 0;
}

.detail-list li {
    margin-bottom: 0.5rem;
    color: var(--text-muted);
}

.schedule-block {
    margin-top: 3rem;
}

.program-subheading {
    margin: 0 0 0.5rem;
    font-family: "Space Grotesk", system-ui, sans-serif;
    font-size: 1.35rem;
    letter-spacing: 0.03em;
}

.schedule-note {
    margin: 0 0 1.25rem;
    font-size: 0.94rem;
    color: var(--text-muted);
}

.schedule-grid {
    display: grid;
    gap: 0.75rem;
}

.schedule-item {
    border-radius: var(--radius-lg);
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-subtle);
    background: rgba(7, 10, 28, 0.95);
}

.faq-summary,
.schedule-summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    width: 100%;
    margin: 0;
    padding: 0;
    border: none;
    background: none;
    color: inherit;
    font: inherit;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
}

.faq-summary:focus-visible,
.schedule-summary:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: 4px;
}

.faq-summary-chevron,
.schedule-summary-chevron {
    flex-shrink: 0;
    font-size: 0.75em;
    opacity: 0.85;
    line-height: 1;
}

.schedule-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 0.35rem;
    font-size: 0.92rem;
}

.schedule-table thead th {
    padding: 0.45rem 0.65rem 0.35rem 0;
    text-align: left;
    font-size: 0.72rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--accent);
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.schedule-table tbody td {
    padding: 0.55rem 0.65rem 0.55rem 0;
    vertical-align: top;
    color: var(--text-muted);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.schedule-table tbody td:first-child {
    width: 38%;
    max-width: 11rem;
    white-space: nowrap;
    color: var(--text);
    font-variant-numeric: tabular-nums;
}

.schedule-table tbody tr:last-child td {
    border-bottom: none;
}

@media (max-width: 600px) {
    .schedule-table tbody td:first-child {
        white-space: normal;
    }
}

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

.person-card {
    border-radius: var(--radius-lg);
    padding: 1.3rem 1.2rem;
    border: 1px solid var(--border-subtle);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.02), rgba(255, 179, 255, 0.08));
    box-shadow: var(--shadow-subtle);
}

.avatar {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    margin-bottom: 0.7rem;
    background-size: cover;
    background-position: center;
    background-image: radial-gradient(circle at 30% 30%, #ffffff, #8cf1ff);
    box-shadow: 0 0 22px rgba(140, 241, 255, 0.8);
}

/* You can later replace these with photos via background-image: url(...) */
.avatar-2 {
    background-image: radial-gradient(circle at 30% 30%, #ffffff, #ffb3ff);
}

.avatar-3 {
    background-image: radial-gradient(circle at 30% 30%, #ffffff, #ffe38c);
}

.avatar-4 {
    background-image: radial-gradient(circle at 30% 30%, #ffffff, #c8b3ff);
}

.person-card h3 {
    margin: 0 0 0.3rem;
    font-size: 1.02rem;
}

.person-role {
    margin: 0 0 0.5rem;
    font-size: 0.92rem;
    color: #c4c8d8;
    font-style: italic;
}

.person-meta {
    margin: 0;
    font-size: 0.86rem;
    color: var(--text-muted);
}

.bio-toggle {
    align-self: flex-start;
    margin-top: 0.5em;
    padding: 0.5em 1em;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    background: none;
    color: inherit;
    font: inherit;
    font-size: 0.9em;
    cursor: pointer;
    transition: border-color 0.2s ease, background-color 0.2s ease;
}

.bio-toggle:hover {
    border-color: rgba(140, 241, 255, 0.45);
    background: rgba(255, 255, 255, 0.04);
}

.bio-toggle:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.bio-toggle-chevron,
.faq-summary-chevron,
.schedule-summary-chevron {
    display: inline-block;
    transition: transform 0.38s cubic-bezier(0.4, 0, 0.2, 1);
}

.bio-toggle-chevron {
    margin-left: 0.15em;
}

.bio-toggle.is-open .bio-toggle-chevron,
.faq-item.is-open .faq-summary-chevron,
.schedule-item.is-open .schedule-summary-chevron {
    transform: rotate(180deg);
}

/* Unrolling disclosure panels (lecturer bios, FAQ, schedule) */
.person-bio,
.faq-answer,
.schedule-answer {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.42s cubic-bezier(0.33, 1, 0.68, 1);
}

.person-bio.is-open,
.faq-item.is-open .faq-answer,
.schedule-item.is-open .schedule-answer {
    grid-template-rows: 1fr;
}

.person-bio-inner,
.faq-answer-inner,
.schedule-answer-inner {
    min-height: 0;
    overflow: hidden;
}

.person-bio .person-meta {
    padding-top: 0.45rem;
}

@media (prefers-reduced-motion: reduce) {

    .person-bio,
    .faq-answer,
    .schedule-answer {
        transition-duration: 0.01ms;
    }

    .bio-toggle-chevron,
    .faq-summary-chevron,
    .schedule-summary-chevron {
        transition-duration: 0.01ms;
    }
}

.section-footnote {
    margin-top: 1.4rem;
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Location */
.location-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
    gap: 2rem;
}

.info-panel {
    border-radius: var(--radius-lg);
    padding: 1.4rem 1.3rem;
    background: rgba(6, 9, 24, 0.96);
    border: 1px solid rgba(140, 241, 255, 0.2);
}

/* Apply */
.apply-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 2rem;
}

.apply-panel {
    border-radius: var(--radius-lg);
    padding: 1.5rem 1.4rem;
    border: 1px solid rgba(255, 255, 255, 0.18);
    background: rgba(4, 7, 20, 0.95);
    box-shadow: var(--shadow-subtle);
}

.apply-status {
    margin: 0 0 0.3rem;
    font-size: 0.94rem;
}

.apply-help {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.application-note {
    margin-top: 0.75rem;
    color: var(--text-muted);
}

/* FAQ */
.faq-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr);
    gap: 0.75rem;
}

.faq-item {
    border-radius: var(--radius-lg);
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-subtle);
    background: rgba(7, 10, 28, 0.95);
}

.faq-answer-inner p {
    margin: 0.6rem 0 0.2rem;
    color: var(--text-muted);
}

/* Contact */
.contact-panel {
    border-radius: var(--radius-lg);
    padding: 1.3rem 1.3rem;
    border: 1px solid var(--border-subtle);
    background: rgba(7, 11, 32, 0.96);
}

.contact-note {
    margin-top: 0.7rem;
    color: var(--text-muted);
}

/* Footer */
.site-footer {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding: 1.6rem 0 2rem;
    background: radial-gradient(circle at top, rgba(140, 241, 255, 0.12), rgba(4, 7, 20, 0.98));
}

.footer-inner {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
    justify-content: space-between;
    font-size: 0.88rem;
    color: var(--text-muted);
}

.footer-inner a {
    color: var(--accent);
    text-decoration: none;
}

/* Links */
a {
    color: var(--accent);
}

a:hover {
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 900px) {

    .hero-inner,
    .program-layout,
    .location-layout,
    .apply-layout {
        grid-template-columns: minmax(0, 1fr);
    }

    .hero {
        padding-top: 3.5rem;
    }

    .hero-visual {
        order: -1;
    }
}

@media (max-width: 768px) {
    .header-cta {
        display: none;
    }

    .site-nav {
        position: absolute;
        inset-inline: 0;
        top: 100%;
        background: rgba(4, 7, 20, 0.98);
        border-bottom: 1px solid rgba(255, 255, 255, 0.08);
        transform-origin: top;
        transform: scaleY(0);
        opacity: 0;
        transition: transform 0.16s ease, opacity 0.16s ease;
    }

    .site-nav.open {
        transform: scaleY(1);
        opacity: 1;
    }

    .site-nav ul {
        flex-direction: column;
        padding: 0.5rem 1.5rem 1rem;
    }

    .nav-toggle {
        display: block;
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }
}

@media (max-width: 600px) {
    .section {
        padding: 3.2rem 0;
    }

    .section-header h2 {
        font-size: 1.5rem;
    }

    .hero-content h1 {
        font-size: 1.9rem;
    }

    .orbit-card {
        width: 220px;
    }
}