/* -------------------------------------------------
   Global Tokens & Base Setup
------------------------------------------------- */
:root {
    --primary-color: #1d4ed8;
    --secondary-color: #2563eb;
    --accent-color: #22d3ee;
    --accent-warm: #f59e0b;
    --neutral-900: #0f172a;
    --neutral-700: #1f2937;
    --neutral-500: #475569;
    --neutral-200: #e2e8f0;
    --neutral-100: #eef2ff;
    --surface-color: rgba(255, 255, 255, 0.78);
    --surface-strong: rgba(255, 255, 255, 0.92);
    --glass-border: rgba(255, 255, 255, 0.32);
    --shadow-sm: 0 16px 40px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 40px 80px rgba(15, 23, 42, 0.16);
    --radius-sm: 12px;
    --radius-md: 18px;
    --radius-lg: 28px;
    --transition-base: all 0.28s ease;
    --gradient-hero: linear-gradient(135deg, rgba(29, 78, 216, 0.92) 0%, rgba(37, 99, 235, 0.88) 50%, rgba(34, 211, 238, 0.85) 100%);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans JP', 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
    font-size: 18px;
    line-height: 1.85;
    color: var(--neutral-700);
    background:
        radial-gradient(140% 200% at 0% 0%, rgba(37, 99, 235, 0.08) 0%, rgba(255, 255, 255, 0) 55%),
        radial-gradient(140% 180% at 100% 0%, rgba(34, 211, 238, 0.08) 0%, rgba(255, 255, 255, 0) 55%),
        #f4f7fb;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--secondary-color);
    text-decoration: none;
    transition: var(--transition-base);
}

a:hover {
    color: var(--accent-color);
}

img {
    max-width: 100%;
    display: block;
}

.container {
    width: min(1200px, 92vw);
    margin: 0 auto;
}

main {
    padding: 4.5rem 0 5rem;
}

.section {
    position: relative;
    background: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 4rem clamp(2rem, 5vw, 4.5rem);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(14px);
    border: 1px solid var(--glass-border);
    margin-bottom: 4.5rem;
    overflow: hidden;
}

.section:last-child {
    margin-bottom: 0;
}

.section::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(120deg, rgba(255, 255, 255, 0.12), transparent 55%);
    pointer-events: none;
}

.section-title {
    font-size: clamp(2rem, 3vw, 2.4rem);
    color: var(--primary-color);
    text-align: center;
    margin-bottom: 2.8rem;
    letter-spacing: 0.05em;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    width: 72px;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-color), var(--secondary-color));
    bottom: -1.1rem;
    left: 50%;
    transform: translateX(-50%);
    border-radius: 999px;
}

.glass-panel {
    background: var(--surface-strong);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    padding: clamp(2rem, 4vw, 2.8rem);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(14px);
}

strong {
    color: var(--primary-color);
}

/* -------------------------------------------------
   Global Navigation
------------------------------------------------- */
.global-nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(14px);
    background: rgba(255, 255, 255, 0.86);
    border-bottom: 1px solid rgba(148, 163, 184, 0.25);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}

.nav-header {
    display: none;
}

.nav-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    padding: 0.85rem 1rem;
    flex-wrap: wrap;
}

.nav-container a {
    color: var(--neutral-700);
    font-weight: 600;
    letter-spacing: 0.02em;
    padding: 0.55rem 1.1rem;
    border-radius: 999px;
    transition: var(--transition-base);
}

.nav-container a:hover,
.nav-container a.active {
    background: rgba(37, 99, 235, 0.12);
    color: var(--primary-color);
}

/* -------------------------------------------------
   Hero Section
------------------------------------------------- */
.hero {
    position: relative;
    padding: clamp(5rem, 10vw, 7.5rem) 0 clamp(4rem, 8vw, 6rem);
    color: #fff;
    background-image: var(--gradient-hero), url('../background-image.png');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(160deg, rgba(15, 23, 42, 0.35), rgba(15, 23, 42, 0));
    z-index: 0;
}

.hero-shape {
    position: absolute;
    border-radius: 999px;
    filter: blur(70px);
    opacity: 0.55;
    z-index: 0;
}

.hero-shape-one {
    width: 320px;
    height: 320px;
    background: rgba(34, 211, 238, 0.65);
    top: -90px;
    left: -120px;
}

.hero-shape-two {
    width: 280px;
    height: 280px;
    background: rgba(37, 99, 235, 0.55);
    bottom: -120px;
    right: -80px;
}

.hero-content {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: minmax(420px, 1.2fr) minmax(260px, 0.8fr);
    gap: clamp(3rem, 7vw, 5rem);
    align-items: start;
}

.hero-copy {
    text-align: left;
    max-width: 580px;
}

.hero h1 {
    font-size: clamp(1.9rem, 5vw, 3rem);
    font-weight: 800;
    margin-block: 1.5rem 1rem;
    line-height: 1.15;
    white-space: nowrap;
}

.hero-theme {
    display: block;
    font-size: clamp(1.1rem, 3vw, 1.6rem);
    font-weight: 600;
    margin-bottom: 0.35rem;
}

.hero-actions {
    margin-top: 2.4rem;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: flex-start;
    align-items: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    padding: 0.95rem 2.4rem;
    font-weight: 600;
    border-radius: 999px;
    cursor: pointer;
    transition: var(--transition-base);
    border: 1px solid transparent;
}

.btn-solid {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: #fff !important;
    box-shadow: 0 18px 35px rgba(37, 99, 235, 0.35);
}

.btn-solid:hover {
    transform: translateY(-1px) scale(1.01);
    box-shadow: 0 22px 45px rgba(37, 99, 235, 0.42);
}

.btn-ghost {
    background: rgba(37, 99, 235, 0.08);
    color: var(--primary-color) !important;
    border-color: rgba(37, 99, 235, 0.3);
    box-shadow: 0 10px 24px rgba(37, 99, 235, 0.12);
}

.btn-ghost:hover {
    background: rgba(37, 99, 235, 0.16);
    color: var(--primary-color) !important;
}

.hero .btn-ghost {
    background: rgba(255, 255, 255, 0.12);
    color: #fff !important;
    border-color: rgba(255, 255, 255, 0.4);
    box-shadow: 0 10px 24px rgba(255, 255, 255, 0.12);
}

.hero .btn-ghost:hover {
    background: rgba(255, 255, 255, 0.22);
    color: #fff !important;
}

.hero-meta {
    display: grid;
    gap: 1rem;
}

.meta-card {
    display: flex;
    gap: 1.2rem;
    align-items: center;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: var(--radius-md);
    padding: 1.35rem 1.6rem;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.1);
}

.meta-icon {
    width: 48px;
    height: 48px;
    display: grid;
    place-items: center;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.18);
    font-size: 1.25rem;
}

.meta-text {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.meta-label {
    font-size: 0.9rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.7);
}

.meta-value {
    font-weight: 600;
    font-size: 1.1rem;
    color: #fff;
}

.meta-value:hover {
    color: #fff;
    text-decoration: underline;
}

/* -------------------------------------------------
   News
------------------------------------------------- */
.news-grid {
    display: grid;
    gap: 1.6rem;
}

.news-card {
    display: grid;
    grid-template-columns: minmax(160px, 200px) 1fr;
    align-items: start;
    gap: 1.5rem;
    padding: 1.5rem 2rem;
    border-radius: var(--radius-md);
    background: var(--surface-strong);
    border: 1px solid rgba(148, 163, 184, 0.2);
    box-shadow: var(--shadow-sm);
    position: relative;
}

.news-card::before {
    content: '';
    position: absolute;
    inset-inline-start: 0;
    top: 18px;
    width: 6px;
    height: calc(100% - 36px);
    border-radius: 999px;
    background: linear-gradient(180deg, var(--accent-color), var(--secondary-color));
    opacity: 0.7;
}

.news-date {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    color: var(--primary-color);
}

.news-card p {
    margin: 0;
    color: var(--neutral-700);
}

/* -------------------------------------------------
   Greeting
------------------------------------------------- */
#greeting .greeting-content {
    display: grid;
    gap: 1.6rem;
}

.greeting-signature {
    justify-self: end;
    text-align: right;
    font-weight: 600;
    color: var(--primary-color);
}

.greeting-signature .name {
    font-size: 1.5rem;
    font-weight: 700;
}

/* -------------------------------------------------
   Overview + Program
------------------------------------------------- */
.overview-program-wrapper {
    display: grid;
    gap: 3.5rem;
}

.overview-card {
    overflow-x: auto;
}

.overview-table {
    width: 100%;
    border-collapse: collapse;
    min-width: 100%;
}

.overview-table th,
.overview-table td {
    padding: 1.2rem 1.4rem;
    border-bottom: 1px solid rgba(148, 163, 184, 0.25);
    text-align: left;
    background: rgba(255, 255, 255, 0.6);
}

.overview-table th {
    width: 240px;
    font-weight: 700;
    color: var(--neutral-700);
    background: rgba(37, 99, 235, 0.05);
}

.theme-subtitle {
    font-size: 0.9rem;
    color: var(--neutral-500);
}

.program-grid {
    display: grid;
    gap: 1.8rem;
}

.program-card {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 1.4rem;
    padding: 1.8rem 2rem;
    border-radius: var(--radius-md);
    background: var(--surface-strong);
    border: 1px solid rgba(148, 163, 184, 0.2);
    box-shadow: var(--shadow-sm);
    align-items: start;
}

.program-icon {
    width: 58px;
    height: 58px;
    border-radius: 18px;
    background: linear-gradient(135deg, rgba(29, 78, 216, 0.15), rgba(34, 211, 238, 0.18));
    display: grid;
    place-items: center;
    font-size: 1.4rem;
    color: var(--primary-color);
}

.program-card h3 {
    font-size: 1.4rem;
    margin-bottom: 0.8rem;
    color: var(--primary-color);
}

.program-card p {
    margin-bottom: 0.8rem;
}

/* -------------------------------------------------
   Abstracts
------------------------------------------------- */
.abstract-intro {
    margin-bottom: 2.5rem;
    display: grid;
    gap: 2rem;
}

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

.abstract-meta-item {
    padding: 1.4rem 1.6rem;
    border-radius: var(--radius-md);
    background: rgba(37, 99, 235, 0.08);
    border: 1px solid rgba(37, 99, 235, 0.18);
}

.abstract-meta-item h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.abstract-panels {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.8rem;
    margin-bottom: 2.8rem;
}

.abstract-card {
    background: var(--surface-strong);
    border-radius: var(--radius-md);
    border: 1px solid rgba(148, 163, 184, 0.25);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
}

.abstract-card h4 {
    font-size: 1.3rem;
    color: var(--primary-color);
}

.abstract-card h5 {
    font-size: 1.1rem;
    color: var(--secondary-color);
    margin: 0.8rem 0 1rem;
    line-height: 1.6;
}

.abstract-card p {
    margin-bottom: 1.2rem;
    text-align: justify;
}

.abstract-card ul {
    margin-left: 1.3rem;
}

.abstract-card li {
    margin-bottom: 0.8rem;
}

.abstract-card li::marker {
    color: var(--accent-color);
}

.abstract-guideline {
    display: grid;
    gap: 1.6rem;
}

.abstract-guideline h3 {
    font-size: 1.25rem;
    color: var(--primary-color);
}

.abstract-guideline ul {
    margin-left: 1.3rem;
}

/* -------------------------------------------------
   Registration
------------------------------------------------- */
.registration-card {
    display: grid;
    gap: 1.6rem;
    text-align: center;
}

.registration-actions {
    display: flex;
    justify-content: center;
}

.registration-meta h3 {
    font-size: 1.2rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

/* -------------------------------------------------
   Venue / Access
------------------------------------------------- */
.venue-grid {
    display: grid;
    gap: 2.5rem;
}

.venue-card {
    display: grid;
    grid-template-columns: minmax(260px, 1fr) 1.1fr;
    gap: 2rem;
    align-items: stretch;
    padding: 2.2rem;
    border-radius: var(--radius-lg);
    background: var(--surface-strong);
    border: 1px solid rgba(148, 163, 184, 0.22);
    box-shadow: var(--shadow-lg);
}

.venue-info h3 {
    font-size: clamp(1.2rem, 2.8vw, 1.6rem);
    margin-bottom: 1.1rem;
    color: var(--primary-color);
}

.venue-info p {
    margin-bottom: 0.8rem;
}

.venue-map iframe {
    width: 100%;
    height: 320px;
    border: none;
    border-radius: var(--radius-md);
    box-shadow: inset 0 0 0 1px rgba(15, 23, 42, 0.06);
}

.parking-link {
    color: var(--accent-warm);
    text-decoration: underline;
}

/* -------------------------------------------------
   Contact
------------------------------------------------- */
.contact-card {
    display: grid;
    gap: 1.8rem;
}

.contact-header {
    display: flex;
    gap: 1.2rem;
    align-items: center;
}

.contact-icon {
    width: 58px;
    height: 58px;
    border-radius: 16px;
    display: grid;
    place-items: center;
    background: linear-gradient(135deg, rgba(29, 78, 216, 0.15), rgba(34, 211, 238, 0.18));
    color: var(--primary-color);
    font-size: 1.4rem;
}

.contact-organization {
    font-weight: 700;
    color: var(--primary-color);
}

.contact-label {
    font-size: 0.95rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--neutral-500);
}

.contact-card .email a {
    font-size: 1.3rem;
    font-weight: 700;
}

/* -------------------------------------------------
   Footer
------------------------------------------------- */
footer {
    background: linear-gradient(135deg, #0f172a, #1d4ed8);
    color: #fff;
    padding: 4rem 0;
}

.footer-container {
    display: grid;
    gap: 2rem;
    align-items: center;
    text-align: center;
}

.footer-brand h3 {
    font-size: 1.3rem;
    margin-bottom: 0.6rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.2rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.78);
    font-weight: 500;
    padding: 0.4rem 0.8rem;
    border-radius: 999px;
}

.footer-links a:hover {
    color: #fff;
    background: rgba(255, 255, 255, 0.12);
}

.footer-meta {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
}

/* -------------------------------------------------
   Reveal animations
------------------------------------------------- */
.reveal-on-scroll {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal-on-scroll.is-visible {
    opacity: 1;
    transform: none;
}

/* -------------------------------------------------
   Responsive
------------------------------------------------- */
@media (max-width: 1200px) {
    .nav-header {
        display: flex;
        justify-content: space-between;
        align-items: center;
        padding: 0.6rem 1rem;
    }

    .nav-logo {
        color: var(--primary-color);
        font-weight: 700;
        letter-spacing: 0.04em;
        white-space: nowrap;
    }

    .hamburger-button {
        display: grid;
        place-items: center;
        width: 44px;
        height: 44px;
        background: rgba(37, 99, 235, 0.08);
        border-radius: 12px;
        border: none;
        cursor: pointer;
        transition: var(--transition-base);
    }

    .hamburger-button span {
        display: block;
        width: 22px;
        height: 2px;
        background: var(--primary-color);
        margin: 5px 0;
        transition: var(--transition-base);
    }

    .hamburger-button:hover {
        background: rgba(37, 99, 235, 0.14);
    }

    .nav-container {
        position: fixed;
        top: 0;
        left: -100%;
        width: 80%;
        max-width: 320px;
        height: 100vh;
        flex-direction: column;
        align-items: flex-start;
        padding: 5rem 2rem 2rem;
        background: rgba(255, 255, 255, 0.96);
        box-shadow: 16px 0 40px rgba(15, 23, 42, 0.18);
        gap: 0.6rem;
        transition: left 0.35s ease;
    }

    .nav-container.active {
        left: 0;
    }

    .nav-container a {
        width: 100%;
        padding: 0.9rem 1.2rem;
        border-radius: var(--radius-sm);
    }

    .hamburger-button.active span:nth-of-type(1) {
        transform: translateY(7px) rotate(45deg);
    }

    .hamburger-button.active span:nth-of-type(2) {
        opacity: 0;
    }

    .hamburger-button.active span:nth-of-type(3) {
        transform: translateY(-7px) rotate(-45deg);
    }
}

@media (max-width: 1150px) {
    main {
        padding: 3.5rem 0 4rem;
    }

    .section {
        padding: 3rem clamp(1.6rem, 5vw, 3rem);
    }

    .hero {
        background-attachment: scroll;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-copy {
        text-align: center;
        margin: 0 auto;
    }

    .hero-actions {
        justify-content: center;
    }

    .hero-meta {
        justify-items: center;
    }

    .meta-card {
        width: min(420px, 100%);
    }

    .program-card,
    .news-card {
        grid-template-columns: 1fr;
    }

}

@media (max-width: 768px) {
    body {
        font-size: 17px;
    }

    .section {
        margin-bottom: 3rem;
    }

    .news-card {
        padding: 1.4rem 1.6rem;
    }

    .overview-table th,
    .overview-table td {
        display: block;
        width: 100%;
    }

    .overview-table th {
        border-bottom: 1px solid rgba(148, 163, 184, 0.3);
    }

    .overview-table td {
        padding-top: 0.6rem;
    }

    .venue-card {
        grid-template-columns: 1fr;
    }

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

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

    .reveal-on-scroll {
        opacity: 1;
        transform: none;
    }
}

@media (max-width: 540px) {
    .hero {
        padding-bottom: 5rem;
    }
}