:root {
    /* Color Palette */
    --primary-color: #0d253f;
    /* Deep Navy - Trust & Professionalism */
    --secondary-color: #c9a227;
    /* Gold/Bronze - Premium & Warmth */
    --accent-color: #e67e22;
    /* Muted Orange - TSC Awareness Ribbon color reference */
    --background-color: #f8f9fa;
    /* Off-white - Cleanliness */
    --surface-color: #ffffff;
    /* Pure white - Cards & Sections */
    --text-color: #333333;
    /* Dark Gray - Readability */
    --text-light: #666666;
    /* Medium Gray - Subtitles */
    --white: #ffffff;

    /* Typography */
    --font-main: 'Helvetica Neue', 'Helvetica', 'Arial', sans-serif;
    --font-heading: 'Garamond', 'Georgia', serif;
    /* Serif for headlines for a premium feel */

    /* Spacing */
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 32px;
    --spacing-xl: 64px;

    /* Shadows */
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 15px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 25px rgba(0, 0, 0, 0.1);

    /* Transitions */
    --transition-speed: 0.3s;
}

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

body {
    font-family: 'Noto Sans JP', var(--font-main);
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.8;
    overflow-x: hidden;
    /* Use the extracted PNG from the provided PDF as the website background. The image covers the viewport and stays fixed while scrolling. */
    background-image: url("ts_back.png");
    background-size: cover;
    background-repeat: no-repeat;
    background-position: center;
    background-attachment: fixed;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: 'Noto Serif JP', var(--font-heading);
    color: var(--primary-color);
    line-height: 1.4;
    letter-spacing: 0.05em;
}

/* Header Styles */
#header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
    padding: 1rem 0;
}

/* Header logo image styles */
.header-logo {
    /* Display the converted logo image at an appropriate size */
    height: 60px;
    width: auto;
    margin-left: 1rem;
}

/* Background PDF container that sits behind all content */
.background-pdf {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.background-pdf embed {
    width: 100%;
    height: 100%;
}
#header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-sm);
    padding: 0.5rem 0;
}

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

.logo a {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

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

.nav-menu a {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-color);
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--secondary-color);
    transition: width 0.3s;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

.nav-menu a:hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    cursor: pointer;
}

/* Hero Section */
#hero {
    height: 100vh;
    width: 100%;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    /* Allow the site-wide background image to be visible in the hero section. Use a semi-transparent overlay for readability. */
    background: rgba(255, 255, 255, 0.8);
    overflow: hidden;
    padding-top: 60px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.1;
    /* Remove the decorative pattern to allow the site-wide background image to show through */
    background-image: none;
    z-index: 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
}

.hero-subtitle {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--secondary-color);
    margin-bottom: 1rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    line-height: 1.2;
    background: linear-gradient(45deg, var(--primary-color) 30%, #2c3e50 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-details {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.detail-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
}

.detail-item:not(:last-child)::after {
    content: '';
    position: absolute;
    right: -1.5rem;
    top: 50%;
    transform: translateY(-50%);
    height: 40px;
    width: 1px;
    background: rgba(0, 0, 0, 0.1);
}

.label {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-light);
    letter-spacing: 0.2em;
    margin-bottom: 0.5rem;
}

.value {
    font-size: 1.25rem;
    color: var(--primary-color);
    font-weight: 500;
}

.day-of-week {
    font-size: 1rem;
    margin-left: 0.3rem;
    color: var(--text-light);
}

.online-tag {
    /* オンライン併用表記をテキストと同色に統一 */
    font-size: 0.9rem;
    color: var(--primary-color);
    display: inline;
    margin-left: 0.3rem;
}

.btn {
    display: inline-block;
    padding: 1rem 2.5rem;
    border-radius: 50px;
    font-weight: 600;
    letter-spacing: 0.05em;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-md);
}

.btn-primary {
    background: var(--primary-color);
    color: var(--white);
    border: 2px solid var(--primary-color);
}

.btn-primary:hover {
    background: transparent;
    color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Secondary button styling for additional calls to action */
.btn-secondary {
    background: var(--secondary-color);
    color: var(--white);
    border: 2px solid var(--secondary-color);
}

.btn-secondary:hover {
    background: transparent;
    color: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Sections */
.section {
    padding: 6rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 3rem;
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--secondary-color);
}

/* Tagline displayed below the hero title */
.hero-tagline {
    /* Increase font size and align items horizontally */
    font-size: 1.35rem;
    color: var(--secondary-color);
    margin-top: 0.5rem;
    margin-bottom: 1.5rem;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

/* Announcement text for concurrent events */
.announcement {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
    text-align: center;
    margin: 2rem auto;
    padding-bottom: 0.8rem;
    position: relative;

    background: none;
    box-shadow: none;
    border-radius: 0;
}

.announcement::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: 0;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background: var(--secondary-color);
}

/* Subtitle below the main hero heading */
.hero-subheading {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-top: -0.5rem;
    margin-bottom: 1rem;
}

/* Logo in the hero tagline */
.tagline-logo {
    height: 1.5em;
    width: auto;
}

/* Additional note styling for registration page */
.additional-note {
    margin-top: 1rem;
    font-weight: 600;
    color: var(--secondary-color);
}

/* Designated info styling for abstract page */
.designated-info {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Map container styling for Leaflet */
#map {
    width: 100%;
    height: 450px;
    border: 0;
}

.access-info-box {
    background: #ffffff;
    max-width: 1000px;
    margin: 0 auto 32px;
    padding: 32px;
    border-radius: 16px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

.access-address {
    text-align: left;
    line-height: 2;
    font-size: 1rem;
    margin-bottom: 0;
}

/* Styles for COI sample images */
.coi-images {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin: 1rem 0;
    justify-content: center;
}

.coi-image {
    max-width: 100%;
    height: auto;
    width: 300px;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
}

.bg-light {
    background-color: #f0f2f5;
}

/* Greeting */
.greeting-content {
    max-width: 800px;
    margin: 0 auto;
    background: var(--white);
    padding: 3rem;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    position: relative;
}

.greeting-content::before {
    content: '"';
    position: absolute;
    top: 1rem;
    left: 2rem;
    font-size: 5rem;
    color: rgba(201, 162, 39, 0.2);
    font-family: serif;
    line-height: 1;
}

.greeting-text p {
    margin-bottom: 1.5rem;
    text-align: justify;
}

.signature {
    text-align: right;
    font-weight: 700;
    margin-top: 2rem;
    font-style: italic;
}

/* Outline */
.outline-list {
    max-width: 800px;
    margin: 0 auto;
    display: grid;
    gap: 1px;
    background: rgba(0, 0, 0, 0.1);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.outline-item {
    display: grid;
    grid-template-columns: 200px 1fr;
    background: var(--white);
}

.outline-item dt {
    padding: 1.5rem;
    background: #f8f9fa;
    font-weight: 700;
    color: var(--primary-color);
    border-right: 1px solid rgba(0, 0, 0, 0.05);
}

.outline-item dd {
    padding: 1.5rem;
}

/* Access */
.access-content {
    text-align: center;
}

.access-address {
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.map-container {
    max-width: 1000px;
    margin: 0 auto;
    box-shadow: var(--shadow-md);
    border-radius: 8px;
    overflow: hidden;
}

/* Footer */
footer {
    background: var(--primary-color);
    color: var(--white);
    padding: 3rem 0;
    text-align: center;
}

.footer-logo {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 1rem;
    opacity: 0.9;
}

.copyright {
    font-size: 0.8rem;
    opacity: 0.6;
}

#news {
    padding: 4rem 1rem;
}

#news .news-section {
    background: #ffffff;
    padding: 32px;
    border-radius: 16px;
    max-width: 900px;
    margin: 0 auto;
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
}

#news h2 {
    margin-bottom: 18px;
    font-size: 1.8rem;
}

.news-item {
    display: flex;
    gap: 20px;
    border-bottom: 1px solid #ddd;
    padding-bottom: 10px;
}

.news-date {
    font-weight: bold;
    min-width: 110px;
}

@media (max-width: 600px) {
    .news-item {
        flex-direction: column;
        gap: 4px;
    }
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.2rem;
    }

    .hero-details {
        flex-direction: column;
        gap: 1.5rem;
    }

    .detail-item:not(:last-child)::after {
        display: none;
    }

    .outline-item {
        grid-template-columns: 1fr;
    }

    .outline-item dt {
        border-right: none;
        border-bottom: 1px solid rgba(0, 0, 0, 0.05);
        padding-bottom: 0.5rem;
    }

    .outline-item dd {
        padding-top: 0.5rem;
    }

    .hamburger {
        display: block;
        z-index: 1001;
    }

    .hamburger span {
        display: block;
        width: 25px;
        height: 3px;
        margin: 5px auto;
        background-color: var(--primary-color);
        transition: all 0.3s ease;
    }

    .hamburger.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 0;
        flex-direction: column;
        background-color: var(--white);
        width: 100%;
        height: 100vh;
        text-align: center;
        transition: 0.3s;
        padding-top: 80px;
        box-shadow: var(--shadow-lg);
    }

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

    .nav-menu ul {
        flex-direction: column;
        gap: 2rem;
    }
}

/* Animation Utilities */
.fade-up-init {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Page Specific Styles */
.page-header {
    background: linear-gradient(135deg, #fdfbfb 0%, #ebedee 100%);
    padding: 8rem 0 4rem;
    text-align: center;
}

.page-title {
    font-size: 2.5rem;
    color: var(--primary-color);
    position: relative;
    display: inline-block;
}

.page-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 3px;
    background: var(--secondary-color);
}

.content-block {
    margin-bottom: 4rem;
}

.sub-title {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--secondary-color);
    padding-left: 1rem;
}

.period-box {
    background: var(--white);
    border: 1px solid rgba(0, 0, 0, 0.1);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
}

.period-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid #eee;
}

.period-item:last-child {
    border-bottom: none;
}

.period-label {
    font-weight: 700;
    color: var(--primary-color);
    width: 150px;
}

.period-date {
    font-size: 1.1rem;
}

.period-box.highlight {
    background: rgba(201, 162, 39, 0.05);
    border: 1px solid var(--secondary-color);
    text-align: center;
}

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

/* Table Styles */
.table-responsive {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--white);
    box-shadow: var(--shadow-sm);
}

.data-table th,
.data-table td {
    padding: 1rem;
    border: 1px solid #eee;
    text-align: left;
}

.data-table th {
    background: var(--primary-color);
    color: var(--white);
    font-weight: 500;
    white-space: nowrap;
}

.data-table td.center {
    text-align: center;
}

.note {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-top: 1rem;
}

/* List Styles */
.category-list {
    list-style: disc;
    padding-left: 2rem;
}

.category-list li {
    margin-bottom: 0.5rem;
}

/* Action Area */
.action-area {
    text-align: center;
    margin-top: 4rem;
    padding: 3rem;
    background: #f8f9fa;
    border-radius: 8px;
}

.btn-lg {
    padding: 1.2rem 3rem;
    font-size: 1.1rem;
}

.coming-soon {
    margin-top: 1rem;
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Nav Active State */
/* Override active nav link styling to match other items */
.nav-menu a.active {
    color: var(--text-color);
}

.nav-menu a.active::after {
    width: 0;
}

/* Highlight styles for navigation links to emphasise registration and abstract pages */
.nav-menu a.nav-highlight {
    background: var(--secondary-color);
    color: var(--white);
    padding: 0.4rem 0.8rem;
    border-radius: 4px;
    font-weight: 600;
    display: inline-block;
    transition: background-color 0.3s ease;
}

.nav-menu a.nav-highlight:hover {
    background: var(--primary-color);
    color: var(--white);
}

@media (max-width: 768px) {
    .period-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .period-text {
        font-size: 1.1rem;
    }
}

/* --------- Abstract page enhancements --------- */
/* Section card styling for abstract submission blocks */
.abstract-section {
    background: var(--white);
    border: 1px solid rgba(0,0,0,0.1);
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow-sm);
}

.abstract-info {
    list-style: none;
    margin: 1rem 0;
    padding: 0;
}

.abstract-info li {
    margin-bottom: 0.5rem;
}

.coi-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.coi-btn {
    display: inline-block;
    border-radius: 10px;
    overflow: hidden;
    transition: 0.2s;
    background: transparent;
    border: none;
    box-shadow: none;
    padding: 0;
}

.coi-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.coi-thumb {
    width: 250px;
    height: auto;
    display: block;
}


@media (max-width: 768px) {
    #hero {
        height: auto;
        min-height: 100vh;
        padding: 120px 1rem 60px;
    }

    .hero-title {
        font-size: 2rem;
        line-height: 1.35;
    }

    .hero-subtitle {
        font-size: 0.85rem;
        line-height: 1.5;
    }

    .hero-subheading {
        font-size: 1.1rem;
    }

    .hero-tagline {
        font-size: 1.05rem;
        flex-wrap: wrap;
        justify-content: center;
        line-height: 1.5;
    }

    .tagline-logo {
        height: 1.3em;
    }

    .hero-actions {
        display: flex;
        flex-direction: column;
        gap: 0.8rem;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 280px;
        padding: 0.8rem 1.5rem;
        text-align: center;
    }

    .announcement {
        font-size: 1.05rem;
        line-height: 1.6;
        display: block;
        margin-left: auto;
        margin-right: auto;
    }

    .section {
        padding: 3rem 1rem;
    }

    .content-block,
    .abstract-section,
    .greeting-content {
        padding: 1.5rem;
    }

    .header-logo {
        height: 42px;
    }

    .logo a {
        font-size: 0.9rem;
    }
}