/* --- 基本設定 --- */
:root {
    --bg-gradient: linear-gradient(135deg, #005f6b 0%, #c8e6c9 35%, #005f6b 70%, #c8e6c9 100%);
    
    --card-bg: rgba(255, 255, 255, 0.7);
    --accent-primary: #26a69a;
    --accent-secondary: #42a5f5;
    --accent-strong: #0277bd;
    
    --text-main: #37474f;   
    --text-on-bg: #ffffff; 
    --text-sub: #78909c;
    --text-on-accent: #ffffff;
}

html {
    scroll-padding-top: 100px;
    scroll-behavior: smooth;
}

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

body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    background: var(--bg-gradient);
    color: var(--text-on-bg);
    text-shadow: 0 2px 5px rgba(0,0,0,0.6);
    line-height: 1.8;
    overflow-x: hidden;
    min-height: 100vh;
}


.about-text, .speaker-card, header, .logo-placeholder {
    color: var(--text-main);
    text-shadow: none; 
}

a { text-decoration: none; color: inherit; transition: 0.3s; }
ul { list-style: none; }

.container {
    max-width: 1100px;
    margin: 0 auto; 
    padding: 0 20px; 
    width: 100%;
}

/* --- ヘッダー --- */
header {
    position: fixed;
    top: 0;
    width: 100%;
    height: 80px; 
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.nav-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--accent-strong);
    white-space: nowrap; 
}

nav ul { display: flex; gap: 30px; }
nav ul li a { font-size: 0.95rem; color: var(--text-main); font-weight: 500; }
nav ul li a:hover { color: var(--accent-secondary); }

.hamburger {
    display: none;
    cursor: pointer;
    width: 30px;
    height: 20px;
    position: relative;
    z-index: 1001;
}
.hamburger span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--text-main);
    position: absolute;
    transition: all 0.3s;
}
.hamburger span:nth-child(1) { top: 0; }
.hamburger span:nth-child(2) { top: 9px; }
.hamburger span:nth-child(3) { bottom: 0; }

.hamburger.open span:nth-child(1) {
    transform: rotate(45deg);
    top: 9px;
}
.hamburger.open span:nth-child(2) {
    opacity: 0;
}
.hamburger.open span:nth-child(3) {
    transform: rotate(-45deg);
    bottom: 9px;
}

section { 
    padding-top: 120px;
    padding-bottom: 160px;
    position: relative;
}

.section-title {
    text-align: center;
    font-size: 2.5rem; 
    margin-bottom: 100px; 
    position: relative;
    color: var(--text-on-bg);
    letter-spacing: 2px;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
    margin: 30px auto 0;
    border-radius: 2px;
}

.hero {
    padding-top: 80px !important;
    padding-bottom: 0 !important;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    background-image: url('header.png'); 
    background-size: cover;
    background-position: center;
    margin-bottom: 0; 
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 95%;
    padding: 20px;
}

.hero-date {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    letter-spacing: 1px;
    color: var(--accent-strong);
    margin-bottom: 20px;
    display: inline-block;
    font-weight: 700;
    font-size: 1.6rem;
    background: rgba(255,255,255,0.7);
    padding: 10px 35px;
    border-radius: 50px;
    border: 2px solid var(--accent-primary);
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    text-shadow: none;
}

.hero-super {
    font-size: clamp(1.5rem, 4vw, 2.2rem);
    font-weight: 700;
    color: #ffffff; 
    margin-bottom: 10px;
    letter-spacing: 0.1em;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.8);
}

.hero h1 {
    font-size: clamp(1.5rem, 5vw, 4.5rem); 
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 30px;
    color: #ffffff;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.8);
    white-space: nowrap;
}

.hero-venue {
    font-size: 1.4rem;
    color: #ffffff;
    margin-bottom: 50px;
    font-weight: 500;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.6);
}

.cta-button {
    display: inline-block;
    background: linear-gradient(45deg, #FFC107, #FFEB3B); 
    color: var(--text-main); 
    padding: 20px 70px;
    font-size: 1.3rem;
    border-radius: 50px;
    font-weight: 700;
    box-shadow: 0 10px 25px rgba(255, 193, 7, 0.4);
    border: none;
    transition: 0.3s;
    text-shadow: none;
}

.cta-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 20px 40px rgba(255, 193, 7, 0.6);
}

.cta-note {
    display: block;
    margin-top: 20px;
    font-size: 1.1rem;
    color: #ffffff;
    font-weight: 500;
    text-shadow: 0 1px 3px rgba(0,0,0,0.6);
}

.about-text {
    background: var(--card-bg);
    padding: 80px; 
    border-radius: 30px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.05);
    font-size: 1.15rem;
    text-align: justify;
    line-height: 2.2; 
    border: 1px solid rgba(255,255,255,0.8);
}

.highlight {
    color: var(--accent-primary);
    font-weight: 700;
    background: linear-gradient(to top, rgba(38, 166, 154, 0.2) 40%, transparent 40%);
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(4, 1fr); 
    gap: 20px; 
    align-items: start;
}

.speaker-card {
    background: var(--card-bg);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 10px 20px rgba(0,0,0,0.03);
    transition: all 0.3s ease;
    cursor: pointer;
    border: 1px solid rgba(255,255,255,0.6);
}

.speaker-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 25px 50px rgba(0,0,0,0.08);
}

.card-img-placeholder {
    width: 100%;
    height: 250px;
    background: linear-gradient(to right, #ece9e6, #ffffff);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-sub);
    font-size: 1.1rem;
    font-weight: 500;
}

.card-header {
    padding: 15px;
    position: relative;
}

.card-role {
    font-size: 0.75rem;
    color: var(--accent-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 5px;
    display: block;
    font-weight: 700;
}

.card-name {
    font-size: 1.1rem; 
    font-weight: 700;
    margin-bottom: 5px;
    color: var(--text-main);
    line-height: 1.3;
}

.card-affil {
    font-size: 0.8rem; 
    color: var(--text-sub);
    line-height: 1.4;
}

.toggle-icon {
    position: absolute;
    right: 15px; 
    top: 25px;   
    transform: translateY(-50%);
    font-size: 1rem; 
    color: var(--accent-primary);
    transition: transform 0.3s ease;
}

.card-bio-container {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
    background: rgba(255,255,255,0.5);
}

.card-bio {
    padding: 0 20px 20px 20px; 
    font-size: 0.9rem;         
    color: var(--text-main);
    line-height: 1.6;         
    border-top: 1px solid rgba(0,0,0,0.05);
    padding-top: 15px;         
}

.speaker-card.active .toggle-icon {
    transform: translateY(-50%) rotate(180deg);
}

.special-guest-card {
    border: 2px solid var(--accent-primary);
    background: linear-gradient(to bottom right, rgba(38, 166, 154, 0.05), rgba(66, 165, 245, 0.05));
}

.sub-header {
    margin-bottom: 60px;
    margin-top: 120px; 
    color: var(--text-on-bg);
    font-size: 1.8rem;
    border-left: 8px solid var(--accent-secondary);
    padding-left: 25px;
}
.sub-header:first-of-type { margin-top: 0; }

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

.program-table th, .program-table td {
    text-align: left;
    padding: 15px; 
    border-bottom: 1px solid rgba(0,0,0,0.05);
    color: var(--text-main);
    font-size: 1.1rem;
}
.program-table th {
    width: 25%;
    color: var(--accent-primary);
    font-weight: 700;
    vertical-align: top;
}

.program-table td strong {
    display: inline-block; 
    margin-right: 25px;
    margin-bottom: 0;
    font-size: 1.15rem;
}

#program .program-note{
  margin: 0 0 18px 0;
  padding: 10px 12px;
  border-left: 3px solid var(--accent-primary);
  background: rgba(0,0,0,0.04);
  color: var(--text);
  font-size: 0.95rem;
  line-height: 1.6;
}
#program .program-note strong{
  font-weight: 700;
}

.access-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.map-placeholder {
    width: 100%;
    height: 400px;
    background: #eceff1;
    border-radius: 25px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-sub);
    box-shadow: inset 0 0 20px rgba(0,0,0,0.05);
    font-weight: 700;
    font-size: 1.2rem;
    overflow: hidden;
    text-shadow: none;
}

.sponsors-area {
    margin-bottom: 80px;
    text-align: center;
}

.logo-placeholder-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 35px; 
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.logo-placeholder {
    width: 200px;
    height: 80px;
    background: #ffffff; 
    border-radius: 12px;
    
    
    border: none; 
    box-shadow: 0 4px 15px rgba(0,0,0,0.1); 

    display: flex;
    align-items: center;
    justify-content: center;
    padding: 15px;           
    overflow: hidden;
}


.logo-placeholder img {
    max-width: 100%;
    max-height: 100%;
    width: auto;
    height: auto;
    object-fit: contain;     
    display: block;
}
.sponsor-list-table {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    border-collapse: separate;
    border-spacing: 0 15px;
}
.sponsor-list-table th {
    text-align: right;
    padding-right: 30px;
    color: var(--text-on-accent);
    font-weight: 700;
    width: 25%;
    vertical-align: top;
    white-space: nowrap;
    text-shadow: 0 2px 4px rgba(0,0,0,0.8);
}
.sponsor-list-table td {
    text-align: left;
    vertical-align: top;
}
.sponsor-link {
    color: var(--text-on-bg);
    border-bottom: 1px solid transparent;
}
.sponsor-link:hover {
    color: var(--accent-secondary);
    border-bottom: 1px solid var(--accent-secondary);
}

footer {
    text-align: center;
    padding: 100px 20px;
    background: rgba(0,0,0,0.3);
    color: #ffffff;
    font-size: 1rem;
}

@media (max-width: 768px) {
    section { 
        padding-top: 100px;
        padding-bottom: 100px;
    }
    .hero {
        padding-top: 80px !important;
        padding-bottom: 0 !important;
    }
    .hero h1 { 
        font-size: 2.5rem; 
        white-space: normal; /
    }

    .hero-content {
        padding-top: 20px; 
    }

    .hero-date {
        margin-top: 10px;
        font-size: 1.2rem;
        padding: 8px 25px;
    }
    
    .hamburger {
        display: block;
    }

    nav ul {
        position: fixed;
        top: 80px; 
        left: 0;
        width: 100%;
        background: rgba(255, 255, 255, 0.98);
        flex-direction: column;
        padding: 20px 0;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        display: none; 
        gap: 20px;
        text-align: center;
    }
    
    nav ul.active {
        display: flex;
    }
    
    nav ul li a {
        display: block;
        padding: 10px;
        font-size: 1.1rem;
    }

    .access-grid { grid-template-columns: 1fr; gap: 50px; }
    .about-text { padding: 40px; }
    .program-table th, .program-table td { padding: 20px; display: block; width: 100%; }
    .program-table th { margin-top: 20px; border-bottom: none; color: var(--accent-secondary); }
    
    .sponsor-list-table th, .sponsor-list-table td {
        display: block;
        width: 100%;
        text-align: center;
        padding: 5px 0;
    }
    .sponsor-list-table th { margin-top: 15px; }

.program-table td strong {
        display: block;       
        margin-right: 0;
        margin-bottom: 8px;  
    }

    .grid-container {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .card-img-placeholder {
        height: auto;      
        aspect-ratio: 1 / 1; 
    }

    .card-img-placeholder img {
        object-position: top center !important; 
    }
    
    .card-name {
        font-size: 0.9rem;
    }
    
    .card-affil {
        font-size: 0.7rem;
    }
    
    .card-role {
        font-size: 0.65rem;
    }
    
    .card-header {
        padding: 10px;
    }
    
    .card-bio {
        padding: 0 15px 15px 15px;
        font-size: 0.85rem;
    }
}