/* =========================================
   CSS Styles (デザイン設定)
   ========================================= */
:root {
    --primary: #1e293b;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --youtube-red: #FF0000;
    --bg-body: #f8fafc;
    --bg-card: #ffffff;
    --border: #e2e8f0;
    --nav-height: 70px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    background-color: var(--bg-body);
    color: var(--primary);
    margin: 0;
    line-height: 1.7;
    padding-top: var(--nav-height);
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
}

p {
    margin-top: 0;
}

/* --- ナビゲーションバー --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 5%;
    box-sizing: border-box;
    z-index: 1000;
}

.nav-logo {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary);
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo-icon {
    width: 32px;
    height: auto;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
    color: #64748b;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--accent);
}

.btn-register {
    background-color: var(--accent);
    color: white !important;
    padding: 0.5rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    box-shadow: 0 2px 10px rgba(37, 99, 235, 0.2);
}

.btn-register:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

/* ハンバーガーボタン */
.hamburger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
    padding: 5px;
}

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

/* --- ヒーローセクション --- */
.hero {
    text-align: center;
    margin-bottom: 0;
    /* 下のCTAとくっつけるため */
    padding: 6rem 1.5rem;
    border-bottom: 1px solid var(--border);
    /* 背景画像の設定 */
    background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)),
        url('DigitalBrainSeminar.jpeg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;

}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    letter-spacing: -0.03em;
    color: #ffffff;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.hero p {
    color: #f8fafc;
    max-width: 600px;
    margin: 0 auto;
    font-size: 1.1rem;
    font-weight: 600;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1.5rem 3rem 1.5rem;
}

/* --- CTA (Call To Action) セクション --- */
.cta-section {
    text-align: center;
    padding: 3rem 1rem;
    margin-bottom: 3rem;
    background-color: white;
    border-bottom: 1px dashed var(--border);
}

.cta-text {
    font-size: 1.1rem;
    color: #475569;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.btn-cta-large {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(90deg, #2fa4e8, #4a54e6);
    color: white !important;
    font-weight: 700;
    font-size: 1.1rem;
    padding: 1rem 3rem;
    border-radius: 6px;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    animation: btn-pulse 3s infinite;
}

.btn-cta-large::before {
    content: '';
    display: inline-block;
    width: 0.5rem;
    height: 0.5rem;
    border-top: 3px solid white;
    border-right: 3px solid white;
    transform: rotate(45deg);
    margin-right: 1rem;
}

.btn-cta-large:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(37, 99, 235, 0.5);
    filter: brightness(1.1);
    animation: none;
    /* Stop pulse on hover to emphasize the hover state */
}

@keyframes btn-pulse {
    0% {
        transform: scale(1);
        box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    }

    50% {
        transform: scale(1.03);
        box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
    }

    100% {
        transform: scale(1);
        box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    }
}


h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    padding-left: 1rem;
    border-left: 4px solid var(--accent);
    display: flex;
    align-items: center;
}

/* --- セミナーカード --- */
.card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 2.5rem;
    margin-bottom: 2rem;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
    transition: transform 0.2s ease;
}

.card:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.badge {
    display: inline-block;
    background: #eff6ff;
    color: var(--accent);
    padding: 0.3rem 0.8rem;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

/* Schedule Box - Designer Style */
.schedule-box {
    display: flex;
    gap: 4rem;
    margin-top: 2rem;
    padding: 1.5rem 0;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.schedule-item {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.schedule-label {
    font-size: 0.75rem;
    font-weight: 850;
    color: var(--accent);
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.schedule-value {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary);
}

.card-title {
    font-size: 1.6rem;
    font-weight: 700;
    margin: 0 0 1rem 0;
    line-height: 1.3;
}

.speaker {
    display: block;
    /*Changed from flex for better text wrapping*/
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
    line-height: 1.5;
    /* Add line height for readability */
}

.speaker::before {
    content: "Speaker:";
    color: var(--accent);
    font-weight: 700;
    margin-right: 0.5rem;
    font-size: 0.9em;
}

.speaker-label {
    color: var(--accent);
    font-weight: 700;
    margin-right: 0.5rem;
}

/* Hide ::before when speaker-label is present */
.speaker:has(.speaker-label)::before {
    display: none;
}

.info-row {
    font-size: 0.95rem;
    color: #64748b;
    margin-bottom: 1.5rem;
}

.detail-row {
    font-size: 0.95rem;
    color: #64748b;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
}

.abstract {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid #f1f5f9;
    font-size: 1rem;
    color: #475569;
    line-height: 1.7;
}

.archive-link {
    text-align: center;
    margin-top: 4rem;
    padding: 2rem;
    background: white;
    border-radius: 12px;
    border: 1px dashed var(--border);
}

/* --- YouTube埋め込み用スタイル --- */
.youtube-section {
    margin-top: 4rem;
    background: #0f172a;
    padding: 3rem 2rem;
    border-radius: 16px;
    color: white;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.3);
}

.youtube-section h3 {
    text-align: center;
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: white;
}

.video-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    /* 16:9 */
    height: 0;
    overflow: hidden;
    max-width: 100%;
    background: #000;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.video-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 0;
}

.channel-link {
    display: block;
    text-align: right;
    margin-top: 1rem;
    color: #94a3b8;
    font-size: 0.9rem;
}

.channel-link:hover {
    color: white;
    text-decoration: underline;
}

/* --- フッター --- */
footer {
    background: #fff;
    border-top: 1px solid var(--border);
    padding: 4rem 1.5rem;
    margin-top: 4rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    max-width: 1000px;
    margin: 0 auto;
}

.footer-col h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    color: var(--accent);
    letter-spacing: 0.05em;
    margin: 0 0 1.2rem 0;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #eff6ff;
    display: inline-block;
}

.footer-col ul {
    list-style: none;
    padding: 0;
    margin: 0;
    font-size: 0.9rem;
    color: #475569;
}

.footer-col li {
    margin-bottom: 0.8rem;
}

.copyright {
    text-align: center;
    margin-top: 4rem;
    font-size: 0.8rem;
    color: #94a3b8;
}

/* --- モバイル対応 --- */
@media (max-width: 768px) {
    .navbar {
        padding: 0 1.5rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .card-title {
        font-size: 1.3rem;
    }

    .speaker {
        font-size: 1rem;
    }

    .affiliation {
        display: block;
        margin-left: 0;
        color: #64748b;
        font-size: 0.9rem;
        margin-top: 0.2rem;
    }

    .card {
        padding: 1.5rem;
    }

    .youtube-section {
        padding: 2rem 1rem;
    }

    .schedule-box {
        flex-direction: column;
        gap: 1.5rem;
        padding: 1.5rem 0;
    }

    .hamburger {
        display: flex;
    }

    .nav-links {
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        align-items: center;
        gap: 2rem;
        padding: 2rem 0;
        border-bottom: 1px solid var(--border);
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
        display: none;
    }

    .nav-links.active {
        display: flex;
        animation: slideDown 0.3s ease forwards;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}