/* =========================================
   Archive Page Styles (過去セミナー専用)
   ========================================= */

/* --- Archive Hero Section --- */
.archive-hero {
    text-align: center;
    padding: 4.5rem 1.5rem;
    background: linear-gradient(-45deg, #667eea, #764ba2, #6B73FF, #8B5CF6);
    background-size: 300% 300%;
    animation: gradientShift 15s ease infinite;
    color: white;
    margin-bottom: 2rem;
    position: relative;
    overflow: hidden;
}

/* Three.js Canvas */
#hero-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.archive-hero .container {
    position: relative;
    z-index: 2;
}

/* Subtle animated gradient */
@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* Subtle decorative glow */
.archive-hero::before {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.12) 0%, transparent 70%);
    top: -150px;
    right: -100px;
    pointer-events: none;
}

.archive-hero h1 {
    font-size: 2.4rem;
    margin: 0 0 0.6rem 0;
    letter-spacing: -0.02em;
    font-weight: 700;
    position: relative;
    z-index: 1;
}

.archive-hero p {
    margin: 0;
    opacity: 0.92;
    font-size: 1.1rem;
    font-weight: 400;
    position: relative;
    z-index: 1;
}

/* --- Year Navigation Tabs --- */
.year-nav {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    padding: 0.5rem;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow);
    width: fit-content;
}

.year-tab {
    padding: 0.75rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    color: #64748b;
    transition: all 0.2s ease;
}

.year-tab:hover {
    background: #f1f5f9;
    color: var(--primary);
}

.year-tab.active {
    background: var(--accent);
    color: white;
}

/* --- Year Section --- */
.year-section h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
    border-left: 4px solid var(--accent);
    padding-left: 1rem;
}

/* --- Archive Cards --- */
.archive-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 1.5rem 2rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.archive-card:hover {
    border-color: var(--accent);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.1);
}

.archive-card .badge {
    font-size: 0.85rem;
    padding: 0.25rem 0.6rem;
    margin-bottom: 0.75rem;
}

.archive-card .card-title {
    font-size: 1.2rem;
    margin: 0 0 0.75rem 0;
    line-height: 1.4;
}

.archive-card .speaker {
    font-size: 0.95rem;
    margin-bottom: 0.5rem;
    padding: 0.5rem 0;
    background: linear-gradient(90deg, #f8fafc, transparent);
    border-radius: 4px;
    padding-left: 0.5rem;
}

.speaker-name {
    font-weight: 600;
    color: #1e293b;
    display: inline;
}

.speaker-affiliation {
    display: block;
    font-size: 0.85rem;
    color: #64748b;
    margin-top: 0.2rem;
    font-weight: 400;
    line-height: 1.3;
}

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

.speaker-entry {
    margin-bottom: 0.5rem;
}

.speaker-entry:last-child {
    margin-bottom: 0;
}

.archive-card .abstract-preview {
    font-size: 0.9rem;
    color: #64748b;
    margin: 0.5rem 0;
    line-height: 1.5;
}

/* --- Card Links --- */
.card-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1rem;
}

.link-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.4rem 0.8rem;
    background: #f1f5f9;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--primary);
    transition: all 0.2s ease;
}

.link-btn:hover {
    background: var(--accent);
    color: white;
}

/* --- Collapsible Card Styles --- */
.archive-card.collapsible .card-header {
    cursor: pointer;
    position: relative;
    padding-right: 2rem;
}

.archive-card.collapsible .expand-icon {
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.8rem;
    color: #94a3b8;
    transition: transform 0.3s ease;
}

.archive-card.collapsible.expanded .expand-icon {
    transform: translateY(-50%) rotate(180deg);
}

.archive-card.collapsible .card-content {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.4s ease, opacity 0.3s ease, padding 0.3s ease;
    padding-top: 0;
}

.archive-card.collapsible.expanded .card-content {
    max-height: 3000px;
    opacity: 1;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
    margin-top: 1rem;
}

.archive-card .abstract {
    font-size: 0.95rem;
    color: #475569;
    line-height: 1.7;
    margin: 0;
    border-top: none;
    padding-top: 0;
}

/* --- Mobile Adjustments --- */
@media (max-width: 768px) {
    .archive-hero {
        padding: 3rem 1.5rem;
    }

    .archive-hero h1 {
        font-size: 1.8rem;
    }

    .archive-hero p {
        font-size: 1rem;
    }

    .year-nav {
        width: 100%;
        justify-content: center;
    }

    .year-tab {
        padding: 0.6rem 1.5rem;
    }

    .archive-card {
        padding: 1.25rem 1.5rem;
    }

    .archive-card .card-title {
        font-size: 1.1rem;
    }

    .card-links {
        flex-direction: column;
    }

    .link-btn {
        justify-content: center;
    }
}