/* Index Page Specific Styles */

/* Hero Section */
.index-hero {
    position: relative;
    min-height: 70vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.hero-gradient {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(circle at 20% 50%, rgba(139, 92, 246, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(59, 130, 246, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(249, 115, 22, 0.2) 0%, transparent 50%);
    animation: gradient-shift 15s ease infinite;
}

@keyframes gradient-shift {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

.hero-content {
    position: relative;
    z-index: 10;
    text-align: center;
    padding: 4rem 2rem;
}

.main-title {
    font-size: 3.5rem;
    font-weight: 900;
    color: var(--color-white);
    margin-bottom: 1rem;
    line-height: 1.1;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    letter-spacing: -0.01em;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.main-subtitle {
    font-size: 1.3rem;
    color: rgba(255, 255, 255, 0.95);
    margin-bottom: 2rem;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    font-weight: 500;
}

.affiliation-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    background-color: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border-radius: 9999px;
    color: var(--color-white);
    font-weight: 600;
    font-size: 1.1rem;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.affiliation-icon {
    font-size: 1.3rem;
}

/* Featured Research Section */
.featured-research {
    padding: 5rem 0;
    background-color: var(--color-light-gray);
}

.section-header {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--color-dark);
    margin-bottom: 3rem;
    text-align: center;
}

/* Paper Cards */
.paper-card {
    display: block;
    position: relative;
    background-color: var(--color-white);
    border-radius: 1.5rem;
    padding: 3rem;
    margin-bottom: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    overflow: hidden;
    border: 2px solid transparent;
}

.paper-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-purple), var(--color-blue), var(--color-orange));
    opacity: 0;
    transition: opacity 0.3s;
}

.paper-card:hover::before {
    opacity: 1;
}

.paper-card.featured {
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.03) 0%, rgba(59, 130, 246, 0.03) 100%);
    border-color: rgba(139, 92, 246, 0.2);
}

.paper-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
    border-color: var(--color-purple);
}

.paper-badge {
    position: absolute;
    top: 2rem;
    right: 2rem;
    padding: 0.5rem 1rem;
    background: linear-gradient(135deg, var(--color-purple), var(--color-blue));
    color: var(--color-white);
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    box-shadow: 0 4px 12px rgba(139, 92, 246, 0.4);
}

.coming-soon-badge {
    position: absolute;
    top: 2rem;
    right: 2rem;
    padding: 0.5rem 1rem;
    background-color: var(--color-gray);
    color: var(--color-white);
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.paper-content {
    position: relative;
}

.paper-header {
    margin-bottom: 1.5rem;
}

.paper-title {
    font-size: 2rem;
    font-weight: 800;
    color: var(--color-dark);
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

.paper-subtitle {
    font-size: 1.25rem;
    color: var(--color-gray);
    font-weight: 500;
    line-height: 1.4;
}

.paper-description {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--color-gray);
    margin-bottom: 2rem;
}

/* Paper Highlights */
.paper-highlights {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
    padding: 2rem;
    background-color: rgba(139, 92, 246, 0.05);
    border-radius: 1rem;
    border-left: 4px solid var(--color-purple);
}

.highlight-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.highlight-icon {
    font-size: 1.8rem;
    flex-shrink: 0;
}

.highlight-text {
    font-size: 0.95rem;
    color: var(--color-dark);
    line-height: 1.5;
}

.highlight-text strong {
    color: var(--color-purple);
    font-size: 1.1rem;
}

/* Paper Tags */
.paper-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.tag {
    padding: 0.5rem 1rem;
    border-radius: 9999px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-white);
    transition: transform 0.2s;
}

.tag:hover {
    transform: scale(1.05);
}

.tag-purple { background-color: var(--color-purple); }
.tag-orange { background-color: var(--color-orange); }
.tag-blue { background-color: var(--color-blue); }
.tag-green { background-color: var(--color-green); }

/* Paper Meta */
.paper-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1.5rem;
    margin-bottom: 1.5rem;
    border-top: 1px solid #e5e7eb;
}

.authors-preview {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.author-avatar-stack {
    display: flex;
    margin-left: 0;
}

.author-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-purple), var(--color-blue));
    border: 3px solid var(--color-white);
    margin-left: -12px;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.author-avatar:first-child {
    margin-left: 0;
}

.author-count {
    font-size: 0.95rem;
    color: var(--color-gray);
    font-weight: 500;
}

.paper-year {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-gray);
    padding: 0.4rem 1rem;
    background-color: var(--color-light-gray);
    border-radius: 0.5rem;
}

/* Paper CTA */
.paper-cta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-purple);
    transition: gap 0.3s;
}

.paper-card:hover .paper-cta {
    gap: 1.25rem;
}

.cta-arrow {
    font-size: 1.5rem;
    transition: transform 0.3s;
}

.paper-card:hover .cta-arrow {
    transform: translateX(5px);
}

/* Coming Soon Grid */
.coming-soon-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.paper-card.coming-soon {
    opacity: 0.7;
    cursor: default;
}

.paper-card.coming-soon:hover {
    transform: none;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

/* Research Themes Section */
.research-themes {
    padding: 5rem 0;
    background-color: var(--color-white);
}

.themes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.theme-card {
    padding: 2.5rem;
    background-color: var(--color-white);
    border-radius: 1.5rem;
    border: 2px solid #e5e7eb;
    text-align: center;
    transition: all 0.3s;
}

.theme-card:hover {
    border-color: var(--color-purple);
    transform: translateY(-4px);
    box-shadow: 0 12px 30px rgba(139, 92, 246, 0.15);
}

.theme-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.theme-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--color-dark);
    margin-bottom: 1rem;
}

.theme-description {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--color-gray);
}

/* Footer */
.footer {
    background-color: var(--color-dark);
    color: #9ca3af;
    padding: 4rem 0 2rem;
}

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

.footer-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.footer-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: 0.5rem;
}

.footer-text {
    line-height: 1.7;
    font-size: 0.95rem;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-links a {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--color-purple);
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    font-size: 0.9rem;
}

.footer-bottom a {
    color: var(--color-purple);
    text-decoration: none;
}

.footer-bottom a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-title {
        font-size: 2.5rem;
    }

    .main-subtitle {
        font-size: 1.2rem;
    }

    .paper-card {
        padding: 2rem;
    }

    .paper-title {
        font-size: 1.5rem;
    }

    .paper-highlights {
        grid-template-columns: 1fr;
        padding: 1.5rem;
    }

    .paper-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .themes-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.paper-card,
.theme-card {
    animation: fadeInUp 0.6s ease-out;
}

.paper-card:nth-child(2) {
    animation-delay: 0.1s;
}

.theme-card:nth-child(1) { animation-delay: 0.1s; }
.theme-card:nth-child(2) { animation-delay: 0.2s; }
.theme-card:nth-child(3) { animation-delay: 0.3s; }
.theme-card:nth-child(4) { animation-delay: 0.4s; }