/* Research Papers Page Styles */

.papers-hero {
    background: linear-gradient(135deg, var(--ue-blue) 0%, var(--ue-orange) 100%);
    color: white;
    padding: 8rem 0 4rem;
    margin-top: 80px;
    text-align: center;
}

.papers-header {
    max-width: 800px;
    margin: 0 auto;
}

.papers-title {
    font-family: 'Playfair Display', serif;
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.papers-subtitle {
    font-size: 1.25rem;
    opacity: 0.95;
    line-height: 1.6;
}

/* Filter Section */
.filter-section {
    background: var(--bg-white);
    padding: 2rem 0;
    border-bottom: 2px solid var(--border-color);
    position: sticky;
    top: 80px;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.filter-wrapper {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.filter-label {
    font-weight: 600;
    color: var(--text-dark);
    font-size: 1rem;
}

.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.filter-btn {
    padding: 0.625rem 1.25rem;
    border: 2px solid var(--border-color);
    background: var(--bg-white);
    color: var(--text-dark);
    border-radius: 25px;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.filter-btn:hover {
    border-color: var(--ue-blue);
    color: var(--ue-blue);
    transform: translateY(-2px);
}

.filter-btn.active {
    background: var(--ue-blue);
    color: white;
    border-color: var(--ue-blue);
}

.filter-btn.active:hover {
    background: var(--ue-orange);
    border-color: var(--ue-orange);
}

.search-box {
    position: relative;
    max-width: 600px;
    margin: 0 auto;
}

.search-input {
    width: 100%;
    padding: 0.875rem 3rem 0.875rem 1.25rem;
    border: 2px solid var(--border-color);
    border-radius: 30px;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s ease;
}

.search-input:focus {
    outline: none;
    border-color: var(--ue-blue);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.search-icon {
    position: absolute;
    right: 1.25rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.25rem;
    pointer-events: none;
}

/* Papers Section */
.papers-section {
    background: var(--bg-light);
    padding: 3rem 0 5rem;
    min-height: 60vh;
}

.papers-stats {
    margin-bottom: 2rem;
    color: var(--text-light);
    font-weight: 500;
}

.papers-stats span {
    color: var(--ue-blue);
    font-weight: 700;
    font-size: 1.125rem;
}

.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.paper-card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border: 2px solid transparent;
    display: flex;
    flex-direction: column;
}

.paper-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
    border-color: var(--ue-blue);
}

.paper-header {
    margin-bottom: 1rem;
}

.paper-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
    line-height: 1.4;
}

.paper-authors {
    font-size: 0.95rem;
    color: var(--text-light);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.paper-venue {
    font-size: 0.875rem;
    color: var(--ue-blue);
    font-weight: 600;
    margin-bottom: 1rem;
    font-style: italic;
}

.paper-year {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: var(--ue-light-blue);
    color: var(--ue-blue);
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.paper-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.paper-tag {
    padding: 0.375rem 0.875rem;
    background: var(--bg-light);
    border-radius: 20px;
    font-size: 0.75rem;
    color: var(--text-dark);
    font-weight: 500;
}

.paper-links {
    display: flex;
    gap: 1rem;
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.paper-link {
    padding: 0.625rem 1.25rem;
    background: var(--ue-blue);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.paper-link:hover {
    background: var(--ue-orange);
    transform: translateY(-2px);
}

.paper-link.secondary {
    background: transparent;
    border: 2px solid var(--ue-blue);
    color: var(--ue-blue);
}

.paper-link.secondary:hover {
    background: var(--ue-blue);
    color: white;
}

.no-results {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-light);
}

.no-results p {
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .papers-title {
        font-size: 2rem;
    }

    .papers-subtitle {
        font-size: 1rem;
    }

    .filter-wrapper {
        flex-direction: column;
        align-items: flex-start;
    }

    .filter-buttons {
        width: 100%;
    }

    .filter-btn {
        flex: 1;
        min-width: calc(50% - 0.375rem);
    }

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

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

    .paper-link {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .papers-hero {
        padding: 6rem 0 3rem;
    }

    .papers-title {
        font-size: 1.75rem;
    }

    .filter-btn {
        min-width: 100%;
        font-size: 0.8rem;
        padding: 0.5rem 1rem;
    }
}