/* Importar fuentes modernas */
@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@300;400;500;600;700&family=Raleway:wght@300;400;500;600&display=swap');

/* Variables CSS para consistencia */
:root {
    --primary-green: #ECF6CE;
    --accent-yellow: #F4FA58;
    --text-gray: #848484;
    --dark-gray: #2c2c2c;
    --light-gray: #f8f9fa;
    --white: #ffffff;
    --shadow-light: 0 2px 10px rgba(0,0,0,0.08);
    --shadow-medium: 0 4px 20px rgba(0,0,0,0.12);
    --shadow-heavy: 0 8px 30px rgba(0,0,0,0.15);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Raleway', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, var(--light-gray) 0%, var(--primary-green) 100%);
    color: var(--dark-gray);
    line-height: 1.6;
    min-height: 100vh;
}

header {
    background: linear-gradient(135deg, var(--dark-gray) 0%, #1a1a1a 100%);
    color: var(--white);
    padding: 2.5rem 1rem;
    text-align: center;
    box-shadow: var(--shadow-heavy);
    position: relative;
    overflow: hidden;
}

header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, transparent 30%, rgba(236, 246, 206, 0.1) 50%, transparent 70%);
    pointer-events: none;
}

header h1 {
    font-family: 'Montserrat', sans-serif;
    font-size: 3.5rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
    background: linear-gradient(135deg, var(--white) 0%, var(--accent-yellow) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
    position: relative;
    z-index: 1;
}

header > p {
    font-size: 1.3rem;
    font-weight: 300;
    margin: 0 0 2rem 0;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

.acknowledgement {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 2rem auto;
    max-width: 600px;
    position: relative;
    z-index: 1;
}

.acknowledgement p {
    margin: 0.5rem 0;
    font-size: 1rem;
    font-weight: 400;
}

.acknowledgement strong {
    color: var(--accent-yellow);
    font-weight: 600;
}

header nav {
    margin-top: 2rem;
    position: relative;
    z-index: 1;
}

header nav a.nav-link {
    display: inline-block;
    color: var(--white);
    text-decoration: none;
    padding: 1rem 2rem;
    background: linear-gradient(135deg, transparent 0%, rgba(236, 246, 206, 0.2) 100%);
    border: 2px solid var(--accent-yellow);
    border-radius: 50px;
    font-weight: 500;
    font-size: 1.1rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

header nav a.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(244, 250, 88, 0.4), transparent);
    transition: left 0.5s;
}

header nav a.nav-link:hover::before {
    left: 100%;
}

header nav a.nav-link:hover {
    background: var(--accent-yellow);
    color: #0D47A1; /* Azul oscuro para mejor contraste */
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(244, 250, 88, 0.4);
}

main {
    padding: 3rem 1rem;
    max-width: 1400px;
    margin: 0 auto;
}

/* Timeline Styles */
.timeline-container {
    background: var(--white);
    margin: 2rem auto;
    padding: 2rem;
    max-width: 1400px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
}

.timeline-container h3 {
    font-family: 'Montserrat', sans-serif;
    font-size: 1.2rem;
    font-weight: 600;
    margin: 0 0 1.5rem 0;
    color: var(--dark-gray);
    text-align: center;
}

.timeline-controls {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.timeline-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: var(--text-gray);
    font-weight: 500;
}

.timeline-slider {
    position: relative;
    height: 40px;
}

.timeline-slider input[type="range"] {
    position: absolute;
    width: 100%;
    height: 8px;
    background: transparent;
    -webkit-appearance: none;
    appearance: none;
    pointer-events: none;
}

.timeline-slider input[type="range"]::-webkit-slider-track {
    height: 8px;
    background: var(--light-gray);
    border-radius: 4px;
}

.timeline-slider input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    height: 20px;
    width: 20px;
    border-radius: 50%;
    background: var(--accent-yellow);
    border: 2px solid var(--dark-gray);
    cursor: pointer;
    pointer-events: all;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

.timeline-slider input[type="range"]::-moz-range-track {
    height: 8px;
    background: var(--light-gray);
    border-radius: 4px;
    border: none;
}

.timeline-slider input[type="range"]::-moz-range-thumb {
    height: 20px;
    width: 20px;
    border-radius: 50%;
    background: var(--accent-yellow);
    border: 2px solid var(--dark-gray);
    cursor: pointer;
    pointer-events: all;
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
}

.timeline-selected {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    font-size: 0.9rem;
    color: var(--dark-gray);
}

#selected-range {
    font-weight: 600;
    color: var(--accent-yellow);
    background: var(--dark-gray);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.85rem;
}

#reset-timeline {
    background: var(--primary-green);
    color: var(--dark-gray);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

#reset-timeline:hover {
    background: var(--accent-yellow);
    transform: translateY(-1px);
}

h2 {
    font-family: 'Montserrat', sans-serif;
    font-size: 2.5rem;
    font-weight: 600;
    text-align: center;
    margin: 0 0 1rem 0;
    color: var(--dark-gray);
}

main > p {
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-gray);
    margin-bottom: 3rem;
}

#paper-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); /* Aún más pequeñas */
    gap: 0.8rem; /* Menos espacio entre fichas */
    padding: 0;
}

.paper-card {
    background: var(--white);
    border: none;
    border-radius: var(--border-radius);
    padding: 0.8rem; /* Padding muy reducido */
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-light);
    position: relative;
    overflow: hidden;
}

.paper-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-green), var(--accent-yellow));
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.paper-card:hover::before {
    transform: scaleX(1);
}

.paper-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-heavy);
}

.paper-card h3 {
    font-family: 'Montserrat', sans-serif;
    font-size: 1.1rem; /* TÍTULO MÁS GRANDE */
    font-weight: 700;
    margin: 0 0 0.6rem 0;
    color: var(--dark-gray);
    line-height: 1.2;
}

.paper-card p {
    margin: 0.05rem 0;
    color: #666;
    font-size: 0.55rem; /* AÚN MÁS PEQUEÑO */
    line-height: 1.3;
}

.paper-doi {
    font-size: 0.55rem; /* AÚN MÁS PEQUEÑO */
    color: #666;
    word-break: break-all;
    background: none;
    padding: 0;
    margin-top: 0.3rem;
    font-family: 'Courier New', monospace;
    text-align: left;
}

.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(5px);
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    background: var(--white);
    margin: 10% auto;
    padding: 3rem;
    border: none;
    width: 90%;
    max-width: 800px;
    border-radius: var(--border-radius);
    position: relative;
    box-shadow: var(--shadow-heavy);
    animation: slideIn 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideIn {
    from { transform: translateY(-30px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.close-button {
    color: var(--text-gray);
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    font-size: 2rem;
    font-weight: bold;
    transition: var(--transition);
    cursor: pointer;
}

.close-button:hover {
    color: var(--dark-gray);
    transform: rotate(90deg);
}

.modal-content h2 {
    font-family: 'Montserrat', sans-serif;
    font-size: 2rem;
    margin: 0 0 1rem 0;
}

.modal-content p {
    margin: 1rem 0;
    font-size: 1.1rem;
    color: var(--text-gray);
}

#modal-doi {
    background: var(--dark-gray); /* Fondo antracita */
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    text-align: center;
}

#modal-doi a {
    color: var(--primary-green); /* Color claro para contraste */
    font-weight: 500;
    text-decoration: none;
    font-size: 1.1rem;
    letter-spacing: 0.5px;
}

#modal-doi a:hover {
    text-decoration: underline;
    color: var(--white);
}

.modal-content a {
    color: var(--dark-gray);
    text-decoration: underline;
    font-weight: 500;
    text-decoration-color: var(--primary-green);
    text-underline-offset: 4px;
    transition: var(--transition);
}

.modal-content a:hover {
    text-decoration-color: var(--dark-gray);
}

iframe {
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
    margin-top: 2rem;
}

footer {
    background: linear-gradient(135deg, var(--dark-gray) 0%, #1a1a1a 100%);
    color: var(--white);
    text-align: center;
    padding: 3rem 1rem;
    margin-top: 3rem;
    position: relative;
    overflow: hidden;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-green), var(--accent-yellow));
}

footer p {
    margin: 0.5rem 0;
    opacity: 0.8;
}

footer a {
    color: var(--accent-yellow);
    text-decoration: none;
    font-weight: 500;
    border-bottom: 2px solid transparent;
    transition: var(--transition);
}

footer a:hover {
    border-bottom-color: var(--accent-yellow);
}

/* Category Filters Styles */
.category-filters-container {
    background: var(--white);
    margin: 2rem auto;
    padding: 2rem;
    max-width: 1400px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
}

.category-filters-container h3 {
    font-family: 'Montserrat', sans-serif;
    font-size: 1.2rem;
    font-weight: 600;
    margin: 0 0 1.5rem 0;
    color: var(--dark-gray);
    text-align: center;
}

.category-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.category-filter-btn {
    background: var(--light-gray);
    color: var(--text-gray);
    border: 2px solid transparent;
    padding: 0.6rem 1.2rem;
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
}

.category-filter-btn:hover {
    background: var(--primary-green);
    color: var(--dark-gray);
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

.category-filter-btn.active {
    background: linear-gradient(135deg, var(--primary-green), var(--accent-yellow));
    color: var(--dark-gray);
    border-color: var(--accent-yellow);
    font-weight: 600;
    box-shadow: var(--shadow-medium);
}

.filter-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.filter-action-btn {
    background: transparent;
    color: var(--text-gray);
    border: 1px solid var(--text-gray);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
}

.filter-action-btn:hover {
    background: var(--text-gray);
    color: var(--white);
}

/* Data Persistence Styles */
.data-persistence-container {
    background: var(--white);
    margin: 2rem auto;
    padding: 2rem;
    max-width: 1400px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
}

.data-persistence-container h3 {
    font-family: 'Montserrat', sans-serif;
    font-size: 1.2rem;
    font-weight: 600;
    margin: 0 0 1.5rem 0;
    color: var(--dark-gray);
    text-align: center;
}

.persistence-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    align-items: center;
}

.export-btn {
    background: linear-gradient(135deg, var(--primary-green), var(--accent-yellow));
    color: var(--dark-gray);
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.export-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
    background: linear-gradient(135deg, var(--accent-yellow), var(--primary-green));
}

.export-btn:active {
    transform: translateY(0);
}

.save-status {
    color: var(--text-gray);
    font-size: 0.85rem;
    font-style: italic;
    padding: 0.5rem;
    border-radius: 15px;
    background: var(--light-gray);
    min-width: 120px;
    text-align: center;
}

.save-status.success {
    color: #2e7d32;
    background: #e8f5e8;
}

.save-status.error {
    color: #d32f2f;
    background: #ffebee;
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2.5rem;
    }
    header > p {
        font-size: 1.1rem;
    }
    .acknowledgement {
        padding: 1rem;
        margin: 1.5rem auto;
    }
    #paper-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    .paper-card {
        padding: 1.5rem;
    }
    .modal-content {
        padding: 2rem;
        width: 95%;
    }
    h2 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    header {
        padding: 2rem 1rem;
    }
    
    header h1 {
        font-size: 2.5rem;
    }
    
    header nav a.nav-link {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }
    
    main {
        padding: 2rem 0.5rem;
    }
    
    .category-filters {
        gap: 0.5rem;
    }
    
    .category-filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.8rem;
    }
    
    .persistence-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .export-btn {
        padding: 1rem;
        justify-content: center;
    }
    
    .filter-actions {
        flex-direction: column;
        gap: 0.5rem;
    }
}

/* Media queries para nuevos elementos */
@media (max-width: 768px) {
    .category-filters-container,
    .data-persistence-container {
        margin: 1rem;
        padding: 1.5rem;
    }
    
    .category-filters {
        gap: 0.5rem;
    }
    
    .category-filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }
    
    .persistence-controls {
        gap: 0.75rem;
    }
    
    .export-btn {
        padding: 0.7rem 1.2rem;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .category-filters-container h3,
    .data-persistence-container h3 {
        font-size: 1.1rem;
    }
    
    .category-filters {
        justify-content: center;
    }
    
    .filter-action-btn {
        padding: 0.6rem 1.2rem;
        font-size: 0.8rem;
    }
    
    .save-status {
        min-width: 100px;
        font-size: 0.8rem;
    }
}

/* Accessibility & UX enhancements */
@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.paper-card:hover h3 {
    color: #0D47A1;
}

#paper-grid p {
    grid-column: 1 / -1;
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-gray);
    padding: 3rem;
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-light);
}

.paper-card:focus,
.paper-card:focus-within,
header nav a.nav-link:focus,
.modal-content a:focus,
.close-button:focus {
    outline: 3px solid var(--accent-yellow);
    outline-offset: 4px;
}

html {
    scroll-behavior: smooth;
}