/* Base Styles */
:root {
    --primary-color: #3498db;
    --primary-dark: #2980b9;
    --secondary-color: #2c3e50;
    --text-color: #333;
    --text-light: #6c757d;
    --white: #fff;
    --bg-light: #f8f9fa;
    --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
}

/* Navigation */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
    box-shadow: var(--shadow-sm);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transition: background 0.4s ease, backdrop-filter 0.4s ease;
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

.navbar.scrolled .navbar-title span,
.navbar.scrolled .nav-links a {
    color: var(--secondary-color);
    text-shadow: none;
}

.navbar-title {
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.navbar-title span {
    color: var(--white);
    font-size: 1.4rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: color 0.4s ease;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 600;
    color: #2c3e50;
}

.logo-img {
    height: 40px;
    width: auto;
    margin-right: 0.5rem;
}

.logo i {
    margin-right: 0.5rem;
    color: #3498db;
}

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

.nav-links a {
    text-decoration: none;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 500;
    font-size: 1rem;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: rgba(255, 255, 255, 0.8);
    transition: var(--transition);
    transform: translateX(-50%);
}

.nav-links a:hover {
    color: var(--white);
    background-color: rgba(255, 255, 255, 0.1);
}

.nav-links a:hover::after {
    width: 80%;
}

.navbar.scrolled .nav-links a::after {
    background: var(--secondary-color);
}

.navbar.scrolled .nav-links a:hover {
    color: var(--primary-color);
    background-color: rgba(52, 152, 219, 0.1);
}

.navbar.scrolled .nav-links a:hover::after {
    background: var(--primary-color);
}

@media (max-width: 768px) {
    .navbar {
        padding: 0.8rem 5%;
    }

    .navbar-title span {
        font-size: 1.2rem;
    }

    .nav-links {
        display: none;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: 0.7rem 5%;
    }

    .navbar-title span {
        font-size: 1.1rem;
    }
}

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 0 1rem;
    background: linear-gradient(135deg, var(--bg-light) 0%, #e9ecef 100%);
    position: relative;
}

.hero-content {
    max-width: 800px;
    padding-bottom: 1rem;
    transform: translateY(-3px);
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: #2c3e50;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

/* Buttons */
.cta-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    justify-content: center;
    align-items: center;
    margin-top: 3rem;
    line-height: 1.3;
    padding-bottom: 2rem;
}

.cta-secondary-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    justify-content: center;
    align-items: center;
    margin-top: 1rem;
    line-height: 1.3;
    padding-bottom: 2rem;
}
.primary-btn, .secondary-btn {
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    border: 2px solid transparent;
}

.primary-btn {
    background-color: var(--primary-color);
    color: var(--white);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.2);
    padding: 1.1rem 2.5rem;
    font-weight: 600;
    font-size: 1.05rem;
}

.primary-btn:hover {
    background-color: var(--primary-dark);
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 8px 25px rgba(52, 152, 219, 0.3);
}

.secondary-btn {
    background-color: transparent;
    color: var(--text-light);
    border-color: #dee2e6;
    padding: 0.8rem 1.8rem;
    font-weight: 500;
    transform: translateY(-3px);
}

.secondary-btn:hover {
    background-color: var(--secondary-color);
    color: var(--white);
    border-color: var(--secondary-color);
    transform: translateY(-3px);
}

.hover-note {
    position: absolute;
    bottom: -80px;
    left: 50%;
    transform: translateX(-50%) translateY(10px);
    background-color: rgba(44, 62, 80, 0.97);
    color: white;
    padding: 12px 20px;
    border-radius: 8px;
    font-size: 0.9rem;
    white-space: normal;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    width: max-content;
    max-width: 400px;
    z-index: 100;
    line-height: 1.5;
    text-align: center;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hover-note::before {
    content: '';
    position: absolute;
    top: -6px;
    left: 50%;
    transform: translateX(-50%);
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-bottom: 6px solid rgba(44, 62, 80, 0.97);
}

.hover-note i {
    color: #f1c40f;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.primary-btn:active {
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(52, 152, 219, 0.3);
}

.primary-btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.4s ease-out, height 0.4s ease-out;
}

.primary-btn:hover::after {
    width: 250px;
    height: 250px;
}

.secondary-btn:active {
    transform: translateY(-1px);
    box-shadow: 0 2px 4px rgba(52, 152, 219, 0.2);
}

/* Features Section */
.features {
    padding: 5rem 5%;
    background-color: var(--white);
}

.features h2 {
    text-align: center;
    margin-bottom: 0;
    color: var(--secondary-color);
    font-size: 2.5rem;
}

/* About Section */
.about {
    padding: 5rem 5%;
    background-color: var(--white);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about h2 {
    margin-bottom: 2rem;
    color: var(--secondary-color);
    font-size: 2.5rem;
}

.about-header {
    margin-bottom: 4rem;
}

.paper-title {
    font-size: 1.5rem;
    color: var(--secondary-color);
    font-weight: 600;
    line-height: 1.4;
    margin: 2rem 0;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.authors-section {
    margin-top: 2.5rem;
}

.authors-section h4 {
    color: var(--text-light);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.authors-list {
    font-style: italic;
    color: var(--text-light);
    line-height: 1.6;
    font-size: 1rem;
    max-width: 800px;
    margin: 0 auto;
}

.resources-section {
    margin-top: 4rem;
}

.resources-section h3 {
    color: var(--secondary-color);
    font-size: 2rem;
    margin-bottom: 1rem;
    text-align: center;
}

.resources-intro {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto 2.5rem auto;
    line-height: 1.6;
}

.lite-app-section {
    padding: 5rem 5%;
    background-color: var(--bg-light);
    text-align: center;
}

.lite-app-section h2 {
    margin-bottom: 1rem;
    color: var(--secondary-color);
    font-size: 2.5rem;
}

.lite-app-section p {
    max-width: 600px;
    margin: 0 auto 2rem auto;
    color: var(--text-light);
    font-size: 1.1rem;
}

.lite-app-container {
    max-width: 1000px;
    margin: 0 auto;
}

.lite-app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.lite-app-icon {
    flex-shrink: 0;
}

.lite-app-icon i {
    font-size: 4rem;
    color: var(--primary-color);
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.1), rgba(52, 152, 219, 0.2));
    padding: 1.5rem;
    border-radius: 50%;
    display: inline-block;
}

.lite-app-title h2 {
    margin: 0 0 0.5rem 0;
    color: var(--secondary-color);
    font-size: 2.5rem;
}

.lite-subtitle {
    color: var(--text-light);
    font-size: 1.2rem;
    margin: 0;
    font-weight: 400;
}

.lite-app-content {
    margin-bottom: 3rem;
}

.lite-features {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.lite-feature {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    background-color: var(--white);
    padding: 1rem 1.5rem;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: var(--transition);
}

.lite-feature:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.lite-feature i {
    color: var(--primary-color);
    font-size: 1.5rem;
    flex-shrink: 0;
}

.lite-feature span {
    color: var(--secondary-color);
    font-weight: 500;
    font-size: 1rem;
}

.lite-notice {
    background-color: rgba(241, 196, 15, 0.1);
    border: 1px solid rgba(241, 196, 15, 0.3);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.notice-header {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.8rem;
    margin-bottom: 1rem;
}

.notice-header i {
    color: #f1c40f;
    font-size: 1.5rem;
}

.notice-header h3 {
    color: var(--secondary-color);
    font-size: 1.3rem;
    margin: 0;
    font-weight: 600;
}

.lite-notice p {
    color: var(--text-light);
    line-height: 1.6;
    margin: 0;
    max-width: 700px;
    margin: 0 auto;
}

.lite-links {
    text-align: center;
    margin-bottom: 1rem;
}

.lite-links p {
    color: var(--text-light);
    font-size: 1rem;
    margin: 0;
}

.lite-links a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.lite-links a:hover {
    text-decoration: underline;
}

.lite-cta {
    text-align: center;
}

.lite-cta button{
    margin-bottom: 0.75rem;
}
.cta-note {
    color: var(--text-light);
    font-size: 0.9rem;
    margin: 1.5rem 0 0 0;
    font-style: italic;
}

/* Contact Section */
.contact {
    padding: 5rem 5%;
    background-color: var(--bg-light);
}

.contact h2 {
    text-align: center;
    color: var(--secondary-color);
    margin-bottom: 2rem;
    font-size: 2.5rem;
}

.contact-intro {
    text-align: center;
    color: var(--text-light);
    font-size: 1.15rem;
    max-width: 600px;
    margin: 0 auto 3rem auto;
    line-height: 1.6;
}

.contact-group {
    margin-bottom: 4rem;
}

.contact-group:last-child {
    margin-bottom: 0;
}

.contact-group-title {
    text-align: center;
    color: var(--secondary-color);
    font-size: 1.8rem;
    margin-bottom: 2rem;
    font-weight: 600;
}

.contact-cards.investigators {
    justify-content: center;
    gap: 2rem;
}

.contact-cards.support {
    justify-content: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-cards {
    display: flex;
    gap: 2rem;
    justify-content: center;
    flex-wrap: wrap;
    max-width: 1200px;
    margin: 0 auto;
}

.contact-card {
    background-color: var(--white);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    padding: 2rem;
    flex: 1;
    min-width: 300px;
    max-width: 500px;
    transition: var(--transition);
}

.contact-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

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

.contact-header h3 {
    color: var(--secondary-color);
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.contact-header .title {
    color: var(--text-light);
    font-size: 1rem;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    color: var(--text-light);
}

.contact-item i {
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-top: 0.2rem;
}

.contact-item span {
    line-height: 1.5;
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

.contact-item a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

@media (max-width: 768px) {
    .contact {
        padding: 3rem 5%;
    }

    .contact h2 {
        font-size: 2rem;
        margin-bottom: 2rem;
    }

    .contact-intro {
        font-size: 1.1rem;
        margin-bottom: 2.5rem;
        padding: 0 1rem;
    }

    .contact-group {
        margin-bottom: 3rem;
    }

    .contact-group-title {
        font-size: 1.5rem;
        margin-bottom: 1.5rem;
    }

    .contact-cards.investigators {
        flex-direction: column;
        align-items: center;
    }

    .contact-cards.support {
        max-width: 100%;
    }

    .contact-cards {
        gap: 1.5rem;
    }

    .contact-card {
        padding: 1.5rem;
        min-width: 280px;
    }
}

@media (max-width: 480px) {
    .contact {
        padding: 2rem 5%;
    }

    .contact h2 {
        font-size: 1.8rem;
    }

    .contact-intro {
        font-size: 1rem;
        margin-bottom: 2rem;
        padding: 0 0.5rem;
    }

    .contact-group {
        margin-bottom: 2.5rem;
    }

    .contact-group-title {
        font-size: 1.4rem;
        margin-bottom: 1.25rem;
    }

    .contact-cards.investigators {
        gap: 1.25rem;
    }

    .contact-card {
        padding: 1.25rem;
        min-width: 250px;
    }

    .contact-header h3 {
        font-size: 1.3rem;
    }
}

/* Footer */
footer {
    padding: 2rem;
    text-align: center;
    background-color: var(--secondary-color);
    color: var(--white);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .resource-cards {
        gap: 1.5rem;
        padding: 0 1rem;
    }

    .app-button,
    .resource-card {
        width: 450px;
    }
}

@media (max-width: 992px) {
    .hero h1 {
        font-size: 3rem;
    }

    .hero p {
        font-size: 1.15rem;
        padding: 0 1rem;
    }

    .app-button,
    .resource-card {
        width: 400px;
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: 1rem 1.5rem;
    }

    .nav-links {
        display: none;
    }

    .hero {
        padding-top: 4rem;
    }

    .hero h1 {
        font-size: 2.5rem;
        padding: 0 1rem;
    }

    .hero p {
        font-size: 1.1rem;
        padding: 0 1.5rem;
    }

    .cta-buttons {
        flex-direction: column;
        align-items: center;
        gap: 1.5rem;
        padding: 0 1rem;
    }

    .resource-cards {
        flex-direction: column;
        align-items: center;
        gap: 1.5rem;
        padding: 0 1rem;
    }

    .app-button,
    .resource-card {
        width: 100%;
        max-width: 400px;
    }
    
    .app-button-content {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
        padding: 1.25rem;
    }
    
    .action-area {
        margin: 0.8rem auto 0;
    }
    
    .app-meta {
        justify-content: center;
    }

    .app-icon-wrapper {
        margin: 0 auto;
    }
    
    .hover-note {
        width: 90%;
        max-width: 300px;
        padding: 1rem;
        bottom: -100px;
    }

    .resource-content {
        text-align: center;
    }

    .resource-content h3 {
        font-size: 1.15rem;
    }

    .resource-content p {
        font-size: 0.9rem;
        margin-bottom: 0.6rem;
    }

    .app-badge {
        font-size: 0.75rem;
        padding: 0.25rem 0.7rem;
    }

    .about {
        padding: 3rem 5%;
    }

    .about h2 {
        font-size: 2rem;
        margin-bottom: 1.5rem;
    }

    .about-header {
        margin-bottom: 3rem;
    }

    .paper-title {
        font-size: 1.4rem;
        margin: 1.5rem 0;
        padding: 0 1rem;
    }

    .authors-section {
        margin-top: 2rem;
    }

    .authors-section h4 {
        font-size: 1rem;
    }

    .authors-list {
        font-size: 0.95rem;
        padding: 0 1rem;
    }

    .resources-section {
        margin-top: 3rem;
    }

    .resources-section h3 {
        font-size: 1.6rem;
    }

    .resources-intro {
        font-size: 1rem;
        padding: 0 1rem;
    }

    .lite-app-header {
        margin-bottom: 1.5rem;
    }

    .lite-app-title h2 {
        font-size: 2rem;
    }

    .lite-subtitle {
        font-size: 1.1rem;
    }

    .lite-notice {
        padding: 1.25rem;
        margin-bottom: 1.25rem;
    }

    .notice-header {
        margin-bottom: 0.8rem;
    }

    .notice-header h3 {
        font-size: 1.2rem;
    }

    .lite-notice p {
        font-size: 0.95rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }

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

    .app-button,
    .resource-card {
        max-width: 320px;
    }

    .app-button-content {
        padding: 1rem;
    }

    .hover-note {
        font-size: 0.85rem;
        padding: 0.8rem;
        max-width: 280px;
        bottom: -110px;
    }

    .app-meta {
        gap: 0.5rem;
    }

    .app-badge {
        font-size: 0.7rem;
        padding: 0.2rem 0.6rem;
    }

    .action-area {
        gap: 0.5rem;
    }

    .action-text {
        font-size: 0.85rem;
    }

    .about {
        padding: 2rem 5%;
    }

    .about h2 {
        font-size: 1.8rem;
        margin-bottom: 1.25rem;
    }

    .about-header {
        margin-bottom: 2.5rem;
    }

    .paper-title {
        font-size: 1.3rem;
        margin: 1.25rem 0;
        padding: 0 0.5rem;
    }

    .authors-section {
        margin-top: 1.5rem;
    }

    .authors-section h4 {
        font-size: 0.95rem;
    }

    .authors-list {
        font-size: 0.9rem;
        padding: 0 0.5rem;
    }

    .resources-section {
        margin-top: 2.5rem;
    }

    .resources-section h3 {
        font-size: 1.4rem;
    }

    .resources-intro {
        font-size: 0.95rem;
        padding: 0 0.5rem;
        margin-bottom: 2rem;
    }

    .lite-app-header {
        margin-bottom: 1.25rem;
    }

    .lite-app-title h2 {
        font-size: 1.8rem;
    }

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

    .lite-notice {
        padding: 1rem;
        margin-bottom: 1rem;
    }

    .notice-header {
        flex-direction: column;
        gap: 0.5rem;
        margin-bottom: 0.6rem;
    }

    .notice-header h3 {
        font-size: 1.1rem;
    }

    .lite-notice p {
        font-size: 0.9rem;
        padding: 0 0.5rem;
    }

    .cta-note {
        font-size: 0.85rem;
        margin-top: 1rem;
    }
}

/* Fix for devices with notches or unusual aspect ratios */
@supports (padding: max(0px)) {
    .navbar {
        padding-left: max(1.5rem, env(safe-area-inset-left));
        padding-right: max(1.5rem, env(safe-area-inset-right));
    }

    .hero,
    .features,
    .about,
    .contact {
        padding-left: max(5%, env(safe-area-inset-left));
        padding-right: max(5%, env(safe-area-inset-right));
    }
}

/* Fix for very small devices */
@media (max-width: 320px) {
    .app-button,
    .resource-card {
        max-width: 280px;
    }

    .hover-note {
        max-width: 250px;
        font-size: 0.8rem;
    }
}

/* Fix for landscape mode on mobile */
@media (max-height: 480px) and (orientation: landscape) {
    .hero {
        min-height: 120vh;
    }

    .hero h1 {
        font-size: 2rem;
        margin-top: 4rem;
    }

    .hover-note {
        bottom: -90px;
    }
}

/* Resource Cards */
.resource-cards {
    display: flex;
    gap: 2rem;
    justify-content: center;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.resource-card {
    display: block;
    background-color: var(--white);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    text-decoration: none;
    width: 500px;
    max-width: 100%;
    border: 1px solid rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.resource-card .app-button-content {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1.5rem;
    position: relative;
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(52, 152, 219, 0.05) 100%);
    width: 100%;
}

.resource-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.resource-card:hover .app-button-content {
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(52, 152, 219, 0.1) 100%);
}

.resource-card:hover .icon-ring {
    transform: scale(1.1);
    border-color: rgba(52, 152, 219, 0.4);
}

.resource-card:hover .action-text {
    opacity: 1;
}

.resource-card:hover .fa-arrow-right {
    opacity: 1;
    transform: translateX(0);
}

.resource-card:hover .app-badge {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
}

@media (max-width: 768px) {
    .resource-cards {
        flex-direction: column;
        align-items: center;
        gap: 1.5rem;
    }

    .resource-card {
        width: 100%;
    }
    
    .resource-card .app-button-content {
        flex-direction: column;
        text-align: center;
        padding: 1.5rem;
    }
    
    .resource-card .action-area {
        margin: 1rem auto 0;
    }
    
    .resource-card .app-meta {
        justify-content: center;
    }
}

.app-button {
    background-color: var(--white);
    color: var(--secondary-color);
    border: 1px solid rgba(0, 0, 0, 0.1);
    cursor: pointer;
    width: 500px;
    margin: 0 auto;
    text-align: left;
    padding: 0;
    overflow: visible;
    position: relative;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    z-index: 1;
}

.app-button:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.app-button:hover .app-button-content {
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(52, 152, 219, 0.1) 100%);
}

.app-button:hover .hover-note {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.app-button-content {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1.5rem;
    position: relative;
    background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(52, 152, 219, 0.05) 100%);
    border-radius: 12px;
    width: 100%;
}

.resource-content {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 0.4rem;
}

.resource-content h3 {
    color: var(--secondary-color);
    margin: 0;
    font-size: 1.2rem;
    font-weight: 600;
    line-height: 1.3;
}

.resource-content p {
    color: var(--text-light);
    font-size: 0.95rem;
    margin: 0;
}

.app-meta {
    display: flex;
    gap: 0.8rem;
    flex-wrap: wrap;
    margin-top: 0.4rem;
}

.app-badge {
    font-size: 0.8rem;
    color: var(--text-light);
    background-color: rgba(108, 117, 125, 0.1);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    transition: var(--transition);
}

.action-area {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    color: var(--primary-color);
    font-weight: 500;
    flex-shrink: 0;
    align-self: center;
}

.action-text {
    font-size: 0.9rem;
    opacity: 0.8;
    transition: var(--transition);
}

.app-button:hover .app-badge,
.resource-card:hover .app-badge {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
}

.app-button:hover .action-text,
.resource-card:hover .action-text {
    opacity: 1;
}

.app-button:hover .fa-arrow-right,
.resource-card:hover .fa-arrow-right {
    opacity: 1;
    transform: translateX(0);
}

@media (max-width: 768px) {
    .app-button,
    .resource-card {
        width: 100%;
        max-width: 500px;
    }
    
    .app-button-content {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .action-area {
        margin: 1rem auto 0;
    }
    
    .app-meta {
        justify-content: center;
    }
    
    .hover-note {
        width: 90%;
        max-width: 300px;
        flex-direction: column;
        padding: 15px;
    }
}

/* Back to Top Button */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 9999;
    box-shadow: var(--shadow-sm);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background-color: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.back-to-top:active {
    transform: translateY(-1px);
}

.back-to-top i {
    font-size: 1.2rem;
    color: var(--white);
}

@media (max-width: 768px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 45px;
        height: 45px;
    }
}

/* Popup Styles */
.popup-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    backdrop-filter: blur(5px);
}

.popup-overlay.active {
    display: flex;
}

.popup-content {
    background-color: var(--white);
    border-radius: 12px;
    padding: 2rem;
    width: 90%;
    max-width: 500px;
    position: relative;
    box-shadow: var(--shadow-lg);
    animation: popupSlideIn 0.3s ease;
}

.popup-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    color: var(--text-light);
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0.5rem;
    transition: var(--transition);
}

.popup-close:hover {
    color: var(--secondary-color);
    transform: rotate(90deg);
}

.popup-header {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 1.5rem;
}

.popup-header i {
    color: #f1c40f;
    font-size: 1.5rem;
}

.popup-header h3 {
    color: var(--secondary-color);
    font-size: 1.3rem;
    margin: 0;
}

.popup-body {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.popup-body p {
    margin-bottom: 0.8rem;
}

.popup-body p:last-child {
    margin-bottom: 0;
}

.countdown-container {
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--text-light);
}

#countdown {
    font-weight: bold;
    color: var(--secondary-color);
}

.popup-buttons {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.popup-cancel {
    background-color: #e9ecef;
    color: var(--text-light);
    border: none;
    padding: 0.8rem 2rem;
    border-radius: 6px;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    flex: 1;
}

.popup-cancel:hover {
    background-color: #dee2e6;
    transform: translateY(-2px);
}

.popup-confirm {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    padding: 0.8rem 2rem;
    border-radius: 6px;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    flex: 1;
}

.popup-confirm:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
}

.popup-confirm:disabled {
    background-color: #e0e0e0;
    color: #a0a0a0;
    cursor: not-allowed;
    transform: none;
}

.popup-confirm:disabled:hover {
    background-color: #e0e0e0;
    transform: none;
}

@media (max-width: 480px) {
    .popup-content {
        padding: 1.5rem;
        margin: 1rem;
    }

    .popup-header h3 {
        font-size: 1.2rem;
    }

    .popup-body {
        font-size: 0.95rem;
    }

    .popup-buttons {
        flex-direction: column;
        gap: 0.8rem;
    }
}

@keyframes popupSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scroll Down Indicator */
.scroll-indicator-container {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
    text-align: center;
    transition: opacity 0.5s ease, visibility 0.5s ease, transform 0.5s ease;
    border-top: 2rem;
    border-bottom: 2rem;
}

.scroll-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-decoration: none;
    color: var(--text-light);
    transition: var(--transition);
}

.scroll-indicator:hover {
    color: var(--secondary-color);
    transform: translateY(-5px);
}

.scroll-indicator .mouse {
    width: 32px;
    height: 52px;
    border: 3px solid var(--text-light);
    border-radius: 16px;
    position: relative;
    margin-bottom: 12px;
    transition: var(--transition);
}

.scroll-indicator .scroller {
    width: 5px;
    height: 10px;
    background-color: var(--text-light);
    border-radius: 2.5px;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    animation: scroll-anim 1.5s infinite;
    transition: var(--transition);
}

.scroll-indicator span {
    font-size: 0.9rem;
    font-weight: 500;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.scroll-indicator:hover .mouse {
    border-color: var(--secondary-color);
    background-color: var(--secondary-color);
}

.scroll-indicator:hover .scroller {
    background-color: var(--secondary-color);
}

@keyframes scroll-anim {
    0% {
        opacity: 0;
        top: 10px;
    }
    30% {
        opacity: 1;
        top: 16px;
    }
    70% {
        opacity: 1;
        top: 24px;
    }
    100% {
        opacity: 0;
        top: 32px;
    }
}

.scroll-indicator-container.hidden {
    opacity: 0;
    visibility: hidden;
    transform: translate(-50%, 20px);
}

/* Detailed Features Section */
.features-header {
    text-align: center;
    margin-bottom: 5rem;
    position: relative;
}

.features-header::after {
    content: '';
    position: absolute;
    bottom: -2rem;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.features-header h2 {
    margin-bottom: 1.5rem;
    position: relative;
    display: inline-block;
}

.features-header p {
    font-size: 1.15rem;
    color: var(--text-light);
    max-width: 700px;
    margin: 1rem auto 3.5rem auto;
    line-height: 1.6;
}

.doc-stats {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 4rem;
    margin: 0 auto;
    padding: 2rem 0;
    border: none;
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.05), rgba(44, 62, 80, 0.05));
    border-radius: 16px;
    max-width: 600px;
}

.detailed-features-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
    margin-top: 5rem;
}

.doc-section.gene-expression {
    padding: 0 2rem 0 0;
    position: relative;
}

.doc-section.gene-expression::after {
    content: '';
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
    width: 1px;
    background: linear-gradient(to bottom, rgba(52, 152, 219, 0.2), transparent);
}

.doc-section.ligand-receptor {
    padding: 0 0 0 2rem;
}

.stat-item {
    text-align: center;
    position: relative;
}

.stat-item:not(:last-child)::after {
    content: '';
    position: absolute;
    right: -2rem;
    top: 50%;
    transform: translateY(-50%);
    width: 1px;
    height: 40px;
    background-color: #e9ecef;
}

.stat-item h4 {
    font-size: 2.8rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    background-color: var(--white);
}

.stat-item span {
    font-size: 1rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.doc-section {
    margin-bottom: 0;
}

.doc-section-header {
    text-align: center;
    margin-bottom: 3rem;
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.05), rgba(44, 62, 80, 0.05));
    color: var(--secondary-color);
    padding: 1.5rem 2rem;
    border-radius: 16px;
    border: 2px solid rgba(52, 152, 219, 0.1);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.doc-section-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.1), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.doc-section-header:hover {
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.1), rgba(44, 62, 80, 0.1));
    border-color: rgba(52, 152, 219, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(52, 152, 219, 0.15);
}

.doc-section-header:hover::before {
    opacity: 1;
}

.doc-section-header h3 {
    font-size: 1.6rem;
    margin-bottom: 0;
    font-weight: 600;
    position: relative;
    z-index: 1;
}

.doc-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.doc-card {
    background-color: var(--white);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 6px 12px rgba(0,0,0,0.08);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    border: 1px solid rgba(0, 0, 0, 0.05);
    position: relative;
}

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

.doc-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.12);
    border-color: rgba(52, 152, 219, 0.2);
}

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

.doc-card-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
    border-bottom: 1px solid #e9ecef;
}

.doc-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.doc-card:hover .doc-card-image img {
    transform: scale(1.05);
}

.doc-card-content {
    padding: 1.5rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.doc-card-content h4 {
    color: var(--secondary-color);
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
    font-weight: 600;
}

.doc-card-content p {
    color: var(--text-light);
    font-size: 0.95rem;
    line-height: 1.6;
    flex-grow: 1;
}

.gene-expression .doc-card {
    background-color: var(--bg-light);
    border-color: transparent;
}

.ligand-receptor .doc-card {
    background-color: var(--white);
    border: 1px solid #e9ecef;
}

@media (max-width: 1024px) {
    .features-header {
        margin-bottom: 4rem;
    }

    .features-header::after {
        width: 60px;
        bottom: -1.5rem;
    }

    .features-header p {
        font-size: 1.1rem;
        margin-bottom: 3rem;
    }

    .doc-stats {
        gap: 3rem;
        padding: 1.5rem 0;
    }

    .detailed-features-container {
        grid-template-columns: 1fr;
        gap: 4rem;
        margin-top: 4rem;
    }

    .doc-section.gene-expression {
        padding: 0;
    }

    .doc-section.gene-expression::after {
        display: none;
    }

    .doc-section.ligand-receptor {
        padding: 0;
    }

    .doc-section {
        margin-bottom: 0;
    }

    .doc-section-header {
        margin-bottom: 2.5rem;
        padding: 1.25rem 1.5rem;
    }

    .doc-section-header h3 {
        font-size: 1.5rem;
    }
}

@media (max-width: 768px) {
    .features-header {
        margin-bottom: 3rem;
    }

    .features-header p {
        font-size: 1rem;
        margin-bottom: 2.5rem;
        padding: 0 1rem;
    }

    .doc-stats {
        flex-direction: column;
        gap: 2rem;
        padding: 1.5rem 2rem;
        margin: 0 1rem;
    }

    .stat-item:not(:last-child)::after {
        display: none;
    }

    .stat-item h4 {
        font-size: 2.5rem;
    }

    .detailed-features-container {
        margin-top: 3rem;
        gap: 3rem;
    }

    .doc-section-header {
        margin-bottom: 2rem;
        padding: 1rem;
    }

    .doc-section-header h3 {
        font-size: 1.4rem;
    }

    .doc-grid {
        gap: 1.5rem;
        grid-template-columns: 1fr;
    }

    .doc-card-image {
        height: 180px;
    }

    .doc-card-content {
        padding: 1.25rem;
    }

    .doc-card-content h4 {
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .features-header {
        margin-bottom: 2.5rem;
    }

    .features-header::after {
        width: 50px;
        bottom: -1rem;
    }

    .features-header h2 {
        font-size: 2rem;
    }

    .features-header p {
        font-size: 0.95rem;
        margin-bottom: 2rem;
        padding: 0 0.5rem;
    }

    .doc-stats {
        padding: 1.25rem 1rem;
        margin: 0 0.5rem;
        gap: 1.5rem;
    }

    .stat-item h4 {
        font-size: 2.2rem;
    }

    .stat-item span {
        font-size: 0.9rem;
    }

    .detailed-features-container {
        margin-top: 2.5rem;
        gap: 2.5rem;
    }

    .doc-section-header {
        margin-bottom: 1.5rem;
        padding: 0.8rem 1rem;
    }

    .doc-section-header h3 {
        font-size: 1.3rem;
    }

    .doc-card-image {
        height: 160px;
    }

    .doc-card-content {
        padding: 1rem;
    }

    .doc-card-content h4 {
        font-size: 1rem;
        margin-bottom: 0.6rem;
    }

    .doc-card-content p {
        font-size: 0.9rem;
    }
}