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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

nav {
    background-color: #fff;
    padding: 1rem 2rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

nav a {
    margin-right: 2rem;
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.2s;
}

nav a:hover {
    color: #0066cc;
}

main {
    max-width: 1000px;
    width: 90%;
    margin: 0 auto;
    padding: 2rem;
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

h1 {
    margin-bottom: 1.5rem;
    color: #222;
}

h3 {
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: #222;
    font-size: 1.3rem;
}

.abstract {
    margin-bottom: 1rem;
    text-align: justify;
    line-height: 1.8;
}

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

.downloads a {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: #ffa800;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.2s;
    width: fit-content;
}

.downloads a:hover {
    background-color: #e67e00;
}

.pdf-viewer {
    margin-top: 2rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    overflow: hidden;
}

.pdf-viewer iframe {
    border: none;
    display: block;
}