:root {
    --primary-color: #004098;
    --accent-color: #ffc107;
    --bg-color: #f8f9fa;
    --text-color: #333;
    --white: #ffffff;
}

body {
    font-family: 'Helvetica Neue', Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
}

header {
    background-color: var(--white);
    padding: 1rem 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.logo {
    font-weight: bold;
    font-size: 1.25rem;
    color: var(--primary-color);
}

nav a {
    text-decoration: none;
    color: var(--text-color);
    margin-left: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.section-title {
    text-align: center;
    margin-bottom: 40px;
    position: relative;
    padding-bottom: 10px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 3px;
    background-color: var(--accent-color);
}

footer {
    background-color: #333;
    color: var(--white);
    text-align: center;
    padding: 40px 0;
    margin-top: 60px;
}

@media (max-width: 768px) {
    nav { display: none; }
}