:root {
    --primary-color: #4a90e2;
    --dark-text: #333;
    --light-text: #f8f9fa;
    --background-color: #ffffff;
    --section-bg-color: #f8f9fa;
    --footer-bg-color: #343a40;
}

body {
    margin: 0;
    font-family: 'Noto Sans JP', sans-serif;
    line-height: 1.7;
    color: var(--dark-text);
    background-color: var(--background-color);
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: var(--background-color);
    padding: 20px 0;
    border-bottom: 1px solid #e9ecef;
}

header h1 {
    margin: 0;
    font-size: 28px;
    text-align: center;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 80px 0;
    background-color: var(--section-bg-color);
}

.hero h2 {
    font-size: 42px;
    margin-top: 0;
    margin-bottom: 20px;
}

.hero p {
    font-size: 18px;
    color: #555;
    margin-bottom: 0;
}

/* Overview & Contact Section */
.overview, .contact {
    padding: 60px 0;
    text-align: center;
}
.overview {
    background-color: var(--background-color);
}
.contact {
    background-color: var(--section-bg-color);
}

.overview h3 {
    font-size: 28px;
    margin-bottom: 20px;
}

.button-primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 18px;
    font-weight: bold;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
}

.button-primary:hover {
    background-color: #357abd;
    transform: translateY(-2px);
}

/* Footer */
footer {
    background-color: var(--footer-bg-color);
    color: var(--light-text);
    padding: 40px 0;
    text-align: center;
}

.footer-nav a {
    color: var(--light-text);
    text-decoration: none;
    margin: 0 15px;
    transition: color 0.3s;
}

.footer-nav a:hover {
    color: var(--primary-color);
}

.copyright {
    margin-top: 20px;
    font-size: 14px;
    color: #adb5bd;
}

/* Modal (Popup) Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.6);
}

.modal-content {
    background-color: #fefefe;
    margin: 10% auto;
    padding: 30px;
    border: 1px solid #888;
    width: 80%;
    max-width: 800px;
    border-radius: 8px;
    position: relative;
}

.modal-text {
    max-height: 60vh;
    overflow-y: auto;
    white-space: pre-wrap; /* 改行を反映させる */
}

.close-button {
    color: #aaa;
    position: absolute;
    top: 15px;
    right: 25px;
    font-size: 28px;
    font-weight: bold;
}

.close-button:hover,
.close-button:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero h2 {
        font-size: 32px;
    }
    .hero p {
        font-size: 16px;
    }
}