/* 共通 */
body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    margin: 0;
    padding: 0;
    color: #333;
    line-height: 1.6;
}

:root {
    --primary-color: #1a73e8;
    --secondary-color: #4285f4;
    --accent-color: #0d47a1;
    --light-blue: #e8f0fe;
    --dark-blue: #0d47a1;
}

.textcenter {
    text-align: center;
}

/* ヘッダー */
header {
    background-color: var(--primary-color);
    color: white;
    padding: 1.5rem 0;
    text-align: center;
}

header h1 {
    color: white;
}

nav {
    background-color: var(--dark-blue);
    padding: 0.8rem 0;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    margin: 0;
    padding: 0;
}

nav li {
    margin: 0 1.5rem;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: opacity 0.3s;
}

nav a:hover {
    opacity: 0.8;
}

.menu-icon {
    display: none;
    font-size: 28px;
    cursor: pointer;
    position: absolute;
    top: 15px;
    right: 20px;
    color: white;
}

#menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9); /* 黒背景 */
    z-index: 1000;
}

/* メニューコンテンツ */
.menu-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    width: 80%;
}

.menu-content ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.menu-content ul li {
    margin: 20px 0;
}

.menu-content ul li a {
    text-decoration: none;
    color: white;
    font-size: 24px;
    font-weight: bold;
}

/* セクション共通 */
section {
    padding: 3rem 10%;
    margin: 0 auto;
}

h1, h2, h3 {
    color: var(--dark-blue);
}

/* プロジェクト概要 */
.project-overview {
    background-color: var(--light-blue);
}

/* 研究紹介セクション */
.research-container {
    margin: 2rem 0;
    /* height: 70vh;
    overflow-y: auto; */
    padding: 0 1rem;
}

.research-container a {
    text-decoration: none;
}

.research-item {
    margin-bottom: 3rem;
    padding: 2rem;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.research-item:hover {
    transform: translateY(-5px);
}

.research-item h3 {
    margin-top: 0;
    margin-bottom: 0;
    color: var(--primary-color);
    font-size: 1.5rem;
}

.research-meta {
    margin-bottom: 1rem;
}

.research-meta p {
    margin: 0.2rem 0;
    font-size: 0.9rem;
    color: #555;
}

.research-content {
    display: flex;
    flex-direction: row;
    gap: 5%;
    align-items: center;
}

.research-image {
    flex: 0 0 40%;
    height: 300px;
    overflow: hidden;
}

.research-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.research-description {
    flex: 0 0 55%;
    color: black;
    max-height: 300px;
    overflow: hidden;
    position: relative;
}

.research-link {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.6rem 1.2rem;
    background-color: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.research-link:hover {
    background-color: var(--dark-blue);
}

/* フッター */
footer {
    background-color: var(--dark-blue);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer-content {
    display: flex;
    justify-content: space-around;
    max-width: 1200px;
    margin: 0 auto;
    flex-wrap: wrap;
}

.footer-section {
    margin: 1rem;
    flex: 1 1 300px;
}

.footer-section h3 {
    color: white;
}

footer a {
    color: white;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .research-content {
        flex-direction: column;
    }
    
    .research-image, .research-description {
        flex: 0 0 100%;
    }
    
    .research-container {
        height: auto;
    }

    nav {
        display: none;
    }

    .menu-icon {
        display: block;
    }

    .research-image {
        height: 150px;
    }
}