body {
    font-family: sans-serif;
    margin: 0;
    background-color: #f0f0f0;
    display: flex;
    flex-direction: column;
    min-height: 100vh; /* 画面いっぱいに広がるように */
}

.gallery-container {
    padding: 20px;
    flex: 1; /* コンテンツがフッターの上にくるように */
}

h1 {
    text-align: center;
    margin-bottom: 40px;
}

.image-gallery {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
}

.image-gallery .thumbnail {
    width: 100%;
    height: auto;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.image-gallery .thumbnail:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 16px rgba(0,0,0,0.2);
}

/* Lightbox styles */
.lightbox {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.85);
    justify-content: center;
    align-items: center;
}

.lightbox.show {
    display: flex;
}

.lightbox-content {
    max-width: 90%;
    max-height: 90%;
    object-fit: contain;
    animation: fadeIn 0.5s;
}

.close-lightbox {
    position: absolute;
    top: 20px;
    right: 35px;
    color: #fff;
    font-size: 40px;
    font-weight: bold;
    cursor: pointer;
    transition: color 0.2s;
}

.close-lightbox:hover {
    color: #bbb;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* Footer styles */
.footer {
    background-color: #e9ecef; /* bg-light に相当 */
    padding: 1.5rem 0; /* py-3 に相当 */
    margin-top: auto; /* mt-auto に相当 */
    text-align: center;
}

.footer .container {
    max-width: 960px; /* Bootstrapのcontainerのデフォルト幅に近い値 */
    margin: 0 auto;
    padding: 0 15px;
}

.footer p {
    margin-bottom: 0.5rem;
}

.footer a {
    color: inherit; /* text-muted の色を継承 */
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

.footer .text-muted {
    color: #6c757d; /* text-muted の色 */
}