:root {
            --bg: #ffffff;
            --text: #1a1a1a;
            --sub-text: #888;
            --accent: #003366; /* 鉄道を象徴する濃紺 */
            --transition: all 0.8s cubic-bezier(0.22, 1, 0.36, 1);
        }

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

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: "Inter", "Yu Gothic", "Hiragino Kaku Gothic ProN", sans-serif;
            background-color: var(--bg);
            color: var(--text);
            line-height: 1.8;
        }

        /* --- Animations --- */
        .reveal {
            opacity: 0;
            transform: translateY(40px);
            transition: var(--transition);
        }

        .reveal.active {
            opacity: 1;
            transform: translateY(0);
        }

        /* --- Header Navigation --- */
        header {
            position: fixed;
            top: 0;
            width: 100%;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 25px 5%;
            z-index: 1000;
            mix-blend-mode: difference;
            color: white;
        }

        .logo {
            font-size: 1.4rem;
            font-weight: 800;
            letter-spacing: 0.3em;
        }

        nav a {
            color: white;
            text-decoration: none;
            margin-left: 25px;
            font-size: 0.75rem;
            letter-spacing: 0.15em;
            font-weight: 600;
        }

        /* --- Hero Section --- */
        .hero {
            height: 100vh;
            position: relative;
            overflow: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .hero-img {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 110%;
            background: url("photos/trainphoto/topphoto/topphoto33.jpg") center center/cover;
            z-index: -1;
            filter: brightness(0.8);
        }

        .hero-content {
            text-align: center;
            color: white;
        }

        .hero-content h1 {
            font-size: 4rem;
            font-weight: 200;
            letter-spacing: 0.4em;
        }

        /* --- Common Section Styles --- */
        section {
            padding: 120px 10%;
        }

        .section-label {
            font-size: 0.7rem;
            color: var(--sub-text);
            letter-spacing: 0.4em;
            text-transform: uppercase;
            margin-bottom: 20px;
            display: block;
        }

        h2 {
            font-size: 2rem;
            font-weight: 300;
            margin-bottom: 50px;
            letter-spacing: 0.1em;
        }

        /* --- News Section --- */
        .news-list {
            list-style: none;
            border-top: 1px solid #eee;
        }

        .news-item {
            padding: 20px 0;
            border-bottom: 1px solid #eee;
            display: grid;
            grid-template-columns: 150px 1fr;
            font-size: 0.9rem;
        }

        .news-date {
            color: var(--sub-text);
        }

        /* --- Gallery Section --- */
        .gallery-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 20px;
            align-items: start;
        }

        .item {
            grid-column: span 1;
            position: relative;
            overflow: hidden;
            cursor: pointer;
            background: #f0f0f0;
        }

        .item img {
            width: 100%;
            height: 300px;
            object-fit: cover;
            display: block;
            transition: var(--transition);
        }

        .item:hover img {
            transform: scale(1.05);
            filter: brightness(0.8);
        }

        /* --- Lightbox / Popup --- */
        .phos-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.9);
            display: flex;
            align-items: center;
            justify-content: center;
            z-index: 10000;
            cursor: pointer;
            animation: fadeIn 0.3s ease;
        }

        .phos-popup-content {
            position: relative;
            max-width: 90%;
            max-height: 90%;
        }

        .popup-img {
            max-width: 100%;
            max-height: 90vh;
            display: block;
            box-shadow: 0 0 30px rgba(0,0,0,0.5);
            border: 2px solid #333;
        }

        .close-btn {
            position: absolute;
            top: -40px;
            right: 0;
            color: white;
            font-size: 30px;
            cursor: pointer;
        }

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

        /* --- Archive Nav --- */
        .archive-nav {
            margin-top: 80px;
            text-align: center;
        }

        .year-links {
            display: flex;
            justify-content: center;
            gap: 15px;
            flex-wrap: wrap;
            margin-top: 20px;
        }

        .year-btn {
            display: inline-block;
            padding: 12px 30px;
            border: 1px solid #ddd;
            text-decoration: none;
            color: var(--text);
            font-size: 0.85rem;
            letter-spacing: 0.1em;
            transition: all 0.4s;
        }

        .year-btn:hover {
            background: var(--text);
            color: #fff;
            border-color: var(--text);
            transform: translateY(-3px);
        }

        /* --- About Section --- */
        .about-flex {
            display: flex;
            align-items: center;
            gap: 60px;
            max-width: 900px;
            margin: 0 auto;
        }

        .about-image {
            flex: 1;
            max-width: 300px;
        }

        .about-image img {
            width: 100%;
            aspect-ratio: 1 / 1;
            object-fit: cover;
            border-radius: 50%;
            filter: grayscale(0.2);
        }

        .about-text {
            flex: 2;
        }

        .about-text h3 {
            font-size: 1.5rem;
            margin-bottom: 20px;
            font-weight: 400;
        }

        .about-text p {
            font-size: 0.95rem;
            color: #555;
            margin-bottom: 20px;
        }

        .gear-info {
            font-size: 0.8rem;
            color: var(--sub-text);
            border-top: 1px solid #eee;
            padding-top: 15px;
        }

        /* --- Links Section --- */
        .link-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 15px;
        }

        .link-card {
            display: flex;
            flex-direction: column;
            padding: 20px;
            background: #fcfcfc;
            border: 1px solid #eee;
            text-decoration: none;
            transition: var(--transition);
        }

        .link-card:hover {
            background: #fff;
            border-color: var(--text);
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0,0,0,0.05);
        }

        .link-name {
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--text);
        }

        .link-url {
            font-size: 0.7rem;
            color: var(--sub-text);
            margin-top: 5px;
        }

        /* --- Footer --- */
        footer {
            padding: 80px 0;
            text-align: center;
            background: #1a1a1a;
            color: #666;
            font-size: 0.7rem;
        }

/* --- Responsive (Mobile Optimization) --- */
@media screen and (max-width: 768px) {

    /* 1. ヘッダー：左寄せに変更 */
    header {
        padding: 20px 5% !important;
        flex-direction: column !important;
        align-items: flex-start !important; /* 左寄せ */
        gap: 10px !important;
    }

    .logo {
        font-size: 1.0rem !important;
        letter-spacing: 0.2em !important;
        margin-left: 0 !important;
    }

    nav {
        display: flex !important;
        justify-content: flex-start !important; /* ナビも左寄せ */
        width: 100% !important;
    }

    nav a {
        margin: 0 15px 0 0 !important; /* 右側に余白を作って並べる */
        font-size: 0.65rem !important;
    }

    /* 2. ヒーローセクション：タイトルも左寄せ */
    .hero .hero-content {
        text-align: left !important;
        width: 100% !important;
        padding: 0 5% !important;
    }

    .hero .hero-content h1 {
        font-size: 1.6rem !important;
        letter-spacing: 0.2em !important;
        line-height: 1.5 !important;
    }

    /* 3. 各セクションの見出し（Photo Gallery / News等）を左寄せ */
    section {
        padding: 60px 5% !important;
    }

    h2 {
        font-size: 1.3rem !important;
        text-align: left !important; /* 左寄せ */
        margin-bottom: 30px !important;
        letter-spacing: 0.1em !important;
    }

    .section-label {
        text-align: left !important;
    }

    /* 4. プロフィール：以前の「中央配置」レイアウト */
    .about-flex {
        flex-direction: column !important; /* 縦並び */
        align-items: center !important;    /* 中央揃え */
        text-align: center !important;     /* テキストも中央 */
        gap: 20px !important;
    }

    .about-image {
        max-width: 150px !important; /* スマホで見やすいサイズ */
        margin: 0 auto !important;
    }

    .about-text h3 {
        font-size: 1.2rem !important;
        margin-bottom: 10px !important;
    }

    /* 5. ギャラリー：横3枚並びを維持 */
    .gallery-grid {
        display: grid !important;
        grid-template-columns: repeat(3, 1fr) !important;
        gap: 2px !important;
        padding: 2px !important;
    }

    .item img {
        height: 100px !important;
    }
}