/* ========================================
   レスポンシブスタイル
   ======================================== */

/* ---- 1024px 以下 ---- */
@media screen and (max-width: 1024px) {
    .features {
        grid-template-columns: repeat(2, 1fr);
    }
    .howto-steps {
        grid-template-columns: repeat(3, 1fr);
    }
    .app-intro {
        flex-direction: column;
    }
    .app-info {
        text-align: center;
    }
    .app-image {
        text-align: center;
        flex: 0 0 auto;
    }
    .screenshot-wrap {
        flex: 0 0 calc(33.333% - 16px);
    }
}

/* ---- 768px 以下 (タブレット/スマホ) ---- */
@media screen and (max-width: 768px) {
    .header-container {
        height: 70px;
    }

    .hamburger-menu { display: block; }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -320px;
        width: 300px;
        height: 100%;
        background-color: #fff;
        padding: 70px 20px 40px;
        overflow-y: auto;
        z-index: 100;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.1);
        transition: right 0.3s ease;
        flex-direction: column;
        display: flex;
    }
    .nav-menu.active { right: 0; }

    .nav-menu ul {
        flex-direction: column;
        gap: 0;
        align-items: flex-start;
        width: 100%;
    }
    .nav-menu li {
        width: 100%;
        border-bottom: 1px solid #eee;
    }
    .nav-menu li:last-child { border-bottom: none; }
    .nav-menu li a {
        display: block;
        padding: 15px 5px;
        font-size: 16px;
        width: 100%;
    }
    .nav-menu li a:after { display: none; }

    .close-menu { display: block; }

    /* モバイルでは言語ドロップダウンを常時展開型に */
    .nav-lang {
        border-top: 2px solid #000;
        padding-top: 10px;
        margin-top: 10px;
    }
    .lang-toggle {
        width: 100%;
        justify-content: space-between;
        padding: 12px 14px;
    }
    .lang-dropdown {
        position: static;
        box-shadow: none;
        border: none;
        width: 100%;
        margin-top: 4px;
    }

    .hero { padding: 50px 20px 30px; }
    .hero h1 { font-size: 36px; }
    .hero p { font-size: 16px; }

    .section { padding: 40px 0; }
    .section-title { margin-bottom: 30px; }
    .section-title h2 { font-size: 28px; }

    .features {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .howto-steps {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .screenshot-wrap {
        flex: 0 0 calc(50% - 16px);
        max-width: none;
    }

    .contact-form { padding: 25px 20px; }

    .legal-doc { padding: 25px 20px; }

    .app-version-info strong { width: 120px; }

    .footer-links ul { justify-content: center; }
}

/* ---- 480px 以下 ---- */
@media screen and (max-width: 480px) {
    .header-container { height: 60px; }
    .logo a { font-size: 20px; }

    .nav-menu {
        width: 100%;
        right: -100%;
    }

    .hero h1 { font-size: 28px; }
    .hero p { font-size: 14px; }

    .section-title h2 { font-size: 24px; }
    .section-subtitle { font-size: 14px; }

    .screenshot-wrap { flex: 0 0 100%; }

    .app-version-info strong {
        width: 100%;
        display: block;
        margin-bottom: 5px;
    }

    .footer-lang { flex-direction: column; }
}