    <style>
/* --- 基本スタイル --- */
body {
    font-family: 'Noto Sans JP', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f8f9fa;
    color: #333;
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

header {
    background-color: #fff;
    padding: 20px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    color: #2c3e50;
    font-size: 2em;
    font-weight: 700;
    margin: 0;
}

header nav {
    display: none; /* デフォルトでは非表示 */
}

header nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column; /* 縦並び */
    align-items: center;
    width: 100%;
}

header nav ul li {
    margin: 15px 0;
}

header nav ul li a {
    color: #555;
    text-decoration: none;
    font-size: 1.1em;
    transition: color 0.3s ease;
}

header nav ul li a:hover {
    color: #3498db;
}

.hamburger-menu {
    display: block; /* デフォルトで表示（スマホサイズ） */
    width: 30px;
    height: 25px;
    position: relative;
    cursor: pointer;
}

.hamburger-menu span {
    display: block;
    position: absolute;
    height: 3px;
    width: 100%;
    background: #333;
    border-radius: 2px;
    opacity: 1;
    left: 0;
    transform: rotate(0deg);
    transition: .25s ease-in-out;
}

.hamburger-menu span:nth-child(1) {
    top: 0px;
}

.hamburger-menu span:nth-child(2),
.hamburger-menu span:nth-child(3) {
    top: 9px;
}

.hamburger-menu span:nth-child(4) {
    top: 18px;
}

.hamburger-menu.open span:nth-child(1) {
    top: 9px;
    transform: rotate(45deg);
}

.hamburger-menu.open span:nth-child(2) {
    opacity: 0;
    left: -60px;
}

.hamburger-menu.open span:nth-child(3) {
    top: 9px;
    transform: rotate(-45deg);
}

.hamburger-menu.open span:nth-child(4) {
    top: 18px;
    transform: rotate(45deg); /* 重ねてXにする場合 */
    opacity: 0;
}

.container {
    max-width: 1200px;
    margin: 40px auto;
    padding: 30px;
    background-color: #fff;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    border-radius: 10px;
}

h1,
h2,
h3 {
    color: #2c3e50;
    text-align: left;
    margin-bottom: 25px;
    line-height: 1.3;
}

.hero h1 {
    text-align: center;
}

h2 {
        font-size: 1.8em;
    font-weight: 600;
    margin-top: 80px;
    border-bottom: 3px solid #3498db;
    padding-bottom: 10px;
    text-align: center;
}

h3 {
        font-size: 1.4em;
    font-weight: 500;
    color: #3498db;
    margin-bottom: 40px;
    text-align: center;
}

p {
    font-size: 1.1em;
    color: #555;
    margin-bottom: 25px;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto 30px;
    border-radius: 8px;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.08);
}

.hero {
    text-align: center;
    padding: 60px 20px;
    background: linear-gradient(135deg, #e0f7fa 0%, #c5e1e6 100%);
    border-radius: 10px;
    margin-bottom: 40px;
}

.hero h1 {
    color: #2c3e50;
    font-size: 3.5em;
    margin-bottom: 20px;
}

.hero p {
    font-size: 1.4em;
    color: #444;
    margin-bottom: 30px;
}

.cta-button {
    display: inline-block;
    background-color: #3498db;
    color: white;
    padding: 18px 40px;
    text-decoration: none;
    border-radius: 8px;
    font-size: 1.2em;
    font-weight: 500;
    transition: background-color 0.3s ease;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.1);
}

.cta-button:hover {
    background-color: #2980b9;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.feature {
    padding: 30px;
    border: 1px solid #eee;
    border-radius: 8px;
    background-color: #fff;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.15);
}

.benefits ul {
    list-style: none;
    padding-left: 0;
}

.benefits li {
    margin-bottom: 20px;
    padding-left: 30px;
    position: relative;
}

.benefits li::before {
    content: '✓';
    position: absolute;
    left: 0;
    top: 0;
    color: #27ae60;
    font-size: 1.5em;
    line-height: 1.6;
}

.pricing {
    margin-bottom: 40px;
}

.pricing h2 {
    text-align: left;
}

.pricing-plans {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 30px;
    margin-top: 30px;
}

.pricing-plan {
    border: 1px solid #ddd;
    border-radius: 10px;
    padding: 20px;
    text-align: center;
    width: 330px;
    background-color: #fff;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}

.pricing-plan:hover {
    transform: translateY(-8px);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.12);
}

.pricing-plan h4 {
    color: #3498db;
    font-size: 2em;
    margin-bottom: 20px;
}

.pricing-plan .price {
    font-size: 2.8em;
    font-weight: bold;
    color: #27ae60;
    margin-bottom: 25px;
}

.pricing-plan ul {
    list-style: none;
    padding: 0;
    margin-bottom: 30px;
}

.pricing-plan li {
    padding: 10px 0;
    border-bottom: 1px solid #eee;
    font-size: 1.1em;
    color: #555;
}

.pricing-plan li:last-child {
    border-bottom: none;
}

.testimonials {
    margin-bottom: 40px;
}

.testimonials h2 {
    text-align: left;
}

.testimonial {
    padding: 30px;
    border: 1px solid #eee;
    border-radius: 8px;
    background-color: #f9f9f9;
    margin-bottom: 25px;
}

.testimonial h3 {
    font-style: italic;
    color: #777;
    margin-bottom: 10px;
    font-size: 1.2em;
    text-align: left;
}

.testimonial p {
    font-size: 1.1em;
    line-height: 1.7;
    color: #666;
    text-align: left;
}

.contact {
    text-align: left;
    padding: 40px 20px;
    background-color: #f0f8ff;
    border-radius: 10px;
    margin-bottom: 40px;
}

.contact h2 {
    font-size: 2.4em;
    color: #3498db;
    text-align: left;
}

.contact p {
    font-size: 1.2em;
    color: #555;
    margin-bottom: 30px;
    text-align: left;
}

.contact a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease;
}

.contact a:hover {
    color: #2980b9;
    text-decoration: underline;
}

footer {
    text-align: center;
    padding: 40px 20px;
    background-color: #2c3e50;
    color: white;
    font-size: 0.9em;
}

/* --- レスポンシブ対応 --- */
@media (max-width: 768px) {
    header {
        flex-direction: row;
        justify-content: space-between;
    }

    header nav {
        display: none;
        position: absolute;
        top: 60px;
        left: 0;
        background-color: #fff;
        width: 100%;
        box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
        z-index: 10;
    }

    header nav.open {
        display: block;
    }

    header nav ul {
        flex-direction: column;
        align-items: stretch;
    }

    header nav ul li {
        margin: 0;
        border-bottom: 1px solid #eee;
    }

    header nav ul li:last-child {
        border-bottom: none;
    }

    header nav ul li a {
        display: block;
        padding: 15px 20px;
        text-align: center;
    }

    .hamburger-menu {
        display: block;
    }

    .container {
        padding: 20px;
        margin-top: 20px;
        margin-bottom: 20px;
    }

    h1 {
        font-size: 2.4em;
        text-align: center;
    }

    h2 {
        font-size: 2em;
        margin-top: 30px;
        text-align: center;
    }

    h3 {
        font-size: 1.4em;
        text-align: center;
    }

    .hero {
        padding: 40px 15px;
    }

    .hero h1 {
        font-size: 2.8em;
    }

    .hero p {
        font-size: 1.2em;
    }

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

    .feature {
        padding: 20px;
    }

    .pricing {
        text-align: center;
    }

    .pricing h2 {
        text-align: center;
    }

    .pricing-plans {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .pricing-plan {
        width: 90%;
        padding: 30px;
    }

    .testimonials h2 {
        text-align: center;
    }

    .testimonial {
        text-align: center;
    }

    .testimonial h3 {
        text-align: center;
    }

    .testimonial p {
        text-align: left;
    }

    .contact {
        text-align: center;
    }

    .contact h2 {
        text-align: center;
    }

    .contact p {
        text-align: center;
    }
}

/* PCサイズではナビゲーションを表示、ハンバーガーメニューを非表示 */
@media (min-width: 769px) {
    header nav {
        display: block;
    }

    header nav ul {
        flex-direction: row;
        align-items: center;
    }

    header nav ul li {
        margin: 0 0 0 20px;
    }

    header nav ul li:first-child {
        margin-left: 0;
    }

    .hamburger-menu {
        display: none;
    }
}
    </style>
