:root {
    --primary-color: #333;
    --secondary-color: #666;
    --background-color: #f4f4f4;
    --card-background: #fff;
    --border-color: #e0e0e0;
    --accent-color: #007bff;
    --font-family: Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    margin: 0;
    background-color: var(--background-color);
    color: var(--primary-color);
}

a {
    text-decoration: none;
    color: var(--primary-color);
}

main {
    max-width: 960px;
    margin: 0 auto;
    padding: 40px 20px;
    min-height: calc(100vh - 150px);
}

/* ヘッダーのスタイル */
.site-header {
    background-color: var(--card-background);
    border-bottom: 1px solid var(--border-color);
    padding: 10px 20px;
}

.header-inner {
    max-width: 960px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.site-logo {
    font-size: 28px;
    font-weight: bold;
    color: black;
}

.site-logo a {
    color: var(--primary-color);
}

/* ハンバーガーメニューのアイコン */
.hamburger-menu {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
    width: 30px;
    height: 30px;
    position: relative;
    z-index: 100;
}

.hamburger-menu span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--primary-color);
    margin-bottom: 5px;
    transition: transform 0.3s, opacity 0.3s;
}

.hamburger-menu[aria-expanded="true"] span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.hamburger-menu[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
}

.hamburger-menu[aria-expanded="true"] span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* ナビゲーションメニュー */
.main-nav {
    width: 100%;
    margin-top: 10px;
}

.main-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* コンテンツボタン */
.content-buttons h2 {
    font-size: 24px;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 5px;
    margin-top: 30px;
}

.button-group {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.content-button {
    display: block;
    padding: 20px;
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    text-align: center;
    color: var(--primary-color);
    font-weight: bold;
    transition: background-color 0.3s;
}

.content-button:hover {
    background-color: #f0f0f0;
}

/* アドセンス広告 */
.ad-space {
    margin: 30px 0;
    text-align: center;
}

.ad-placeholder {
    width: 100%;
    height: 250px;
    background-color: #f9f9f9;
    border: 1px dashed var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--secondary-color);
}

/* フッター */
.site-footer {
    background-color: var(--primary-color);
    color: var(--card-background);
    padding: 20px;
    text-align: center;
   
}

.footer-nav ul {
    list-style: none;
    padding: 0;
    margin: 0 0 10px 0;
    display: flex;
    justify-content: center;
    gap: 15px;
}

.footer-nav a {
    color: var(--card-background);
    opacity: 0.8;
}

em{
      font-size: 10px;
}

.copyright {
    font-size: 14px;
    opacity: 0.6;
}

/* プレビュー表示エリア */
.preview-container {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--card-background);
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    padding: 20px;
    width: 90%;
    max-width: 400px;
    display: none;
    z-index: 1000;
    border-radius: 8px;
}

.preview-container.visible {
    display: block;
}

.preview-image {
    width: 100%;
    height: auto;
    margin-bottom: 15px;
    border-radius: 5px;
}

.preview-title {
    font-size: 20px;
    font-weight: bold;
    margin-bottom: 10px;
}

.preview-description {
    font-size: 14px;
    color: var(--secondary-color);
}

/* レスポンシブ対応 */
@media (max-width: 767px) {
    .hamburger-menu {
        display: block;
    }
    .main-nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        height: 100%;
        background-color: var(--card-background);
        padding-top: 60px;
        transition: right 0.3s;
        z-index: 99;
    }
    .main-nav[aria-hidden="false"] {
        right: 0;
    }
    .main-nav ul {
        flex-direction: column;
        align-items: center;
        gap: 25px;
    }
}

@media (min-width: 768px) {
    .header-inner {
        flex-wrap: nowrap;
    }
    .main-nav {
        position: static;
        width: auto;
        height: auto;
        padding-top: 0;
    }
    .main-nav ul {
        flex-direction: row;
        gap: 20px;
    }
    .button-group {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .button-group {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* preview.css */
.preview-container {
    position: fixed;
    background: white;
    border: 1px solid #ddd;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    opacity: 0;
    transition: opacity 0.2s;
    padding: 15px;
    max-width: 300px;
}

.preview-container.visible {
    opacity: 1;
}

.preview-container img {
    max-width: 100%;
    height: auto;
}

/* 初期状態: 非表示 */
.main-nav {
    display: none;
}

/* aria-hidden="false" になった時に表示 */
.main-nav[aria-hidden="false"] {
    display: block; /* または flex, grid など */
}