:root {
    --bg-color: #ffffff;
    --text-color: #2c3e50;
    --accent-color: #3498db;
    --secondary-bg: #f8f9fa;
    --link-hover: #2980b9;
    --nav-bg: #ffffff;
    --nav-border: #e5e7eb;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
    --border-color: #e5e7eb;
}

/* ダークモード */
html:not(.light-mode) body,
body:not(.light-mode) {
    --bg-color: #0d1117;
    --text-color: #e6edf3;
    --accent-color: #58a6ff;
    --secondary-bg: #161b22;
    --link-hover: #79c0ff;
    --nav-bg: #0d1117;
    --nav-border: #30363d;
    --success-color: #2ea043;
    --warning-color: #d29922;
    --danger-color: #da3633;
    --border-color: #30363d;
}

/* ライトモード強制 */
html.light-mode body,
body.light-mode {
    --bg-color: #ffffff;
    --text-color: #2c3e50;
    --accent-color: #3498db;
    --secondary-bg: #f8f9fa;
    --link-hover: #2980b9;
    --nav-bg: #ffffff;
    --nav-border: #e5e7eb;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
    --border-color: #e5e7eb;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding-top: 60px;
    overflow-y: scroll; /* 常にスクロールバーのスペースを確保 */
}

/* 初期読み込み時のちらつき防止 */
/* 空の要素は非表示 */
.language-selector-text:empty,
.theme-selector-text:empty {
    visibility: hidden;
}

/* i18n要素の制御 */
[data-i18n]:not(.i18n-loaded) {
    visibility: hidden;
}

[data-i18n].i18n-loaded {
    visibility: visible;
}

/* セレクタテキストのロード状態 */
.language-selector-text.i18n-loaded,
.theme-selector-text.i18n-loaded {
    visibility: visible;
}

/* ナビゲーションバー */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: var(--nav-bg);
    border-bottom: 1px solid var(--nav-border);
    z-index: 1000;
    /* transition: transform 0.3s; 削除 */
}

.navbar-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-width: 0;
    position: relative;
}

.navbar-controls {
    display: flex;
    align-items: center;
    gap: 12px;
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-color);
    font-size: 1.25rem;
    font-weight: 600;
    flex-shrink: 0;
}

.navbar-logo {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--accent-color), var(--link-hover));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

.navbar-nav {
    display: flex;
    gap: 30px;
    list-style: none;
    margin-left: auto;
    margin-right: 20px;
    flex-shrink: 0;
}

.navbar-nav a {
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.95rem;
    opacity: 0.8;
    /* transition: opacity 0.3s; 削除 */
    position: relative;
    white-space: nowrap;
}

.navbar-nav a:hover {
    opacity: 1;
}

/* アクティブリンクの色変化を一時的に無効化 */
.navbar-nav a.active {
    opacity: 1;
    /* color: var(--accent-color); */
}

.navbar-nav a.active::after {
    content: '';
    position: absolute;
    bottom: -22px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-color);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 8px;
    z-index: 1002;
    position: relative;
}

/* テーマ切り替えドロップダウン */
.theme-selector {
    position: relative;
}

/* 言語切り替えドロップダウン */
.language-selector {
    position: relative;
}

.language-selector-button {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    cursor: pointer;
    padding: 6px 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    min-width: 100px;
}

.language-selector-button:hover {
    background: var(--secondary-bg);
}

.language-selector-text {
    flex: 1;
    text-align: left;
    opacity: 0;
    transition: opacity 0.1s ease;
}

.language-selector-text.loaded,
.language-selector-text.i18n-loaded {
    opacity: 1;
}

.language-selector-button svg {
    width: 12px;
    height: 12px;
    opacity: 0.6;
}

.language-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 4px;
    background: var(--nav-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all 0.2s ease;
    z-index: 1000;
    min-width: 100%;
}

.language-dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    display: block;
    width: 100%;
    padding: 8px 16px;
    background: none;
    border: none;
    color: var(--text-color);
    text-align: left;
    cursor: pointer;
    font-size: 14px;
    font-family: inherit;
    transition: background 0.2s ease;
    position: relative;
}

.language-option:hover {
    background: var(--secondary-bg);
}

.language-option.active::after {
    content: '✓';
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--primary-color);
}

.theme-selector-button {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    cursor: pointer;
    padding: 6px 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-radius: 8px;
    font-size: 14px;
    font-family: inherit;
    min-width: 120px;
}

.theme-selector-button:hover {
    background: var(--secondary-bg);
}

.theme-selector-text {
    flex: 1;
    text-align: left;
    opacity: 0;
    transition: opacity 0.1s ease;
}

.theme-selector-text.loaded,
.theme-selector-text.i18n-loaded {
    opacity: 1;
}

.theme-selector-button svg {
    width: 12px;
    height: 12px;
    opacity: 0.6;
}

.theme-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: 4px;
    background: var(--nav-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    min-width: 160px;
    display: none;
    z-index: 10;
}

.theme-dropdown.active {
    display: block;
}

.theme-option {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 16px;
    cursor: pointer;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    color: var(--text-color);
    font-size: 14px;
    font-family: inherit;
}

.theme-option:hover {
    background: var(--secondary-bg);
}

.theme-option:first-child {
    border-radius: 8px 8px 0 0;
}

.theme-option:last-child {
    border-radius: 0 0 8px 8px;
}

.theme-option.active {
    font-weight: 600;
    color: var(--accent-color);
}

.theme-option.active::after {
    content: '✓';
    margin-left: auto;
    color: var(--accent-color);
}


/* モバイルメニューオーバーレイ */
.mobile-menu-overlay {
    display: none;
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
    z-index: 998;
    opacity: 0;
    transition: opacity 0.3s;
}

.mobile-menu-overlay.active {
    display: block;
    opacity: 1;
}

/* モバイル対応 */
@media (max-width: 1024px) {
    .navbar {
        overflow: visible;
        z-index: 1001 !important;  /* ヘッダーを最前面に！ */
    }
    
    /* モバイルメニューをポップアップスタイルに変更 */
    .navbar-nav {
        position: fixed;
        top: 70px;
        right: 10px;
        width: auto;
        min-width: 250px;
        max-width: 320px;
        background: var(--nav-bg);
        flex-direction: column;
        padding: 10px 0;
        gap: 0;
        border: 1px solid var(--nav-border);
        border-radius: 12px;
        transform: scale(0.95) translateY(-10px);
        opacity: 0;
        visibility: hidden;
        pointer-events: none; /* 非表示時は完全に無効化 */
        transition: transform 0.2s ease-out, opacity 0.2s ease-out, visibility 0s linear 0.2s;
        z-index: 1000;
        overflow-y: auto;
        max-height: calc(100vh - 90px);
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
    }

    .navbar-nav.active {
        transform: scale(1) translateY(0);
        opacity: 1;
        visibility: visible;
        pointer-events: auto; /* アクティブ時は有効化 */
        transition: transform 0.2s ease-out, opacity 0.2s ease-out, visibility 0s;
    }

    .navbar-nav a.active::after {
        display: none;
    }
    
    .navbar-nav li {
        text-align: left;
        margin: 0;
    }
    
    .navbar-nav a {
        padding: 12px 20px;
        border-radius: 0;
        transition: background 0.2s;
        display: block;
        font-size: 15px;
    }
    
    .navbar-nav a:hover {
        background: var(--secondary-bg);
    }

    .navbar-controls {
        display: none;
    }
    
    /* モバイルメニュー内にコントロールを表示 */
    .navbar-nav .mobile-controls {
        display: flex;
        flex-direction: column;
        gap: 0;
        padding: 0;
        border-top: 1px solid var(--nav-border);
        margin-top: 10px;
    }
    
    /* モバイル用のセクションスタイル */
    .navbar-nav .mobile-section {
        padding: 10px 20px;
        border-bottom: 1px solid var(--nav-border);
    }
    
    .navbar-nav .mobile-section-title {
        font-size: 12px;
        opacity: 0.7;
        margin-bottom: 8px;
        text-transform: uppercase;
        letter-spacing: 0.05em;
    }
    
    .navbar-nav .mobile-options {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
        gap: 8px;
    }
    
    .navbar-nav .mobile-option-button {
        padding: 10px 8px;
        background: var(--secondary-bg);
        border: 1px solid var(--border-color);
        border-radius: 6px;
        color: var(--text-color);
        font-size: 14px;
        cursor: pointer;
        transition: all 0.2s;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        text-align: center;
    }
    
    .navbar-nav .mobile-option-button.active {
        background: var(--accent-color);
        color: white;
        border-color: var(--accent-color);
    }
    
    .navbar-nav .mobile-option-button:hover {
        transform: translateY(-1px);
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    }

    .mobile-menu-toggle {
        display: block;
        position: absolute;
        right: 20px;
        top: 50%;
        transform: translateY(-50%);
        z-index: 1002;
    }
}

/* より小さな画面向けの調整 */
@media (max-width: 767px) {
    .navbar-brand {
        font-size: 1.1rem;
    }
    
    .navbar-nav {
        font-size: 1rem;
    }
    
    .mobile-menu-toggle {
        padding: 6px;
    }
}

/* 共通フッター */
.common-footer {
    margin-top: 60px;
    padding: 30px 0;
    border-top: 1px solid var(--border-color);
    background: var(--secondary-bg);
    width: 100%;
}

.footer-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 15px;
}

.footer-links a {
    color: var(--text-color);
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s;
}

.footer-links a:hover {
    opacity: 1;
}

.copyright {
    font-size: 0.9rem;
    opacity: 0.6;
    margin: 0;
}

/* ページトランジション（無効化） */
/*
.page-transition {
    animation: fadeIn 0.2s ease-out;
}

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

/* 共通スタイル */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px 20px 40px;
}

/* コンテンツページ用の統一レイアウト */
.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 20px;
}

.page-header {
    background: var(--secondary-bg);
    padding: 40px 0;
    text-align: center;
    margin-bottom: 0;
}

.page-header h1 {
    font-size: 2rem;
    font-weight: 400;
    letter-spacing: -0.02em;
    margin-bottom: 20px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 20px;
}

h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.button {
    display: inline-block;
    padding: 12px 24px;
    background: var(--accent-color);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    transition: background 0.3s;
}

.button:hover {
    background: var(--link-hover);
}