/* ====== 1/3: ベースCSS（core-styles.css） ====== */

/* フォント定義 */
@font-face {
    font-family: 'チェックアンドＵ－Ｆｏフォント';
    src: url('https://ero-video.fun/css/font/CP and U-Fo.woff') format('woff'),
        url('https://ero-video.fun/css/font/CP and U-Fo.otf') format('truetype');
    font-weight: normal;
    font-style: normal;
    font-display: swap;
}

/* CSS変数定義 */
:root {
    --primary-color: rgb(66, 130, 198);
    --secondary-color: rgb(103, 100, 186);
    --accent-color: rgb(119, 152, 205);
    --background-color: #f8f9ff;
    --card-background: #ffffff;
    --text-color: #2c3e50;
    --text-light: #6b7280;
    --favorite-color: #e53935;
    --success-color: #4caf50;
    --border-radius: 12px;
    --shadow: 0 8px 32px rgba(102, 126, 234, 0.15);
    --shadow-hover: 0 20px 60px rgba(102, 126, 234, 0.25);
    --gradient: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    --transition: all 0.2s ease-out;
    
    --safe-area-inset-top: env(safe-area-inset-top);
    --safe-area-inset-bottom: env(safe-area-inset-bottom);
    --safe-area-inset-left: env(safe-area-inset-left);
    --safe-area-inset-right: env(safe-area-inset-right);
    --mobile-header-height: 60px;
    --mobile-touch-target: 44px;
    --mobile-menu-width: 280px;
    --mobile-animation: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ダークモード */
.dark-mode {
    --background-color: rgb(30, 30, 43);
    --card-background: #16213e;
    --text-color: #eee;
    --text-light: #bbb;
}

/* リセット */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

/* ベースボディ（スクロール連動なし） */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
    -webkit-overflow-scrolling: touch;
    transform: translateZ(0);
    backface-visibility: hidden;
}

/* 🔥 重要：デスクトップのみパディング */
@media (min-width: 769px) {
    body {
        padding-top: 120px;
    }
}

/* アーカイブフォント */
.archive {
    font-family: 'チェックアンドＵ－Ｆｏフォント';
    text-decoration: none;
    color: var(--text-color);
}

a.archive:hover {
    color: var(--text-light);
    transform: translateY(-2px);
}

/* ====== ヘッダー（クリーンバージョン） ====== */
.header { 
    background: var(--gradient);
    color: white; 
    padding: 0; 
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.3); 
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    backdrop-filter: blur(20px) saturate(180%);
    will-change: transform;
    backface-visibility: hidden;
    perspective: 1000px;
}

.header-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
}

.logo {
    font-size: 2rem;
    font-weight: 900;
    background: linear-gradient(45deg, #fff, #e8f4fd);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    letter-spacing: -0.5px;
    transition: var(--transition);
    font-family: 'チェックアンドＵ－Ｆｏフォント', sans-serif;
}

.logo:hover {
    transform: translateY(-2px) scale(1.05);
    text-shadow: 0 8px 20px rgba(255, 255, 255, 0.3);
}

.header-center {
    flex: 1;
    display: flex;
    justify-content: center;
    margin: 0 2rem;
}

/* 検索フォーム */
.search-form {
    position: relative;
    max-width: 600px;
    width: 100%;
}

.search-container {
    position: relative;
    width: 100%;
}

.search-box {
    width: 100%;
    padding: 0.9rem 1.2rem 0.9rem 3rem;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50px;
    background: rgba(255, 255, 255, 0.15);
    color: white;
    font-size: 1.1rem;
    transition: var(--transition);
    backdrop-filter: blur(10px);
    outline: none;
}

.search-box::placeholder {
    color: rgba(255, 255, 255, 0.8);
}

.search-box:focus {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.6);
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.2);
}

.search-icon {
    position: absolute;
    left: 1.2rem;
    top: 50%;
    transform: translateY(-50%);
    color: rgba(255, 255, 255, 0.8);
    font-size: 1.2rem;
    z-index: 9;
    pointer-events: none;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-menu {
    display: flex;
    gap: 0.5rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-item a {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    color: white;
    text-decoration: none;
    border-radius: 25px;
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.95rem;
    backdrop-filter: blur(10px);
}

.nav-item a:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.1);
}

.nav-item.active a {
    background: rgba(255, 255, 255, 0.25);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.2);
}

.mode-toggle {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    padding: 0.6rem 1.2rem;
    border-radius: 50px;
    cursor: pointer;
    backdrop-filter: blur(10px);
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.mode-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.1);
}

.mobile-search-toggle,
.mobile-menu-toggle {
    display: none;
}

/* ====== フッター（クリーンバージョン） ====== */
.footer {
    background: var(--card-background);
    border-top: 1px solid rgba(102, 126, 234, 0.1);
    margin-top: 4rem;
    /* 🔥 重要：position指定なし（JS側で制御） */
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 3rem 2rem 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-link {
    color: var(--text-light);
    text-decoration: none;
    transition: var(--transition);
    padding: 0.25rem 0;
}

.footer-link:hover {
    color: var(--primary-color);
}

.footer-bottom {
    border-top: 1px solid rgba(102, 126, 234, 0.1);
    text-align: center;
    padding: 2rem;
    color: var(--text-light);
}

.footer-note {
    margin-top: 0.5rem;
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ====== コアコンポーネント ====== */
.video-card,
.video-thumbnail,
.video-thumbnail img,
.sidebar-video {
    transform: translateZ(0);
    backface-visibility: hidden;
}

.video-card {
    background: var(--card-background);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease-out, box-shadow 0.2s ease-out;
    position: relative;
    cursor: pointer;
    will-change: auto;
}

.video-card:hover {
    transform: translate3d(0, -8px, 0);
    box-shadow: var(--shadow-hover);
    will-change: transform;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.2s ease-out;
    will-change: auto;
}

.video-card:hover .video-thumbnail img {
    transform: scale3d(1.05, 1.05, 1);
    will-change: transform;
}

/* ====== 基本アニメーション ====== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translate3d(0, 20px, 0);
    }
    to {
        opacity: 1;
        transform: translate3d(0, 0, 0);
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

@keyframes slideUp {
    from {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
    to {
        opacity: 0;
        transform: translateX(-50%) translateY(-20px);
    }
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ====== パフォーマンス最適化 ====== */
.video-thumbnail img {
    transform: translateZ(0);
    content-visibility: auto;
    contain-intrinsic-size: 300px 169px;
}

.videos-grid {
    contain: layout style paint;
}