:root {
    --brand-color: #BCE2E8;
    --accent-color: #5FA6B3;
    --text-color: #1D1C1D;
    --text-secondary: #616061;
    --bg-color: #FFFFFF;
    --bg-secondary: #F8F8F8;
    --border-color: #E0E0E0;
    --max-width: 800px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.7;
    -webkit-text-size-adjust: 100%;
}

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

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

/* ============================================
   ヘッダー
   ============================================ */
.site-header {
    background-color: var(--brand-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 12px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.header-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
}

.header-app-name {
    font-size: 1.2rem;
    font-weight: 700;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 12px;
}

.header-nav a {
    font-size: 0.95rem;
    font-weight: 500;
    padding: 6px 14px;
    border-radius: 6px;
    transition: background-color 0.2s;
}

.header-nav a:hover {
    background-color: rgba(0, 0, 0, 0.08);
}

.header-lang-switch {
    display: flex;
    align-items: center;
    gap: 4px;
}

.lang-icon {
    font-size: 1rem;
}

.header-lang-switch select {
    appearance: none;
    -webkit-appearance: none;
    background-color: rgba(255, 255, 255, 0.5);
    border: 1px solid rgba(0, 0, 0, 0.15);
    border-radius: 6px;
    padding: 4px 24px 4px 8px;
    font-size: 0.85rem;
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23333'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 8px center;
}

.header-lang-switch select:hover {
    background-color: rgba(255, 255, 255, 0.8);
}

/* ============================================
   メインコンテンツ
   ============================================ */
main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 32px 20px;
}

/* ============================================
   ヒーローイメージ
   ============================================ */
.hero-image {
    text-align: center;
    padding: 24px 0;
}

.hero-image img {
    max-width: 100%;
    border-radius: 8px;
}

/* ============================================
   概要テキスト
   ============================================ */
.app-overview {
    text-align: center;
    padding: 24px 0;
}

.app-overview p {
    font-size: 1rem;
    line-height: 1.9;
    color: var(--text-secondary);
}

/* ============================================
   ダウンロードセクション
   ============================================ */
.app-download {
    text-align: center;
    padding: 32px 0;
}

.app-download .app-icon {
    width: 80px;
    height: 80px;
    border-radius: 18px;
    margin-bottom: 12px;
}

.app-download .app-name {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.app-store-link {
    display: inline-block;
}

.app-store-badge {
    height: 44px;
}

/* ============================================
   アプリヒーロー（旧：他ページ用に残す）
   ============================================ */
.app-hero {
    text-align: center;
    padding: 40px 0;
}

.app-hero .app-icon {
    width: 100px;
    height: 100px;
    border-radius: 22px;
    margin-bottom: 16px;
}

.app-hero h1 {
    font-size: 1.8rem;
    margin-bottom: 16px;
}

/* ============================================
   アプリセクション
   ============================================ */
.app-section {
    margin-top: 48px;
}

.section-heading {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 8px;
    border-bottom: 3px solid var(--brand-color);
}

.app-section p {
    font-size: 0.95rem;
    line-height: 1.8;
    margin-bottom: 16px;
}

/* ============================================
   メインイメージ
   ============================================ */
.app-main-image {
    text-align: center;
    margin: 24px 0;
}

.app-main-image img {
    max-width: 100%;
    border-radius: 8px;
}

/* ============================================
   スクリーンショット横スクロール
   ============================================ */
.screenshot-scroll {
    display: flex;
    gap: 12px;
    overflow-x: auto;
    padding: 16px 0;
    -webkit-overflow-scrolling: touch;
}

.screenshot-scroll img {
    height: 400px;
    width: auto;
    border-radius: 8px;
    flex-shrink: 0;
}

/* ============================================
   機能紹介
   ============================================ */
.feature-item {
    margin-bottom: 28px;
}

.feature-item h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 8px;
    padding-left: 14px;
    border-left: 4px solid var(--brand-color);
}

.feature-item p {
    color: var(--text-secondary);
}

/* ============================================
   CTA（ダウンロード誘導）
   ============================================ */
.app-cta {
    text-align: center;
    padding: 40px 0;
    margin-top: 48px;
    background-color: var(--accent-color);
    border-radius: 12px;
    color: #FFFFFF;
}

.app-cta .app-icon {
    width: 80px;
    height: 80px;
    border-radius: 18px;
    margin-bottom: 16px;
}

.cta-text {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 16px;
}

/* ============================================
   ガイド：カード一覧
   ============================================ */
.guide-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin: 24px 0 40px;
}

.guide-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px 16px;
    text-align: center;
    cursor: pointer;
    transition: box-shadow 0.3s, transform 0.3s;
}

@media (hover: hover) {
    .guide-card:hover {
        box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
        transform: translateY(-4px);
    }
}

.guide-card-img {
    max-width: 100%;
    max-height: 80px;
    margin-bottom: 12px;
    border: none;
}

.guide-card h2 {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-color);
    line-height: 1.4;
}

/* ============================================
   ガイド：閉じるボタン
   ============================================ */
.guide-close-btn {
    display: block;
    margin: 24px auto 0;
    padding: 8px 32px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background-color 0.2s;
}

.guide-close-btn:hover {
    background-color: var(--border-color);
}

/* ============================================
   ガイド：ページタイトル
   ============================================ */
.guide-page-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.guide-img {
    display: block;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    max-width: 350px;
    margin-bottom: 12px;
}

/* ============================================
   ガイド：折りたたみセクション
   ============================================ */
details {
    border-bottom: 1px solid var(--border-color);
}

summary {
    cursor: pointer;
    padding: 16px 0;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

summary::-webkit-details-marker {
    display: none;
}

summary::after {
    content: "＋";
    font-size: 1.2rem;
    color: var(--text-secondary);
    transition: transform 0.2s;
}

details[open] summary::after {
    content: "−";
}

.section-title {
    font-size: 1.05rem;
    font-weight: 700;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: "";
    display: block;
    height: 8px;
    background-color: var(--brand-color);
    opacity: 0.8;
    margin-top: -8px;
}

/* ============================================
   ガイド：サブタイトル
   ============================================ */
.sub-title {
    font-size: 1rem;
    font-weight: 600;
    padding: 10px 0 10px 14px;
    border-left: 4px solid var(--brand-color);
    margin: 20px 0 10px;
}

/* ============================================
   ガイド：コンテンツ
   ============================================ */
.guide-content {
    padding: 8px 0 24px;
}

.guide-content p {
    margin-bottom: 12px;
    font-size: 0.95rem;
    line-height: 1.8;
}

.guide-content .note {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.guide-content img {
    border: 1px solid var(--border-color);
    border-radius: 4px;
    max-width: 350px;
    margin-bottom: 12px;
}

/* ============================================
   フッター
   ============================================ */
.site-footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    margin-top: 60px;
}

.footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 24px 20px;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 12px;
}

.footer-links a {
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--text-color);
}

.footer-copyright {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

/* ============================================
   ハンバーガーボタン
   ============================================ */
.nav-hamburger {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    flex-direction: column;
    gap: 5px;
}

.nav-hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-color);
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
}

.nav-hamburger.is-open span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-hamburger.is-open span:nth-child(2) {
    opacity: 0;
}

.nav-hamburger.is-open span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ============================================
   レスポンシブ
   ============================================ */
@media (max-width: 600px) {
    .header-app-name {
        font-size: 1rem;
    }

    .nav-hamburger {
        display: flex;
    }

    .header-nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--brand-color);
        flex-direction: column;
        padding: 12px 20px;
        gap: 0;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    }

    .header-nav.is-open {
        display: flex;
    }

    .header-nav a {
        padding: 12px 14px;
        border-bottom: 1px solid rgba(0, 0, 0, 0.08);
        border-radius: 0;
        font-size: 0.95rem;
    }

    .header-nav a:last-of-type {
        border-bottom: none;
    }

    .header-lang-switch {
        padding: 12px 14px;
        border-top: 1px solid rgba(0, 0, 0, 0.08);
    }

    .app-hero h1 {
        font-size: 1.4rem;
    }

    .guide-content img {
        max-width: 100%;
    }

    .guide-cards {
        display: none;
    }

    .guide-img {
        max-width: 100%;
    }

    .screenshot-scroll img {
        height: 300px;
    }
}