/* ==========================================================================
   基本設定
   ========================================================================== */
:root {
    --primary-bg: #fdfdfd;      /* オフホワイト */
    --text-dark: #333;          /* ダークグレー */
    --accent-blue: #2d3a8e;     /* 信頼の深青 */
    --accent-gold: #c3a669;     /* 希望のゴールド */
    --subtle-gray: #f8f9fa;     /* セクション背景 */
    --light-blue: #eaf0f6;      /* 淡い青 */
}

/* ==========================================================================
   リセット・ベーススタイル
   ========================================================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans JP', sans-serif;
    color: var(--text-dark);
    background-color: var(--primary-bg);
    line-height: 1.8;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==========================================================================
   タイポグラフィ
   ========================================================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: 'Noto Serif JP', serif;
    font-weight: 700;
    color: var(--accent-blue);
}

.section-title {
    font-size: 2.2rem;
    text-align: center;
    margin-bottom: 1.5rem;
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background-color: var(--accent-gold);
}

.section-intro {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 3rem auto;
    font-size: 1.1rem;
    line-height: 1.9;
}

/* ==========================================================================
   レイアウト
   ========================================================================== */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 20px;
}

.container-narrow {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

section {
    padding: 6rem 0;
}

/* ==========================================================================
   セクション別スタイル
   ========================================================================== */

/* ヒーローセクション */
.hero-section {
    background: linear-gradient(to bottom, #ffffff, var(--subtle-gray));
    text-align: center;
    padding: 6rem 0 4rem 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-content {
    max-width: 800px;
}

.hero-subtitle {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--accent-blue);
    margin-bottom: 0.5rem;
}

.hero-title {
    font-family: 'M PLUS Rounded 1c', sans-serif;
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.4;
    margin-bottom: 0.5rem;
}

.hero-catchphrase {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    color: var(--text-dark);
}

.hero-description {
    margin-bottom: 2.5rem;
    line-height: 1.9;
}

.hero-benefits {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
    font-weight: 500;
}

.hero-benefits span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hero-benefits .fa-check-circle {
    color: var(--accent-gold);
}

/* Amazonボタン */
.amazon-button {
    display: inline-block;
    background-color: #FF9900; /* Amazon Orange */
    color: #fff;
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1.3rem;
    font-weight: 700;
    text-decoration: none;
    padding: 1rem 3rem;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.3s;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.amazon-button:hover {
    background-color: #E68A00;
    transform: translateY(-3px);
}

.amazon-button .fa-amazon {
    margin-right: 0.75rem;
}

/* 書籍カバーセクション */
.book-cover-section {
    padding: 3rem 0;
    text-align: center;
    background-color: var(--subtle-gray);
}

.book-cover-image {
    max-width: 300px;
    height: auto;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    border-radius: 8px;
}

/* 問題提起セクション */
.problem-section {
    background-color: var(--primary-bg);
}

.lead-text {
    font-size: 1.1rem;
    line-height: 2;
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.lead-text p {
    margin-bottom: 2rem;
}

/* なぜ違うのか？セクション */
.differentiator-section {
    background-color: var(--light-blue);
}

.features-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.feature-card {
    background: #fff;
    padding: 2.5rem;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0,0,0,0.05);
}

.feature-card h4 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.card-icon {
    font-size: 2.5rem;
    color: var(--accent-blue);
    margin-bottom: 1.5rem;
}

/* 生徒の成長物語セクション */
.story-section {
    background-color: var(--primary-bg);
}

.story-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.story-card {
    background: var(--subtle-gray);
    padding: 2rem;
    border-radius: 8px;
    border-top: 4px solid var(--accent-gold);
}

.story-character {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    text-align: center;
}

.story-character small {
    font-size: 0.9rem;
    font-weight: 400;
    color: #666;
}

.story-quote {
    font-weight: 700;
    font-style: italic;
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--accent-blue);
}

/* 社会的証明セクション */
.testimonials-section {
    background-color: var(--subtle-gray);
}

.testimonial-grid {
    display: grid;
    gap: 2rem;
}

.testimonial-item {
    background-color: #fff;
    border-left: 5px solid var(--accent-gold);
    padding: 2rem;
    border-radius: 5px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
}

.testimonial-text {
    font-style: italic;
    margin-bottom: 1rem;
}

.testimonial-author {
    font-weight: 700;
    text-align: right;
    color: var(--accent-blue);
}

/* CTAセクション */
.cta-section {
    background-color: var(--accent-blue);
    color: #fff;
    text-align: center;
}

.cta-section .container {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.cta-section .cta-text {
    font-size: 1.3rem;
    margin-bottom: 2.5rem;
    color: #fff;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
}

.app-button {
    display: inline-block;
    background-color: #4CAF50; /* Green */
    color: #fff;
    font-family: 'Noto Sans JP', sans-serif;
    font-size: 1.3rem;
    font-weight: 700;
    text-decoration: none;
    padding: 1rem 3rem;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.3s;
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.app-button:hover {
    background-color: #45a049;
    transform: translateY(-3px);
}

.app-button .fa-mobile-alt {
    margin-right: 0.75rem;
}

/* フッター */
.footer {
    background-color: #333;
    color: #ccc;
    text-align: center;
    padding: 2rem 0;
    font-size: 0.9rem;
}

.footer .container .publisher {
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.footer .container .copyright {
    margin-top: 1rem;
}

.sns-links {
    margin-bottom: 1rem;
}

.sns-links a {
    color: #fff;
    text-decoration: none;
    transition: color 0.3s;
}

.sns-links a:hover {
    color: var(--accent-gold);
}

/* トップへ戻るボタン */
.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--accent-blue);
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    text-align: center;
    line-height: 50px;
    font-size: 1.5rem;
    text-decoration: none;
    display: none; /* Initially hidden */
    z-index: 1000;
    transition: opacity 0.3s, background-color 0.3s;
}

.back-to-top:hover {
    background-color: #3c4ba0;
}

/* AdSense */
.ad-container {
    padding: 2rem 0;
    text-align: center;
}

/* ==========================================================================
   レスポンシブ
   ========================================================================== */
@media (max-width: 768px) {
    body {
        font-size: 15px;
    }

    section {
        padding: 4rem 0;
    }

    .hero-title {
        font-size: 2.2rem;
    }

    .hero-catchphrase {
        font-size: 1.3rem;
    }

    .hero-benefits {
        flex-direction: column;
        gap: 1rem;
    }

    .section-title {
        font-size: 1.8rem;
        margin-bottom: 2rem;
    }

    .features-grid,
    .story-grid {
        grid-template-columns: 1fr;
    }

    .amazon-button {
        font-size: 1.1rem;
        padding: 0.8rem 2rem;
    }
}