/* =================================
   カスタム変数と基本設定 (モダン版)
================================= */
:root {
    /* スタイリッシュな色ベース */
    --color-light-bg: #f7f7ff; /* Clean Off-White */
    --color-card-bg: #ffffff; /* White - カード背景 */
    
    /* モダンなアクセントカラー (ゲーミング/テック風) */
    --color-primary-accent: #9f12a8; /* Deep Purple (よりクールに) */
    --color-secondary-accent: #06b6d4;  /* Bright Cyan/Turquoise */
    
    /* テキストカラー */
    --color-text-dark: #111827;
    --color-text-mid: #4b5563; /* Gray 600 */
}

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--color-light-bg);
    color: var(--color-text-dark);
    font-family: 'Inter', sans-serif;
    margin: 0;
    line-height: 1.6;
    scroll-behavior: smooth;
}

.container {
    max-width: 1280px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

/* =================================
   汎用コンポーネント
================================= */
h1, h2, h3 {
    font-weight: 800; /* Extra Bold */
    line-height: 1.2;
}

.section-padding {
    padding-top: 6rem;
    padding-bottom: 6rem;
}

.text-center {
    text-align: center;
}
.mb-16 {
    margin-bottom: 4rem;
}

/* モダンでインタラクティブなボタン */
.btn {
    display: inline-block;
    padding: 1rem 3.5rem;
    font-weight: 800;
    border-radius: 0.75rem; 
    transition: all 0.2s cubic-bezier(0.25, 0.46, 0.45, 0.94); /* 気持ちの良いイージング */
    text-decoration: none;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 1.125rem;
    
    /* クリーンな立体感 */
    border: none;
    background-image: linear-gradient(to right, var(--color-secondary-accent), var(--color-primary-accent));
    color: white;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 0 15px rgba(6, 182, 212, 0.5); /* 光沢感 */
}

.btn:hover {
    transform: translateY(-2px); 
    box-shadow: 0 6px 10px -2px rgba(0, 0, 0, 0.2), 0 0 20px rgba(6, 182, 212, 0.8);
}

.btn:active {
    transform: translateY(0); 
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    opacity: 0.9;
}

/* モダンなカードデザイン */
.card {
    background-color: var(--color-card-bg);
    padding: 2rem;
    border-radius: 1.5rem; 
    /* 薄いボーダーとソフトなドロップシャドウ */
    border: 1px solid rgba(0, 0, 0, 0.1); 
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s cubic-bezier(0.165, 0.84, 0.44, 1);
    position: relative;
    overflow: hidden;
}

/* アクセントカラーのエッジを追加 (わくわく感) */
.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: linear-gradient(to right, var(--color-secondary-accent), var(--color-primary-accent));
}


.card:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.15);
}

.card img {
    width: 100%;
    height: 250px;
    object-fit: cover;
}

/* =================================
   1. Header/Navigation
================================= */
.header {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(247, 247, 255, 0.9);
    backdrop-filter: blur(10px); 
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 0.75rem;
    padding-bottom: 0.75rem;
}

.logo {
    font-size: 1.75rem;
    font-weight: 900;
    letter-spacing: -0.05em;
    /* ロゴをクリーンなグラデーションに */
    background: linear-gradient(45deg, var(--color-primary-accent), var(--color-secondary-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
    text-decoration: none;
    text-shadow: none; 
}

.header-cta {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-weight: 700;
    border-radius: 0.5rem; 
    color: var(--color-primary-accent);
    background-color: transparent;
    border: 2px solid var(--color-primary-accent);
    box-shadow: none;
}
.header-cta:hover {
    background-color: var(--color-primary-accent);
    color: white;
    transform: none;
    box-shadow: 0 0 10px rgba(159, 18, 168, 0.5);
}

/* =================================
   2. Hero Section
================================= */
.hero {
    position: relative;
    padding-top: 4rem;
    padding-bottom: 7rem;
    overflow: hidden;
    /* ヒーロー背景を落ち着かせ、クリーンに */
    background-image: linear-gradient(180deg, var(--color-light-bg) 0%, #e0f2fe 100%);
    border-bottom: 4px solid var(--color-primary-accent); 
}

.hero-content {
    position: relative;
    z-index: 20;
    text-align: center;
}

.hero-title {
    font-size: 2.8rem;
    font-weight: 900;
    margin-bottom: 1.5rem;
}

.hero-title-highlight {
    /* テキストグラデーションをロゴと統一 */
    background: linear-gradient(45deg, var(--color-primary-accent), var(--color-secondary-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
    text-shadow: none;
}

.hero-subtitle {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--color-text-mid);
    margin-bottom: 3rem;
    max-width: 56rem;
    margin-left: auto;
    margin-right: auto;
}

/* =================================
   3. Core Value Proposition
================================= */
.value-prop {
    background-color: #f0f9ff;
    padding-top: 3rem;
    padding-bottom: 3rem;
    border-bottom: 1px dashed rgba(0, 0, 0, 0.1);
}
.value-prop h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--color-text-dark);
}
.value-prop-highlight {
    color: var(--color-primary-accent);
    text-shadow: none;
}
.value-prop-highlight-from {
    color: var(--color-primary-accent);
    text-shadow: none;
}
.value-prop-highlight-to {
    color: #ed1616;
    text-shadow: none;
}
.value-prop .sns-link {
    list-style: none;
    padding-inline-start: 0;
}

/* =================================
   4. What is OnlineGameEnglish?
================================= */
.card-grid {
    display: grid;
    gap: 2rem;
    grid-template-columns: 1fr;
}
.card-grid h3 {
    font-size: 1.5rem;
    color: var(--color-text-dark);
    font-weight: 700;
}
.card-grid .icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--color-secondary-accent);
    animation: pulse 2s infinite; 
}

/* =================================
   5. Benefits Section
================================= */
.benefits {
    background-color: var(--color-light-bg);
}
.benefit-grid {
    display: grid;
    gap: 2rem;
    grid-template-columns: 1fr;
}
.benefit-grid .icon {
    width: 45px;
}
.benefit-item {
    padding: 1.5rem;
    border-radius: 1rem;
    background-color: var(--color-card-bg);
    border: 1px solid rgba(0, 0, 0, 0.1);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    transition: all 0.2s ease;
}
.benefit-item:hover {
    box-shadow: 0 8px 12px -3px rgba(0, 0, 0, 0.1);
    transform: translateY(-3px);
    border-left: 5px solid var(--color-secondary-accent); /* ホバーでラインを出現 */
}
.benefit-item h4 {
    font-size: 1.25rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
}
.benefit-item h4 span:first-child {
    color: var(--color-primary-accent);
    margin-right: 0.5rem;
}

/* =================================
   6. 3-Step Process
================================= */
.steps {
    background-color: #fefcfb;
}
.steps h2 {
    margin-bottom: 4rem;
}
.step-grid {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}
.step-item {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 0 1rem;
    flex: 1 1 0%;
}
.step-circle {
    width: 4rem;
    height: 4rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: var(--color-primary-accent);
    font-size: 1.75rem;
    font-weight: 900;
    margin-bottom: 1rem;
    color: white;
    /* クリーンなサークルデザイン */
    border: 4px solid var(--color-card-bg); 
    box-shadow: 0 0 0 2px var(--color-primary-accent);
}
.step-item h3 {
    font-size: 1.5rem;
    color: var(--color-secondary-accent);
    font-weight: 800;
    text-shadow: none;
}

/* =================================
   7. Supported Games & Recommended
================================= */
.games-recommended-grid {
    display: grid;
    gap: 3rem;
    grid-template-columns: 1fr;
}
.games h2, .recommended h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    /* 垂直ラインをモダンなスタイルに */
    border-left: 5px solid var(--color-secondary-accent);
    padding-left: 1rem;
    color: var(--color-text-dark);
}
.game-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background-color: var(--color-card-bg);
    border-radius: 0.75rem;
    border: 1px solid rgba(0, 0, 0, 0.1);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    transition: background-color 0.1s;
}
.game-item:hover {
    background-color: #f3f4f6;
}
.game-item span:first-child {
    font-size: 1.75rem;
}
.game-item span:last-child {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--color-primary-accent);
}
.game-item .icon {
    width: 45px;
}

.recommended ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}
.recommended li {
    font-size: 1.125rem;
    padding: 1rem;
    background-color: var(--color-card-bg);
    border-radius: 0.75rem;
    border: 1px solid rgba(0, 0, 0, 0.1);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    display: flex;
    align-items: flex-start;
}
.recommended li span {
    color: var(--color-secondary-accent);
    font-size: 1.5rem;
    margin-right: 0.75rem;
}

/* =================================
   8. FAQ
================================= */
.faq h2 {
    margin-bottom: 4rem;
}
.faq-item {
    background-color: var(--color-card-bg);
    padding: 1.5rem;
    border-radius: 0.75rem;
    border-left: 4px solid var(--color-secondary-accent); /* アクセントライン */
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    margin-bottom: 1rem;
}
.faq-item h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--color-primary-accent);
}

/* =================================
   9. Final CTA
================================= */
.final-cta {
    background-image: linear-gradient(135deg, var(--color-secondary-accent), var(--color-primary-accent));
    color: white;
    padding-top: 6rem;
    padding-bottom: 6rem;
}
.final-cta h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    text-shadow: none;
}
.final-cta p {
    font-size: 1.25rem;
    font-weight: 400;
    margin-bottom: 2.5rem;
}
.final-cta .btn {
    background: #ffffff;
    color: var(--color-text-dark);
    border: none;
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.3);
    font-weight: 800;
}
.final-cta .btn:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.4);
}
.final-cta .btn:active {
    transform: translateY(-1px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
}
.final-cta .link {
    color: #fff;
}

/* =================================
   Footer
================================= */
.footer {
    background-color: #e0f2fe; 
    border-top: 1px solid rgba(0, 0, 0, 0.1);
    padding-top: 2rem;
    padding-bottom: 2rem;
}
.footer-text {
    text-align: center;
    font-size: 0.875rem;
    color: var(--color-text-mid);
}
.footer-link {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
}

/* =================================
   レスポンシブデザイン (タブレット以上)
================================= */
@media (min-width: 640px) { /* sm */
    .hero-title {
        font-size: 4rem;
    }
    .hero-subtitle {
        font-size: 1.5rem;
    }
    .value-prop h2 {
        font-size: 2.5rem;
    }
    .benefit-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .final-cta h2 {
        font-size: 3rem;
    }
}

/* =================================
   レスポンシブデザイン (デスクトップ以上)
================================= */
@media (min-width: 1024px) { /* lg */
    .hero {
        padding-top: 8rem;
        padding-bottom: 10rem;
    }
    .hero-title {
        font-size: 5.5rem;
    }
    .card-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .benefit-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .step-grid {
        flex-direction: row;
        justify-content: space-between;
        gap: 1rem;
    }
    .step-item {
         padding: 0 2rem;
    }
    .games-recommended-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* アニメーション */
@keyframes pulse {
    0% {
        box-shadow: 0 0 0 0 rgba(6, 182, 212, 0.4);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(6, 182, 212, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(6, 182, 212, 0);
    }
}

/* アイコンのパルスアニメーション適用 */
.card-grid .icon {
    animation: pulse 2s infinite;
}