:root {
    --primary-color: #1e88e5;
    --accent-color: #26c6da;
    --dark-bg: #121212;
    --dark-surface: #1e1e1e;
    --dark-card: #262626;
    --text-primary: rgba(255, 255, 255, 0.87);
    --text-secondary: rgba(255, 255, 255, 0.6);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
}

body {
    background-color: var(--dark-bg);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: var(--dark-surface);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 100;
    padding: 15px 0;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 24px;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.logo i {
    color: var(--accent-color);
}

.auth-buttons {
    display: flex;
    gap: 15px;
}

.btn {
    padding: 8px 20px;
    border-radius: 24px;
    font-weight: 600;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    border: none;
}

.btn-primary:hover {
    background-color: #1976d2;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.btn-outline {
    background-color: transparent;
    color: white;
    border: 2px solid var(--primary-color);
}

.btn-outline:hover {
    background-color: rgba(30, 136, 229, 0.1);
    transform: translateY(-2px);
}

.hero {
    background: rgba(0, 0, 0, 0.7); /* 半透明の黒 */
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
}

.hero-content {
    max-width: 800px;
    padding: 0 20px;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    font-weight: 800;
    word-break: keep-all; /* 日本語の不自然な改行を防ぐ */
}

.hero p {
    font-size: 1.2rem;
    line-height: 1.8;
    margin-bottom: 30px;
    color: var(--text-secondary);
    word-break: keep-all; /* 改行制御 */
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    margin-top: 30px;
}

.hero .btn {
    padding: 12px 30px;
    font-size: 18px;
}

@media (min-width: 768px) {
    .pc-only {
        display: inline;
    }

    .hero h1 {
        font-size: 4rem;
    }

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


main {
    padding: 80px 0;
}

.section {
    padding: 60px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
    font-size: 2.5rem;
    position: relative;
    color: var(--text-primary);
}

.section-title::after {
    content: '';
    position: absolute;
    width: auto;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    bottom: -10px;
    left: 0;
    right: 0;
    margin: 0 auto;
    max-width: 300px;
}

.about {
    background-color: var(--dark-surface);
    padding: 80px 0;
}

.about-content {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
    gap: 50px;
}

.about-text {
    flex: 1.2;
    min-width: 350px;
}

.about-text h3 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--accent-color);
    font-weight: 600;
}

.about-text p {
    line-height: 1.9;
    margin-bottom: 1.8em;
    word-break: keep-all;
    color: var(--text-secondary);
    font-size: 1.05rem;
}

.about-text p:last-child {
    margin-bottom: 0;
}

.highlight-text {
    color: var(--text-primary);
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.feature-list {
    margin: 25px 0;
    padding-left: 0;
    list-style: none;
}

.feature-list li {
    position: relative;
    padding-left: 30px;
    margin-bottom: 12px;
    color: var(--text-secondary);
    font-size: 1.05rem;
}

.feature-list li::before {
    content: '●';
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-size: 1.2rem;
}

.about-image {
    flex: 1;
    min-width: 300px;
    text-align: center;
}

.about-image img {
    max-width: 100%;
    border-radius: 12px;
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
    transition: transform 0.3s ease;
}

.about-image img:hover {
    transform: scale(1.02);
}

.features {
    padding: 80px 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.feature-card {
    background-color: var(--dark-card);
    border-radius: 12px;
    padding: 30px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: var(--accent-color);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.feature-title {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.feature-description {
    color: var(--text-secondary);
    font-size: 1rem;
}

.news {
    background-color: var(--dark-surface);
    padding: 80px 0;
}

.news-list {
    background-color: var(--dark-card);
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
}

.news-item {
    padding: 15px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.news-item:last-child {
    border-bottom: none;
}

.news-date {
    font-size: 0.9rem;
    color: var(--accent-color);
    margin-bottom: 5px;
}

.news-content {
    color: var(--text-secondary);
}

footer {
    background-color: var(--dark-surface);
    padding: 40px 0 20px;
    text-align: center;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.footer-links {
    margin: 10px 0;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 5px 10px;
    transition: color 0.3s ease;
}

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

.copyright {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 20px;
}

.footer-site-link {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-site-link:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

@media (max-width: 768px) {
    .header-container {
        flex-direction: column;
        gap: 15px;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: 15px;
    }
    
    .about-content {
        flex-direction: column;
        gap: 30px;
    }
    
    .about-text {
        min-width: 100%;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .feature-list li {
        font-size: 1rem;
    }
}
  
.closing-message p {
    font-size: 1.8rem;
    font-weight: 700;
    line-height: 1.4;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: none;
    margin: 0;
    letter-spacing: 0.5px;
}

.comment-section br {
    display: block;
    margin: 10px 0;
    content: "";
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .closing-message p {
        font-size: 1.3rem;
        line-height: 1.5;
    }
}

@media (max-width: 768px) {
    header {
        padding: 10px 0;
    }

    .header-container {
        flex-direction: column;
        gap: 15px;
        align-items: center; /* 中央寄せ */
    }

    .logo {
        font-size: 18px;       /* ロゴ文字サイズを小さく */
        white-space: nowrap;   /* 改行させない */
    }

    .logo i {
        font-size: 18px;       /* アイコンも小さく */
    }

    .auth-buttons {
        width: 100%;
        display: flex;
        justify-content: center;
        gap: 10px;
        flex-wrap: wrap;       /* ボタンが重ならないように */
    }

    .btn {
        padding: 6px 15px;
        font-size: 14px;
    }
}

/* 横スクロール防止 */
html, body {
    max-width: 100vw;
    overflow-x: hidden; /* 必要に応じて */
}

/* ヘッダーの折り返し許可 */
.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap; /* ここを追加 */
}

.auth-buttons {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;  /* 折り返し許可 */
    justify-content: flex-end;
}

/* スマホ用調整 */
@media (max-width: 768px) {
    header {
        padding: 10px 0;
    }

    .header-container {
        flex-direction: column;
        align-items: center;
        gap: 15px;
        flex-wrap: nowrap;
        width: 100%;
        max-width: 100%;
    }

    .logo {
        font-size: 18px;
        white-space: nowrap;
        width: auto;
        max-width: 100%;
        overflow-wrap: break-word;
    }

    .logo i {
        font-size: 18px;
    }

    .auth-buttons {
        justify-content: center;
        gap: 10px;
        width: 100%;
        flex-wrap: wrap;
    }

    .btn {
        padding: 6px 15px;
        font-size: 14px;
        white-space: nowrap;
        max-width: 100%;
        box-sizing: border-box;
    }
}

.about-content {
    display: flex;
    flex-wrap: wrap; /* 折り返しを許可 */
    align-items: flex-start;
    gap: 50px;
}

/* テキスト部分の最小幅を柔軟に */
.about-text {
    flex: 1 1 350px; /* 基本幅350pxで、縮小も可能 */
    min-width: 250px; /* 必要に応じて調整 */
    max-width: 100%;  /* 幅が親要素超えないように */
    word-break: break-word; /* 長い単語がある場合に改行 */
}

/* 画像部分も幅調整 */
.about-image {
    flex: 1 1 300px;
    min-width: 200px;
    max-width: 100%;
    text-align: center;
}

/* スマホ以下のメディアクエリで縦並び */
@media (max-width: 768px) {
    .about-content {
        flex-direction: column;
        gap: 30px;
    }
    .about-text,
    .about-image {
        min-width: 100%;
        max-width: 100%;
    }
}

.about-text {
    flex: 1 1 350px;
    min-width: 250px;
    max-width: 100%;
    overflow-wrap: break-word;
    word-break: break-word;
    overflow: visible !important;
}

.about-text p {
    white-space: normal !important;
    overflow-wrap: break-word;
    word-break: break-word;
    word-wrap: break-word;
    max-width: 100%;
}