/* ===== HELIX デザイン案1: ダークストリート系 ===== */
:root {
    /* カラーパレット - ダークストリート */
    --md-primary: #ff3366; /* ネオンピンク */
    --md-primary-dark: #cc0033;
    --md-primary-light: #ff6690;
    --md-secondary: #00ffff; /* シアン */
    --md-secondary-dark: #00cccc;
    --md-secondary-light: #66ffff;
    --md-accent: #ffcc00; /* イエロー */
    --md-accent-dark: #cc9900;
    --md-accent-light: #ffdd55;
    --md-bg: #0a0a0a; /* 黒背景 */
    --md-bg-dark: #000000;
    --md-bg-secondary: #1a1a1a; /* カード背景 */
    --md-text: #ffffff; /* 白テキスト */
    --md-text-light: #ffffff;
    --md-text-muted: #999999;
    --md-border: #333333;
    /* フォント */
    --md-font-family: 'Zen Kaku Gothic New', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --md-font-family-headings: 'Zen Kaku Gothic New', sans-serif;
    /* サイズ・間隔 */
    --md-sidebar-width: 280px;
    --md-content-max-width: 1200px;
    --md-header-height: 64px;
    --md-border-radius: 8px;
    --md-border-radius-lg: 12px;
    --md-elevation-z2: 0px 2px 8px rgba(255, 51, 102, 0.2);
    --md-elevation-z8: 0px 8px 16px rgba(255, 51, 102, 0.3);
    --md-elevation-z16: 0px 16px 32px rgba(255, 51, 102, 0.4);
    --md-transition-duration: 0.3s;
    --md-transition-timing-function: cubic-bezier(0.4, 0.0, 0.2, 1);
}

/* リセットとベース設定 */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html,
body {
    height: 100%;
    width: 100%;
    overflow-x: hidden;
}

body {
    font-family: var(--md-font-family);
    background-color: var(--md-bg);
    color: var(--md-text);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
    font-weight: 300;
}

h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--md-font-family-headings);
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 0.5em;
    letter-spacing: 0.5px;
}

a {
    color: var(--md-primary);
    text-decoration: none;
    transition: color var(--md-transition-duration);
}

a:hover {
    color: var(--md-primary-light);
}

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

ul {
    list-style: none;
}

/* ===== レイアウト ===== */
.site-container {
    display: flex;
    min-height: 100vh;
    width: 100%;
    position: relative;
}

/* サイドバー */
.sidebar {
    width: var(--md-sidebar-width);
    background: linear-gradient(180deg, #1a1a1a 0%, #0a0a0a 100%);
    border-right: 2px solid var(--md-primary);
    position: fixed;
    height: 100vh;
    z-index: 100;
    overflow-y: auto;
    transition: transform var(--md-transition-duration);
    box-shadow: var(--md-elevation-z8);
}

.sidebar-header {
    padding: 24px 16px;
    text-align: center;
    border-bottom: 1px solid var(--md-border);
    background: linear-gradient(135deg, rgba(255, 51, 102, 0.1) 0%, rgba(0, 255, 255, 0.1) 100%);
}

.logo-container {
    width: 80%;
    max-width: 200px;
    margin: 0 auto 16px;
}

.logo {
    width: 100%;
    height: auto;
    object-fit: contain;
    filter: drop-shadow(0 0 10px rgba(255, 51, 102, 0.5));
}

.sidebar-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--md-primary);
    text-transform: uppercase;
    letter-spacing: 2px;
}

/* タブナビゲーション */
.tab-navigation {
    padding: 16px 8px;
}

.tab-link {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    margin-bottom: 4px;
    border-radius: var(--md-border-radius);
    color: var(--md-text-muted);
    transition: all var(--md-transition-duration);
    text-decoration: none;
    border-left: 3px solid transparent;
}

.tab-link:hover {
    background: linear-gradient(90deg, rgba(255, 51, 102, 0.1) 0%, transparent 100%);
    color: var(--md-text);
    border-left-color: var(--md-primary);
}

.tab-link.active {
    background: linear-gradient(90deg, rgba(255, 51, 102, 0.2) 0%, transparent 100%);
    color: var(--md-primary);
    font-weight: 500;
    border-left-color: var(--md-primary);
}

.tab-link .material-icons {
    margin-right: 12px;
    font-size: 24px;
}

/* メインコンテンツ */
.main-content {
    flex: 1;
    margin-left: var(--md-sidebar-width);
    padding: 24px;
    max-width: calc(100% - var(--md-sidebar-width));
}

/* ヒーローセクション */
.hero-section {
    padding: 48px 0;
    text-align: center;
    margin-bottom: 48px;
    position: relative;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80%;
    height: 2px;
    background: linear-gradient(90deg, transparent 0%, var(--md-primary) 50%, transparent 100%);
}

.main-title {
    font-size: 2.5rem;
    margin-bottom: 24px;
    color: var(--md-text);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.year-tag {
    display: inline-block;
    font-size: 1rem;
    background: linear-gradient(135deg, var(--md-primary) 0%, var(--md-secondary) 100%);
    color: var(--md-text-light);
    padding: 6px 16px;
    border-radius: 20px;
    margin-left: 12px;
    font-weight: 700;
    box-shadow: 0 4px 12px rgba(255, 51, 102, 0.4);
}

.hero-quote {
    max-width: 700px;
    margin: 0 auto;
    font-style: italic;
    color: var(--md-text-muted);
    line-height: 1.8;
    padding: 24px;
    border-left: 3px solid var(--md-primary);
    background: rgba(255, 51, 102, 0.05);
    border-radius: var(--md-border-radius);
}

.quote-author {
    font-size: 0.875rem;
    margin-top: 12px;
    text-align: right;
    color: var(--md-primary);
}

/* セクションスタイル */
.section-title {
    font-size: 1.75rem;
    margin-bottom: 32px;
    color: var(--md-text);
    display: flex;
    align-items: center;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.section-title .material-icons {
    margin-right: 12px;
    font-size: 28px;
    color: var(--md-primary);
}

/* タブコンテンツ */
.tab-content {
    display: none;
    animation: fade-in 0.4s var(--md-transition-timing-function);
}

.tab-content.active {
    display: block;
}

@keyframes fade-in {
    from {
        opacity: 0;
        transform: translateY(16px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 三大原則 */
.principles-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-top: 24px;
}

.principle-card {
    background: var(--md-bg-secondary);
    border-radius: var(--md-border-radius-lg);
    padding: 32px;
    box-shadow: var(--md-elevation-z2);
    border: 1px solid var(--md-border);
    transition: all var(--md-transition-duration);
    position: relative;
    overflow: hidden;
}

.principle-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--md-primary) 0%, var(--md-secondary) 100%);
}

.principle-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--md-elevation-z8);
    border-color: var(--md-primary);
}

.principle-number h3 {
    font-size: 1.25rem;
    color: var(--md-primary);
    margin-bottom: 16px;
    font-weight: 700;
}

.principle-text {
    color: var(--md-text);
    line-height: 1.7;
}

.highlight {
    color: var(--md-primary);
    font-weight: 700;
}

/* アコーディオン */
.accordion-container {
    max-width: 900px;
    margin: 0 auto;
}

.accordion-item {
    margin-bottom: 12px;
    border-radius: var(--md-border-radius-lg);
    overflow: hidden;
    background: var(--md-bg-secondary);
    box-shadow: var(--md-elevation-z2);
    border: 1px solid var(--md-border);
    transition: all var(--md-transition-duration);
}

.accordion-item:hover {
    border-color: var(--md-primary);
}

.accordion-header {
    width: 100%;
    text-align: left;
    padding: 20px 24px;
    background: transparent;
    border: none;
    color: var(--md-text);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all var(--md-transition-duration);
}

.accordion-header:hover {
    background: rgba(255, 51, 102, 0.1);
    color: var(--md-primary);
}

.accordion-header .material-icons {
    transition: transform var(--md-transition-duration);
    color: var(--md-primary);
}

.accordion-item.active .accordion-header .material-icons {
    transform: rotate(180deg);
}

.accordion-panel {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--md-transition-duration);
    padding: 0 24px;
    color: var(--md-text-muted);
    line-height: 1.8;
}

.accordion-item.active .accordion-panel {
    max-height: 1000px;
    padding: 0 24px 24px 24px;
}

.accordion-panel p {
    margin-bottom: 12px;
}

.accordion-panel strong {
    color: var(--md-primary);
    font-weight: 600;
}

.accordion-panel a {
    color: var(--md-secondary);
    text-decoration: underline;
}

/* 最後に */
.conclusion {
    text-align: center;
    padding: 48px 24px;
}

.conclusion-text {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 48px;
    line-height: 1.8;
    color: var(--md-text);
}

.return-button-container {
    margin: 32px auto;
    max-width: 300px;
}

.return-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 16px 32px;
    background: linear-gradient(135deg, var(--md-primary) 0%, var(--md-secondary) 100%);
    color: var(--md-text-light);
    border-radius: 30px;
    font-weight: 700;
    text-align: center;
    box-shadow: 0 4px 16px rgba(255, 51, 102, 0.4);
    transition: all var(--md-transition-duration);
    text-decoration: none;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.return-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(255, 51, 102, 0.6);
}

.return-button .material-icons {
    margin-right: 8px;
}

/* フッター */
.site-footer {
    text-align: center;
    padding: 32px 0 24px;
    margin-top: 64px;
    color: var(--md-text-muted);
    font-size: 0.875rem;
    border-top: 1px solid var(--md-border);
}

/* レスポンシブ設定 */
@media (max-width: 992px) {
    .main-title {
        font-size: 2rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .principle-card {
        padding: 24px;
    }
}

@media (max-width: 768px) {
    :root {
        --md-sidebar-width: 240px;
    }

    .sidebar {
        transform: translateX(-100%);
        z-index: 1000;
        width: 85%;
        max-width: 300px;
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .sidebar-overlay {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.8);
        z-index: 990;
        opacity: 0;
        transition: opacity var(--md-transition-duration);
    }

    .sidebar-overlay.active {
        display: block;
        opacity: 1;
    }

    .main-content {
        margin-left: 0;
        max-width: 100%;
        padding: 16px;
    }

    .main-title {
        font-size: 1.75rem;
    }

    .year-tag {
        font-size: 0.875rem;
        display: block;
        margin: 12px auto 0;
        width: fit-content;
    }

    .hero-section {
        padding: 32px 0;
        margin-top: 48px;
    }

    .mobile-menu-toggle {
        display: flex;
        position: fixed;
        top: 16px;
        left: 16px;
        z-index: 1100;
        background: linear-gradient(135deg, var(--md-primary) 0%, var(--md-secondary) 100%);
        border: none;
        color: var(--md-text-light);
        width: 48px;
        height: 48px;
        border-radius: 50%;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        box-shadow: 0 4px 16px rgba(255, 51, 102, 0.6);
        -webkit-tap-highlight-color: transparent;
    }

    .accordion-header {
        padding: 16px;
    }

    .tab-link {
        padding: 16px;
    }

    .main-content {
        -webkit-overflow-scrolling: touch;
    }

    html,
    body {
        position: fixed;
        overflow: hidden;
        width: 100%;
        height: 100%;
    }

    .site-container {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }
}

@media (max-width: 480px) {
    .main-title {
        font-size: 1.5rem;
    }

    .section-title {
        font-size: 1.25rem;
    }

    .principle-card {
        padding: 20px;
    }

    .accordion-header {
        font-size: 0.95rem;
    }
}