/* -----------------------------------------
   Mathematical Aesthetics Style Sheet
   Designed for Mobile, Tablet, and Desktop
   ----------------------------------------- */

/* フォントとベース設定 */
@import url('https://fonts.googleapis.com/css2?family=Cinzel:wght@400;600&family=Noto+Sans+JP:wght@300;400;500;700&family=Playfair+Display:ital,wght@0,400;1,400&family=Roboto+Mono:wght@300;400&display=swap');

:root {
    --bg-primary: #0a0a0c;       /* 漆黒 */
    --bg-secondary: #121215;     /* カードやセクション用 */
    --text-primary: #f0f2f5;     /* 高い視認性を持つ白 */
    --text-secondary: #9098a5;   /* 控えめなグレー */
    --border-color: rgba(255, 255, 255, 0.08); /* 細く繊細な線 */
    --accent-color: #ffffff;     /* 装飾は基本白のみの極限のミニマリズム */
    --accent-glow: rgba(255, 255, 255, 0.15);
    
    --font-serif: 'Playfair Display', 'Noto Sans JP', serif;
    --font-sans: 'Noto Sans JP', sans-serif;
    --font-mono: 'Roboto Mono', monospace;
    --font-logo: 'Cinzel', serif;
}

/* 基本リセット */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    -webkit-font-smoothing: antialiased;
}

body {
    overflow-x: hidden;
    line-height: 1.75;
}

a {
    color: inherit;
    text-decoration: none;
    transition: color 0.3s cubic-bezier(0.25, 1, 0.5, 1);
}

/* -----------------------------------------
   ヘッダーとナビゲーション
   ----------------------------------------- */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    background-color: rgba(10, 10, 12, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1.25rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-logo);
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.math-symbol {
    font-family: var(--font-serif);
    font-style: italic;
    color: var(--accent-color);
    font-weight: 400;
}

.nav-menu {
    display: flex;
    gap: 2.5rem;
}

.nav-link {
    font-size: 0.9rem;
    font-weight: 400;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    position: relative;
    padding: 0.25rem 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--accent-color);
    transition: width 0.3s ease;
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link.active {
    color: var(--text-primary);
}

/* -----------------------------------------
   ヒーローセクション
   ----------------------------------------- */
.hero-section {
    height: 100vh;
    width: 100vw;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    padding: 2rem;
}

.canvas-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

#polytope-canvas {
    display: block;
    width: 100%;
    height: 100%;
    opacity: 0.45;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 800px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero-title {
    font-family: var(--font-logo);
    font-size: 4rem;
    font-weight: 400;
    letter-spacing: 0.25em;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
}

.hero-tagline {
    font-family: var(--font-serif);
    font-size: 1.15rem;
    font-style: italic;
    color: var(--text-secondary);
    line-height: 1.8;
    max-width: 600px;
    font-weight: 300;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
    margin-top: 2rem;
}

.hero-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.9rem 1.4rem;
    border-radius: 999px;
    border: 1px solid var(--border-color);
    font-size: 0.95rem;
    letter-spacing: 0.05em;
    transition: all 0.3s ease;
}

.hero-button.primary {
    background-color: var(--accent-color);
    color: var(--bg-primary);
}

.hero-button.secondary {
    background-color: rgba(255, 255, 255, 0.04);
    color: var(--text-primary);
}

.hero-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.25);
}

.scroll-indicator {
    position: absolute;
    bottom: 3rem;
    display: flex;
    justify-content: center;
}

.arrow-down {
    width: 1px;
    height: 50px;
    background: linear-gradient(to bottom, var(--accent-color), transparent);
    animation: scrollAnimation 2s infinite ease-in-out;
}

@keyframes scrollAnimation {
    0% { transform: scaleY(0); transform-origin: top; }
    50% { transform: scaleY(1); transform-origin: top; }
    50.1% { transform: scaleY(1); transform-origin: bottom; }
    100% { transform: scaleY(0); transform-origin: bottom; }
}

/* -----------------------------------------
   セクション構造
   ----------------------------------------- */
.main-content {
    position: relative;
    z-index: 5;
    background-color: var(--bg-primary);
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 7rem 2rem;
}

.section-title {
    font-family: var(--font-logo);
    font-size: 2rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    margin-bottom: 3.5rem;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.75rem;
}

/* -----------------------------------------
   コンセプト(About)セクション
   ----------------------------------------- */
.concept-section {
    border-bottom: 1px solid var(--border-color);
}

.concept-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 5rem;
    align-items: center;
}

.concept-text p {
    margin-bottom: 1.5rem;
    font-weight: 300;
    color: var(--text-secondary);
}

.concept-text .concept-lead {
    font-size: 1.25rem;
    color: var(--text-primary);
    font-family: var(--font-serif);
    line-height: 1.7;
}

.concept-quote blockquote {
    font-family: var(--font-serif);
    font-style: italic;
    font-size: 1.5rem;
    line-height: 1.6;
    border-left: 2px solid var(--accent-color);
    padding-left: 2rem;
}

.concept-quote cite {
    display: block;
    margin-top: 1rem;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-style: normal;
}

/* -----------------------------------------
   Socials セクション (新規)
   ----------------------------------------- */
.socials-section {
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

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

.social-card {
    display: flex;
    flex-direction: column;
    padding: 2rem;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(255,255,255,0.03), rgba(255,255,255,0.01));
    transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.social-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255,255,255,0.25);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}

.social-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: rgba(255,255,255,0.05);
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.social-card h3 {
    font-family: var(--font-logo);
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
    letter-spacing: 0.05em;
}

.social-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
    flex-grow: 1;
}

.social-card span {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-color);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

/* -----------------------------------------
   記事一覧
   ----------------------------------------- */
.section-header-row {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    flex-wrap: wrap;
    gap: 1rem;
}

.section-header-row .section-title {
    flex-grow: 1;
    border: none;
    margin-bottom: 0;
}

.view-all-link {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 0.85rem;
    border-radius: 999px;
}

.view-all-link:hover {
    color: var(--text-primary);
    border-color: rgba(255, 255, 255, 0.25);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-top: 3.5rem;
}

/* 記事カード */
.article-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    height: 100%;
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), 
                border-color 0.4s cubic-bezier(0.16, 1, 0.3, 1),
                box-shadow 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.article-card:hover {
    transform: translateY(-5px);
    border-color: rgba(255, 255, 255, 0.25);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.card-image-wrapper {
    position: relative;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    overflow: hidden;
    background-color: #000;
}

.card-image-wrapper img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: grayscale(100%) contrast(1.1);
    opacity: 0.75;
    transition: transform 0.6s cubic-bezier(0.16, 1, 0.3, 1),
                filter 0.6s cubic-bezier(0.16, 1, 0.3, 1),
                opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.article-card:hover .card-image-wrapper img {
    transform: scale(1.05);
    filter: grayscale(0%) contrast(1.0);
    opacity: 0.9;
}

.card-category {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background-color: rgba(10, 10, 12, 0.85);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.6rem;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: 3px;
    z-index: 10;
}

.card-content {
    padding: 1.75rem;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 0.8rem;
}

.card-tag {
    display: inline-block;
    padding: 0.2rem 0.5rem;
    border-radius: 999px;
    border: 1px solid var(--border-color);
    font-family: var(--font-mono);
    font-size: 0.66rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.card-date {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    font-weight: 300;
}

.card-title {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 400;
    line-height: 1.4;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.card-excerpt {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    font-weight: 300;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.card-footer {
    display: flex;
    justify-content: flex-end;
}

.read-more {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    border-bottom: 1px solid transparent;
    transition: all 0.3s;
}

.article-card:hover .read-more {
    color: var(--text-primary);
    border-bottom-color: var(--text-primary);
}

/* プレースホルダー・ローディングアニメーション */
.loading-placeholder {
    grid-column: 1/-1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 5rem 0;
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
}

.spinner {
    width: 30px;
    height: 30px;
    border: 2px solid var(--border-color);
    border-top: 2px solid var(--text-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1.5rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* -----------------------------------------
   記事詳細ページ専用レイアウト (article.html)
   ----------------------------------------- */
.article-page {
    background-color: var(--bg-primary);
}

.article-detail-layout {
    min-height: 100vh;
    padding-top: 100px;
}

.article-detail-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 3rem 1.5rem 7rem 1.5rem;
}

.back-navigation {
    margin-bottom: 3rem;
}

.back-link {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s;
}

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

.article-wrapper {
    transition: opacity 0.5s ease;
}

.article-wrapper.hide {
    opacity: 0;
    pointer-events: none;
    position: absolute;
}

.loading-placeholder.hide {
    display: none;
}

.article-detail-header {
    margin-bottom: 3rem;
}

.article-meta-row {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
    font-family: var(--font-mono);
}

.article-detail-category {
    text-transform: uppercase;
    font-size: 0.8rem;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.25rem 0.75rem;
    border-radius: 3px;
}

.article-detail-date {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.article-detail-title {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 400;
    line-height: 1.3;
    color: var(--text-primary);
    margin-bottom: 2rem;
}

.detail-eyecatch-container {
    width: 100%;
    max-height: 450px;
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    background-color: #000;
}

.detail-eyecatch-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    filter: grayscale(10%) contrast(1.05);
    opacity: 0.95;
    display: block;
}

/* 記事詳細本文のスタイリング */
.article-detail-content {
    font-size: 1.05rem;
    line-height: 1.9;
    color: var(--text-primary);
    font-weight: 300;
}

.article-detail-content p {
    margin-bottom: 2rem;
    color: #e2e8f0;
}

.article-detail-content h1,
.article-detail-content h2,
.article-detail-content h3,
.article-detail-content h4 {
    font-family: var(--font-serif);
    font-weight: 400;
    color: var(--text-primary);
    margin-top: 3.5rem;
    margin-bottom: 1.25rem;
    letter-spacing: 0.05em;
    line-height: 1.4;
}

.article-detail-content h1 {
    font-size: 2rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.article-detail-content h2 {
    font-size: 1.6rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.4rem;
}

.article-detail-content h3 {
    font-size: 1.3rem;
}

.article-detail-content ul,
.article-detail-content ol {
    margin-bottom: 2rem;
    padding-left: 2rem;
}

.article-detail-content li {
    margin-bottom: 0.5rem;
}

.article-detail-content blockquote {
    border-left: 2px solid var(--accent-color);
    padding-left: 1.5rem;
    margin: 2.5rem 0;
    font-style: italic;
    color: var(--text-secondary);
}

.article-detail-content code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    color: #f1f5f9;
}

.article-detail-content pre {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 6px;
    overflow-x: auto;
    margin: 2.5rem 0;
}

.article-detail-content pre code {
    background-color: transparent;
    border: none;
    padding: 0;
    border-radius: 0;
    font-size: 0.85rem;
}

.article-detail-content img {
    max-width: 100%;
    height: auto;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    margin: 3rem auto;
    display: block;
    filter: grayscale(10%);
}

.article-detail-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 2.5rem 0;
    font-size: 0.95rem;
}

.article-detail-content th,
.article-detail-content td {
    border: 1px solid var(--border-color);
    padding: 0.75rem 1rem;
    text-align: left;
}

.article-detail-content th {
    background-color: var(--bg-secondary);
    font-weight: 500;
}

/* -----------------------------------------
   アーカイブ・一覧系
   ----------------------------------------- */
.archive-page .site-header {
    position: sticky;
}

.archive-hero {
    padding: 8rem 2rem 4rem;
    border-bottom: 1px solid var(--border-color);
}

.archive-hero .section-container {
    padding: 0;
}

.archive-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.archive-search {
    flex: 1;
    min-width: 220px;
    padding: 0.95rem 1rem;
    border-radius: 999px;
    border: 1px solid var(--border-color);
    background-color: rgba(255,255,255,0.04);
    color: var(--text-primary);
}

.archive-search:focus {
    outline: none;
    border-color: rgba(255,255,255,0.3);
    box-shadow: 0 0 0 3px rgba(255,255,255,0.08);
}

.archive-count {
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.85rem;
}

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

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.footer-brand {
    font-family: var(--font-logo);
    font-size: 1.25rem;
    letter-spacing: 0.1em;
}

.logo-symbol {
    font-family: var(--font-serif);
    font-style: italic;
    color: var(--accent-color);
}

.footer-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.footer-copy {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 300;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

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

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


/* -----------------------------------------
   レスポンシブメディアクエリ
   ----------------------------------------- */

/* タブレット対応 (Max-width: 992px) */
@media (max-width: 992px) {
    .concept-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    
    .articles-grid,
    .social-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }

    .hero-title {
        font-size: 2.8rem;
    }
}

/* モバイル対応 (Max-width: 768px) */
@media (max-width: 768px) {
    html {
        font-size: 15px;
    }

    .header-container {
        padding: 1rem 1.5rem;
    }

    .nav-menu {
        gap: 1.5rem;
    }

    .hero-section {
        padding: 1rem;
    }

    .hero-title {
        font-size: 2.2rem;
        letter-spacing: 0.15em;
    }

    .hero-tagline {
        font-size: 1rem;
    }

    .social-grid,
    .articles-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .section-container {
        padding: 4rem 1.5rem;
    }

    .footer-container {
        flex-direction: column;
        align-items: flex-start;
        padding: 3rem 1.5rem;
    }

    .footer-info {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
        width: 100%;
    }

    .footer-links {
        width: 100%;
        justify-content: flex-start;
    }
    
    .article-detail-title {
        font-size: 1.8rem;
    }
    
    .article-detail-content {
        font-size: 1rem;
    }
    /* 検索バーのUI改善 */
    .archive-controls {
        display: flex;
        align-items: center;
        gap: 1rem;
        margin-bottom: 2rem;
        padding: 1rem;
        background: var(--bg-secondary);
        border: 1px solid var(--border-color);
        border-radius: 8px;
    }

    .search-input {
        flex: 1;
        background: transparent;
        border: none;
        border-bottom: 1px solid var(--border-color);
        padding: 0.5rem;
        color: var(--text-primary);
        font-size: 1rem;
        outline: none;
        transition: border-color 0.3s ease;
    }

    .search-input:focus {
        border-bottom-color: var(--accent-color);
    }

    .search-input::placeholder {
        color: var(--text-secondary);
    }

    #archive-count {
        color: var(--text-secondary);
        font-size: 0.9rem;
        font-family: var(--font-mono);
    }
}