/* =========================================
   Blind Books - 表紙のない本屋
   Design System & Styles
   ========================================= */

/* CSS Variables */
:root {
    /* Colors */
    --color-bg: #F9F8F4;
    --color-text: #2B2B2B;
    --color-accent: #1D3557;
    --color-star: #CCA43B;
    --color-shadow: rgba(43, 43, 43, 0.08);
    --color-shadow-hover: rgba(43, 43, 43, 0.15);

    /* Fonts */
    --font-handwritten: 'Zen Kurenaido', sans-serif;
    --font-serif: 'Shippori Mincho', serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 5rem;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Reset & Base */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-serif);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.8;
    min-height: 100vh;

    /* Paper texture effect */
    background-image:
        radial-gradient(ellipse at 20% 30%, rgba(29, 53, 87, 0.02) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 70%, rgba(204, 164, 59, 0.03) 0%, transparent 50%);
}

/* =========================================
   Header
   ========================================= */
.site-header {
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    border-bottom: 1px solid rgba(43, 43, 43, 0.1);
    background: linear-gradient(180deg, var(--color-bg) 0%, rgba(249, 248, 244, 0.95) 100%);
    position: sticky;
    top: 0;
    z-index: 100;
}

.site-logo {
    font-family: var(--font-handwritten);
    font-size: 2.5rem;
    color: var(--color-accent);
    letter-spacing: 0.1em;
    margin-bottom: var(--spacing-xs);
    animation: fadeInDown 0.8s ease-out;
}

.site-tagline {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    color: var(--color-text);
    opacity: 0.7;
    letter-spacing: 0.3em;
}

.site-nav {
    margin-top: var(--spacing-md);
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
}

.nav-link {
    font-family: var(--font-serif);
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.9rem;
    position: relative;
    padding: var(--spacing-xs) 0;
    transition: color var(--transition-fast);
}

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

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

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

/* =========================================
   Hero Section
   ========================================= */
.hero {
    padding: var(--spacing-xxl) var(--spacing-md);
    text-align: center;
    position: relative;
    min-height: 50vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.hero-content {
    animation: fadeInUp 1s ease-out 0.3s both;
}

.hero-lead {
    font-family: var(--font-handwritten);
    font-size: clamp(1.8rem, 5vw, 3rem);
    color: var(--color-accent);
    line-height: 1.6;
    margin-bottom: var(--spacing-xs);
}

.hero-sub {
    font-family: var(--font-serif);
    font-size: clamp(1rem, 2.5vw, 1.3rem);
    color: var(--color-text);
    margin-top: var(--spacing-lg);
    opacity: 0.8;
}

.hero-decoration {
    margin-top: var(--spacing-xl);
    animation: float 3s ease-in-out infinite;
}

.quill {
    font-size: 2.5rem;
    opacity: 0.6;
}

/* =========================================
   About Section
   ========================================= */
.about-section {
    padding: var(--spacing-xxl) var(--spacing-md);
    max-width: 700px;
    margin: 0 auto;
}

.section-title {
    font-family: var(--font-handwritten);
    font-size: 1.8rem;
    color: var(--color-accent);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 40px;
    height: 2px;
    background-color: var(--color-star);
    margin: var(--spacing-sm) auto 0;
}

.about-text {
    text-align: center;
}

.about-text p {
    margin-bottom: var(--spacing-md);
    font-size: 1.05rem;
}

/* =========================================
   Books Section
   ========================================= */
.books-section {
    padding: var(--spacing-xxl) var(--spacing-md);
    max-width: 1400px;
    margin: 0 auto;
}

.section-subtitle {
    text-align: center;
    color: var(--color-text);
    opacity: 0.7;
    margin-bottom: var(--spacing-xl);
    font-size: 0.95rem;
}

/* Masonry Grid */
.book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
    align-items: start;
}

/* =========================================
   Book Card
   ========================================= */
.book-card {
    background: var(--color-bg);
    border-radius: var(--radius-md);
    box-shadow:
        0 2px 8px var(--color-shadow),
        0 1px 3px var(--color-shadow);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition:
        transform var(--transition-medium),
        box-shadow var(--transition-medium);
    position: relative;
    overflow: hidden;
}

.book-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-accent), var(--color-star));
    opacity: 0;
    transition: opacity var(--transition-medium);
}

.book-card:hover {
    transform: translateY(-4px);
    box-shadow:
        0 8px 24px var(--color-shadow-hover),
        0 4px 8px var(--color-shadow);
}

.book-card:hover::before {
    opacity: 1;
}

/* Card Content */
.card-catchcopy {
    font-family: var(--font-handwritten);
    font-size: 1.25rem;
    color: var(--color-accent);
    text-align: center;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-xs);
    white-space: pre-line;
    /* キャッチコピーは改行を活かしたポエム調に */
}

.card-column {
    font-family: var(--font-serif);
    font-size: 0.9rem;
    color: var(--color-text);
    line-height: 2;
    margin-bottom: var(--spacing-lg);
    padding: 0 var(--spacing-sm);
    /* コラムは滑らかに流れるテキスト */
    text-align: justify;
    text-justify: inter-ideograph;
    letter-spacing: 0.02em;
}

/* Star Rating - シンプル版（3軸横並び） */
.card-ratings {
    border-top: 1px dashed rgba(43, 43, 43, 0.15);
    padding-top: var(--spacing-md);
    display: flex;
    justify-content: space-around;
    gap: var(--spacing-xs);
}

.rating-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.rating-label {
    color: var(--color-text);
    opacity: 0.7;
    font-size: 0.7rem;
    letter-spacing: 0.05em;
}

.rating-stars {
    display: flex;
    gap: 1px;
}

.rating-stars .star {
    color: var(--color-star);
    font-size: 0.75rem;
}

.rating-stars .star.filled {
    text-shadow: 0 0 3px rgba(204, 164, 59, 0.3);
}

.rating-stars .star.empty {
    opacity: 0.25;
}

/* Genre Badge */
.genre-badge {
    display: inline-block;
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    background: var(--color-accent);
    color: var(--color-bg);
    font-family: var(--font-serif);
    font-size: 0.7rem;
    padding: 4px 10px;
    border-radius: 20px;
    letter-spacing: 0.05em;
}

/* Card Hint */
.card-hint {
    text-align: center;
    margin-top: var(--spacing-md);
    font-size: 0.8rem;
    color: var(--color-text);
    opacity: 0.5;
    transition: opacity var(--transition-fast);
}

.book-card:hover .card-hint {
    opacity: 0.8;
}

/* =========================================
   Flip Card Modal
   ========================================= */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(43, 43, 43, 0.7);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-md);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.flip-card-container {
    position: relative;
    perspective: 1500px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.modal-close {
    position: absolute;
    top: -50px;
    right: 0;
    width: 44px;
    height: 44px;
    border: none;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    font-size: 1.5rem;
    color: var(--color-text);
    cursor: pointer;
    z-index: 10;
    transition: transform 0.2s, background 0.2s;
}

.modal-close:hover {
    transform: scale(1.1);
    background: #fff;
}

/* フリップカード本体 */
.flip-card {
    width: 340px;
    height: 480px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.flip-card.flipped {
    transform: rotateY(180deg);
}

.flip-card-front,
.flip-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: var(--radius-lg);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

/* 前面 */
.flip-card-front {
    background: linear-gradient(145deg, var(--color-bg) 0%, #f0efe9 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.front-content {
    padding: var(--spacing-xl);
    text-align: center;
}

.front-label {
    font-family: var(--font-serif);
    font-size: 0.85rem;
    color: var(--color-text);
    opacity: 0.6;
    margin-bottom: var(--spacing-lg);
}

.front-catchcopy {
    font-family: var(--font-handwritten);
    font-size: 1.3rem;
    color: var(--color-accent);
    line-height: 1.8;
    margin-bottom: var(--spacing-xl);
    white-space: pre-line;
}

.front-reveal {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    color: var(--color-text);
    opacity: 0.8;
    font-style: italic;
    line-height: 1.7;
}

/* 背面 */
.flip-card-back {
    background: linear-gradient(145deg, #fff 0%, var(--color-bg) 100%);
    transform: rotateY(180deg);
}

.back-content {
    padding: var(--spacing-lg);
    text-align: center;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.back-image {
    margin-bottom: var(--spacing-md);
}

.back-image img {
    max-width: 160px;
    max-height: 220px;
    object-fit: contain;
    border-radius: var(--radius-sm);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.back-title {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.back-author {
    font-family: var(--font-serif);
    font-size: 0.85rem;
    color: var(--color-text);
    opacity: 0.7;
    margin-bottom: var(--spacing-md);
}

.back-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: 0 var(--spacing-md);
}

.back-buttons .btn {
    width: 100%;
    text-align: center;
    padding: 12px;
    font-size: 0.9rem;
}

/* フリップボタン */
.flip-btn {
    margin-top: var(--spacing-lg);
    padding: 16px 48px;
    font-family: var(--font-serif);
    font-size: 1.1rem;
    background: var(--color-accent);
    color: #fff;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
    box-shadow: 0 4px 20px rgba(29, 53, 87, 0.3);
}

.flip-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(29, 53, 87, 0.4);
    background: #152740;
}

/* ボタンスタイル */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-sm);
    font-family: var(--font-serif);
    font-size: 0.9rem;
    text-decoration: none;
    transition: background-color 0.2s, transform 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
}

.btn-rakuten {
    background: #bf0000;
    color: #fff;
    border: 1px solid #bf0000;
}

.btn-rakuten:hover {
    background: #8f0000;
}

.btn-amazon {
    background: #232f3e;
    color: #fff;
    border: 1px solid #232f3e;
}

.btn-amazon:hover {
    background: #131921;
}

/* レスポンシブ */
@media (max-width: 400px) {
    .flip-card {
        width: 300px;
        height: 440px;
    }

    .front-catchcopy {
        font-size: 1.1rem;
    }

    .back-image img {
        max-width: 120px;
        max-height: 180px;
    }
}

/* =========================================
   Footer
   ========================================= */
.site-footer {
    padding: var(--spacing-xl) var(--spacing-md);
    text-align: center;
    border-top: 1px solid rgba(43, 43, 43, 0.1);
    margin-top: var(--spacing-xxl);
}

.footer-text {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.footer-logo {
    font-family: var(--font-handwritten);
    color: var(--color-accent);
}

.footer-divider {
    margin: 0 var(--spacing-sm);
    opacity: 0.3;
}

.footer-copy {
    font-size: 0.8rem;
    color: var(--color-text);
    opacity: 0.5;
}

/* =========================================
   Animations
   ========================================= */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

@keyframes revealBook {
    0% {
        opacity: 0;
        transform: perspective(600px) rotateY(-180deg) scale(0.8);
    }

    50% {
        opacity: 0.5;
        transform: perspective(600px) rotateY(-90deg) scale(1.05);
    }

    100% {
        opacity: 1;
        transform: perspective(600px) rotateY(0deg) scale(1);
    }
}

@keyframes cardFlipIn {
    0% {
        transform: perspective(1000px) rotateY(-180deg) scale(0.5);
        opacity: 0;
    }

    50% {
        transform: perspective(1000px) rotateY(-90deg) scale(0.9);
        opacity: 0.5;
    }

    100% {
        transform: perspective(1000px) rotateY(0deg) scale(1);
        opacity: 1;
    }
}

/* Card entrance animation */
.book-card {
    animation: fadeInUp 0.6s ease-out both;
}

.book-card:nth-child(1) {
    animation-delay: 0.1s;
}

.book-card:nth-child(2) {
    animation-delay: 0.2s;
}

.book-card:nth-child(3) {
    animation-delay: 0.3s;
}

.book-card:nth-child(4) {
    animation-delay: 0.4s;
}

.book-card:nth-child(5) {
    animation-delay: 0.5s;
}

.book-card:nth-child(6) {
    animation-delay: 0.6s;
}

/* =========================================
   Responsive Design
   ========================================= */
@media (max-width: 768px) {
    .site-logo {
        font-size: 2rem;
    }

    .site-nav {
        gap: var(--spacing-md);
    }

    .nav-link {
        font-size: 0.85rem;
    }

    .hero {
        padding: var(--spacing-xl) var(--spacing-md);
        min-height: 40vh;
    }

    .book-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .book-card {
        padding: var(--spacing-md);
    }

    .card-catchcopy {
        font-size: 1.25rem;
    }

    .modal-content {
        padding: var(--spacing-lg);
    }

    .modal-image img {
        max-width: 150px;
    }

    .modal-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        text-align: center;
    }
}

@media (min-width: 1200px) {
    .book-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* =========================================
   Utility Classes
   ========================================= */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}