/* ===========================
   Minimal Book-like Design
   Black & White
   =========================== */

/* CSS Custom Properties */
:root {
    /* Colors - Pure Black & White */
    --bg-primary: #ffffff;
    --bg-secondary: #fafafa;
    --text-primary: #000000;
    --text-secondary: #666666;
    --text-tertiary: #999999;
    --border-color: #e5e5e5;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'Helvetica Neue', 'Segoe UI', system-ui, sans-serif;

    /* Layout */
    --content-width: 680px;
    --wide-width: 900px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 1.25rem; font-weight: 700; }
h2 { font-size: 1.125rem; }
h3 { font-size: 0.9375rem; }
h4, h5, h6 { font-size: 0.875rem; }

p { margin-bottom: var(--spacing-lg); }

a {
    color: var(--text-primary);
    text-decoration: none;
    border-bottom: 1px solid var(--text-primary);
    transition: opacity 0.2s ease;
}

a:hover { opacity: 0.6; }

::selection {
    background-color: var(--text-primary);
    color: var(--bg-primary);
}

/* Header */
.site-header {
    padding: var(--spacing-xl) var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
}

.navbar {
    max-width: var(--wide-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-name {
    font-size: 0.875rem;
    font-weight: 600;
    border: none;
}

.site-name:hover { opacity: 0.6; }

.nav-links {
    list-style: none;
    display: flex;
    gap: var(--spacing-lg);
    margin: 0;
    align-items: center;
}

.nav-links a {
    font-size: 0.8125rem;
    border: none;
    opacity: 0.6;
}

.nav-links a:hover { opacity: 1; }

/* Main Content */
.main-content {
    flex: 1;
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-xl);
    width: 100%;
}

/* Intro */
.intro { margin-bottom: var(--spacing-xl); }
.intro-text {
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Content Sections */
.content-section {
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    margin-bottom: var(--spacing-md);
    margin-left: calc(var(--spacing-xs) * -1);
}

/* Post List */
.post-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.post-item {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.post-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: var(--spacing-md);
}

.post-title {
    font-size: 0.75rem;
    font-weight: 600;
    margin: 0;
    flex: 1;
}

.post-title a { border: none; }
.post-title a:hover { opacity: 0.6; }

.post-date {
    font-size: 0.6875rem;
    color: var(--text-tertiary);
    white-space: nowrap;
}

.post-excerpt {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.5;
}

.post-source {
    margin-top: var(--spacing-sm);
}

.source-badge {
    display: inline-block;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
    padding: 0.25rem 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

.view-more {
    display: inline-block;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    border: none;
}

.view-more:hover {
    color: var(--text-primary);
    opacity: 1;
}

/* Book List */
.book-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.book-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.book-title {
    font-size: 0.875rem;
    font-weight: 600;
    margin: 0;
}

.book-title a { border: none; }
.book-title a:hover { opacity: 0.6; }

.book-author {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin: 0;
}

/* Books Grid */
.books-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
}

.book-card {
    display: grid;
    grid-template-columns: 140px 1fr;
    gap: var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: var(--spacing-xl);
    align-items: start;
}

.book-card:last-child {
    border-bottom: none;
}

.book-cover-link {
    display: block;
    border: none;
    transition: opacity 0.2s ease;
}

.book-cover-link:hover {
    opacity: 0.8;
}

.book-cover {
    width: 140px;
    height: auto;
    border-radius: 4px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    display: block;
}

.book-cover-placeholder {
    width: 140px;
    height: 210px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
}

.book-details {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.book-meta-row {
    display: flex;
    justify-content: space-between;
    align-items: start;
    gap: var(--spacing-md);
}

.book-status {
    display: inline-block;
    font-size: 0.5625rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-tertiary);
    padding: 0.2rem 0.45rem;
    border: 1px solid var(--border-color);
    border-radius: 2px;
    white-space: nowrap;
    flex-shrink: 0;
}

.book-card-title {
    font-size: 1rem;
    font-weight: 600;
    margin: 0;
    line-height: 1.3;
    flex: 1;
}

.book-card-title a {
    border: none;
}

.book-card-title a:hover {
    opacity: 0.6;
}

.book-card-author {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin: 0;
    font-weight: 500;
}

.book-review {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

.book-rating {
    font-size: 0.9375rem;
    color: var(--text-primary);
    margin: 0;
}

.book-rating .star-filled {
    opacity: 1;
}

.book-rating .star-empty {
    opacity: 0.3;
}

.book-no-rating {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    font-style: italic;
    margin: 0;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

.pagination-link {
    font-size: 0.8125rem;
    color: var(--text-primary);
    border: none;
    padding: 0.5rem 1rem;
    transition: opacity 0.2s ease;
}

.pagination-link:hover:not(.disabled) {
    opacity: 0.6;
}

.pagination-link.disabled {
    opacity: 0.3;
    cursor: not-allowed;
    pointer-events: none;
}

.pagination-info {
    font-size: 0.8125rem;
    color: var(--text-secondary);
}

/* Post Detail */
.post { padding: var(--spacing-3xl) var(--spacing-xl); }
.post-container {
    max-width: var(--content-width);
    margin: 0 auto;
}

.back-link {
    display: inline-block;
    font-size: 0.9375rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    border: none;
}

.back-link:hover {
    color: var(--text-primary);
    opacity: 1;
}

.post-header {
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
}

.post-title {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1.2;
}

.post-meta {
    display: flex;
    gap: var(--spacing-md);
    color: var(--text-tertiary);
    font-size: 0.9375rem;
}

.post-tags {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

.tag {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    padding: 0.25rem 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

/* Post Content */
.post-content {
    font-size: 1.0625rem;
    line-height: 1.8;
}

.post-content h1,
.post-content h2,
.post-content h3 {
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
}

.post-content h1 { font-size: 1.75rem; }
.post-content h2 { font-size: 1.5rem; }
.post-content h3 { font-size: 1.25rem; }

.post-content ul,
.post-content ol {
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-xl);
}

.post-content li { margin-bottom: var(--spacing-sm); }

.post-content blockquote {
    padding-left: var(--spacing-lg);
    border-left: 2px solid var(--border-color);
    margin: var(--spacing-xl) 0;
    font-style: italic;
    color: var(--text-secondary);
}

.post-content img {
    max-width: 100%;
    height: auto;
    margin: var(--spacing-xl) 0;
}

.post-content code {
    font-family: 'SF Mono', 'Monaco', 'Consolas', monospace;
    font-size: 0.9em;
    background: var(--bg-secondary);
    padding: 0.2em 0.4em;
    border-radius: 3px;
}

.post-content pre {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: var(--spacing-lg);
    overflow-x: auto;
    margin: var(--spacing-xl) 0;
}

.post-content pre code {
    background: none;
    padding: 0;
}

/* Notes */
.notes-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2xl);
}

.note-card {
    border-bottom: 1px solid var(--border-color);
    padding-bottom: var(--spacing-xl);
}

.note-card:last-child { border-bottom: none; }

.note-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: var(--spacing-md);
    gap: var(--spacing-md);
}

.note-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.note-date {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    white-space: nowrap;
}

.note-content {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Footer */
.site-footer {
    margin-top: auto;
    padding: var(--spacing-2xl) var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

.footer-links {
    max-width: var(--wide-width);
    margin: 0 auto;
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.footer-links a {
    font-size: 0.9375rem;
    color: var(--text-tertiary);
    border: none;
}

.footer-links a:hover {
    color: var(--text-primary);
    opacity: 1;
}

/* Error Pages */
.error-page {
    text-align: left;
    padding: var(--spacing-3xl) 0;
}

.error-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.error-subtitle {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.error-message {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--text-primary);
    color: var(--bg-primary);
    border: none;
    border-radius: 4px;
}

.btn:hover { opacity: 0.8; }

/* Empty State */
.empty-state {
    padding: var(--spacing-2xl) 0;
    color: var(--text-tertiary);
}

/* Responsive */
@media (max-width: 768px) {
    .site-header { padding: var(--spacing-lg) var(--spacing-md); }
    .navbar {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    .main-content { padding: var(--spacing-2xl) var(--spacing-md); }
    .post { padding: var(--spacing-2xl) var(--spacing-md); }
    .post-header {
        flex-direction: column;
        align-items: flex-start;
    }

    /* Book cards mobile */
    .book-card {
        grid-template-columns: 90px 1fr;
        gap: var(--spacing-md);
    }

    .book-cover {
        width: 90px;
    }

    .book-cover-placeholder {
        width: 90px;
        height: 135px;
        font-size: 1.5rem;
    }
}