/* ================================
   图书馆模式（library） —— 暖白、长文阅读
   PRD 3.2: #faf9f6 / #2c2c2c / #2563eb
   字体 18px / 行高 1.8 / 正文栏宽 max 680px
   ================================ */

:root {
    --bg: #faf9f6;
    --fg: #2c2c2c;
    --muted: #7a7268;
    --muted-soft: #a89e93;
    --accent: #2563eb;
    --border: #ece8e0;
    --tag-bg: #f1ede4;
    --tag-fg: #6b5f50;
    --content-max: 680px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Serif SC", "Source Han Serif SC", "Songti SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--fg);
    font-size: 18px;
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.page {
    max-width: var(--content-max);
    margin: 0 auto;
    padding: 0 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ================================
   顶部导航
   ================================ */
.site-header {
    padding: 2rem 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.site-title {
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--fg);
    text-decoration: none;
    letter-spacing: 0.04em;
}

.site-title:hover {
    color: var(--accent);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.nav-links a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.9rem;
    letter-spacing: 0.06em;
}

.nav-links a:hover {
    color: var(--fg);
}

/* 右上角"回篝火旁"切换按钮 */
.fireside-switch {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 12px;
    border: 1px solid var(--border);
    border-radius: 999px;
    color: var(--muted) !important;
    font-size: 0.85rem !important;
    letter-spacing: 0.08em !important;
    transition: color 0.3s ease, border-color 0.3s ease, background 0.3s ease;
    background: transparent;
}

.fireside-switch:hover {
    color: #b8580f !important;
    border-color: #ff9f43;
    background: #fff7ec;
}

.fireside-switch__icon {
    font-size: 0.9rem;
}

/* ================================
   主体 & 页脚
   ================================ */
main {
    flex: 1;
    padding: 1rem 0 3rem;
}

footer {
    text-align: center;
    padding: 2rem 0 2.5rem;
    color: var(--muted-soft);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
    margin-top: 2rem;
}

/* ================================
   通用排版
   ================================ */
h1, h2, h3, h4 {
    font-weight: 600;
    color: var(--fg);
    letter-spacing: 0.02em;
}

h1 { font-size: 1.75rem; margin: 0 0 0.5rem; line-height: 1.35; }
h2 { font-size: 1.35rem; margin: 2.5rem 0 1rem; line-height: 1.4; }
h3 { font-size: 1.1rem; margin: 2rem 0 0.75rem; }

p {
    margin: 0 0 1.25rem;
}

a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid rgba(37, 99, 235, 0.2);
    transition: border-color 0.2s ease;
}

a:hover {
    border-bottom-color: var(--accent);
}

/* 导航和无装饰场景下不需要下划线 */
.site-title,
.nav-links a,
.post-list a,
.post-meta a,
.related-posts a,
.cta-fireside {
    border-bottom: none;
}

ul, ol {
    margin: 0 0 1.25rem 1.5rem;
}

li {
    margin-bottom: 0.4rem;
}

blockquote {
    border-left: 3px solid var(--accent);
    padding: 0.2rem 0 0.2rem 1.25rem;
    margin: 1.5rem 0;
    color: var(--muted);
    font-style: normal;
}

code {
    font-family: "Fira Code", "JetBrains Mono", Consolas, monospace;
    font-size: 0.92em;
}

p code, li code {
    background: #f1ede4;
    padding: 0.1rem 0.4rem;
    border-radius: 3px;
}

pre {
    background: #f4f0e8;
    padding: 1rem 1.2rem;
    border-radius: 6px;
    overflow-x: auto;
    margin: 1.5rem 0;
    line-height: 1.6;
    font-size: 0.92rem;
}

pre code {
    background: transparent;
    padding: 0;
}

img {
    max-width: 100%;
    height: auto;
    border-radius: 4px;
    display: block;
    margin: 1.5rem auto;
}

hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 2rem 0;
}

/* ================================
   文章列表（图书馆首页 / /library/）
   ================================ */
.library-intro {
    margin-bottom: 2.5rem;
}

.library-intro__title {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.library-intro__desc {
    color: var(--muted);
    font-size: 0.95rem;
}

.post-list {
    list-style: none;
    margin: 0;
    padding: 0;
}

.post-item {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border);
}

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

.post-item time {
    display: block;
    font-size: 0.82rem;
    color: var(--muted-soft);
    letter-spacing: 0.05em;
    margin-bottom: 0.35rem;
}

.post-item h2 {
    font-size: 1.2rem;
    margin: 0 0 0.5rem;
    font-weight: 500;
    line-height: 1.45;
}

.post-item h2 a {
    color: var(--fg);
}

.post-item h2 a:hover {
    color: var(--accent);
}

.post-item__summary {
    margin: 0 0 0.6rem;
    color: var(--muted);
    font-size: 0.95rem;
    line-height: 1.7;
}

.post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 0.5rem;
}

.post-tag {
    display: inline-block;
    padding: 2px 10px;
    background: var(--tag-bg);
    color: var(--tag-fg);
    border-radius: 999px;
    font-size: 0.78rem;
    letter-spacing: 0.04em;
    text-decoration: none;
    border: none;
}

.post-tag:hover {
    background: #e5dfd0;
    color: var(--fg);
    border: none;
}

/* ================================
   单篇文章
   ================================ */
.post-header {
    margin-bottom: 2.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
}

.post-header h1 {
    font-size: 1.9rem;
    margin-bottom: 0.75rem;
    line-height: 1.35;
}

.post-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    color: var(--muted-soft);
    font-size: 0.85rem;
}

.post-meta time {
    letter-spacing: 0.05em;
}

.post-content {
    margin-bottom: 3rem;
}

.post-content > * + h2,
.post-content > * + h3 {
    margin-top: 2.2rem;
}

/* 底部"去篝火旁问我"CTA */
.cta-fireside {
    display: block;
    margin: 3rem 0 1rem;
    padding: 1.4rem 1.5rem;
    background: linear-gradient(135deg, #fff7ec 0%, #fdf3df 100%);
    border: 1px solid #f0e4cf;
    border-radius: 10px;
    color: #6b4a1f !important;
    text-align: center;
    font-size: 0.95rem;
    letter-spacing: 0.04em;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.cta-fireside:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(255, 159, 67, 0.18);
}

.cta-fireside__hint {
    display: block;
    font-size: 0.8rem;
    color: var(--muted-soft);
    margin-bottom: 0.4rem;
    letter-spacing: 0.1em;
}

.cta-fireside__action {
    color: #b8580f;
    font-weight: 500;
}

/* ================================
   响应式
   ================================ */
@media (max-width: 600px) {
    body { font-size: 17px; line-height: 1.75; }
    .page { padding: 0 1.1rem; }
    .site-header { padding: 1.4rem 0 1rem; }
    .post-header h1 { font-size: 1.5rem; }
    h2 { font-size: 1.2rem; }
}

@media (max-width: 380px) {
    .nav-links { gap: 0.8rem; }
    .nav-links a { font-size: 0.82rem; }
}