/* ==========================================================================
   yeah空间 — 站点样式
   纯静态、无外部依赖，适配桌面与移动端，支持深色模式
   ========================================================================== */

:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --surface-alt: #f0f2f6;
  --text: #1c2028;
  --text-soft: #4a5262;
  --muted: #7b8496;
  --border: #e4e8ef;
  --accent: #2f6df0;
  --accent-soft: #eaf1fe;
  --accent-strong: #1f52c4;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
  --radius: 14px;
  --radius-sm: 9px;
  --container: 880px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC",
    Roboto, Helvetica, Arial, sans-serif;
  --font-serif: "Iowan Old Style", "Songti SC", "Source Han Serif SC", "Noto Serif CJK SC",
    Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151b;
    --surface: #191d25;
    --surface-alt: #1f242e;
    --text: #e8ebf0;
    --text-soft: #b9c1cf;
    --muted: #8b94a5;
    --border: #2a303b;
    --accent: #6f9bff;
    --accent-soft: #1c2740;
    --accent-strong: #9bbbff;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.28);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-strong);
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

/* ---------- 头部 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 62px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  letter-spacing: 0.01em;
}

.brand:hover {
  color: var(--text);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), var(--accent-strong));
  color: #fff;
  font-size: 16px;
  font-weight: 800;
  line-height: 1;
}

.brand-text {
  font-size: 17px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: wrap;
}

.site-nav a {
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--text-soft);
  font-size: 15px;
  transition: background 0.15s ease, color 0.15s ease;
}

.site-nav a:hover {
  background: var(--surface-alt);
  color: var(--text);
  text-decoration: none;
}

.site-nav a[aria-current="page"] {
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 600;
}

/* ---------- 主体 ---------- */

main {
  flex: 1 0 auto;
  padding: 40px 0 8px;
}

.hero {
  padding: 26px 0 34px;
}

.hero h1 {
  margin: 0 0 12px;
  font-size: clamp(30px, 5.2vw, 44px);
  line-height: 1.22;
  letter-spacing: -0.015em;
}

.hero .lead {
  margin: 0;
  max-width: 62ch;
  color: var(--text-soft);
  font-size: 17px;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
  padding: 0;
  list-style: none;
}

.hero-tags li {
  padding: 4px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-size: 13.5px;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin: 34px 0 16px;
}

.section-head h2 {
  margin: 0;
  font-size: 20px;
  letter-spacing: -0.01em;
}

.section-head .more {
  font-size: 14.5px;
  white-space: nowrap;
}

/* ---------- 文章列表 ---------- */

.post-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.post-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: transform 0.16s ease, border-color 0.16s ease;
}

.post-card:hover {
  transform: translateY(-2px);
  border-color: color-mix(in srgb, var(--accent) 38%, var(--border));
}

.post-card > a {
  display: block;
  padding: 20px 22px;
  color: inherit;
}

.post-card > a:hover {
  text-decoration: none;
  color: inherit;
}

.post-card h3 {
  margin: 0 0 8px;
  font-size: 19px;
  line-height: 1.45;
  letter-spacing: -0.01em;
}

.post-card .excerpt {
  margin: 0 0 12px;
  color: var(--text-soft);
  font-size: 15.5px;
}

.post-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 13.5px;
}

.post-meta .dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.6;
}

.tag {
  padding: 2px 9px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-size: 12.5px;
}

/* ---------- 关于卡片 ---------- */

.about-card {
  margin-top: 34px;
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.about-card h2 {
  margin: 0 0 10px;
  font-size: 18px;
}

.about-card p {
  margin: 0 0 10px;
  color: var(--text-soft);
  font-size: 15.5px;
}

.about-card p:last-child {
  margin-bottom: 0;
}

/* ---------- 文章正文 ---------- */

.article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 34px 34px 28px;
}

.article-head {
  padding-bottom: 18px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.article-head h1 {
  margin: 0 0 12px;
  font-size: clamp(25px, 4.2vw, 33px);
  line-height: 1.32;
  letter-spacing: -0.015em;
}

.article-body {
  font-size: 16.5px;
}

.article-body h2 {
  margin: 34px 0 12px;
  font-size: 21px;
  letter-spacing: -0.01em;
}

.article-body h3 {
  margin: 26px 0 10px;
  font-size: 18px;
}

.article-body p {
  margin: 0 0 16px;
}

.article-body ul,
.article-body ol {
  margin: 0 0 16px;
  padding-left: 24px;
}

.article-body li {
  margin-bottom: 7px;
}

.article-body li::marker {
  color: var(--muted);
}

.article-body blockquote {
  margin: 20px 0;
  padding: 4px 18px;
  border-left: 3px solid var(--accent);
  background: var(--surface-alt);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-soft);
}

.article-body blockquote p:last-child {
  margin-bottom: 0;
}

.article-body code {
  padding: 2px 6px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface-alt);
  font-family: var(--font-mono);
  font-size: 0.88em;
}

.article-body pre {
  margin: 0 0 18px;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-alt);
  overflow-x: auto;
  font-size: 14px;
  line-height: 1.65;
}

.article-body pre code {
  padding: 0;
  border: 0;
  background: none;
  font-size: inherit;
}

.article-body hr {
  margin: 30px 0;
  border: 0;
  border-top: 1px solid var(--border);
}

.article-foot {
  margin-top: 30px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-size: 14.5px;
}

/* ---------- 页脚 ---------- */

.site-footer {
  flex-shrink: 0;
  margin-top: 56px;
  padding: 30px 0 34px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

.footer-inner {
  display: grid;
  gap: 8px;
  text-align: center;
}

.footer-brand {
  margin: 0;
  font-weight: 600;
  font-size: 15.5px;
}

.footer-desc {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.footer-nav {
  margin: 6px 0 2px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 6px 18px;
  font-size: 14px;
}

.footer-nav a {
  color: var(--text-soft);
}

/* 备案信息：需在页面底部清晰可见 */
.footer-icp {
  margin: 10px 0 0;
  font-size: 14px;
  color: var(--text-soft);
}

.footer-icp a {
  color: var(--text-soft);
}

.footer-icp a:hover {
  color: var(--accent);
}

.footer-meta {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 13px;
}

/* ---------- 归档页 ---------- */

.page-title {
  margin: 0 0 8px;
  font-size: clamp(26px, 4.6vw, 34px);
  letter-spacing: -0.015em;
}

.page-desc {
  margin: 0 0 26px;
  color: var(--text-soft);
}

.year-group {
  margin-bottom: 28px;
}

.year-group > h2 {
  margin: 0 0 12px;
  font-size: 15px;
  color: var(--muted);
  font-weight: 600;
  letter-spacing: 0.06em;
}

.archive-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 2px solid var(--border);
}

.archive-list li {
  position: relative;
  padding: 0 0 14px 20px;
}

.archive-list li::before {
  content: "";
  position: absolute;
  left: -7px;
  top: 9px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--bg);
}

.archive-list time {
  display: block;
  color: var(--muted);
  font-size: 13.5px;
}

.archive-list .title {
  font-size: 16.5px;
}

/* ---------- 提示条 ---------- */

.callout {
  margin: 22px 0;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: var(--accent-soft);
  color: var(--text-soft);
  font-size: 15px;
}

.callout p:last-child {
  margin-bottom: 0;
}

/* ---------- 移动端 ---------- */

@media (max-width: 640px) {
  body {
    font-size: 15.5px;
  }

  .header-inner {
    min-height: 56px;
  }

  .brand-text {
    font-size: 16px;
  }

  .site-nav a {
    padding: 6px 9px;
    font-size: 14px;
  }

  /* 窄屏：进一步收紧头部，避免导航被挤出屏幕 */
  .site-nav {
    gap: 0;
  }

  .site-nav a {
    padding: 6px 8px;
    font-size: 13.5px;
  }

  main {
    padding-top: 26px;
  }

  .hero {
    padding: 16px 0 24px;
  }

  .article {
    padding: 24px 20px 20px;
  }

  .post-card > a {
    padding: 17px 18px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .brand {
    gap: 7px;
  }

  .brand-mark {
    width: 26px;
    height: 26px;
    border-radius: 8px;
    font-size: 14px;
  }

  .brand-text {
    font-size: 15px;
  }

  .site-nav a {
    padding: 6px 7px;
    font-size: 13px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  * {
    transition: none !important;
    animation: none !important;
  }
}