/* ==========================================================================
   Freesun's blog · 全站样式
   纯静态站点，无框架、无构建。所有设计变量集中在 :root，
   换配色或字体只需要改这一块。
   ========================================================================== */

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

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

:root {
  /* 色彩：暖纸 / 墨色 / 朱红 */
  --paper: #f7f4ee;
  --surface: #fffdf8;
  --ink: #1b1916;
  --ink-soft: #565148;
  --ink-faint: #8a8375;
  --rule: #ded7c9;
  --accent: #a8402c;

  /* 字体：标题用衬线，正文用系统无衬线，避免加载外部字体 */
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", Georgia, "Times New Roman", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;

  /* 尺度 */
  --wrap: 68rem;
  --measure: 44rem;
  --leading: 1.7;
}

:root[data-theme="dark"] {
  --paper: #141312;
  --surface: #1b1917;
  --ink: #e9e4da;
  --ink-soft: #b2aa9c;
  --ink-faint: #7d7467;
  --rule: #302c26;
  --accent: #e2795f;
  --leading: 1.78; /* 浅字深底会显瘦，行距多给一点 */
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: var(--leading);
  font-kerning: normal;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main { flex: 1; }

a { color: inherit; text-decoration: none; }

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

button { font: inherit; }

::selection {
  background: var(--accent);
  color: var(--paper);
}

:where(a, button):focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip {
  position: absolute;
  left: -9999px;
  top: 1rem;
  z-index: 100;
  padding: 0.6rem 1rem;
  background: var(--surface);
  border: 1px solid var(--rule);
  color: var(--ink);
  font-size: 0.875rem;
}

.skip:focus { left: 1rem; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 2.5rem);
}

/* ---------- 页头 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--paper);
  border-bottom: 1px solid var(--rule);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 4.5rem;
  flex-wrap: wrap;
}

.brand {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding-block: 0.75rem;
  transition: color 0.2s ease;
}

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

.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(0.85rem, 3vw, 1.75rem);
  font-size: 0.9375rem;
  letter-spacing: 0.06em;
}

.site-nav a {
  position: relative;
  padding-block: 0.5rem;
  color: var(--ink-soft);
  transition: color 0.2s ease;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] { color: var(--ink); }

.site-nav a::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  bottom: 0.1rem;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.site-nav a:hover::after,
.site-nav a[aria-current="page"]::after { transform: scaleX(1); }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: 1px solid var(--rule);
  border-radius: 50%;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.theme-toggle svg {
  width: 1rem;
  height: 1rem;
}

.theme-toggle .icon-sun { display: none; }

[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* 窄屏下压缩页头，避免英文站点名单行放不下 */
@media (max-width: 26rem) {
  .header-inner { gap: 0.75rem; }
  .brand { font-size: 1.0625rem; }
  .site-nav { gap: 0.7rem; font-size: 0.875rem; }
  .theme-toggle { width: 2.25rem; height: 2.25rem; }
}

/* ---------- 首页首屏 ---------- */

.hero {
  padding-block: clamp(4rem, 11vw, 7.5rem) clamp(2.5rem, 6vw, 4rem);
}

.hero-eyebrow {
  margin: 0 0 1.5rem;
  font-size: 0.8125rem;
  letter-spacing: 0.3em;
  color: var(--ink-faint);
}

.hero h1 {
  max-width: 20ch;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2.125rem, 5.5vw, 3.5rem);
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -0.01em;
}

.hero-lead {
  max-width: 32em;
  margin: 1.75rem 0 0;
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--ink-soft);
}

/* ---------- 文章列表 ---------- */

.post-index { padding-bottom: 2rem; }

.section-head {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.section-head h2 {
  margin: 0;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.3em;
  color: var(--ink-faint);
  white-space: nowrap;
}

.section-head::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--rule);
}

.post-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--rule);
}

.post-item { border-bottom: 1px solid var(--rule); }

.post-item.pinned {
  background: color-mix(in srgb, var(--accent) 4%, transparent);
  border-bottom: 1px solid var(--rule);
}

.pin-badge {
  display: inline-block;
  margin-right: 0.5rem;
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  background: var(--accent);
  color: #fff;
  font-family: var(--mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  vertical-align: middle;
  line-height: 1.4;
  transform: translateY(-1px);
}

.post-link {
  display: grid;
  grid-template-columns: 8.5rem 1fr;
  gap: 0 2rem;
  padding-block: 1.875rem;
}

.post-date {
  padding-top: 0.35rem;
  font-family: var(--mono);
  font-size: 0.8125rem;
  letter-spacing: 0.02em;
  color: var(--ink-faint);
  transition: color 0.2s ease;
}

.post-body {
  display: block;
  min-width: 0;
}

.post-title {
  display: block;
  font-family: var(--serif);
  font-size: 1.375rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
  transition: color 0.2s ease;
}

.post-summary {
  display: block;
  margin-top: 0.5rem;
  max-width: 34em;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--ink-soft);
}

.post-tags {
  display: block;
  margin-top: 0.75rem;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
}

.post-link:hover .post-title { color: var(--accent); }
.post-link:hover .post-date { color: var(--ink-soft); }

@media (max-width: 44rem) {
  .post-link {
    grid-template-columns: 1fr;
    gap: 0.6rem;
  }

  .post-date { padding-top: 0; }
}

/* ---------- 内页（关于 / 联系） ---------- */

.page {
  max-width: var(--measure);
  margin-inline: auto;
  padding-block: clamp(3.5rem, 9vw, 6rem) 0;
}

.page-title {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(2rem, 4.5vw, 2.75rem);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.page-intro {
  max-width: 32em;
  margin: 1.5rem 0 0;
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--ink-soft);
}

.monogram {
  display: grid;
  place-items: center;
  width: 4.5rem;
  height: 4.5rem;
  margin-bottom: 2rem;
  border: 1px solid var(--rule);
  font-family: var(--serif);
  font-size: 1.875rem;
  color: var(--accent);
}

.prose {
  margin-top: 3rem;
}

.prose p {
  margin: 0 0 1.5rem;
  line-height: 1.95;
}

.prose h2 {
  margin: 3rem 0 1rem;
  font-family: var(--serif);
  font-size: 1.3125rem;
  font-weight: 600;
  line-height: 1.45;
}

.prose a {
  color: var(--accent);
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
}

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

.rule {
  height: 1px;
  margin: 3rem 0;
  border: 0;
  background: var(--rule);
}

.facts {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: 0.9rem 1.5rem;
  margin: 2.5rem 0 0;
  font-size: 0.9375rem;
}

.facts dt {
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--ink-faint);
  padding-top: 0.2rem;
}

.facts dd {
  margin: 0;
  color: var(--ink-soft);
}

.page-intro a {
  color: var(--accent);
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
}

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

.contact-email {
  display: inline-block;
  margin-top: 2.5rem;
  padding-bottom: 0.2rem;
  font-family: var(--serif);
  font-size: clamp(1.375rem, 3.5vw, 1.875rem);
  color: var(--ink);
  border-bottom: 1px solid var(--accent);
  word-break: break-all;
  transition: color 0.2s ease;
}

.contact-email:hover { color: var(--accent); }

.contact-note {
  margin-top: 1rem;
  font-size: 0.875rem;
  color: var(--ink-faint);
}

/* ---------- 页脚 ---------- */

.site-footer {
  margin-top: clamp(4rem, 10vw, 7rem);
  padding-block: 2.25rem 3rem;
  border-top: 1px solid var(--rule);
  font-size: 0.8125rem;
  color: var(--ink-faint);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem 2rem;
}

.footer-inner p { margin: 0; }

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}