/* ==========================================================================
   拾光集 · 个人随笔 — design system
   基调：宣纸暖白 + 墨色文字 + 朱砂印章红
   字体：Noto Serif SC（正文/标题）+ Noto Sans SC（元信息）
   ========================================================================== */

:root {
  --paper: #f6f2e9;
  --paper-deep: #efe9dc;
  --ink: #26221b;
  --ink-soft: #57503f;
  --ink-faint: #8a8171;
  --line: rgba(38, 34, 27, 0.14);
  --seal: #a83228;
  --seal-deep: #8e2a22;
  --card: rgba(255, 253, 248, 0.72);
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", serif;
  --sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 14px;
  --max-read: 44rem;
  --max-wide: 68rem;
}

[data-theme="dark"] {
  --paper: #17150f;
  --paper-deep: #1e1b14;
  --ink: #e7e0d0;
  --ink-soft: #b3ab98;
  --ink-faint: #7d7665;
  --line: rgba(231, 224, 208, 0.16);
  --seal: #cf5b4e;
  --seal-deep: #e06a5c;
  --card: rgba(30, 27, 20, 0.66);
}

/* ---------- 基础 ---------- */

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--serif);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(ellipse 120% 60% at 15% -10%, rgba(168, 50, 40, 0.05), transparent 55%),
    radial-gradient(ellipse 90% 50% at 100% 0%, rgba(120, 100, 60, 0.05), transparent 60%),
    linear-gradient(180deg, transparent 0, transparent 100%);
  background-attachment: fixed;
  line-height: 1.9;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.4s ease, color 0.4s ease;
}

/* 纸纹噪点 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.5;
  background-image:
    repeating-linear-gradient(0deg, rgba(0, 0, 0, 0.012) 0 1px, transparent 1px 3px),
    repeating-linear-gradient(90deg, rgba(0, 0, 0, 0.008) 0 1px, transparent 1px 4px);
  z-index: 0;
}

a {
  color: var(--ink);
  text-decoration-color: var(--seal);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: color 0.25s ease;
}

a:hover {
  color: var(--seal);
}

img {
  max-width: 100%;
}

:focus-visible {
  outline: 2px solid var(--seal);
  outline-offset: 3px;
  border-radius: 2px;
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -60px;
  z-index: 100;
  padding: 8px 18px;
  background: var(--seal);
  color: #fff;
  border-radius: 6px;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 12px;
}

/* ---------- 顶栏 ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: color-mix(in srgb, var(--paper) 82%, transparent);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 14px 28px;
  display: flex;
  align-items: center;
  gap: 24px;
}

.brand {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand::before {
  content: "";
  width: 9px;
  height: 9px;
  background: var(--seal);
  border-radius: 1.5px;
  transform: rotate(45deg);
  flex: none;
}

.site-nav {
  display: flex;
  gap: 4px;
  margin-left: auto;
}

.site-nav a {
  padding: 6px 14px;
  border-radius: 999px;
  font-family: var(--sans);
  font-size: 0.86rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  color: var(--ink-soft);
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--ink);
  background: var(--card);
  box-shadow: inset 0 0 0 1px var(--line);
}

.icon-btn {
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink);
  width: 38px;
  height: 38px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 1rem;
  display: grid;
  place-items: center;
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.icon-btn:hover {
  transform: rotate(12deg) scale(1.05);
  border-color: var(--seal);
}

.icon-btn .icon-sun {
  display: none;
}

[data-theme="dark"] .icon-btn .icon-sun {
  display: inline;
}

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

/* ---------- 首页 Hero ---------- */

.hero {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 96px 28px 72px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 40px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.seal {
  width: 108px;
  height: 108px;
  background: var(--seal);
  color: #f7f0e2;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 4rem;
  font-weight: 700;
  transform: rotate(-4deg);
  box-shadow: 0 14px 30px rgba(168, 50, 40, 0.28);
  border: 1px solid rgba(255, 255, 255, 0.18);
}

.seal small {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.4em;
  margin-top: -12px;
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.6rem, 7vw, 4.6rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: 0.06em;
}

.hero .tagline {
  margin: 18px 0 6px;
  font-size: 1.15rem;
  color: var(--ink-soft);
  letter-spacing: 0.08em;
}

.hero .meta {
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--ink-faint);
  letter-spacing: 0.14em;
}

.hero-vertical {
  position: absolute;
  right: 20px;
  bottom: 24px;
  writing-mode: vertical-rl;
  font-size: 0.8rem;
  letter-spacing: 0.5em;
  color: var(--ink-faint);
  opacity: 0.75;
  user-select: none;
}

/* ---------- 随笔列表 ---------- */

.section-essays {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 0 28px 96px;
  position: relative;
  z-index: 1;
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  border-bottom: 2px solid var(--ink);
  padding-bottom: 14px;
  margin-bottom: 34px;
}

.section-head h2 {
  margin: 0;
  font-size: 1.7rem;
  letter-spacing: 0.16em;
}

.section-head .count {
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--ink-faint);
  letter-spacing: 0.1em;
}

.section-head .divider-dot {
  width: 8px;
  height: 8px;
  background: var(--seal);
  transform: rotate(45deg);
  margin-left: auto;
  flex: none;
}

.tag-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: -6px 0 28px;
}

.tag-chip {
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 999px;
  padding: 5px 16px;
  font-family: var(--sans);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  cursor: pointer;
  transition: all 0.25s ease;
}

.tag-chip:hover {
  border-color: var(--seal);
  color: var(--seal);
}

.tag-chip[aria-pressed="true"] {
  background: var(--seal);
  border-color: var(--seal);
  color: #f7f0e2;
}

.post-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
}

.post-card {
  position: relative;
  display: block;
  padding: 26px 28px 24px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-decoration: none;
  overflow: hidden;
  transition: transform 0.3s cubic-bezier(0.2, 0.8, 0.3, 1), box-shadow 0.3s ease;
}

.post-card::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--seal), transparent 70%);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s ease;
}

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 34px rgba(38, 34, 27, 0.12);
}

.post-card:hover::after {
  transform: scaleX(1);
}

.post-card time {
  font-family: var(--sans);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  color: var(--ink-faint);
}

.post-card h3 {
  margin: 10px 0 8px;
  font-size: 1.28rem;
  line-height: 1.45;
  letter-spacing: 0.03em;
}

.post-card .excerpt {
  margin: 0 0 16px;
  font-size: 0.92rem;
  color: var(--ink-soft);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-card .tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.post-card .tag {
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  padding: 2px 10px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--seal) 10%, transparent);
  color: var(--seal);
  border: 1px solid color-mix(in srgb, var(--seal) 35%, transparent);
}

.post-card .arrow {
  position: absolute;
  right: 20px;
  bottom: 18px;
  font-size: 1.1rem;
  color: var(--ink-faint);
  opacity: 0;
  transform: translateX(-6px);
  transition: all 0.3s ease;
}

.post-card:hover .arrow {
  opacity: 1;
  transform: translateX(0);
  color: var(--seal);
}

.empty-tip {
  display: none;
  text-align: center;
  color: var(--ink-faint);
  padding: 48px 0;
  font-family: var(--sans);
}

.empty-tip.show {
  display: block;
}

/* ---------- 关于页 ---------- */

.about-page {
  max-width: var(--max-read);
  margin: 0 auto;
  padding: 80px 28px 96px;
  position: relative;
  z-index: 1;
}

.about-page h1 {
  font-size: 2.4rem;
  letter-spacing: 0.1em;
  margin: 0 0 10px;
}

.about-page .lead {
  font-size: 1.1rem;
  color: var(--ink-soft);
}

.about-page .prose {
  margin-top: 40px;
}

.about-card {
  margin-top: 44px;
  padding: 30px 34px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--sans);
  font-size: 0.92rem;
  color: var(--ink-soft);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 14px 22px;
  align-items: baseline;
}

.about-card dt {
  color: var(--ink-faint);
  letter-spacing: 0.2em;
  font-size: 0.8rem;
}

.about-card dd {
  margin: 0;
}

/* ---------- 文章页 ---------- */

.essay-page {
  max-width: var(--max-read);
  margin: 0 auto;
  padding: 72px 28px 90px;
  position: relative;
  z-index: 1;
}

.read-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--seal), var(--seal-deep));
  z-index: 60;
  transition: width 0.1s linear;
}

.essay-head {
  margin-bottom: 52px;
  border-bottom: 1px solid var(--line);
  padding-bottom: 36px;
}

.essay-head .kicker {
  font-family: var(--sans);
  font-size: 0.8rem;
  letter-spacing: 0.28em;
  color: var(--seal);
  text-transform: uppercase;
  margin: 0 0 16px;
}

.essay-head h1 {
  margin: 0 0 18px;
  font-size: clamp(1.9rem, 4.5vw, 2.7rem);
  line-height: 1.35;
  letter-spacing: 0.04em;
}

.essay-head .meta-line {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  align-items: center;
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--ink-faint);
  letter-spacing: 0.06em;
}

.essay-head .meta-line .dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--seal);
  display: inline-block;
}

/* 正文排版 */
.prose {
  font-size: 1.05rem;
}

.prose > p {
  margin: 0 0 1.6em;
  text-align: justify;
  text-indent: 2em;
  letter-spacing: 0.02em;
}

.prose > p:first-of-type::first-letter {
  font-size: 3.1em;
  font-weight: 700;
  line-height: 1;
  float: left;
  margin: 0.08em 0.12em 0 0;
  color: var(--seal);
}

.prose p.note {
  text-indent: 0;
  padding: 18px 22px;
  border-left: 3px solid var(--seal);
  background: var(--card);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 0.95rem;
  color: var(--ink-soft);
}

.prose blockquote {
  margin: 2em 0;
  padding: 6px 0 6px 26px;
  border-left: 3px solid var(--seal);
  font-style: normal;
  color: var(--ink-soft);
}

.prose blockquote p {
  text-indent: 0;
}

.prose h2 {
  font-size: 1.45rem;
  letter-spacing: 0.08em;
  margin: 2.4em 0 0.9em;
  display: flex;
  align-items: center;
  gap: 14px;
}

.prose h2::before {
  content: "";
  width: 7px;
  height: 7px;
  background: var(--seal);
  transform: rotate(45deg);
  flex: none;
}

.end-mark {
  margin-top: 64px;
  text-align: center;
  font-family: var(--sans);
  font-size: 0.85rem;
  letter-spacing: 0.5em;
  color: var(--ink-faint);
  position: relative;
}

.end-mark::before,
.end-mark::after {
  content: "";
  position: absolute;
  top: 50%;
  width: 56px;
  height: 1px;
  background: var(--line);
}

.end-mark::before {
  left: calc(50% - 120px);
}

.end-mark::after {
  right: calc(50% - 120px);
}

/* 上下篇 */
.essay-nav {
  margin-top: 60px;
  border-top: 1px solid var(--line);
  padding-top: 28px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
}

.essay-nav a {
  font-size: 0.95rem;
  text-decoration: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  max-width: 46%;
}

.essay-nav .dir {
  font-family: var(--sans);
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  color: var(--ink-faint);
}

.essay-nav a.next {
  text-align: right;
  margin-left: auto;
}

/* ---------- 页脚 ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 44px 28px 56px;
  text-align: center;
  position: relative;
  z-index: 1;
}

.site-footer .quote {
  font-size: 0.98rem;
  color: var(--ink-soft);
  letter-spacing: 0.1em;
  margin: 0 0 14px;
}

.site-footer .copy {
  font-family: var(--sans);
  font-size: 0.78rem;
  color: var(--ink-faint);
  letter-spacing: 0.16em;
}

.site-footer .copy.icp {
  margin: 8px 0 0;
}

.site-footer .copy.beian-name {
  margin: 12px 0 4px;
  font-size: 0.82rem;
  color: var(--ink-soft);
  letter-spacing: 0.2em;
}

.site-footer .copy.icp a {
  color: var(--ink-faint);
  text-decoration: none;
  border-bottom: 1px dotted var(--line);
  transition: color 0.25s ease;
}

.site-footer .copy.icp a:hover,
.site-footer .copy.icp a:focus-visible {
  color: var(--ink);
  outline: none;
}

/* ---------- 返回顶部 ---------- */

.to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink-soft);
  cursor: pointer;
  font-size: 1.1rem;
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition: all 0.3s ease;
  z-index: 55;
}

.to-top.show {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.to-top:hover {
  color: var(--seal);
  border-color: var(--seal);
}

/* ---------- 响应式 ---------- */

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .hero {
    grid-template-columns: 1fr;
    padding: 64px 22px 56px;
    gap: 28px;
  }

  .hero .seal {
    width: 84px;
    height: 84px;
    font-size: 3rem;
  }

  .hero-vertical {
    display: none;
  }

  .section-essays,
  .essay-page,
  .about-page {
    padding-left: 22px;
    padding-right: 22px;
  }

  .post-list {
    grid-template-columns: 1fr;
  }

  .header-inner {
    padding: 12px 18px;
    gap: 14px;
  }

  .site-nav a {
    padding: 6px 10px;
    font-size: 0.8rem;
  }

  .brand {
    font-size: 1.05rem;
  }
}

@media (max-width: 420px) {
  .site-nav a:nth-of-type(2) {
    display: none;
  }
}

/* ---------- 打印 ---------- */

@media print {
  .site-header,
  .to-top,
  .read-progress,
  .essay-nav,
  .icon-btn {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
    font-size: 12pt;
  }

  .essay-page {
    padding: 0;
    max-width: 100%;
  }
}

/* ---------- 动效偏好 ---------- */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}