/* ==========================================================
   hexo-theme-letter · 书信主题样式
   思源宋体 / 宣纸质感 / 蜡印拆信 / 信纸缓展 / 文字浮现
   ========================================================== */

:root {
  /* 主体字体：思源宋体（在线加载失败时回落本机宋体栈） */
  --serif: 'Noto Serif SC', 'Source Han Serif SC', '思源宋体', 'Songti SC', 'STSong', 'SimSun', serif;

  /* 浪漫色板：粉白 × 玫瑰金 */
  --paper: #fdf5f4;          /* 信纸：微粉白 */
  --paper-edge: #f7e6e4;
  --ink: #5d3a48;            /* 文字：深玫瑰褐 */
  --ink-soft: #96707e;
  --ink-faint: #c3a3ad;
  --line: #efd5d9;           /* 粉金细线 */

  /* 火漆蜡印：玫瑰红 */
  --wax: #e05578;
  --wax-deep: #b2385c;
  --wax-light: #f28ba6;

  /* 信封：粉米 */
  --envelope: #f8e9e5;
  --envelope-flap: #f4dcd5;

  /* 页面底色：粉白 → 玫瑰粉 */
  --bg: #fdf0ee;
  --bg-deep: #f6dbe0;

  --shadow-soft: 0 10px 30px rgba(160, 90, 110, 0.12);
  --shadow-lift: 0 18px 44px rgba(160, 90, 110, 0.2);
  --glow: 0 0 42px rgba(224, 85, 120, 0.22);   /* 柔光 */

  /* 动画 */
  --ease-unfold: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-romantic: cubic-bezier(0.2, 0.9, 0.3, 1.1);  /* 慢速弹性，带轻微回弹 */
  --dur-unfold: 1.2s;
  --dur-fade: 0.55s;       /* 文字浮现时长（head.ejs 可按配置覆盖） */
  --stagger: 60ms;         /* 段落浮现间隔（head.ejs 可按配置覆盖） */
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--serif);
  color: var(--ink);
  background:
    radial-gradient(ellipse at 50% -20%, rgba(255, 250, 235, 0.5), transparent 60%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-deep) 100%);
  background-attachment: fixed;
  line-height: 1.9;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container { width: min(880px, 94vw); margin: 0 auto; }

a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

/* ==========================================================
   顶栏 / 页脚
   ========================================================== */
.site-head {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(253, 240, 238, 0.82);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.site-head__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-head__brand {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-indent: 0.2em;
}

.site-head__nav { display: flex; gap: 26px; }

.site-head__link {
  font-size: 14.5px;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
  transition: color 0.3s;
}
.site-head__link:hover { color: var(--wax); }

.main {
  position: relative;   /* 层叠在粒子层之上 */
  z-index: 1;
  padding: 40px 0 0;
}

.site-foot {
  margin-top: 80px;
  padding: 34px 0;
  border-top: 1px solid var(--line);
  text-align: center;
  color: var(--ink-faint);
  font-size: 13px;
  letter-spacing: 0.08em;
}
.site-foot p { margin: 4px 0; }
.site-foot a { color: var(--ink-soft); }
.site-foot a:hover { color: var(--wax); }

/* ==========================================================
   首页：题头 + 信封卡片
   ========================================================== */
.home__hero { text-align: center; padding: 64px 0 8px; }

.home__title {
  margin: 0;
  font-size: clamp(34px, 6vw, 52px);
  font-weight: 600;
  letter-spacing: 0.18em;
  text-indent: 0.18em;
}

.home__subtitle {
  margin: 20px 0 0;
  color: var(--ink-soft);
  font-size: 15px;
  letter-spacing: 0.5em;
  text-indent: 0.5em;
}

.home__hero::after {
  content: '❖';
  display: block;
  margin: 26px auto 0;
  color: var(--ink-faint);
  font-size: 12px;
  letter-spacing: 1em;
  text-indent: 1em;
}

.letter-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(272px, 1fr));
  gap: 28px;
  margin-top: 44px;
}

.letter-card {
  position: relative;
  display: block;
  background: linear-gradient(180deg, #fef6f4, #fbeef0);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 24px 26px 22px;
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  transition: transform 0.45s var(--ease-unfold), box-shadow 0.45s;
}

.letter-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 44px;
  background: linear-gradient(180deg, #f4e0d8, #eccec6);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transition: height 0.4s var(--ease-unfold);
  z-index: 0;
}

.letter-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lift);
}
.letter-card:hover::before { height: 58px; }

.letter-card__top {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.letter-card__date {
  font-size: 13px;
  color: var(--ink-faint);
  letter-spacing: 0.15em;
}
.letter-card__date em {
  font-style: normal;
  margin-left: 8px;
  font-size: 11px;
  color: var(--ink-faint);
}

.letter-card__seal {
  position: relative;
  flex: none;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: radial-gradient(circle at 34% 30%, var(--wax-light), var(--wax) 60%, var(--wax-deep));
  box-shadow: inset 0 -2px 5px rgba(0, 0, 0, 0.3), 0 3px 8px rgba(58, 49, 38, 0.28);
  color: rgba(255, 244, 232, 0.88);
  font-size: 16px;
  font-weight: 600;
  transition: transform 0.35s var(--ease-unfold);
}
.letter-card__seal::after {
  content: '';
  position: absolute;
  inset: -5px;
  border-radius: 50%;
  box-shadow: 0 0 0 0 rgba(169, 50, 38, 0);
  transition: box-shadow 0.5s;
}
.letter-card:hover .letter-card__seal { transform: scale(1.12) rotate(-4deg); }
.letter-card:hover .letter-card__seal::after { box-shadow: 0 0 18px 4px rgba(169, 50, 38, 0.35); }

.letter-card__title {
  margin: 14px 0 8px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.5;
}

.letter-card__excerpt {
  margin: 0;
  font-size: 14.5px;
  color: var(--ink-soft);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.letter-card__more {
  display: block;
  margin-top: 16px;
  font-size: 13px;
  color: var(--wax);
  letter-spacing: 0.2em;
  text-indent: 0.2em;
  text-align: right;
  transition: letter-spacing 0.35s;
}
.letter-card:hover .letter-card__more { letter-spacing: 0.3em; }

/* ==========================================================
   书信舞台：信封 + 信纸（拆信动画）
   ========================================================== */
.letter {
  position: relative;
  width: min(720px, 100%);
  margin: 8px auto 60px;
  perspective: 1400px;
}

/* ---- 信封 ---- */
.envelope {
  position: absolute;
  left: 50%;
  top: 6px;
  transform: translateX(-50%);
  width: min(560px, 100%);
  aspect-ratio: 8 / 5;
  cursor: pointer;
  user-select: none;
  z-index: 2;
  transition:
    opacity 0.7s ease 0.1s,
    transform 0.7s var(--ease-unfold) 0.1s;
}

.envelope__pocket {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, #f8e9e5, #f1dcd6);
  border-radius: 4px;
  box-shadow: var(--shadow-soft);
  overflow: hidden;
}

/* 信封口袋下部的两个侧三角 */
.envelope__pocket::before {
  content: '';
  position: absolute;
  left: 0; bottom: 0;
  width: 50%; height: 56%;
  background: linear-gradient(135deg, #f1dbd4, #e9cdc4);
  clip-path: polygon(0 0, 100% 0, 0 100%);
}
.envelope__pocket::after {
  content: '';
  position: absolute;
  right: 0; bottom: 0;
  width: 50%; height: 56%;
  background: linear-gradient(225deg, #edd6cf, #e5c8be);
  clip-path: polygon(0 0, 100% 0, 100% 100%);
}

/* 信封封盖：翻开动画（rotateX 翻转） */
.envelope__flap {
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 52%;
  background: linear-gradient(180deg, #f6e3dc, #eed1c9);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transform-origin: top center;
  transform-style: preserve-3d;
  transition: transform 0.62s var(--ease-romantic);
  z-index: 3;
}

/* 封盖内衬（翻开后露出的浅色纸面） */
.envelope__flap::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, #fdf2ef, #f7e3de);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  opacity: 0;
  transition: opacity 0.35s 0.15s;
}

.letter.is-opening .envelope__flap { transform: rotateX(180deg); }
.letter.is-opening .envelope__flap::after { opacity: 1; }

.envelope__addressee {
  position: absolute;
  left: 0; right: 0;
  bottom: 16%;
  text-align: center;
  font-size: 18px;
  letter-spacing: 0.4em;
  text-indent: 0.4em;
  color: var(--ink-soft);
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

/* 火漆蜡印 */
.envelope__seal {
  position: absolute;
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 86px;
  height: 86px;
  border-radius: 50%;
  background: radial-gradient(circle at 34% 28%, var(--wax-light), var(--wax) 58%, var(--wax-deep));
  box-shadow:
    inset 0 -5px 10px rgba(0, 0, 0, 0.35),
    inset 0 3px 6px rgba(255, 255, 255, 0.28),
    0 6px 14px rgba(58, 49, 38, 0.3);
  color: rgba(255, 244, 232, 0.88);
  font-size: 34px;
  font-weight: 600;
  text-indent: 0.1em;
  z-index: 4;
  transition: transform 0.4s var(--ease-unfold);
}
.envelope__seal::before {
  content: '';
  position: absolute;
  inset: 7px;
  border: 1px dashed rgba(255, 240, 220, 0.5);
  border-radius: 50%;
}
.envelope:hover .envelope__seal,
.envelope:focus-visible .envelope__seal {
  transform: translate(-50%, -50%) scale(1.07);
}
.envelope:focus-visible { outline: 2px solid var(--wax-light); outline-offset: 6px; border-radius: 4px; }

/* 点击瞬间：蜡印被按压入信封 */
.letter.is-pressing .envelope__seal {
  transform: translate(-50%, -50%) scale(0.9);
  box-shadow:
    inset 0 -3px 6px rgba(0, 0, 0, 0.4),
    inset 0 2px 4px rgba(255, 255, 255, 0.2),
    0 2px 6px rgba(58, 49, 38, 0.25);
}

/* 封盖翻开时，信封轻轻一颤 */
@keyframes envelope-quiver {
  0%, 100% { transform: translateX(-50%) rotate(0deg); }
  25% { transform: translateX(-50%) rotate(-0.7deg) translateY(-2px); }
  50% { transform: translateX(-50%) rotate(0.5deg); }
  75% { transform: translateX(-50%) rotate(-0.3deg) translateY(1px); }
}
.letter.is-opening .envelope {
  animation: envelope-quiver 0.6s var(--ease-unfold);
}

.envelope__hint {
  position: absolute;
  right: 16px; bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--ink-faint);
}

/* 开信后：信封如纸般摊平展开、柔光模糊隐退，信纸接管 */
.letter.is-unsealed .envelope {
  opacity: 0;
  transform: translateX(-50%) translateY(-58px) scaleX(1.18) scaleY(0.72) rotateX(8deg);
  filter: blur(3px);
  box-shadow: var(--glow);
  pointer-events: none;
  transition:
    opacity 0.9s ease 0.1s,
    transform 0.9s var(--ease-unfold) 0.1s,
    filter 0.9s ease 0.1s,
    box-shadow 0.9s ease 0.1s;
}

/* ---- 信纸：轻纱帷幕式展开（从中缝向两侧揭开 + 弹性缓动 + 柔光） ---- */
.paper {
  position: relative;
  z-index: 1;
  background:
    repeating-linear-gradient(0deg, rgba(93, 58, 72, 0.014) 0 1px, transparent 1px 3px),
    linear-gradient(180deg, #fef7f5, #fbeff0);
  border: 1px solid var(--line);
  border-radius: 3px;
  box-shadow:
    var(--shadow-soft),
    inset 0 0 0 1px rgba(255, 255, 255, 0.6);
  padding: 60px 64px 64px;
  transform-origin: 50% 0;
  transform: rotateX(3deg) translateY(20px);
  clip-path: inset(0 50% 0 50%);   /* 两侧帷幕先闭合于中缝 */
  will-change: clip-path, transform;
  transition:
    clip-path var(--dur-unfold) var(--ease-unfold),
    transform var(--dur-unfold) var(--ease-romantic),
    box-shadow 0.9s ease 0.8s;
}

.paper.is-open {
  clip-path: inset(0 0% 0 0%);    /* 帷幕向两侧缓缓揭开 */
  transform: rotateX(0deg) translateY(0);
  box-shadow:
    var(--shadow-lift),
    var(--glow),
    inset 0 0 0 1px rgba(255, 255, 255, 0.6);
}

/* 信纸顶部饰线 */
.paper::before {
  content: '';
  position: absolute;
  top: 26px; left: 50%;
  transform: translateX(-50%);
  width: 140px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line), transparent);
}
.paper::after {
  content: '❖';
  position: absolute;
  top: 10px; left: 50%;
  transform: translateX(-50%);
  color: var(--ink-faint);
  font-size: 12px;
  background: #fef7f5;
  padding: 0 10px;
  z-index: 1;
}

/* ---- 信纸头部 ---- */
.paper__head {
  text-align: center;
  margin-bottom: 40px;
  padding-bottom: 26px;
  border-bottom: 1px dashed var(--line);
}

.paper__title {
  margin: 0;
  font-size: clamp(26px, 4.4vw, 34px);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-indent: 0.14em;
  line-height: 1.5;
}

.paper__meta {
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--ink-faint);
  letter-spacing: 0.18em;
}

.paper__sign {
  margin-top: 52px;
  text-align: right;
  font-size: 17px;
  letter-spacing: 0.3em;
  text-indent: 0.3em;
  color: var(--ink);
}
.paper__sign::before {
  content: '—— ';
  color: var(--ink-faint);
  letter-spacing: 0.1em;
}

/* ==========================================================
   正文排版（Markdown 渲染内容）
   ========================================================== */
.markdown-body { line-height: 2.05; letter-spacing: 0.02em; }

/* 中文习惯：段落首行缩进两字 */
.markdown-body p {
  margin: 0 0 1.25em;
  text-indent: 2em;
}

.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  font-weight: 700;
  letter-spacing: 0.06em;
}
.markdown-body h2 {
  margin: 2.2em 0 0.8em;
  padding-left: 14px;
  border-left: 3px solid var(--wax);
  font-size: 24px;
  text-indent: 0;
}
.markdown-body h3 {
  margin: 1.8em 0 0.6em;
  font-size: 20px;
}
.markdown-body h2 + p, .markdown-body h3 + p { text-indent: 2em; }

.markdown-body blockquote {
  margin: 1.5em 0;
  padding: 12px 20px;
  border-left: 3px solid var(--line);
  background: rgba(224, 85, 120, 0.08);
  color: var(--ink-soft);
}
.markdown-body blockquote p { text-indent: 0; margin-bottom: 0.6em; }
.markdown-body blockquote p:last-child { margin-bottom: 0; }

.markdown-body a {
  color: var(--wax);
  border-bottom: 1px dotted var(--wax);
  transition: border-color 0.3s;
}
.markdown-body a:hover { border-bottom-style: solid; }

.markdown-body strong { font-weight: 700; }

.markdown-body ul,
.markdown-body ol { padding-left: 2.2em; margin: 1em 0; }
.markdown-body li { margin: 0.35em 0; }
.markdown-body li p { text-indent: 0; }

.markdown-body code {
  font-family: 'Cascadia Code', 'JetBrains Mono', Consolas, 'Courier New', monospace;
  font-size: 0.86em;
  background: rgba(58, 49, 38, 0.07);
  padding: 2px 6px;
  border-radius: 3px;
}

.markdown-body pre {
  background: #352f27;
  color: #ece5d4;
  padding: 18px 20px;
  border-radius: 4px;
  overflow: auto;
  font-size: 14px;
  line-height: 1.7;
  box-shadow: var(--shadow-soft);
}
.markdown-body pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.markdown-body table {
  border-collapse: collapse;
  margin: 1.6em auto;
  font-size: 15px;
}
.markdown-body th,
.markdown-body td {
  border: 1px solid var(--line);
  padding: 8px 16px;
  text-align: left;
}
.markdown-body th {
  background: rgba(224, 85, 120, 0.12);
  font-weight: 600;
}

.markdown-body img {
  display: block;
  margin: 1.6em auto;
  border-radius: 4px;
  box-shadow: var(--shadow-soft);
}

.markdown-body hr {
  border: none;
  margin: 3em 0;
  text-align: center;
}
.markdown-body hr::before {
  content: '❖ ❖ ❖';
  font-size: 12px;
  color: var(--ink-faint);
  letter-spacing: 1em;
  text-indent: 1em;
}

/* 首字下沉：如一枚殷红的印 */
.letter.drop-cap .markdown-body > p:first-of-type {
  text-indent: 0;
}
.letter.drop-cap .markdown-body > p:first-of-type::first-letter {
  float: left;
  margin: 0.06em 0.16em 0 0;
  font-size: 3.1em;
  line-height: 1;
  font-weight: 600;
  color: var(--wax);
}

/* ---- 文字浮现动画：段落逐次浮现（stagger 由 --i 与 --stagger 控制） ---- */
.markdown-body > *,
.paper__head {
  opacity: 0;
  transform: translateY(14px);
  transition:
    opacity var(--dur-fade) ease,
    transform calc(var(--dur-fade) + 0.08s) var(--ease-unfold);
  transition-delay: calc(var(--i, 0) * var(--stagger));
}

.markdown-body > *.is-visible,
.paper__head.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 标题装饰线：浮现时从中线向两侧划出 */
.paper__title {
  position: relative;
  display: inline-block;
}
.paper__title::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: -12px;
  width: 0;
  height: 2px;
  transform: translateX(-50%);
  background: linear-gradient(90deg, transparent, var(--wax), transparent);
  opacity: 0.7;
  transition: width 0.9s var(--ease-unfold) 0.2s;
}
.paper__head.is-visible .paper__title::after { width: 100%; }

/* 引用块：浮现时左侧竖线由上而下划出 */
.markdown-body blockquote {
  position: relative;
  border-left: none;
  padding-left: 24px;
}
.markdown-body blockquote::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 3px;
  background: linear-gradient(180deg, var(--line), var(--wax-light));
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.5s var(--ease-unfold);
}
.markdown-body blockquote.is-visible::before { transform: scaleY(1); }

/* ==========================================================
   归档 / 分页
   ========================================================== */
.archive__head { text-align: center; padding: 40px 0 20px; }
.archive__title {
  margin: 0;
  font-size: 30px;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-indent: 0.2em;
}
.archive__head::after {
  content: '';
  display: block;
  width: 120px;
  height: 1px;
  background: var(--line);
  margin: 22px auto 0;
}

.archive__list {
  border-left: 2px solid var(--line);
  margin-left: 12px;
  padding-left: 26px;
}

.archive__year {
  position: relative;
  margin: 34px 0 10px;
  font-size: 22px;
  font-weight: 600;
  letter-spacing: 0.1em;
}
.archive__year::before {
  content: '';
  position: absolute;
  left: -33px; top: 50%;
  transform: translateY(-50%);
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--wax);
  animation: dot-pulse 2.6s ease-out infinite;
}

@keyframes dot-pulse {
  0% { box-shadow: 0 0 0 0 rgba(169, 50, 38, 0.35); }
  70% { box-shadow: 0 0 0 10px rgba(169, 50, 38, 0); }
  100% { box-shadow: 0 0 0 0 rgba(169, 50, 38, 0); }
}

.archive__item {
  display: flex;
  gap: 18px;
  align-items: baseline;
  padding: 11px 0;
  border-bottom: 1px dashed var(--line);
  transition: padding-left 0.3s;
}
.archive__item:hover { padding-left: 10px; }

.archive__item-date {
  flex: none;
  min-width: 84px;
  font-size: 13px;
  color: var(--ink-faint);
  letter-spacing: 0.12em;
}
.archive__item-title {
  font-size: 17px;
  letter-spacing: 0.03em;
  transition: color 0.3s;
}
.archive__item:hover .archive__item-title { color: var(--wax); }

.archive__empty { text-align: center; color: var(--ink-faint); padding: 60px 0; }

.pagination {
  margin: 48px 0 16px;
  text-align: center;
  letter-spacing: 0.05em;
}
.pagination .page-number,
.pagination .extend {
  display: inline-block;
  min-width: 36px;
  margin: 0 3px;
  padding: 5px 11px;
  border: 1px solid var(--line);
  border-radius: 3px;
  color: var(--ink-soft);
  background: rgba(254, 246, 244, 0.7);
  transition: all 0.3s;
}
.pagination .page-number:hover,
.pagination .extend:hover {
  border-color: var(--wax);
  color: var(--wax);
}
.pagination .current {
  background: var(--wax);
  border-color: var(--wax);
  color: #fff;
}
.pagination .space { border: none; background: none; }

/* ==========================================================
   浪漫粒子：爱心上浮 + 花瓣飘落（Canvas）
   ========================================================== */
.letter-particles {
  position: fixed;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;              /* 背景之上、内容之下 */
}

/* ==========================================================
   响应式
   ========================================================== */
@media (max-width: 640px) {
  body {
    font-size: 16px;
    background-attachment: scroll;   /* fixed 在移动端开销大且 iOS 不支持 */
  }
  .main { padding-top: 24px; }
  .paper { padding: 48px 22px 52px; }
  .paper__title { font-size: 24px; }
  .envelope { width: 100%; }
  .envelope__seal { width: 72px; height: 72px; font-size: 28px; }
  .envelope__addressee { font-size: 15px; }
  .letter-list { grid-template-columns: 1fr; }
  .site-head__brand { font-size: 17px; }
}