/* ============================================================
   essays 流动随笔 · 样式
   深墨夜色调 + 暖金点缀 + 霞鹜文楷
   ============================================================ */

:root {
  --accent: #e8c68a;
  --accent-soft: rgba(232, 198, 138, 0.16);
  --text: #e9e2d0;
  --text-dim: #9b8f7d;
  --bg-top: #0d0e13;
  --bg-bottom: #16171f;
  --font: 'LXGW WenKai', 'Kaiti SC', 'STKaiti', 'KaiTi', serif;
}

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

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

body {
  font-family: var(--font);
  color: var(--text);
  background-color: var(--bg-top);
  line-height: 2;
  letter-spacing: 0.04em;
  overflow-x: hidden;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

/* 背景：固定伪元素层（不使用 background-attachment: fixed，规避移动端滚动闪烁） */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -2;
  background:
    linear-gradient(180deg, var(--bg-top), var(--bg-bottom) 70%),
    radial-gradient(60% 45% at 50% 0%, rgba(232, 198, 138, 0.10), transparent 70%),
    radial-gradient(45% 35% at 85% 90%, rgba(120, 140, 190, 0.08), transparent 70%);
  pointer-events: none;
}

/* 粒子画布（display:block + 独立图层提升，避免滚动/合成时的闪烁线） */
#particles {
  position: fixed;
  inset: 0;
  z-index: -1;
  display: block;
  pointer-events: none;
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
  backface-visibility: hidden;
}

/* ============ 封面（缓冲/开启） ============ */
#cover {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  cursor: default;
  background:
    radial-gradient(70% 55% at 50% 38%, rgba(232, 198, 138, 0.10), transparent 68%),
    linear-gradient(180deg, var(--bg-top), var(--bg-bottom));
  transition: opacity 1.1s ease, visibility 1.1s ease, transform 1.1s ease;
}

.cover-inner {
  position: relative;
  z-index: 1;
  padding: 2rem;
  animation: coverIn 1.6s ease both;
}

/* 封面繁星画布 */
#coverCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  display: block;
  pointer-events: none;
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
}

@keyframes coverIn {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0); }
}

.cover-eyebrow {
  font-size: 0.9rem;
  letter-spacing: 0.55em;
  text-indent: 0.55em;
  color: var(--text-dim);
  margin-bottom: 1.6rem;
  animation: fadeIn 2.2s 0.4s ease both;
}

.cover-title {
  font-size: clamp(2.2rem, 9vw, 3.6rem);
  font-weight: 600;
  letter-spacing: 0.28em;
  text-indent: 0.28em;
  color: var(--accent);
  text-shadow: 0 0 34px rgba(232, 198, 138, 0.35);
  animation: fadeIn 1.4s 0.8s ease both;
}

.cover-subtitle {
  margin-top: 1.5rem;
  font-size: 1.05rem;
  color: var(--accent);
  letter-spacing: 0.22em;
  font-style: italic;
  opacity: 0.9;
  animation: fadeIn 1.4s 1.3s ease both;
}

/* 封面提示留空时不占位 */
#coverTip:empty { display: none; }

/* 开启按钮 */
#coverBtn {
  margin-top: 3.2rem;
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.9rem 2.6rem;
  border: 1px solid var(--accent-soft);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-family: inherit;
  font-size: 1.05rem;
  letter-spacing: 0.35em;
  text-indent: 0.35em;
  cursor: pointer;
  transition: all 0.4s ease;
  animation: fadeIn 1.2s 1.8s ease both;
}
#coverBtn:hover { background: rgba(232, 198, 138, 0.28); transform: translateY(-2px); }
#coverBtn::after {
  content: '';
  position: absolute;
  inset: -6px;
  border-radius: 999px;
  border: 1px solid rgba(232, 198, 138, 0.5);
  animation: pulse 2.6s ease-out infinite;
}
@keyframes pulse {
  0%   { transform: scale(1); opacity: 0.9; }
  70%  { transform: scale(1.18); opacity: 0; }
  100% { transform: scale(1.18); opacity: 0; }
}

.cover-tip {
  margin-top: 2.4rem;
  font-size: 0.8rem;
  color: rgba(155, 143, 125, 0.7);
  letter-spacing: 0.2em;
  animation: fadeIn 1.4s 2.4s ease both;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* 开启后的封面退场 */
body.opened #cover {
  opacity: 0;
  visibility: hidden;
  transform: scale(1.06);
}

/* ============ 正文舞台 ============ */
#stage {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 1.4s ease, transform 1.4s ease;
}
body.opened #stage {
  opacity: 1;
  transform: translateY(0);
}

#essay {
  max-width: 34rem;
  margin: 0 auto;
  padding: 9rem 1.6rem 6rem;
}

/* 阅读进度条 */
#progressBar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  z-index: 50;
  background: transparent;
  transform-origin: 0 0;
  transform: scaleX(0);
  pointer-events: none;
}
#progressBar::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, var(--accent));
  box-shadow: 0 0 8px rgba(232, 198, 138, 0.7);
}

/* 音乐按钮（右上角） */
#musicBtn {
  position: fixed;
  top: 1rem;
  right: 1rem;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1rem;
  border: 1px solid var(--accent-soft);
  border-radius: 999px;
  background: rgba(13, 14, 19, 0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  color: var(--accent);
  font-family: inherit;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.8s ease 0.5s;
}
body.opened #musicBtn { opacity: 1; }
/* 音符跳动图标（三根音柱，播放时跳动；暂停时静止且变暗） */
#musicBtn .music-icon {
  display: inline-flex;
  align-items: flex-end;
  gap: 2.5px;
  width: 17px;
  height: 16px;
}
#musicBtn .music-icon i {
  display: block;
  width: 3.5px;
  border-radius: 2px;
  background: var(--accent);
  height: 5px;
  transform-origin: bottom;
  opacity: 0.55;
  transition: height 0.3s ease, opacity 0.3s ease;
}
#musicBtn.playing .music-icon i { opacity: 1; }
#musicBtn.playing { box-shadow: 0 0 16px rgba(232, 198, 138, 0.4); }
#musicBtn.playing .music-icon i:nth-child(1) { animation: eq-a .7s ease-in-out infinite alternate; }
#musicBtn.playing .music-icon i:nth-child(2) { animation: eq-b .55s ease-in-out infinite alternate; }
#musicBtn.playing .music-icon i:nth-child(3) { animation: eq-c .8s ease-in-out infinite alternate; }
@keyframes eq-a { from { height: 5px;  } to { height: 15px; } }
@keyframes eq-b { from { height: 14px; } to { height: 3px;  } }
@keyframes eq-c { from { height: 8px;  } to { height: 16px; } }

/* 底部歌词条 */
#lyricBar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 50;
  display: flex;
  justify-content: center;
  padding: 0.8rem 1.2rem calc(0.8rem + env(safe-area-inset-bottom));
  pointer-events: none;
  background: linear-gradient(transparent, rgba(13, 14, 19, 0.85));
}
#lyricLine {
  max-width: 30rem;
  text-align: center;
  font-size: 0.92rem;
  letter-spacing: 0.1em;
  color: var(--text-dim);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.5s ease, transform 0.5s ease, color 0.5s ease;
}
#lyricLine.on { opacity: 1; transform: translateY(0); color: var(--accent); }

/* ============ 正文排版 ============ */
.hero {
  text-align: center;
  margin-bottom: 5rem;
}
.hero-eyebrow {
  color: var(--text-dim);
  font-size: 0.85rem;
  letter-spacing: 0.5em;
  text-indent: 0.5em;
  margin-bottom: 1.6rem;
}
.hero-title {
  font-size: clamp(1.9rem, 7.5vw, 2.8rem);
  font-weight: 600;
  letter-spacing: 0.16em;
  text-indent: 0.16em;
  color: var(--accent);
  text-shadow: 0 0 28px rgba(232, 198, 138, 0.28);
  line-height: 1.5;
}
.hero-greet {
  margin-top: 1.4rem;
  color: var(--accent);
  font-size: 1.05rem;
  letter-spacing: 0.2em;
}
.hero-line {
  width: 3rem;
  height: 1px;
  margin: 2.4rem auto 0;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
}

.flow-section { margin-bottom: 0; }

.section-head {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.3em;
  text-indent: 0.3em;
  color: var(--accent);
  margin-bottom: 1.4rem;
}

.paragraph {
  font-size: 1.22rem;
  line-height: 2.15;
  letter-spacing: 0.06em;
  margin-bottom: 2.6rem;
  text-align: justify;
}

/* 歌词插页 */
.lyric-card {
  margin: 3rem 0;
  padding: 2.6rem 1.4rem;
  text-align: center;
  border-top: 1px solid var(--accent-soft);
  border-bottom: 1px solid var(--accent-soft);
  background: rgba(232, 198, 138, 0.05);
}
.lyric-card-mark {
  display: block;
  color: var(--accent);
  font-size: 1.3rem;
  margin-bottom: 1.2rem;
  animation: floaty 3.4s ease-in-out infinite;
}
.lyric-card p {
  font-size: 1.18rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  line-height: 2.2;
}
@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-6px); }
}

/* 落款 */
.sign {
  text-align: right;
  margin-top: 5rem;
  padding-top: 2.4rem;
  border-top: 1px solid var(--accent-soft);
  color: var(--text-dim);
  font-size: 1rem;
  letter-spacing: 0.18em;
  line-height: 2.3;
}
.sign p:last-child { color: var(--accent); }

/* ============ 滚动渐入 ============ */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  filter: blur(5px);
  transition:
    opacity 0.95s ease,
    transform 0.95s ease,
    filter 0.95s ease;
}
.reveal.in-view {
  opacity: 1;
  transform: translateY(0);
  filter: blur(0);
}
.flow-section .section-head.reveal {
  transition:
    opacity 0.9s ease,
    transform 0.9s ease,
    filter 0.9s ease,
    letter-spacing 0.9s ease;
  letter-spacing: 0.45em;
  text-indent: 0.45em;
}
.flow-section .section-head.reveal.in-view { letter-spacing: 0.3em; text-indent: 0.3em; }

/* 禁用动画偏好 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; filter: none; }
}

/* 小屏微调 */
@media (max-width: 480px) {
  #essay { padding-top: 6.5rem; }
  .paragraph { font-size: 1.16rem; }
}

/* ============ 目录页（多篇随笔） ============ */
body.picker-mode #musicBtn,
body.picker-mode #lyricBar { display: none; }

.essay-list {
  text-align: center;
  padding-top: 2rem;
}
.essay-list-title {
  font-size: 1.6rem;
  letter-spacing: 0.3em;
  text-indent: 0.3em;
  color: var(--accent);
  margin-bottom: 0.6rem;
}
.essay-list-sub {
  color: var(--text-dim);
  font-size: 0.9rem;
  letter-spacing: 0.2em;
  margin-bottom: 3rem;
}
.essay-item {
  display: block;
  text-align: left;
  margin: 1.1rem 0;
  padding: 1.3rem 1.4rem;
  border: 1px solid var(--accent-soft);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.02);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.35s ease, background 0.35s ease, transform 0.35s ease;
}
.essay-item:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: translateY(-2px);
}
.essay-item-title {
  display: block;
  font-size: 1.15rem;
  letter-spacing: 0.12em;
  color: var(--accent);
}
.essay-item-desc {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-dim);
  letter-spacing: 0.08em;
}
.essay-item-arrow {
  float: right;
  color: var(--text-dim);
  margin-top: -1.2rem;
}