/* =========================================================================
   序 · Base
   Reset / 排版 / 通用组件（按钮、标签、头像、时间轴原子）/ 页头 / 页脚
   ========================================================================= */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 1.5rem);
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color var(--dur-3) var(--ease), color var(--dur-3) var(--ease);
}

h1, h2, h3, h4, p, ul, ol, figure, blockquote { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg { display: block; max-width: 100%; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--dur-1) var(--ease), opacity var(--dur-1) var(--ease);
}

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

:focus-visible {
  outline: 1px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

/* ---------- 布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--w-page);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--text { max-width: var(--w-text); }
.container--narrow { max-width: var(--w-narrow); }

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* ---------- 顶部滚动进度（时间推进感） ---------- */
.scroll-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  background: var(--line);
  z-index: 120;
}
.scroll-progress__bar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  opacity: .7;
  transition: width 120ms linear;
  box-shadow: 0 0 8px rgba(162, 85, 58, 0.3);
}

/* ---------- 页头 ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: var(--paper);
  transition: border-color var(--dur-2) var(--ease), background-color var(--dur-3) var(--ease);
  border-bottom: 1px solid transparent;
}
.site-header.is-stuck { border-bottom-color: var(--line); }

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-3);
}

.brand { display: inline-flex; align-items: baseline; gap: .5rem; }
.brand__mark {
  font-family: var(--font-serif);
  font-size: 1.375rem;
  line-height: 1;
  letter-spacing: .04em;
}
.brand__series {
  font-size: var(--fs-micro);
  letter-spacing: var(--ls-wide);
  color: var(--ink-3);
  text-transform: uppercase;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: clamp(1.25rem, 2.4vw, 2.25rem);
  font-size: var(--fs-sm);
}
/* 重要：用 :not(.btn) 收窄范围，避免 (0,1,1) 覆盖掉 .btn--solid 的 (0,1,0) 颜色规则 */
.nav__list a:not(.btn) {
  color: var(--ink-2);
  position: relative;
  transition: color var(--dur-1) var(--ease);
}

/* Nav link underline animation */
.nav__list a:not(.btn)::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-2) var(--ease);
}

.nav__list a:not(.btn):hover { color: var(--ink); }
.nav__list a:not(.btn):hover::after { transform: scaleX(1); }
.nav__cta { margin-left: .25rem; }

.site-header__tools { display: flex; align-items: center; gap: .25rem; }

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: var(--r-sm);
  color: var(--ink-2);
  transition: color var(--dur-1) var(--ease), background-color var(--dur-1) var(--ease);
}
.icon-btn:hover { color: var(--ink); background: var(--ghost); }
.icon { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.3; stroke-linecap: round; stroke-linejoin: round; }

/* 主题图标：按当前主题显示其一 */
.theme-toggle .icon--moon { display: none; }
:root[data-theme="dark"] .theme-toggle .icon--sun { display: none; }
:root[data-theme="dark"] .theme-toggle .icon--moon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon--sun { display: none; }
  :root:not([data-theme="light"]) .theme-toggle .icon--moon { display: block; }
}

.nav-toggle { display: none; }
.nav-toggle__bars { display: block; width: 18px; }
.nav-toggle__bars i {
  display: block; height: 1px; background: currentColor;
  transition: transform var(--dur-2) var(--ease), opacity var(--dur-2) var(--ease);
}
.nav-toggle__bars i + i { margin-top: 5px; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:first-child { transform: translateY(3px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:last-child { transform: translateY(-3px) rotate(-45deg); }

/* ---------- 排版组件 ---------- */
.eyebrow {
  font-size: var(--fs-micro);
  letter-spacing: var(--ls-wide);
  text-transform: uppercase;
  color: var(--ink-3);
}

.display {
  font-family: var(--font-serif);
  font-size: var(--fs-display);
  line-height: 1.34;
  letter-spacing: .01em;
  font-weight: 400;
  position: relative;
  /* 入场后从中心展开一条极细强调线 */
}
.display::after {
  content: "";
  position: absolute;
  bottom: -.45em;
  left: 50%;
  width: 56px;
  height: 1px;
  background: var(--accent);
  transform: translateX(-50%) scaleX(0);
  transform-origin: center;
  transition: transform var(--dur-3) var(--ease) calc(var(--reveal-delay, 0ms) + 220ms);
}
.display.is-in::after {
  transform: translateX(-50%) scaleX(1);
}
.display--serif { font-family: var(--font-serif); }

.prose { color: var(--ink-2); }
.prose p + p { margin-top: .5em; }
.prose__strong { color: var(--ink); }

.section__index {
  font-size: var(--fs-xs);
  letter-spacing: var(--ls-mid);
  color: var(--ink-3);
  margin-bottom: var(--sp-4);
}
.section__lead {
  margin-top: var(--sp-4);
  color: var(--ink-2);
  font-size: var(--fs-lead);
  line-height: 1.95;
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 46px;
  padding: 0 1.6rem;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-size: var(--fs-sm);
  font-weight: 500;
  letter-spacing: .04em;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
  transition: background-color var(--dur-2) var(--ease),
              color var(--dur-2) var(--ease),
              border-color var(--dur-2) var(--ease),
              transform var(--dur-2) var(--ease),
              opacity var(--dur-2) var(--ease),
              box-shadow var(--dur-2) var(--ease);
}

/* Button ripple effect on hover */
.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.15);
  transform: translate(-50%, -50%);
  transition: width 0.6s ease, height 0.6s ease;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn--sm { height: 36px; padding: 0 1.1rem; font-size: var(--fs-xs); }
.btn--lg { height: 54px; padding: 0 2.4rem; font-size: var(--fs-body); }

.btn--solid { background: var(--ink); color: var(--paper); }
.btn--solid:hover {
  background: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(162, 85, 58, 0.25);
}
.btn--solid:active { transform: translateY(0); }

.btn--quiet {
  color: var(--ink-2);
  border-color: var(--line-2);
  position: relative;
}

.btn--quiet::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  right: 50%;
  height: 2px;
  background: var(--accent);
  transition: left var(--dur-2) var(--ease),
              right var(--dur-2) var(--ease);
}

.btn--quiet:hover {
  color: var(--ink);
  border-color: var(--ink);
}

.btn--quiet:hover::after {
  left: 20%;
  right: 20%;
}

/* CTA 内嵌箭头：hover 时滑入 */
.btn__arrow {
  width: 14px;
  height: 8px;
  margin-left: 0;
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity var(--dur-2) var(--ease),
              transform var(--dur-2) var(--ease),
              margin-left var(--dur-2) var(--ease);
}
.btn:hover .btn__arrow,
.btn:focus-visible .btn__arrow {
  opacity: 1;
  transform: translateX(0);
  margin-left: .55rem;
}

/* ---------- 标签 / 头像 ---------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  height: 26px;
  padding: 0 .625rem;
  border: 1px solid var(--line);
  border-radius: var(--r-pill);
  font-size: var(--fs-xs);
  color: var(--ink-2);
  letter-spacing: .02em;
}
.chip--place::before {
  content: ""; width: 4px; height: 4px; border-radius: 50%;
  background: var(--accent); opacity: .8;
}
.chip--note { color: var(--ink-3); }
.chip--link { color: var(--accent); border-color: var(--accent-line); }
.chip--link:hover { background: var(--accent-soft); }

.avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px; height: 30px;
  border-radius: 50%;
  border: 1px solid var(--line-2);
  background: var(--paper-2);
  font-size: var(--fs-xs);
  color: var(--ink-2);
  letter-spacing: 0;
}
.avatar--xs { width: 22px; height: 22px; font-size: var(--fs-micro); }
.avatar--me { background: var(--ink); color: var(--paper); border-color: var(--ink); }

/* ---------- 时间轴原子 ---------- */
.tl { position: relative; }
.tl__row {
  position: relative;
  display: grid;
  grid-template-columns: 4.5rem 1px 1fr;
  align-items: baseline;
  column-gap: 1.1rem;
  padding-block: .55rem;
}
.tl__time {
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  color: var(--ink-3);
  letter-spacing: .02em;
  font-variant-numeric: tabular-nums;
}
.tl__dot {
  position: relative;
  align-self: stretch;
  background: var(--line-2);
  transform-origin: top;
}
.tl__dot::after {
  content: "";
  position: absolute;
  top: .62em; left: 50%;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--paper);
  border: 1px solid var(--line-2);
  transform: translateX(-50%);
}
.tl__row:first-child .tl__dot::after { background: var(--accent); border-color: var(--accent); }
.tl__text { color: var(--ink); }

/* ---------- 占位图片 ---------- */
.ph {
  display: block;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: linear-gradient(135deg, var(--ph-a), var(--ph-b));
  position: relative;
}
.ph::after {
  content: "图片";
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-size: var(--fs-xs);
  letter-spacing: var(--ls-mid);
  color: var(--ink-3);
}

/* ---------- 页脚 ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding-block: var(--sp-5);
}
.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-3);
  font-size: var(--fs-xs);
  color: var(--ink-3);
}
.site-footer__brand { letter-spacing: var(--ls-mid); color: var(--ink-2); }
.site-footer__nav { display: flex; gap: 1.5rem; }
.site-footer__nav a:hover { color: var(--ink); }

/* Footer link underline animation */
.site-footer__nav a {
  position: relative;
  transition: color var(--dur-1) var(--ease);
}

.site-footer__nav a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-2) var(--ease);
}

.site-footer__nav a:hover::after {
  transform: scaleX(1);
}

/* ---------- 通用分隔线 ---------- */
.hairline { height: 1px; background: var(--line); border: 0; }

/* ---------- 页面加载动画 ---------- */
@keyframes page-load-fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

body {
  animation: page-load-fade-in 600ms ease-out;
}

/* ---------- 平滑滚动指示器 ---------- */
@keyframes scroll-indicator-bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(6px); }
}

.scroll-indicator {
  animation: scroll-indicator-bounce 2s ease-in-out infinite;
}

/* ---------- 脉冲动画（用于实时指示器等） ---------- */
@keyframes pulse-soft {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.7; transform: scale(1.05); }
}

.pulse-soft {
  animation: pulse-soft 2s ease-in-out infinite;
}

/* ---------- 渐变流动动画 ---------- */
@keyframes gradient-flow {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.gradient-animated {
  background-size: 200% 200%;
  animation: gradient-flow 8s ease infinite;
}

/* ---------- 视差效果辅助类 ---------- */
.parallax-slow {
  will-change: transform;
  transition: transform 0.1s linear;
}

.parallax-fast {
  will-change: transform;
  transition: transform 0.05s linear;
}

/* ---------- 主区块骨架 ---------- */
.section {
  padding-block: clamp(5rem, 12vw, 11rem);
  position: relative;
}

/* Section entrance animation */
.section[data-reveal-section] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur-4) var(--ease),
              transform var(--dur-4) var(--ease);
}

.section[data-reveal-section].is-in-view {
  opacity: 1;
  transform: translateY(0);
}

.section__head { margin-bottom: clamp(3rem, 7vw, 5.5rem); }

/* 时间刻度底纹：极轻，只作为背景存在 */
.time-rule {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(to right, var(--line) 0 1px, transparent 1px 72px),
    repeating-linear-gradient(to right, var(--line-2) 0 1px, transparent 1px 360px);
  opacity: .5;
  mask-image: linear-gradient(to bottom, transparent, #000 18%, #000 82%, transparent);
}

/* ---------- 入场动画（IntersectionObserver 加 .is-in） ---------- */
[data-reveal],
[data-stagger] > * {
  opacity: 0;
  transform: translateY(var(--reveal-y, 14px)) scale(var(--reveal-scale, 1));
  transform-origin: center;
  transition:
    opacity var(--reveal-dur, var(--dur-3)) var(--ease),
    transform var(--reveal-dur, var(--dur-3)) var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}
[data-reveal].is-in,
[data-stagger].is-in > * { opacity: 1; transform: translateY(0) scale(1); }

/* ---------- 尊重减少动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  [data-reveal], [data-stagger] > * { opacity: 1 !important; transform: none !important; }
}