/* ═══════════════════════════════════════════
   2025 年度回顾 — 共享样式
   ═══════════════════════════════════════════ */

:root {
  --bg: #f6f1eb;
  --bg-deep: #ede6dc;
  --text: #2c2825;
  --text-light: #6b6560;
  --text-lighter: #9a9490;
  --accent: #c45d3e;
  --accent-soft: #d4876f;
  --accent-bg: rgba(196, 93, 62, 0.06);
  --border: #d8d0c6;
  --border-light: #e6dfd6;
  --quote-bg: #f0e8de;
  --card-bg: #faf7f3;
  --shadow: rgba(44, 40, 37, 0.06);
  --font-serif: 'Noto Serif SC', 'Source Han Serif SC', 'Songti SC', serif;
  --font-display: 'Playfair Display', var(--font-serif);
}

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

html {
  font-size: 17px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-serif);
  line-height: 1.9;
  min-height: 100vh;
}

/* ── Noise texture overlay ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
}

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

/* ═══════════════════════════════════════════
   Navigation
   ═══════════════════════════════════════════ */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.8rem 2rem;
  background: rgba(246, 241, 235, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.site-nav.scrolled {
  box-shadow: 0 2px 20px var(--shadow);
}

.nav-home {
  font-weight: 600;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  color: var(--text);
  transition: color 0.2s;
}

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

.nav-links {
  display: flex;
  gap: 0.3rem;
}

.nav-links a {
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  padding: 0.35rem 0.9rem;
  border-radius: 2px;
  color: var(--text-light);
  transition: all 0.2s;
  position: relative;
}

.nav-links a:hover:not(.disabled) {
  color: var(--accent);
  background: var(--accent-bg);
}

.nav-links a.active {
  color: var(--accent);
  font-weight: 600;
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 1.5px;
  background: var(--accent);
  border-radius: 1px;
}

.nav-links a.disabled {
  color: var(--text-lighter);
  opacity: 0.5;
  cursor: default;
}

/* ═══════════════════════════════════════════
   Article Header
   ═══════════════════════════════════════════ */
.header {
  padding: 6rem 2rem 2rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 1px;
  background: var(--accent);
}

.header-label {
  font-family: var(--font-display);
  font-size: 0.75rem;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.2s forwards;
}

.header h1 {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(2.4rem, 6vw, 3.6rem);
  letter-spacing: 0.15em;
  color: var(--text);
  margin-bottom: 1rem;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.4s forwards;
}

.header-meta {
  font-size: 0.85rem;
  color: var(--text-lighter);
  letter-spacing: 0.05em;
  opacity: 0;
  animation: fadeUp 0.8s ease 0.6s forwards;
}

/* ═══════════════════════════════════════════
   Article Content
   ═══════════════════════════════════════════ */
.content {
  max-width: 680px;
  margin: 0 auto;
  padding: 3rem 2rem 6rem;
}

.content p {
  margin-bottom: 1.8rem;
  text-indent: 2em;
  text-align: justify;
  font-weight: 400;
}

.content p.no-indent { text-indent: 0; }

.content em {
  font-style: normal;
  color: var(--accent);
  font-weight: 500;
}

.content strong {
  font-weight: 600;
  color: var(--text);
}

/* ── Lead paragraph ── */
.lead {
  font-size: 1.1rem;
  color: var(--text-light);
  border-left: 2px solid var(--accent-soft);
  padding-left: 1.5rem;
  margin-bottom: 2.5rem !important;
  text-indent: 0 !important;
  line-height: 2;
}

/* ── Divider ── */
.divider {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin: 3rem 0;
}

.divider::before,
.divider::after {
  content: '';
  width: 40px;
  height: 1px;
  background: var(--border);
}

.divider-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent-soft);
}

/* ── Section title ── */
.section-title {
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text);
  margin-bottom: 1.8rem;
  text-align: center;
  letter-spacing: 0.08em;
}

/* ── Thesis card ── */
.thesis {
  background: var(--card-bg);
  border: 1px solid var(--border-light);
  border-radius: 2px;
  padding: 2rem 2.2rem;
  margin: 2.5rem 0;
  text-align: center;
  position: relative;
}

.thesis p {
  text-indent: 0 !important;
  margin-bottom: 0 !important;
  font-weight: 500;
  font-size: 1.05rem;
  line-height: 2;
  color: var(--text);
}

.thesis::before {
  content: '✦';
  position: absolute;
  top: -0.6rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--card-bg);
  padding: 0 0.8rem;
  color: var(--accent);
  font-size: 0.8rem;
}

/* ── Observation ── */
.observation {
  margin: 2.5rem 0;
  position: relative;
  padding-left: 2.8rem;
}

.observation-number {
  position: absolute;
  left: 0;
  top: 0.15rem;
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--accent);
  opacity: 0.35;
  line-height: 1;
}

.observation-title {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--accent);
  letter-spacing: 0.06em;
  margin-bottom: 0.8rem;
  display: block;
}

.observation p {
  text-indent: 0 !important;
  margin-bottom: 1rem !important;
}

/* ── Pull quote ── */
.pull-quote {
  margin: 3rem -1rem;
  padding: 2.2rem 2.5rem;
  background: var(--accent-bg);
  border-left: 3px solid var(--accent);
}

.pull-quote p {
  text-indent: 0 !important;
  margin-bottom: 0 !important;
  font-weight: 500;
  font-size: 1.02rem;
  line-height: 2;
  color: var(--text);
}

.pull-quote .attribution {
  display: block;
  margin-top: 1rem;
  font-size: 0.82rem;
  color: var(--text-lighter);
  font-weight: 400;
}

/* ── Product section ── */
.product-section { margin: 2rem 0; }

.product-name {
  display: inline-block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--accent);
  letter-spacing: 0.1em;
  border-bottom: 1px solid var(--accent-soft);
  padding-bottom: 2px;
  margin-bottom: 1rem;
}

.product-section p { text-indent: 0 !important; }

/* ── Closing ── */
.closing {
  text-align: center;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-light);
}

.closing p {
  text-indent: 0 !important;
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text-light);
  letter-spacing: 0.04em;
}

/* ── Transition ── */
.transition {
  text-align: center;
  font-style: italic;
  color: var(--text-light);
  margin: 2.5rem 0 !important;
  text-indent: 0 !important;
  font-size: 0.95rem;
}

/* ═══════════════════════════════════════════
   Page-End Navigation (prev / next)
   ═══════════════════════════════════════════ */
.page-nav {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 2rem 3rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.page-nav a {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  padding: 1.2rem 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--border-light);
  border-radius: 2px;
  transition: all 0.25s;
  flex: 1;
  max-width: 48%;
}

.page-nav a:hover:not(.disabled) {
  border-color: var(--accent-soft);
  box-shadow: 0 4px 16px var(--shadow);
  transform: translateY(-1px);
}

.page-nav a.disabled {
  opacity: 0.4;
  cursor: default;
  pointer-events: none;
}

.page-nav a.next { align-items: flex-end; text-align: right; margin-left: auto; }

.page-nav .nav-direction {
  font-size: 0.72rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-lighter);
}

.page-nav .nav-title {
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--text);
  letter-spacing: 0.04em;
}

.page-nav a:hover:not(.disabled) .nav-title { color: var(--accent); }

/* ═══════════════════════════════════════════
   Footer
   ═══════════════════════════════════════════ */
.footer {
  text-align: center;
  padding: 2rem;
  font-size: 0.75rem;
  color: var(--text-lighter);
  letter-spacing: 0.1em;
}

.footer-line {
  width: 30px;
  height: 1px;
  background: var(--border);
  margin: 0 auto 1rem;
}

/* ═══════════════════════════════════════════
   Animations
   ═══════════════════════════════════════════ */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ═══════════════════════════════════════════
   Responsive
   ═══════════════════════════════════════════ */
@media (max-width: 720px) {
  html { font-size: 15.5px; }
  .site-nav { padding: 0.7rem 1.2rem; }
  .nav-links a { padding: 0.3rem 0.6rem; font-size: 0.72rem; }
  .header { padding: 5rem 1.5rem 1.5rem; }
  .content { padding: 2rem 1.2rem 4rem; }
  .pull-quote { margin: 2rem -0.5rem; padding: 1.5rem 1.8rem; }
  .observation { padding-left: 2.2rem; }
  .page-nav { padding: 0 1.2rem 2rem; }
}

@media (max-width: 480px) {
  html { font-size: 15px; }
  .site-nav { padding: 0.6rem 1rem; }
  .nav-links a { padding: 0.25rem 0.45rem; font-size: 0.7rem; }
  .header { padding: 4rem 1rem 1.5rem; }
  .content { padding: 1.5rem 1rem 3rem; }
  .observation { padding-left: 0; padding-top: 2.2rem; }
  .observation-number { top: 0; left: 0; }
  .page-nav { flex-direction: column; padding: 0 1rem 2rem; }
  .page-nav a { max-width: 100%; }
  .page-nav a.next { align-items: flex-start; text-align: left; }
}

@media print {
  body::before { display: none; }
  .site-nav { display: none; }
  .header { padding: 2rem 0 1rem; }
  .content { max-width: 100%; padding: 1rem 0; }
  .animate-on-scroll { opacity: 1; transform: none; }
  .page-nav { display: none; }
}