/* ── tokens ── */
:root {
  --ink:        #1a1a18;
  --ink-mid:    #4a4a46;
  --ink-soft:   #8a8a84;
  --paper:      #f7f5f0;
  --paper-warm: #ede9e0;
  --moss:       #3d5a4c;
  --moss-light: #e8efe9;
  --clay:       #c4714a;
  --clay-light: #f5ece6;
  --sand:       #d4c9b0;
  --serif:      'DM Serif Display', Georgia, serif;
  --sans:       'DM Sans', system-ui, sans-serif;
  --max:        1120px;
  --prose:      680px;
  --ease-out:   cubic-bezier(0.16, 1, 0.3, 1);
}

/* ── reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  font-size: 16px;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }

/* ── nav ── */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 1.25rem 2.5rem;
  background: rgba(247, 245, 240, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--sand);
}
.nav-logo { font-family: var(--serif); font-size: 1.25rem; letter-spacing: -0.01em; }
.nav-links { display: flex; gap: 2rem; align-items: center; }
.nav-links a {
  font-size: 0.875rem; font-weight: 300;
  letter-spacing: 0.04em; color: var(--ink-mid);
  position: relative;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: -2px; left: 0; right: 0;
  height: 1px; background: var(--clay);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.3s var(--ease-out);
}
.nav-links a:hover::after, .nav-links a.active::after { transform: scaleX(1); }
.nav-back {
  font-size: 0.8125rem; color: var(--ink-soft);
  display: flex; align-items: center; gap: 0.4rem;
  transition: color 0.2s;
}
.nav-back:hover { color: var(--ink); }
.nav-back::after { display: none; }

/* ── buttons ── */
.btn-primary {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  background: var(--moss); color: var(--paper);
  font-family: var(--sans); font-size: 0.875rem;
  font-weight: 400; letter-spacing: 0.02em;
  border: none; border-radius: 2rem; cursor: pointer;
  transition: background 0.2s, transform 0.2s;
  text-decoration: none;
}
.btn-primary:hover { background: var(--ink); transform: translateY(-1px); }
.btn-ghost {
  font-size: 0.875rem; color: var(--ink-mid);
  text-decoration: underline; text-underline-offset: 4px;
  text-decoration-color: var(--sand);
}
.btn-ghost:hover { text-decoration-color: var(--clay); }

/* ── footer ── */
footer {
  border-top: 1px solid var(--paper-warm);
  padding: 2.5rem;
  display: flex; align-items: center; justify-content: space-between;
}
.footer-logo { font-family: var(--serif); font-size: 1.125rem; }
.footer-nav { display: flex; gap: 2rem; font-size: 0.8125rem; color: var(--ink-soft); }
.footer-nav a:hover { color: var(--ink); }

/* ── reveal ── */
.reveal { opacity: 0; transform: translateY(1.5rem); transition: opacity 0.65s var(--ease-out), transform 0.65s var(--ease-out); }
.reveal.visible { opacity: 1; transform: none; }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* ── reading progress bar ── */
.reading-progress { position: fixed; top: 0; left: 0; right: 0; z-index: 200; height: 2px; background: var(--sand); }
.reading-progress-fill { height: 100%; background: var(--clay); width: 0%; transition: width 0.1s linear; }

/* ── responsive ── */
@media (max-width: 600px) {
  nav { padding: 1rem 1.25rem; }
  footer { flex-direction: column; gap: 1.5rem; text-align: center; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}