/* ============ CSS Variables ============ */
:root {
  --color-bg: #faf8f5;
  --color-text: #2c2c2c;
  --color-accent: #3a5a6b;
  --color-accent-light: #4a7a8a;
  --color-muted: #7a7a7a;
  --color-border: #e0d8d0;
  --color-card-bg: #ffffff;
  --color-note-bg: #f0f5f8;
  --color-topbar-bg: #ffffff;
  --color-drawer-bg: #faf8f5;
  --color-shadow: rgba(0,0,0,0.08);

  --font-body: 'Georgia', 'Times New Roman', serif;
  --font-heading: -apple-system, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
  --font-size: 18px;
  --line-height: 1.85;

  --content-max-width: 720px;
  --topbar-height: 52px;
  --progress-height: 3px;
  --drawer-width: 300px;
}

html.dark {
  --color-bg: #1a1a1a;
  --color-text: #e0dcd8;
  --color-accent: #6eb5c9;
  --color-accent-light: #7ad4e8;
  --color-muted: #9a9a9a;
  --color-border: #3a3a3a;
  --color-card-bg: #242424;
  --color-note-bg: #1e2a2f;
  --color-topbar-bg: #222222;
  --color-drawer-bg: #1e1e1e;
  --color-shadow: rgba(0,0,0,0.3);
}

/* ============ Reset & Base ============ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: var(--font-size); scroll-behavior: smooth; }

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

/* ============ Top Navigation Bar ============ */
.topbar {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--topbar-height);
  background: var(--color-topbar-bg);
  border-bottom: 1px solid var(--color-border);
  display: flex; align-items: center; padding: 0 12px;
  z-index: 100;
  box-shadow: 0 1px 3px var(--color-shadow);
}
.topbar .title {
  flex: 1; text-align: center;
  font-family: var(--font-heading); font-size: 14px;
  color: var(--color-muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  padding: 0 8px;
}
.topbar button {
  background: none; border: none; font-size: 16px;
  color: var(--color-text); cursor: pointer;
  padding: 8px 10px; border-radius: 4px;
  min-width: 44px; min-height: 44px;
  display: flex; align-items: center; justify-content: center;
}
.topbar button:hover { background: var(--color-border); }
.topbar button:disabled { opacity: 0.3; cursor: not-allowed; }
.topbar .controls { display: flex; gap: 2px; }

/* ============ Progress Bar ============ */
.progress {
  position: fixed; top: var(--topbar-height); left: 0; right: 0;
  height: var(--progress-height);
  background: var(--color-border); z-index: 99;
}
.progress .bar {
  height: 100%; width: 0%;
  background: var(--color-accent);
  transition: width 0.1s linear;
}

/* ============ Sidebar Drawer ============ */
#drawer {
  position: fixed; top: 0; left: -100%;
  width: var(--drawer-width); height: 100vh;
  background: var(--color-drawer-bg); z-index: 200;
  overflow-y: auto; transition: left 0.3s ease;
  padding: 20px 0;
  box-shadow: 2px 0 8px var(--color-shadow);
}
#drawer.open { left: 0; }
#drawer-mask {
  display: none; position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0,0,0,0.4); z-index: 150;
}
#drawer-mask.show { display: block; }
.drawer-group { margin-bottom: 16px; }
.drawer-group h3 {
  font-family: var(--font-heading); font-size: 11px;
  color: var(--color-muted); text-transform: uppercase;
  letter-spacing: 1px; padding: 8px 20px; margin: 0;
}
.drawer-link {
  display: block; padding: 10px 20px;
  color: var(--color-text); text-decoration: none;
  font-size: 14px; line-height: 1.4;
  border-left: 3px solid transparent;
}
.drawer-link:hover { background: var(--color-border); }
.drawer-link.active {
  background: var(--color-note-bg);
  border-left-color: var(--color-accent);
  color: var(--color-accent); font-weight: 600;
}

/* ============ Main Content ============ */
.reader {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: calc(var(--topbar-height) + var(--progress-height) + 40px) 24px 60px;
}
.reader h1 {
  font-family: var(--font-heading); font-size: 1.8em;
  color: var(--color-text); margin-bottom: 20px; line-height: 1.3;
}
.reader h2 {
  font-family: var(--font-heading); font-size: 1.3em;
  color: var(--color-accent); margin: 2em 0 1em;
  padding-top: 0.5em;
  border-top: 1px solid var(--color-border); line-height: 1.4;
}
.eyebrow {
  font-family: var(--font-heading); font-size: 13px;
  color: var(--color-muted); margin-bottom: 8px; letter-spacing: 0.5px;
}
.lead {
  font-style: italic; color: var(--color-accent-light);
  border-left: 3px solid var(--color-accent);
  padding-left: 16px; margin-bottom: 32px; line-height: 1.7;
}
.reader p { margin-bottom: 1em; }
.reader p.center { text-align: center; color: var(--color-muted); }
.reader blockquote {
  border-left: 3px solid var(--color-accent);
  padding-left: 16px; margin: 1.5em 0;
  color: var(--color-muted); font-size: 0.95em;
}
.reader blockquote p { margin-bottom: 0.5em; }
.reader figure {
  margin: 2em 0; text-align: center;
}
.reader figure img {
  max-width: 100%; height: auto;
  border: 1px solid var(--color-border); border-radius: 4px;
}
.reader figure figcaption {
  font-size: 0.85em; color: var(--color-muted);
  margin-top: 8px; font-style: italic;
}
.note-box {
  background: var(--color-note-bg);
  border-left: 4px solid var(--color-accent);
  padding: 16px 20px; margin: 1.5em 0;
  border-radius: 0 4px 4px 0;
}
.note-box p { margin-bottom: 0.5em; }
.note-box p:last-child { margin-bottom: 0; }

/* ============ Index Page ============ */
.index-page .cover {
  text-align: center; padding: 40px 0 30px;
  border-bottom: 1px solid var(--color-border); margin-bottom: 30px;
}
.index-page .cover h1 { font-size: 2.4em; margin-bottom: 12px; }
.index-page .cover .subtitle {
  font-size: 16px; color: var(--color-accent); margin-bottom: 8px;
}
.index-page .cover .author {
  font-size: 15px; color: var(--color-muted); margin-bottom: 4px;
}
.index-page .cover .translator {
  font-size: 13px; color: var(--color-muted);
}
.index-page .intro { margin-bottom: 30px; }
.index-page .intro p { color: var(--color-muted); margin-bottom: 1em; }

.part-divider {
  text-align: center; margin: 24px 0 8px;
  font-family: var(--font-heading); font-size: 13px;
  color: var(--color-accent); letter-spacing: 0.5px;
}
.part-divider span {
  background: var(--color-bg); padding: 0 12px;
  position: relative;
}
.part-divider::before {
  content: ''; position: absolute; left: 0; right: 0;
  top: 50%; height: 1px; background: var(--color-border);
}
.part-divider { position: relative; }

.card-list { display: grid; grid-template-columns: 1fr; gap: 16px; }
.card {
  display: block; background: var(--color-card-bg);
  border: 1px solid var(--color-border); border-radius: 8px;
  padding: 20px; text-decoration: none; color: var(--color-text);
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover {
  box-shadow: 0 4px 12px var(--color-shadow);
  transform: translateY(-2px);
}
.card .card-label {
  font-family: var(--font-heading); font-size: 12px;
  color: var(--color-accent); text-transform: uppercase;
  letter-spacing: 1px; display: block; margin-bottom: 6px;
}
.card h3 {
  font-family: var(--font-heading); font-size: 1.1em;
  margin-bottom: 8px; line-height: 1.3;
}
.card .card-quote {
  font-size: 14px; font-style: italic;
  color: var(--color-accent-light); line-height: 1.5;
}

/* ============ Bottom Navigation ============ */
.nav-foot {
  display: flex; justify-content: space-between; align-items: center;
  max-width: var(--content-max-width);
  margin: 40px auto 0; padding: 20px 24px 40px;
  border-top: 1px solid var(--color-border);
}
.nav-foot a, .nav-foot span {
  font-family: var(--font-heading); font-size: 14px;
  color: var(--color-accent); text-decoration: none; min-width: 80px;
}
.nav-foot a:hover { text-decoration: underline; }
.nav-foot .prev { text-align: left; }
.nav-foot .center { text-align: center; color: var(--color-muted); }
.nav-foot .next { text-align: right; }

/* ============ Responsive ============ */
@media (max-width: 767px) {
  :root { --font-size: 16px; --drawer-width: 80vw; }
  .topbar .title { font-size: 12px; }
  .topbar button { padding: 6px 8px; font-size: 14px; }
  .reader { padding-left: 16px; padding-right: 16px; }
  .reader h1 { font-size: 1.5em; }
  .index-page .cover h1 { font-size: 1.8em; }
  .nav-foot { padding: 16px 16px 32px; }
  .nav-foot a, .nav-foot span { font-size: 13px; min-width: 60px; }
}
@media (max-width: 374px) {
  .topbar .controls { gap: 0; }
  .topbar button { min-width: 36px; padding: 6px 4px; }
}