/* ============================================================
   W Eiji 論 — Plain Document + Sidebar
   ============================================================ */

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

:root {
  --sidebar-w: 260px;
  --fg: #1a1a1a;
  --fg2: #555;
  --fg3: #888;
  --fg4: #aaa;
  --link: #0066cc;
  --coral: #e07050;
  --accent-border: #999;
  --bg: #fff;
  --bg2: #f7f7f7;
  --border: #e5e5e5;
  --border2: #eee;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  --font-serif: Georgia, "Hiragino Mincho ProN", "Yu Mincho", serif;
  --mono: "SF Mono", "Consolas", "Liberation Mono", monospace;
}

html { font-size: 19px; }

body {
  font-family: var(--font);
  color: var(--fg);
  background: var(--bg);
  line-height: 1.7;
  display: flex;
  min-height: 100vh;
}


/* ============================================================
   SIDEBAR
   ============================================================ */

.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: #3d9dc2;
  border-right: none;
  height: 100vh;
  position: sticky;
  top: 0;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding: 20px 16px 16px;
  background: var(--coral);
  border-bottom: none;
}

.sidebar-title {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  text-decoration: none;
  letter-spacing: -0.01em;
}

.sidebar-body {
  padding: 12px 0;
  flex: 1;
  overflow-y: auto;
}

.nav-section {
  margin-bottom: 8px;
}

.nav-heading {
  font-size: 15px;
  font-weight: 700;
  color: #fff;
  padding: 8px 16px 4px;
  letter-spacing: 0.01em;
}

.nav-list {
  list-style: none;
}

.nav-group-label {
  font-size: 12px;
  font-weight: 600;
  color: rgba(255,255,255,0.6);
  padding: 8px 16px 2px;
  letter-spacing: 0.02em;
}

.nav-list a {
  display: block;
  font-size: 15px;
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  padding: 4px 16px;
  line-height: 1.5;
  transition: background 0.15s, color 0.15s;
}

.nav-list a:hover {
  background: rgba(255,255,255,0.1);
  color: #fff;
}

.nav-list a.active {
  background: rgba(255,255,255,0.15);
  color: #fff;
  font-weight: 600;
}

.tag {
  font-size: 11px;
  color: rgba(255,255,255,0.5);
  font-family: var(--mono);
  font-weight: 400;
}


/* ============================================================
   MAIN CONTENT
   ============================================================ */

.content {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.content-body {
  max-width: 860px;
  padding: 40px 40px 60px;
  flex: 1;
}

.content-body h1 {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 4px;
}

.lead {
  font-size: 18px;
  color: var(--fg2);
  margin: 0 0 28px;
}

.abstract {
  border-left: 3px solid var(--accent-border);
  padding-left: 16px;
  margin-bottom: 32px;
}

.abstract p {
  font-size: 18px;
  color: var(--fg2);
  margin-bottom: 8px;
  line-height: 1.8;
}

.abstract p:last-child { margin-bottom: 0; }

.content-body h2 {
  font-size: 21px;
  font-weight: 700;
  margin: 32px 0 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--accent-border);
  display: inline-block;
}

.structure {
  margin: 0;
}

.structure dt {
  font-size: 18px;
  font-weight: 700;
  margin-top: 16px;
  color: var(--fg);
}

.structure dd {
  font-size: 17px;
  color: var(--fg2);
  margin: 4px 0 0;
  line-height: 1.8;
}

.vis-list {
  list-style: none;
  margin: 8px 0 0;
}

.vis-list li {
  border-bottom: 1px solid var(--border2);
}

.vis-list a {
  display: block;
  font-size: 15px;
  color: var(--link);
  text-decoration: none;
  padding: 6px 0;
}

.vis-list a:hover { text-decoration: underline; }

.vis-list {
  list-style: none;
  margin: 8px 0 0;
}

.vis-list li {
  border-bottom: 1px solid var(--border2);
}

.vis-list a {
  display: block;
  font-size: 13.5px;
  color: var(--link);
  text-decoration: none;
  padding: 6px 0;
}

.vis-list a:hover { text-decoration: underline; }

.content-footer {
  padding: 24px 40px;
  border-top: 1px solid var(--border2);
  font-size: 13px;
  color: var(--fg3);
}


/* ============================================================
   READER PAGE (chapter content)
   ============================================================ */

.reader-page {
  display: flex;
  min-height: 100vh;
}

.reader-header {
  padding: 20px 40px 0;
  max-width: 860px;
}

.reader-back {
  font-size: 14px;
  color: var(--link);
  text-decoration: none;
}

.reader-back:hover { text-decoration: underline; }

.reader-content {
  max-width: 860px;
  padding: 16px 40px 60px;
}

.reader-content h1 {
  font-size: 30px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 24px 0 8px;
  line-height: 1.4;
}

.reader-content h2 {
  font-size: 23px;
  font-weight: 700;
  margin: 32px 0 8px;
  padding-top: 16px;
  border-top: 2px solid var(--accent-border);
}

.reader-content h3 {
  font-size: 19px;
  font-weight: 700;
  margin: 24px 0 6px;
}

.reader-content h4 {
  font-size: 18px;
  font-weight: 700;
  margin: 16px 0 4px;
}

.reader-content p {
  font-size: 18px;
  margin-bottom: 12px;
  line-height: 1.8;
}

.reader-content blockquote {
  border-left: 3px solid var(--accent-border);
  padding: 8px 16px;
  margin: 16px 0;
  color: var(--fg2);
  font-style: italic;
}

.reader-content blockquote p {
  margin-bottom: 6px;
}

.reader-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 16px;
}

.reader-content th,
.reader-content td {
  padding: 6px 10px;
  border-bottom: 1px solid var(--border2);
  text-align: left;
  vertical-align: top;
}

.reader-content th {
  font-size: 14px;
  font-weight: 600;
  color: var(--fg2);
  border-bottom-color: var(--border);
}

.reader-content pre {
  background: var(--bg2);
  padding: 12px 16px;
  margin: 16px 0;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.5;
  border-radius: 4px;
  border: 1px solid var(--border2);
}

.reader-content code {
  font-family: var(--mono);
  font-size: 0.9em;
  background: var(--bg2);
  padding: 1px 4px;
  border-radius: 3px;
}

.reader-content pre code {
  background: none;
  padding: 0;
}

.reader-content hr {
  border: none;
  border-top: 1px solid var(--border2);
  margin: 28px 0;
}

.reader-content strong { font-weight: 700; }

.reader-content ul,
.reader-content ol {
  margin: 8px 0 12px 20px;
  font-size: 18px;
}

.reader-content li {
  margin-bottom: 4px;
  line-height: 1.7;
}

.reader-content img {
  max-width: 100%;
  height: auto;
  margin: 16px 0;
}

.reader-content a {
  color: var(--link);
  text-decoration: none;
}

.reader-content a:hover {
  text-decoration: underline;
}


/* ============================================================
   MOBILE: sidebar → hamburger overlay
   ============================================================ */

.sidebar-toggle {
  display: none;
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 6px 10px;
  font-size: 16px;
  cursor: pointer;
  color: var(--fg);
}

@media (max-width: 800px) {
  .sidebar {
    position: fixed;
    left: 0; top: 0; bottom: 0;
    z-index: 999;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    box-shadow: none;
  }

  .sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 20px rgba(0,0,0,0.08);
  }

  .sidebar-toggle { display: block; }

  .content-body,
  .reader-content,
  .reader-header {
    padding-left: 20px;
    padding-right: 20px;
  }

  .content-body { padding-top: 56px; }
  .reader-header { padding-top: 56px; }
}