/* ─── Reset & base ─────────────────────────────────────────────────────────── */

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

:root {
  --sidebar-width: 260px;
  --progress-h: 3px;
  --orange-bg: #fff7ed;
  --orange-border: #f97316;
  --orange-text: #7c2d12;
  --code-bg: #0f172a;
  --code-text: #e2e8f0;
  --accent: #2563eb;
  --accent-light: #eff6ff;
  --border: #e5e7eb;
  --text: #111827;
  --muted: #6b7280;
  --radius: 6px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, Monaco, Consolas, monospace;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 32px;
}

body {
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: #fff;
}

/* ─── Progress bar ──────────────────────────────────────────────────────────── */

#progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: var(--progress-h);
  width: 0%;
  background: var(--accent);
  z-index: 1000;
  transition: width 0.1s linear;
}

/* ─── Sidebar ───────────────────────────────────────────────────────────────── */

#sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  overflow-y: auto;
  background: #fafafa;
  border-right: 1px solid var(--border);
  padding: 24px 0 40px;
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 0;
}

#sidebar-header {
  padding: 0 20px 20px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 12px;
}

#site-title {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
}

#total-time {
  font-size: 11px;
  color: var(--muted);
  margin-top: 2px;
}

#nav-list {
  list-style: none;
  padding: 0;
}

#nav-list li a {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 20px;
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.4;
  border-left: 3px solid transparent;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}

#nav-list li a:hover {
  color: var(--text);
  background: #f0f0f0;
}

#nav-list li a.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: var(--accent-light);
  font-weight: 500;
}

.nav-title {
  flex: 1;
}

.nav-time {
  font-size: 11px;
  color: var(--muted);
  white-space: nowrap;
  background: #e5e7eb;
  padding: 1px 6px;
  border-radius: 20px;
  flex-shrink: 0;
}

#nav-list li a.active .nav-time {
  background: #bfdbfe;
  color: #1d4ed8;
}

/* ─── Hamburger ─────────────────────────────────────────────────────────────── */

#hamburger {
  display: none;
  position: fixed;
  top: 14px;
  left: 14px;
  z-index: 300;
  width: 36px;
  height: 36px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  padding: 6px;
}

#hamburger span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
}

#hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
#hamburger.open span:nth-child(2) { opacity: 0; }
#hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ─── Main content ──────────────────────────────────────────────────────────── */

#content {
  margin-left: var(--sidebar-width);
  max-width: 780px;
  padding: 60px 56px 120px;
}

/* ─── Sections ──────────────────────────────────────────────────────────────── */

.section-block {
  padding-bottom: 64px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 64px;
}

.section-block:last-child {
  border-bottom: none;
}

/* ─── Typography ────────────────────────────────────────────────────────────── */

.section-block h1 {
  font-size: 28px;
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 24px;
  color: var(--text);
}

.section-block h2 {
  font-size: 20px;
  font-weight: 600;
  margin-top: 40px;
  margin-bottom: 12px;
  color: var(--text);
}

.section-block h3 {
  font-size: 17px;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 10px;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.section-block h4 {
  font-size: 15px;
  font-weight: 600;
  margin-top: 24px;
  margin-bottom: 8px;
}

.section-block p {
  margin-bottom: 14px;
}

.section-block ul,
.section-block ol {
  margin: 0 0 14px 20px;
}

.section-block li {
  margin-bottom: 4px;
}

.section-block a {
  color: var(--accent);
  text-decoration: none;
}

.section-block a:hover {
  text-decoration: underline;
}

.section-block code {
  font-family: var(--mono);
  font-size: 0.875em;
  background: #f1f5f9;
  padding: 1px 5px;
  border-radius: 3px;
  border: 1px solid #e2e8f0;
}

.section-block pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 14px;
  line-height: 1.6;
  margin-bottom: 16px;
}

.section-block pre code {
  background: none;
  padding: 0;
  border: none;
  color: inherit;
  font-size: inherit;
}

.section-block blockquote {
  border-left: 3px solid var(--border);
  padding-left: 16px;
  color: var(--muted);
  margin: 16px 0;
}

.section-block hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 32px 0;
}

/* ─── Section header with time badge ───────────────────────────────────────── */

.section-header {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.section-header h1 {
  margin-bottom: 0;
  flex: 1;
}

.time-badge {
  display: inline-flex;
  align-items: center;
  background: #f1f5f9;
  color: var(--muted);
  font-size: 12px;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 20px;
  white-space: nowrap;
  margin-top: 6px;
  border: 1px solid var(--border);
}

/* ─── Context blocks ────────────────────────────────────────────────────────── */

.block-context {
  background: var(--orange-bg);
  border-left: 3px solid var(--orange-border);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 14px 18px;
  margin: 20px 0;
}

.block-context-title {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--orange-border);
  margin-bottom: 8px;
}

.block-context p:last-child,
.block-context ul:last-child,
.block-context ol:last-child {
  margin-bottom: 0;
}

/* ─── Prompt blocks ─────────────────────────────────────────────────────────── */

.block-prompt {
  position: relative;
  background: var(--code-bg);
  border-radius: var(--radius);
  margin: 20px 0;
}

.block-prompt pre {
  background: none;
  margin: 0;
  padding: 16px 48px 16px 18px;
  white-space: pre-wrap;
  word-break: break-word;
}

.block-prompt .copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: rgba(255,255,255,0.08);
  color: #94a3b8;
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 4px;
  padding: 3px 8px;
  font-size: 11px;
  font-family: var(--font);
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  letter-spacing: 0.03em;
}

.block-prompt .copy-btn:hover {
  background: rgba(255,255,255,0.14);
  color: #e2e8f0;
}

.block-prompt .copy-btn.copied {
  color: #4ade80;
  border-color: rgba(74,222,128,0.3);
}

/* ─── Aside blocks ──────────────────────────────────────────────────────────── */

.block-aside {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 20px 0;
  overflow: hidden;
}

.block-aside summary {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  cursor: pointer;
  font-weight: 500;
  font-size: 14px;
  background: #f8fafc;
  user-select: none;
  list-style: none;
}

.block-aside summary::-webkit-details-marker { display: none; }

.block-aside summary::before {
  content: "▶";
  font-size: 10px;
  color: var(--muted);
  transition: transform 0.2s;
  flex-shrink: 0;
}

.block-aside[open] summary::before {
  transform: rotate(90deg);
}

.block-aside .aside-body {
  padding: 14px 16px;
  border-top: 1px solid var(--border);
  font-size: 14px;
}

.block-aside .aside-body p:last-child,
.block-aside .aside-body ul:last-child {
  margin-bottom: 0;
}

/* ─── Tab blocks ────────────────────────────────────────────────────────────── */

.block-tabs {
  margin: 20px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.tab-bar {
  display: flex;
  background: #f8fafc;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
}

.tab-btn {
  padding: 8px 16px;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  font-size: 13px;
  font-family: var(--font);
  font-weight: 500;
  color: var(--muted);
  white-space: nowrap;
  transition: color 0.15s, border-color 0.15s;
  margin-bottom: -1px;
}

.tab-btn:hover {
  color: var(--text);
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  background: #fff;
}

.tab-panel {
  display: none;
  padding: 16px 20px;
}

.tab-panel.active {
  display: block;
}

.tab-panel p:last-child,
.tab-panel ul:last-child,
.tab-panel ol:last-child {
  margin-bottom: 0;
}

/* ─── Definition tooltips ──────────────────────────────────────────────────── */

.def {
  border-bottom: 1px dotted var(--muted);
  cursor: help;
}

.def sup {
  font-size: 10px;
  color: var(--muted);
  margin-left: 1px;
}

/* ─── Time block (inline, handled by section header) ───────────────────────── */

.block-time {
  display: none; /* time is shown in the section header; suppress inline */
}

/* ─── Responsive ────────────────────────────────────────────────────────────── */

@media (max-width: 768px) {
  #hamburger {
    display: flex;
  }

  #sidebar {
    transform: translateX(-100%);
    transition: transform 0.25s ease;
  }

  #sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 20px rgba(0,0,0,0.12);
  }

  #content {
    margin-left: 0;
    padding: 60px 20px 80px;
  }
}

@media (max-width: 480px) {
  #content {
    padding: 56px 16px 80px;
  }

  .section-block h1 {
    font-size: 22px;
  }

  .tab-btn {
    padding: 8px 12px;
    font-size: 12px;
  }
}