@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  --blue: #1496ff;
  --blue-hover: #0077e6;
  --navy: #000f2e;
  --navy-light: #1a2744;
  --text: #212121;
  --text-secondary: #525252;
  --text-muted: #6b7280;
  --border: #e5e6e8;
  --border-light: #f0f1f3;
  --bg-subtle: #f7f8fa;
  --bg-code: #f0f4f8;
  --gold: #e6a800;
  --gold-bg: #fef9ec;
}

@media screen {
  html {
    background: #0b0f1a;
  }
  body {
    background: #ffffff;
    max-width: 52em;
    margin: 3em auto;
    padding: 2.8em 3.5em;
    box-shadow:
      0 1px 3px rgba(0, 15, 46, 0.06),
      0 8px 24px rgba(0, 15, 46, 0.1),
      0 24px 60px rgba(0, 15, 46, 0.12);
    position: relative;
    border-top: 3px solid var(--blue);
    border-radius: 0 0 4px 4px;
  }
}

body {
  font: 13pt/1.65 'Inter', 'Helvetica Neue', Arial, sans-serif;
  color: var(--text);
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1 {
  font: 2.1em/1.15 'Inter', sans-serif;
  font-weight: 300;
  text-align: center;
  margin: 0 0 0.1em;
  letter-spacing: -0.02em;
  color: var(--navy);
}

.subtitle {
  text-align: center;
  color: var(--text-muted);
  margin: 0 0 2.2em;
  font-size: 0.88em;
  font-weight: 400;
  letter-spacing: 0.03em;
}

.ill {
  display: block;
  margin: 2.5em auto 1.8em;
  width: 85%;
  height: auto;
}

/* ——— Links ——— */
a {
  color: var(--blue);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--blue-hover);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ——— Inline code ——— */
code {
  font-family: 'JetBrains Mono', 'SF Mono', 'Cascadia Code', 'Consolas', monospace;
  font-size: 0.82em;
  font-weight: 400;
  background: var(--bg-code);
  color: var(--navy-light);
  padding: 0.15em 0.45em;
  border-radius: 4px;
  border: 1px solid var(--border);
  white-space: nowrap;
  letter-spacing: -0.01em;
  vertical-align: baseline;
}

/* ——— TOC ——— */
.toc {
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 1.2em 0;
  margin-bottom: 2.2em;
}

.toc-label {
  font-weight: 600;
  letter-spacing: 0.08em;
  font-size: 0.72em;
  text-transform: uppercase;
  margin-bottom: 0.8em;
  color: var(--blue);
}

.toc ol {
  list-style: none;
  padding: 0;
  margin: 0;
  columns: 2;
  column-gap: 2.5em;
  column-rule: 1px solid var(--border-light);
}

.toc li {
  break-inside: avoid;
  padding: 0.18em 0;
}

.toc a {
  color: var(--text);
  text-decoration: none;
  font-size: 0.88em;
  transition: color 0.15s ease;
}

.toc a:hover {
  color: var(--blue);
  text-decoration: none;
}

.toc .num {
  display: inline-block;
  width: 1.8em;
  text-align: right;
  margin-right: 0.5em;
  color: var(--blue);
  font-size: 0.82em;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

/* ——— Phase headings ——— */
.phase {
  font-weight: 600;
  letter-spacing: 0.1em;
  font-size: 0.8em;
  text-transform: uppercase;
  color: var(--blue);
  text-align: center;
  margin: 3.5em 0 1.5em;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.7em;
}

/* ——— Concept entries ——— */
.entry {
  margin-bottom: 2em;
  scroll-margin-top: 1em;
}

.entry-head {
  font-weight: 700;
  font-size: 1.08em;
  margin-bottom: 0.25em;
  color: var(--navy);
  letter-spacing: -0.005em;
}

.entry-num {
  color: var(--blue);
  font-weight: 600;
  font-size: 0.88em;
  margin-right: 0.3em;
  font-variant-numeric: tabular-nums;
}

.entry p {
  margin: 0.5em 0 0;
  text-indent: 0;
}

/* ——— Term highlights ——— */
.term {
  font-weight: 600;
  color: var(--navy);
}

.it {
  font-style: italic;
}

/* ——— Code / example blocks ——— */
.ex {
  font-family: 'JetBrains Mono', 'SF Mono', 'Cascadia Code', 'Consolas', monospace;
  font-size: 0.76em;
  line-height: 1.7;
  background: var(--bg-subtle);
  border-left: 3px solid var(--blue);
  padding: 1em 1.2em;
  margin: 0.8em 0;
  white-space: pre;
  overflow-x: auto;
  color: var(--navy-light);
  border-radius: 0 6px 6px 0;
}

/* ——— Definition pairs ——— */
.defs {
  margin: 1.2em 0;
  padding: 0;
  display: grid;
  grid-template-columns: 9em 1fr;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.defs dt {
  font-weight: 600;
  padding: 0.4em 0.6em 0.4em 0;
  border-bottom: 1px solid var(--border-light);
  color: var(--navy);
  font-size: 0.9em;
}

.defs dd {
  margin: 0;
  padding: 0.4em 0 0.4em 0.6em;
  border-bottom: 1px solid var(--border-light);
  font-size: 0.93em;
  color: var(--text-secondary);
}

.defs dt:nth-of-type(even),
.defs dd:nth-of-type(even) {
  background: var(--bg-subtle);
}

.defs dt:last-of-type,
.defs dd:last-of-type {
  border-bottom: none;
}

/* ——— Note callouts ——— */
.note {
  font-size: 0.86em;
  color: var(--text-secondary);
  margin: 1em 0;
  text-indent: 0 !important;
  padding: 0.7em 1em 0.7em 1em;
  border-left: 3px solid var(--gold);
  background: var(--gold-bg);
  border-radius: 0 6px 6px 0;
  line-height: 1.55;
}

.note a {
  color: var(--blue);
}

/* ——— Screenshots ——— */
.screenshot {
  display: block;
  max-width: 100%;
  margin: 1.8em auto;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow:
    0 1px 3px rgba(0, 15, 46, 0.04),
    0 4px 16px rgba(0, 15, 46, 0.06);
  transition: box-shadow 0.2s ease;
}

.screenshot:hover {
  box-shadow:
    0 2px 6px rgba(0, 15, 46, 0.06),
    0 8px 24px rgba(0, 15, 46, 0.1);
}

/* ——— Footer ——— */
footer {
  border-top: 1px solid var(--border);
  margin-top: 3.5em;
  padding-top: 1em;
  text-align: center;
  font-size: 0.76em;
  color: #adadad;
  letter-spacing: 0.01em;
}

footer a {
  color: var(--text-muted);
  text-decoration: none;
}

footer a:hover {
  color: var(--blue);
}

/* ——— Download link ——— */
.download-pptx {
  position: absolute;
  top: 1.8em;
  right: 2.2em;
  transition: opacity 0.15s ease, transform 0.15s ease;
  opacity: 0.55;
}

.download-pptx:hover {
  opacity: 1;
  transform: scale(1.08);
  text-decoration: none;
}

.download-pptx img {
  width: 36px !important;
  height: 36px !important;
  max-width: 36px;
  display: block;
}

/* ——— Selection ——— */
::selection {
  background: rgba(20, 150, 255, 0.15);
}

/* ——— Responsive ——— */
@media (max-width: 700px) {
  body {
    padding: 1.5em 1.2em;
    font-size: 12pt;
    margin: 0;
    border-radius: 0;
    box-shadow: none;
  }
  .toc ol { columns: 1; }
  .defs { grid-template-columns: 1fr; }
  .defs dt { float: none; width: auto; }
  .defs dd { margin-left: 0; }
  .ill { width: 100%; }
  code { white-space: normal; }
}

@media (max-width: 700px) {
  html { background: #fff; }
  body { border-top-width: 2px; }
}