/* AI in Action — Shared Design System */
/* Fonts: JetBrains Mono (code/headings) + Source Serif 4 (prose) */

:root {
  --bg: #0c0e13;
  --surface: #151820;
  --surface-2: #1c2029;
  --border: #2a2e3a;
  --text: #e0e2e8;
  --text-dim: #7a7f8e;
  --accent: #6ee7b7;
  --accent-dim: rgba(110,231,183,0.12);
  --orange: #fb923c;
  --orange-dim: rgba(251,146,60,0.12);
  --blue: #60a5fa;
  --blue-dim: rgba(96,165,250,0.12);
  --red: #f87171;
  --purple: #c084fc;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Source Serif 4', Georgia, serif;
  line-height: 1.7;
  padding: 2rem;
  max-width: 920px;
  margin: 0 auto;
}

/* Typography */
h1 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.5px;
  margin-bottom: 0.25rem;
}

h2 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.05rem;
  color: var(--orange);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

h2 .num {
  color: var(--text-dim);
  font-weight: 400;
}

h3 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.92rem;
  color: var(--blue);
  margin: 1.5rem 0 0.5rem;
}

p { margin-bottom: 1rem; color: var(--text); }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

em { color: var(--text); font-style: italic; }
strong { color: var(--text); }

code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82em;
  background: var(--surface-2);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent);
}

.subtitle {
  color: var(--text-dim);
  font-size: 0.95rem;
  margin-bottom: 2.5rem;
  font-style: italic;
}

/* Lists */
ul, ol {
  margin: 0.5rem 0 1rem 1.5rem;
  color: var(--text-dim);
  font-size: 0.92rem;
}

li { margin-bottom: 0.3rem; }

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.88rem;
}

th {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--accent);
  text-align: left;
  padding: 0.6rem 0.8rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

td {
  padding: 0.5rem 0.8rem;
  border-bottom: 1px solid var(--border);
  color: var(--text-dim);
}

tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--surface); }

/* Diagram boxes */
.diagram-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 2rem;
  margin: 1.5rem 0;
  overflow-x: auto;
}

.diagram-box pre {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  line-height: 1.5;
  color: var(--text-dim);
  margin: 0;
}

.diagram-box .label { color: var(--accent); font-weight: 600; }
.diagram-box .highlight { color: var(--orange); }
.diagram-box .info { color: var(--blue); }
.diagram-box .dim { color: #4a4e5a; }

/* Code blocks */
.code-block {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.25rem;
  margin: 1rem 0;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  line-height: 1.65;
  overflow-x: auto;
  white-space: pre;
  color: var(--text-dim);
}

.code-block .kw { color: var(--purple); }
.code-block .fn { color: var(--blue); }
.code-block .str { color: var(--accent); }
.code-block .comment { color: #4a4e5a; font-style: italic; }
.code-block .key { color: var(--orange); }

/* Flow / loop steps */
.loop-container,
.flow-container {
  display: flex;
  flex-direction: column;
  gap: 0;
  align-items: center;
}

.loop-step,
.flow-step {
  display: flex;
  align-items: center;
  gap: 1rem;
  width: 100%;
  max-width: 680px;
}

.step-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--text-dim);
  width: 24px;
  text-align: right;
  flex-shrink: 0;
}

.step-box {
  flex: 1;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  line-height: 1.5;
  position: relative;
}

.step-box.user { background: var(--blue-dim); border-left: 3px solid var(--blue); }
.step-box.model { background: var(--accent-dim); border-left: 3px solid var(--accent); }
.step-box.code { background: var(--orange-dim); border-left: 3px solid var(--orange); }
.step-box.result { background: rgba(192,132,252,0.1); border-left: 3px solid var(--purple); }

.step-label {
  font-weight: 700;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 0.3rem;
}

.step-box.user .step-label { color: var(--blue); }
.step-box.model .step-label { color: var(--accent); }
.step-box.code .step-label { color: var(--orange); }
.step-box.result .step-label { color: var(--purple); }

.arrow-down {
  display: flex;
  justify-content: center;
  padding: 0.3rem 0;
  color: var(--text-dim);
  font-size: 1rem;
}

.loop-bracket {
  border: 1px dashed var(--text-dim);
  border-radius: 8px;
  padding: 0.8rem;
  margin: 0.5rem 0;
  width: 100%;
  max-width: 720px;
  position: relative;
}

.loop-label {
  position: absolute;
  top: -0.6rem;
  left: 1rem;
  background: var(--surface);
  padding: 0 0.5rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--red);
  font-weight: 600;
}

/* Pitfall cards */
.pitfall {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin: 0.75rem 0;
}

.pitfall-title {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--red);
  margin-bottom: 0.3rem;
}

.pitfall p { font-size: 0.9rem; margin-bottom: 0; color: var(--text-dim); }

/* Tags */
.tag {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.tag.critical { background: rgba(248,113,113,0.15); color: var(--red); }
.tag.important { background: var(--orange-dim); color: var(--orange); }
.tag.tip { background: var(--accent-dim); color: var(--accent); }

/* Exercises */
.exercise {
  background: var(--surface-2);
  border-left: 3px solid var(--blue);
  padding: 1rem 1.25rem;
  margin: 0.75rem 0;
  border-radius: 0 8px 8px 0;
}

.exercise-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--blue);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* Q&A */
.qa { margin: 0.75rem 0; }
.qa-q {
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.2rem;
}
.qa-hint { color: var(--text-dim); font-size: 0.88rem; font-style: italic; }

/* Concept cards (module 01) */
.concept-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin: 1rem 0;
}

.concept-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
}

.concept-card h4 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82rem;
  color: var(--orange);
  margin-bottom: 0.4rem;
}

.concept-card p {
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 0;
  line-height: 1.5;
}

/* Metric cards (module 02) */
.metric-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 1rem 0;
}

.metric-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
}

.metric-card h4 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.metric-card p {
  font-size: 0.82rem;
  color: var(--text-dim);
  margin: 0;
  font-family: 'JetBrains Mono', monospace;
  line-height: 1.5;
}

/* Quick reference box (module 01) */
.ref-box {
  background: var(--surface);
  border: 1px solid var(--accent);
  border-radius: 12px;
  padding: 1.5rem 2rem;
  margin: 1.5rem 0;
}

.ref-box h3 {
  color: var(--accent);
  margin-top: 0;
  margin-bottom: 1rem;
  font-size: 0.95rem;
}

.ref-row {
  display: flex;
  gap: 1rem;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  line-height: 1.5;
}

.ref-label {
  font-family: 'JetBrains Mono', monospace;
  color: var(--orange);
  font-weight: 600;
  min-width: 110px;
  font-size: 0.78rem;
}

.ref-value { color: var(--text-dim); }

/* Info box (module 03) */
.info-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  font-size: 0.9rem;
  color: var(--text-dim);
}

/* Advanced topic items (module 03) */
.adv-topic {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.8rem 1rem;
  margin: 0.5rem 0;
}

.adv-topic strong {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  color: var(--purple);
}

.adv-topic p { font-size: 0.88rem; margin-bottom: 0; color: var(--text-dim); }

/* Module cards (root index) */
.module-grid {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

.module-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  text-decoration: none;
  transition: border-color 0.2s, transform 0.2s;
}

.module-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  text-decoration: none;
}

.module-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.7rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 0.3rem;
}

.module-card h3 {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1rem;
  color: var(--accent);
  margin: 0 0 0.5rem;
}

.module-card p {
  font-size: 0.9rem;
  color: var(--text-dim);
  margin: 0;
  line-height: 1.5;
}

.module-tags {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.module-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.65rem;
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--surface-2);
  color: var(--text-dim);
}

/* Responsive */
@media (max-width: 640px) {
  body { padding: 1rem; }
  .concept-grid { grid-template-columns: 1fr; }
  .metric-grid { grid-template-columns: 1fr; }
}