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

:root {
  --bg: #fafafa;
  --fg: #1a1a1a;
  --muted: #737373;
  --border: #e5e5e5;
  --tag-bg: #f0f0f0;
  --mono: 'IBM Plex Mono', monospace;
  --sans: 'IBM Plex Sans', sans-serif;
}

.dark {
  --bg: #141414;
  --fg: #e5e5e5;
  --muted: #8a8a8a;
  --border: #2a2a2a;
  --tag-bg: #1e1e1e;
}

.dark ::selection {
  background: var(--fg);
  color: var(--bg);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: var(--fg);
  color: var(--bg);
}

.container {
  max-width: 780px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- HEADER --- */
header {
  padding: 80px 0 60px;
  border-bottom: 1px solid var(--border);
}

header h1 {
  font-family: var(--mono);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 24px;
}

header p.lead {
  font-size: 20px;
  line-height: 1.5;
  max-width: 620px;
  color: var(--fg);
}

header p.lead strong {
  font-weight: 600;
}

header p.sub {
  margin-top: 16px;
  font-size: 15px;
  color: var(--muted);
  max-width: 600px;
}

/* --- RULES --- */
.rules {
  padding: 40px 0;
  border-bottom: 1px solid var(--border);
}

.rules h2 {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 20px;
}

.rules-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.rule {
  font-size: 14px;
  color: var(--fg);
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 3px;
}

.rule span {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  margin-right: 8px;
}

/* --- PHASE HEADERS --- */
.phase-header {
  padding: 48px 0 32px;
  border-bottom: 1px solid var(--border);
}

.phase-label {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 8px;
}

.phase-header h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 12px;
}

.phase-header .phase-desc {
  font-size: 15px;
  color: var(--muted);
  max-width: 620px;
  line-height: 1.6;
  margin-bottom: 20px;
}

/* --- STACK TAGS --- */
.stack-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.stack-tag {
  font-family: var(--mono);
  font-size: 12px;
  padding: 4px 10px;
  background: var(--tag-bg);
  border-radius: 2px;
  color: var(--fg);
}

.stack-tag.new {
  border: 1px solid var(--fg);
  background: transparent;
}

/* --- PROJECTS --- */
.projects {
  padding: 20px 0 40px;
}

.project {
  padding: 48px 0;
  border-bottom: 1px solid var(--border);
}

.project:last-child {
  border-bottom: none;
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
  gap: 16px;
}

.project-num {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
  flex-shrink: 0;
  padding-top: 4px;
}

.project h3 {
  font-size: 20px;
  font-weight: 600;
  line-height: 1.3;
}

.project-desc {
  font-size: 15px;
  color: var(--fg);
  margin-bottom: 20px;
  max-width: 650px;
  line-height: 1.65;
}

.business-ctx {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 20px;
  max-width: 650px;
  line-height: 1.6;
  padding-left: 16px;
  border-left: 2px solid var(--border);
  font-style: italic;
}

.project-section {
  margin-bottom: 20px;
}

.project-section h4 {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 10px;
}

.project-section ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.project-section ul li {
  font-size: 14px;
  color: var(--fg);
  padding-left: 16px;
  position: relative;
  line-height: 1.55;
}

.project-section ul li::before {
  content: '-';
  position: absolute;
  left: 0;
  color: var(--muted);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin-top: 16px;
}

.project-tag {
  font-family: var(--mono);
  font-size: 11px;
  padding: 2px 8px;
  background: var(--tag-bg);
  border-radius: 2px;
  color: var(--muted);
}

.phases {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.phase {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 14px;
}

.phase-num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  flex-shrink: 0;
  min-width: 18px;
}

.phase-text {
  color: var(--fg);
}

.decisions {
  margin-top: 16px;
  padding: 16px 20px;
  border-left: 2px solid var(--border);
}

.decisions h4 {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 10px;
}

.decisions p {
  font-size: 13px;
  color: var(--muted);
  line-height: 1.6;
}

/* --- FOOTER --- */
footer {
  padding: 40px 0;
  border-top: 1px solid var(--border);
  text-align: center;
}

footer p {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--muted);
}

.progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: var(--fg);
  width: 0%;
  z-index: 100;
  transition: width 0.1s linear;
}

@media (max-width: 600px) {
  header {
    padding: 48px 0 40px;
  }
  header p.lead {
    font-size: 17px;
  }
  .rules-grid {
    grid-template-columns: 1fr;
  }
  .project h3 {
    font-size: 18px;
  }
  .project-header {
    flex-direction: column;
    gap: 4px;
  }
  .phase-header h2 {
    font-size: 20px;
  }
}