:root {
  --bg: #f4f1ea;
  --surface: #fbf9f5;
  --ink: #181a19;
  --ink-muted: #525754;
  --border: #d5cfc3;
  --accent: #c84b28;
  --accent-dark: #9e371a;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  --max-width: 1080px;
  --radius: 4px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background-color: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

main {
  flex: 1;
}

h1, h2, h3, p, ul, ol, dl, figure {
  margin-top: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: 1.5rem;
}

/* Header & Navigation */
.site-header {
  border-bottom: 1px solid var(--border);
  background-color: var(--surface);
}

.header-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-block: 1.15rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-size: 1.05rem;
}

.brand-mark {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background-color: var(--accent);
  box-shadow: 0 0 0 3px var(--surface), 0 0 0 4.5px var(--ink);
}

.nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--ink-muted);
  padding-block: 0.25rem;
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--ink);
}

.nav-link.active {
  color: var(--ink);
  font-weight: 600;
  border-bottom-color: var(--accent);
}

/* Typography & Shared Sections */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

h1 {
  font-size: clamp(2.1rem, 4.5vw, 3.35rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
}

h2 {
  font-size: clamp(1.45rem, 2.6vw, 1.95rem);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

h3 {
  font-size: 1.2rem;
  line-height: 1.3;
  margin-bottom: 0.6rem;
}

.lead {
  font-size: 1.15rem;
  color: var(--ink-muted);
  max-width: 62ch;
  margin-bottom: 1.75rem;
}

.page-header {
  padding-block: 4rem 2.5rem;
  border-bottom: 1px solid var(--border);
}

.section-block {
  padding-block: 4rem;
}

.section-header {
  margin-bottom: 2.25rem;
}

.section-header p {
  color: var(--ink-muted);
  margin-bottom: 0;
}

/* Buttons */
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.35rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--ink);
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.btn-primary {
  background-color: var(--ink);
  color: var(--surface);
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background-color: var(--accent);
  border-color: var(--accent);
}

.btn-secondary {
  background-color: transparent;
  color: var(--ink);
}

.btn-secondary:hover,
.btn-secondary:focus-visible {
  background-color: var(--surface);
}

/* Home Hero */
.hero {
  padding-block: 4.5rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.85fr;
  gap: 3rem;
  align-items: center;
}

.wave-diagram {
  width: 100%;
  max-width: 360px;
  display: block;
  margin-inline: auto;
}

/* Metrics Band */
.metrics-band {
  background-color: var(--surface);
  border-block: 1px solid var(--border);
  padding-block: 2.5rem;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.metric-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.1;
  margin-bottom: 0.4rem;
}

.metric-label {
  font-size: 0.92rem;
  color: var(--ink-muted);
}

/* Cards */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
}

.card-index {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
  margin-bottom: 1rem;
}

.card p {
  color: var(--ink-muted);
  margin-bottom: 0;
  font-size: 0.96rem;
}

/* Callout */
.callout-box {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius);
  padding: 2.25rem;
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 2rem;
  align-items: center;
}

.callout-box p {
  margin-bottom: 0.4rem;
  color: var(--ink-muted);
}

.contact-details p {
  color: var(--ink);
  font-size: 0.95rem;
}

/* Projects Page */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 2.25rem;
}

.filter-btn {
  appearance: none;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-muted);
  cursor: pointer;
}

.filter-btn:hover,
.filter-btn:focus-visible {
  border-color: var(--ink);
  color: var(--ink);
}

.filter-btn.active {
  background-color: var(--ink);
  border-color: var(--ink);
  color: var(--surface);
}

.project-list {
  display: grid;
  gap: 1.75rem;
}

.project-item {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
}

.project-item.is-hidden {
  display: none;
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.tag {
  color: var(--accent);
  text-transform: uppercase;
  font-weight: 700;
}

.location {
  color: var(--ink-muted);
}

.project-item p {
  color: var(--ink-muted);
  max-width: 72ch;
}

.spec-row {
  display: flex;
  flex-wrap: wrap;
  gap: 2.25rem;
  margin-bottom: 0;
  padding-top: 1.15rem;
  border-top: 1px solid var(--border);
}

.spec-row dt {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.spec-row dd {
  margin-left: 0;
  font-weight: 700;
  font-size: 1rem;
}

/* Methodology Page */
.phase-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 1.25rem;
}

.phase-item {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 1.5rem;
}

.phase-number {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent);
}

.phase-content p {
  margin-bottom: 0;
  color: var(--ink-muted);
}

.table-wrap {
  overflow-x: auto;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.92rem;
}

.data-table th,
.data-table td {
  padding: 0.9rem 1rem;
  border-bottom: 1px solid var(--border);
}

.data-table th {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background-color: var(--bg);
}

.data-table tbody tr:last-child td {
  border-bottom: none;
}

/* Archive Page */
.archive-list {
  display: grid;
  gap: 1.25rem;
}

.archive-entry {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 1.5rem;
  align-items: baseline;
}

.archive-entry time {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-muted);
}

.archive-entry p {
  color: var(--ink-muted);
  margin-bottom: 0.65rem;
}

.mono-note {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--accent);
}

/* 404 Page */
.not-found-section {
  padding-block: 6rem;
}

.null-wave {
  max-width: 480px;
  margin-block: 2rem;
}

.null-wave svg {
  width: 100%;
  display: block;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  background-color: var(--surface);
  padding-block: 1.75rem;
  margin-top: 2rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  font-size: 0.88rem;
  color: var(--ink-muted);
}

.footer-inner p {
  margin-bottom: 0;
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.25rem;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--ink);
}

@media (max-width: 820px) {
  .hero-grid,
  .metrics-grid,
  .cards-grid,
  .callout-box,
  .phase-item,
  .archive-entry {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-block: 3rem;
  }
}