/* ---------- Design tokens ---------- */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', 'Cascadia Code', Menlo, monospace;

  --max: 760px;
  --radius: 12px;

  --bg: #0b0d11;
  --surface: #12151b;
  --surface-2: #171b22;
  --text: #e7eaee;
  --muted: #97a0ad;
  --border: #232935;
  --accent: #8aa6ff;
  --accent-weak: rgba(138, 166, 255, 0.12);
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.02), 0 8px 30px rgba(0, 0, 0, 0.28);
}

:root[data-theme='light'] {
  --bg: #ffffff;
  --surface: #f7f8fa;
  --surface-2: #f0f2f5;
  --text: #14171d;
  --muted: #5c6470;
  --border: #e6e9ee;
  --accent: #3f5bd6;
  --accent-weak: rgba(63, 91, 214, 0.09);
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: 'cv11', 'ss01';
}

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: -999px;
}
.skip-link:focus {
  left: 16px;
  top: 12px;
  background: var(--surface);
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  z-index: 10;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 14px max(20px, calc((100% - var(--max)) / 2));
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--border);
}

.brand {
  font-family: var(--font-mono);
  font-weight: 600;
  letter-spacing: 0.04em;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 4px 8px;
}

.nav {
  display: flex;
  gap: 20px;
  margin-left: auto;
  font-size: 0.9rem;
  color: var(--muted);
}
.nav a:hover {
  color: var(--text);
}

.theme-toggle {
  display: inline-grid;
  place-items: center;
  width: 36px;
  height: 36px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}
.theme-toggle:hover {
  border-color: var(--accent);
}

/* ---------- Layout ---------- */
main {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 20px;
}

.section {
  padding: 64px 0;
  border-top: 1px solid var(--border);
}

.section-title {
  display: flex;
  align-items: baseline;
  gap: 12px;
  font-size: 1.05rem;
  font-weight: 600;
  margin: 0 0 8px;
}
.section-index {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent);
}
.section-note {
  color: var(--muted);
  margin: 0 0 28px;
  max-width: 60ch;
}

/* ---------- Hero ---------- */
.hero {
  padding: 72px 0 64px;
}
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.02em;
  color: var(--muted);
  margin: 0 0 14px;
}
.hero h1 {
  font-size: clamp(2.4rem, 7vw, 3.4rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin: 0 0 18px;
  font-weight: 700;
}
.lead {
  font-size: 1.2rem;
  margin: 0 0 14px;
  max-width: 40ch;
}
.sub {
  color: var(--muted);
  margin: 0 0 28px;
  max-width: 56ch;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.btn {
  display: inline-flex;
  align-items: center;
  padding: 9px 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  font-size: 0.92rem;
  font-weight: 500;
  transition:
    border-color 0.15s ease,
    transform 0.15s ease,
    background 0.15s ease;
}
.btn:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}
.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0d11;
}
:root[data-theme='light'] .btn-primary {
  color: #fff;
}

.availability {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 26px;
  font-size: 0.9rem;
  color: var(--muted);
}
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #34d399;
  box-shadow: 0 0 0 4px rgba(52, 211, 153, 0.16);
}

/* ---------- Projects ---------- */
.projects {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}
.card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 20px;
  transition:
    border-color 0.15s ease,
    transform 0.15s ease,
    box-shadow 0.15s ease;
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.card h3 {
  font-family: var(--font-mono);
  font-size: 0.98rem;
  font-weight: 500;
  margin: 0 0 10px;
}
.card h3 a:hover {
  color: var(--accent);
}
.card-domain {
  font-size: 0.8rem !important;
  color: var(--muted) !important;
  margin: -4px 0 12px !important;
}
.card p {
  margin: 0 0 14px;
  font-size: 0.94rem;
  color: var(--text);
}
.card-meta {
  font-size: 0.8rem !important;
  color: var(--muted) !important;
  margin: 12px 0 0 !important;
  font-family: var(--font-mono);
}

.tags {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.tags li {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
  background: var(--accent-weak);
  border: 1px solid transparent;
  padding: 3px 8px;
  border-radius: 999px;
}

/* ---------- Approach ---------- */
.approach {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.approach-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  background: var(--surface);
}
.approach-item h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}
.approach-item p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

/* ---------- Stack ---------- */
.stack {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px 32px;
}
.stack-group h3 {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin: 0 0 12px;
}

/* ---------- Timeline ---------- */
.timeline {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 8px;
}
.timeline li {
  padding: 18px 0;
  border-bottom: 1px solid var(--border);
}
.timeline li:last-child {
  border-bottom: 0;
}
.timeline-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 16px;
  flex-wrap: wrap;
}
.timeline-head h3 {
  margin: 0;
  font-size: 1rem;
}
.when {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--muted);
  white-space: nowrap;
}
.timeline p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

/* ---------- Contact ---------- */
.contact-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 2px;
}
.contact-list li {
  display: flex;
  align-items: baseline;
  gap: 18px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}
.contact-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--muted);
  width: 84px;
  flex: none;
}
.contact-list a:hover {
  color: var(--accent);
}

/* ---------- Footer ---------- */
.site-footer {
  max-width: var(--max);
  margin: 0 auto;
  padding: 32px 20px 48px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  color: var(--muted);
  font-size: 0.85rem;
}

/* ---------- Responsive ---------- */
@media (max-width: 620px) {
  .nav {
    display: none;
  }
  .projects,
  .approach,
  .stack {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto;
    transition: none !important;
  }
}