/*
 * main.css — core layout, typography, and component styles.
 *
 * Design principles:
 *   - Mobile-first: base styles are for small screens; breakpoints add width
 *   - All colours via var(--color-*) — never hardcoded
 *   - Semantic HTML5 elements styled directly where possible
 *   - WCAG 2.1 AA contrast ratios enforced through token choices in themes.css
 */

@import url("themes.css");

/* ── Reset + base ────────────────────────────────────────────────────────── */

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
               Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  transition: background-color 0.2s ease, color 0.2s ease;
}

/* ── Skip-to-content (accessibility) ────────────────────────────────────── */

.skip-link {
  position: absolute;
  top: -100%;
  left: 1rem;
  padding: 0.5rem 1rem;
  background: var(--color-accent-primary);
  color: var(--color-text-inverse);
  font-weight: 600;
  border-radius: 0 0 4px 4px;
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 0;
}

/* ── Focus styles ────────────────────────────────────────────────────────── */

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

/* ── Typography ─────────────────────────────────────────────────────────── */

h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  color: var(--color-text-primary);
  font-weight: 700;
}

h1 { font-size: clamp(1.75rem, 4vw, 2.75rem); }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); }
h3 { font-size: clamp(1.1rem, 2.5vw, 1.4rem); }
h4 { font-size: 1.1rem; }

p { margin-bottom: 1rem; color: var(--color-text-secondary); }
p:last-child { margin-bottom: 0; }

a {
  color: var(--color-text-link);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color 0.15s ease;
}

a:hover { color: var(--color-text-link-hover); }

strong { color: var(--color-text-primary); }

code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.875em;
  color: var(--color-text-code);
  background: var(--color-bg-code);
  padding: 0.125em 0.35em;
  border-radius: 3px;
}

pre {
  background: var(--color-bg-code);
  border: 1px solid var(--color-border-default);
  border-radius: 6px;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin: 1.25rem 0;
}

pre code {
  background: none;
  padding: 0;
  color: var(--color-text-primary);
  font-size: 0.875rem;
}

ul, ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--color-text-secondary);
}

li { margin-bottom: 0.25rem; }

hr {
  border: none;
  border-top: 1px solid var(--color-border-default);
  margin: 2rem 0;
}

/* ── Layout ─────────────────────────────────────────────────────────────── */

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.container--wide { max-width: 1200px; }

/* ── Navigation ─────────────────────────────────────────────────────────── */

.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-nav-bg);
  border-bottom: 1px solid var(--color-nav-border);
  backdrop-filter: saturate(180%) blur(8px);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.5rem;
}

.site-nav__logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.site-nav__logo:hover { color: var(--color-accent-primary); }

.site-nav__links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

.site-nav__links a {
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
}

.site-nav__links a:hover { color: var(--color-accent-primary); }

.theme-toggle {
  background: none;
  border: 1px solid var(--color-border-default);
  border-radius: 6px;
  cursor: pointer;
  padding: 0.35rem 0.5rem;
  color: var(--color-text-secondary);
  font-size: 1rem;
  line-height: 1;
  transition: border-color 0.15s, background 0.15s;
}

.theme-toggle:hover {
  border-color: var(--color-border-strong);
  background: var(--color-bg-elevated);
}

/* ── Hero section ────────────────────────────────────────────────────────── */

.hero {
  background: var(--color-hero-bg);
  padding: 4rem 0 3rem;
  border-bottom: 1px solid var(--color-border-default);
}

.hero__title {
  font-size: clamp(2rem, 5vw, 3.25rem);
  margin-bottom: 0.5rem;
  letter-spacing: -0.03em;
}

.hero__title span { color: var(--color-accent-primary); }

.hero__subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: var(--color-text-secondary);
  margin-bottom: 1.25rem;
  font-weight: 500;
}

.hero__pitch {
  font-size: 1.05rem;
  color: var(--color-text-secondary);
  max-width: 640px;
  line-height: 1.7;
  margin-bottom: 1.75rem;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* ── Buttons ─────────────────────────────────────────────────────────────── */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.6rem 1.25rem;
  border-radius: 6px;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 2px solid transparent;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.btn--primary {
  background: var(--color-accent-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-accent-primary);
}

.btn--primary:hover {
  background: var(--color-accent-hover);
  border-color: var(--color-accent-hover);
  color: var(--color-text-inverse);
}

.btn--outline {
  background: transparent;
  color: var(--color-accent-primary);
  border-color: var(--color-accent-primary);
}

.btn--outline:hover {
  background: var(--color-accent-muted);
}

/* ── Sections ────────────────────────────────────────────────────────────── */

.section {
  padding: 3.5rem 0;
}

.section--alt {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border-default);
  border-bottom: 1px solid var(--color-border-default);
}

.section__header {
  margin-bottom: 2rem;
}

.section__title {
  margin-bottom: 0.5rem;
}

.section__subtitle {
  color: var(--color-text-muted);
  font-size: 1rem;
}

/* ── Experience cards ────────────────────────────────────────────────────── */

.experience-grid {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .experience-grid {
    grid-template-columns: repeat(auto-fit, minmax(420px, 1fr));
  }
}

.experience-card {
  background: var(--color-bg-primary);
  border: 1px solid var(--color-border-default);
  border-radius: 10px;
  padding: 1.5rem;
  box-shadow: var(--color-card-shadow);
  transition: box-shadow 0.2s, transform 0.2s;
  text-decoration: none;
  color: inherit;
  display: block;
}

.experience-card:hover {
  box-shadow: var(--color-card-shadow-hover);
  transform: translateY(-2px);
  color: inherit;
  text-decoration: none;
}

.experience-card__meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
  flex-wrap: wrap;
}

.experience-card__period {
  background: var(--color-bg-elevated);
  padding: 0.1rem 0.5rem;
  border-radius: 4px;
}

.experience-card__title {
  font-size: 1.15rem;
  margin-bottom: 0.6rem;
  color: var(--color-text-primary);
}

.experience-card__summary {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

.tag {
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  border: 1px solid var(--color-tag-border);
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
}

/* ── Skills grid ─────────────────────────────────────────────────────────── */

.skills-grid {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.skill-group__title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.skill-group__items {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  padding: 0;
}

/* ── About section ───────────────────────────────────────────────────────── */

.about__content {
  max-width: 720px;
}

.about__content p + p { margin-top: 0.75rem; }

/* ── Contact section ─────────────────────────────────────────────────────── */

.contact__links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  list-style: none;
  padding: 0;
  margin-top: 1.5rem;
}

.contact__link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  border: 1px solid var(--color-border-default);
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
}

.contact__link:hover {
  border-color: var(--color-accent-primary);
  color: var(--color-accent-primary);
  background: var(--color-accent-muted);
}

.contact__link svg {
  width: 1.1em;
  height: 1.1em;
}

/* ── Footer ──────────────────────────────────────────────────────────────── */

.site-footer {
  border-top: 1px solid var(--color-border-default);
  padding: 2rem 0;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

/* ── Case study / blog post prose ────────────────────────────────────────── */

.prose {
  max-width: 720px;
}

.prose h2 {
  font-size: 1.4rem;
  margin: 2rem 0 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--color-border-default);
}

.prose h3 {
  font-size: 1.15rem;
  margin: 1.5rem 0 0.5rem;
}

.prose ul, .prose ol {
  margin: 0.75rem 0 1rem;
}

.prose li { margin-bottom: 0.4rem; }

.prose p { margin-bottom: 1rem; }

.prose strong { font-weight: 600; }

/* ── Detail page layout ──────────────────────────────────────────────────── */

.detail-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border-default);
  background: var(--color-bg-secondary);
}

.detail-header__back {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  margin-bottom: 1.25rem;
}

.detail-header__back:hover { color: var(--color-accent-primary); }

.detail-header__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 0.75rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.detail-body {
  padding: 2.5rem 0;
}

/* ── Blog index ──────────────────────────────────────────────────────────── */

.post-list {
  list-style: none;
  padding: 0;
}

.post-list__item {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--color-border-default);
}

.post-list__item:last-child { border-bottom: none; }

.post-list__date {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.25rem;
}

.post-list__title {
  font-size: 1.15rem;
  margin-bottom: 0.4rem;
}

.post-list__summary {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

/* ── 404 page ────────────────────────────────────────────────────────────── */

.error-page {
  text-align: center;
  padding: 6rem 0;
}

.error-page__code {
  font-size: 5rem;
  font-weight: 800;
  color: var(--color-border-strong);
  line-height: 1;
  margin-bottom: 1rem;
}

/* ── Utilities ───────────────────────────────────────────────────────────── */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-muted { color: var(--color-text-muted); }
.text-accent { color: var(--color-accent-primary); }
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }

/* ── Responsive adjustments ──────────────────────────────────────────────── */

@media (max-width: 480px) {
  .site-nav__links {
    gap: 1rem;
  }

  .hero {
    padding: 2.5rem 0 2rem;
  }

  .section {
    padding: 2.5rem 0;
  }

  .contact__links {
    flex-direction: column;
  }
}

@media (min-width: 768px) {
  .hero {
    padding: 5rem 0 4rem;
  }

  .section {
    padding: 4.5rem 0;
  }
}