/* ============================================================
   LAYOUT.CSS — Containers, Nav, Sections, Grids, Footer
   No component-level styles here — those live in components.css
   ============================================================ */

/* ── Containers ──────────────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--content-default); /* 960px */
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.container--wide {
  max-width: var(--content-wide); /* 1200px */
  padding-inline: var(--space-5);
  margin-inline: auto;
}

.container--narrow {
  max-width: var(--content-narrow); /* 640px */
  padding-inline: var(--space-5);
  margin-inline: auto;
}

@media (min-width: 768px) {
  .container,
  .container--wide,
  .container--narrow {
    padding-inline: var(--space-8);
  }
}

/* ── Navigation ──────────────────────────────────────────── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-nav);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-divider);
  transition:
    background-color var(--transition-slow),
    box-shadow var(--transition-slow);
}

@media (min-width: 768px) {
  .nav {
    background: oklch(from var(--color-surface) l c h / 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }
}

/* Elevated state when scrolled — toggled by main.js */
.nav--scrolled {
  background: oklch(from var(--color-surface) l c h / 0.95);
  box-shadow: var(--shadow-md);
}

/* Nav is open on mobile */
.nav--open .nav-drawer {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}
.nav--open .nav-drawer {
  aria-hidden: false; /* JS also sets this */
}

.nav-inner {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-5);
  height: 64px;
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

@media (min-width: 768px) {
  .nav-inner {
    padding-inline: var(--space-8);
  }
}

/* Nav links — hidden on mobile, shown on desktop */
.nav-links {
  display: none;
  align-items: center;
  gap: var(--space-1);
  margin-inline: auto; /* push to centre */
}

@media (min-width: 768px) {
  .nav-links {
    display: flex;
  }
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

/* Mobile hamburger — hidden on desktop */
.nav-mobile-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--color-text);
}

@media (min-width: 768px) {
  .nav-mobile-toggle {
    display: none;
  }
}

/* ── Mobile Nav Drawer ───────────────────────────────────── */
.nav-drawer {
  position: fixed;
  top: 64px; /* height of nav */
  left: 0;
  right: 0;
  z-index: calc(var(--z-nav) - 1);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-4) var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  transform: translateY(-110%);
  opacity: 0;
  pointer-events: none;
  transition:
    transform var(--transition-slow),
    opacity var(--transition-slow);
}

@media (min-width: 768px) {
  .nav-drawer {
    display: none;
  }
}

/* ── Section Base ────────────────────────────────────────── */
.section {
  padding-block: clamp(var(--space-16), 8vw, var(--space-32));
  position: relative;
}

/* Alternating section surface — creates rhythm without colour */
.section--surface {
  background: var(--color-surface);
}

/* Extra top padding for hero to clear fixed nav */
.section--hero {
  padding-top: calc(64px + clamp(var(--space-16), 10vw, var(--space-32)));
  padding-bottom: clamp(var(--space-16), 8vw, var(--space-32));
  overflow: hidden; /* contains the ::before watermark */
}

/* Subtle "AA" watermark — low-opacity background decoration */
.section--hero::before {
  content: "AA";
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(180px, 30vw, 420px);
  color: var(--color-primary);
  opacity: 0.03;
  position: absolute;
  right: -2vw;
  top: 50%;
  transform: translateY(-50%);
  line-height: 1;
  pointer-events: none;
  user-select: none;
  letter-spacing: -0.05em;
  z-index: var(--z-base);
}

/* Hero content sits above the watermark */
.hero-content {
  position: relative;
  z-index: var(--z-raised);
  max-width: 680px;
}

/* ── Section Header ──────────────────────────────────────── */
.section-header {
  margin-bottom: var(--space-12);
}

/* ── About Grid ──────────────────────────────────────────── */
.about-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-10);
}

@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr 300px;
    gap: var(--space-12);
  }
}

/* ── Skills Grid ─────────────────────────────────────────── */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

@media (min-width: 600px) {
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  .skills-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ── Experience Timeline Container ──────────────────────── */
.timeline {
  display: flex;
  flex-direction: column;
  gap: 0; /* gap handled inside each item with padding */
  position: relative;
}

/* Vertical timeline spine */
.timeline::before {
  content: "";
  position: absolute;
  left: 11px; /* aligns with marker centre */
  top: var(--space-3);
  bottom: var(--space-3);
  width: 2px;
  background: var(--color-border);
  border-radius: var(--radius-full);
}

@media (min-width: 768px) {
  .timeline::before {
    left: 50%;
    transform: translateX(-50%);
  }
}

/* ── Projects Grid ───────────────────────────────────────── */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 960px) {
  /* First card spans full width as featured */
  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .projects-grid .project-card--featured {
    grid-column: 1 / -1;
  }
}

/* ── Research Layout ─────────────────────────────────────── */
.research-metrics {
  margin-bottom: var(--space-10);
}

.publications-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

/* ── Education + Certifications ──────────────────────────── */
.edu-certs-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-12);
}

@media (min-width: 768px) {
  .edu-certs-grid {
    grid-template-columns: 280px 1fr;
    gap: var(--space-16);
  }
}

.education-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-8);
}

.certifications-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-3);
  align-content: start;
}

/* ── Contact Layout ──────────────────────────────────────── */
.contact-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

/* ── Footer ──────────────────────────────────────────────── */
.footer {
  padding-block: var(--space-8);
  border-top: 1px solid var(--color-divider);
  background: var(--color-surface);
}

.footer-inner {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.footer-sep {
  color: var(--color-text-faint);
}