/* =========================================================================
   Juan Diego Arango — personal landing page
   Design concept: the page reads as a data pipeline. A source (About) is
   transformed (Experience), typed by a stack (Skills), grounded by
   credentials (Education) and resolved into an output (Contact). The
   vertical "rail" on the left is that pipeline made literal, and doubles
   as in-page navigation.
   ========================================================================= */

/* ---------- Design tokens ---------- */
:root {
  --bg: #fafaf7;
  --surface: #f1f0ea;
  --ink: #161b1e;
  --ink-muted: #5b6360;
  --line: #dbd8cd;
  --accent: #2f6f4e;
  --accent-ink: #1f4a34;
  --accent-contrast: #fafaf7;

  --font-sans: "IBM Plex Sans", -apple-system, "Segoe UI", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --content-width: 760px;
  --radius: 3px;
  --focus-ring: 2px solid var(--accent);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1210;
    --surface: #171b18;
    --ink: #f2f1ea;
    --ink-muted: #9ca39d;
    --line: #2a2f2b;
    --accent: #5fbf95;
    --accent-ink: #dff5ea;
    --accent-contrast: #0f1210;
  }
}

:root[data-theme="dark"] {
  --bg: #0f1210;
  --surface: #171b18;
  --ink: #f2f1ea;
  --ink-muted: #9ca39d;
  --line: #2a2f2b;
  --accent: #5fbf95;
  --accent-ink: #dff5ea;
  --accent-contrast: #0f1210;
}

/* ---------- Reset ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, p { margin: 0; }
a { color: inherit; text-decoration: none; }

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

:focus-visible { outline: var(--focus-ring); outline-offset: 3px; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-contrast);
  padding: 0.75em 1.25em;
  z-index: 200;
  font-family: var(--font-mono);
  font-size: 0.85rem;
}
.skip-link:focus { left: 0; }

/* ---------- Header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.02em;
}
.nav-brand .bracket { color: var(--accent); }

.nav-links {
  display: flex;
  gap: 2rem;
}
.nav-links a {
  font-size: 0.9rem;
  color: var(--ink-muted);
  position: relative;
  padding-bottom: 0.2rem;
  transition: color 0.15s ease;
}
.nav-links a:hover,
.nav-links a:focus-visible { color: var(--ink); }
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 0;
  height: 1px;
  background: var(--accent);
  transition: width 0.2s ease;
}
.nav-links a:hover::after,
.nav-links a:focus-visible::after { width: 100%; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--ink);
  border-radius: 1px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Pipeline rail (desktop only) ---------- */
.rail {
  position: fixed;
  left: 2rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 50;
  display: flex;
  align-items: center;
}
.rail-line {
  position: absolute;
  left: 3px;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--line);
}
.rail-nodes {
  display: flex;
  flex-direction: column;
  gap: 2.4rem;
}
.rail-nodes a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.rail-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--bg);
  border: 1px solid var(--ink-muted);
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
  flex: none;
}
.rail-code {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--ink-muted);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.2s ease, transform 0.2s ease, color 0.2s ease;
}
.rail-nodes a:hover .rail-code,
.rail-nodes a:focus-visible .rail-code,
.rail-nodes a.active .rail-code {
  opacity: 1;
  transform: translateX(0);
}
.rail-nodes a:hover .rail-dot,
.rail-nodes a:focus-visible .rail-dot { border-color: var(--accent); }
.rail-nodes a.active .rail-dot {
  background: var(--accent);
  border-color: var(--accent);
  transform: scale(1.3);
}
.rail-nodes a.active .rail-code { color: var(--accent); }

@media (max-width: 1200px) {
  .rail { display: none; }
}

/* ---------- Hero ---------- */
.hero {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: clamp(3.5rem, 9vw, 7rem) 1.5rem clamp(3rem, 6vw, 5rem);
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}
.hero-photo {
  width: 64px;
  height: 64px;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
}
.hero-photo img { width: 100%; height: 100%; object-fit: cover; }

.prompt {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--ink-muted);
}
.prompt-sign { color: var(--accent); font-weight: 600; margin-right: 0.4em; }

.hero h1 {
  font-size: clamp(2.75rem, 6vw, 5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 0.98;
}

.role {
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  color: var(--ink-muted);
  font-weight: 500;
}
.role-sep { color: var(--accent); margin: 0 0.35em; }

.lede {
  max-width: 56ch;
  font-size: 1.05rem;
  color: var(--ink-muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 0.5rem;
}

.btn {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.92rem;
  padding: 0.85em 1.5em;
  border-radius: var(--radius);
  border: 1px solid transparent;
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}
.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
}
.btn-primary:hover { transform: translateY(-1px); background: var(--accent-ink); }
.btn-secondary {
  border-color: var(--line);
  color: var(--ink);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }
.btn-icon {
  padding: 0.7em;
  border: 1px solid var(--line);
  color: var(--ink);
}
.btn-icon:hover { border-color: var(--accent); color: var(--accent); }

/* ---------- Sections ---------- */
.section {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: clamp(3rem, 6vw, 4.5rem) 1.5rem;
  border-top: 1px solid var(--line);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.9rem;
}

.section-title {
  font-size: clamp(1.4rem, 2.6vw, 1.85rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 1.5rem;
}

.section-text {
  max-width: 62ch;
  color: var(--ink-muted);
  font-size: 1.02rem;
}

/* ---------- Experience timeline ---------- */
.timeline {
  position: relative;
  padding-left: 1.6rem;
}
.timeline::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 1px;
  background: var(--line);
}
.timeline-item {
  position: relative;
  padding-bottom: 2.75rem;
}
.timeline-item:last-child { padding-bottom: 0; }
.timeline-marker {
  position: absolute;
  left: -1.6rem;
  top: 0.35rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--bg);
}
.timeline-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem 1rem;
}
.timeline-head h3 {
  font-size: 1.1rem;
  font-weight: 700;
}
.timeline-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-muted);
  white-space: nowrap;
}
.timeline-org {
  font-size: 0.92rem;
  color: var(--accent);
  font-weight: 600;
  margin-top: 0.2rem;
}
.timeline-summary {
  margin-top: 0.6rem;
  color: var(--ink-muted);
  font-size: 0.96rem;
  max-width: 62ch;
}
.timeline-content ul {
  margin-top: 0.8rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.timeline-content ul li {
  position: relative;
  padding-left: 1.1rem;
  font-size: 0.94rem;
  color: var(--ink-muted);
  max-width: 64ch;
}
.timeline-content ul li::before {
  content: "›";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-family: var(--font-mono);
}

/* ---------- Skills ---------- */
.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}
.skills-grid li {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.5em 0.85em;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.skills-grid li:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- Education ---------- */
.education-list {
  display: flex;
  flex-direction: column;
  gap: 1.6rem;
}
.education-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.3rem 1rem;
  padding-bottom: 1.6rem;
  border-bottom: 1px solid var(--line);
}
.education-list li:last-child { border-bottom: none; padding-bottom: 0; }
.education-list h3 {
  font-size: 1.05rem;
  font-weight: 700;
  flex: 1 1 auto;
}
.edu-org {
  font-size: 0.92rem;
  color: var(--ink-muted);
  flex: 1 1 100%;
}
.edu-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-muted);
  white-space: nowrap;
}

/* ---------- Contact ---------- */
.contact-links {
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  margin-top: 1.75rem;
}
.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  width: fit-content;
  font-size: 1rem;
  color: var(--ink);
  padding: 0.4em 0;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.contact-link svg { color: var(--accent); flex: none; }
.contact-link:hover,
.contact-link:focus-visible {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ---------- Footer ---------- */
.site-footer {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
  border-top: 1px solid var(--line);
}
.site-footer p {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--ink-muted);
}

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
  .nav-toggle { display: flex; }
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
  }
  .nav-links.open { max-height: 20rem; }
  .nav-links li { border-top: 1px solid var(--line); }
  .nav-links a { display: block; padding: 1rem 1.5rem; }
  .nav-links a::after { display: none; }

  .hero-photo { width: 56px; height: 56px; }
  .timeline-head { flex-direction: column; }
  .education-list li { flex-direction: column; align-items: flex-start; }
}