/* ==========================================================================
   Vikram Kaushik — Personal Site
   Design tokens: editorial slate (navy-on-off-white), restrained bronze accent
   ========================================================================== */

:root {
  /* Color */
  --bg: #F7F6F2;
  --surface: #FFFFFF;
  --surface-alt: #F0EEE7;
  --ink: #14212C;
  --ink-secondary: #3E4C58;
  --ink-muted: #5B6670;
  --line: #DEDBD2;
  --line-strong: #C7C2B4;
  --navy: #1B3A5C;
  --navy-dark: #14212C;
  --bronze: #8B5A2B;
  --bronze-soft: #F2EAD9;
  --focus: #1B3A5C;

  /* Type */
  --font-display: 'Source Serif 4', Georgia, serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'IBM Plex Mono', 'SF Mono', Consolas, monospace;

  /* Scale */
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2.5rem;
  --space-5: 4rem;
  --space-6: 6rem;

  --radius: 6px;
  --max-width: 780px;
  --max-width-wide: 1040px;
}

/* ---- Reset ---- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: var(--navy); }
a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
  html { scroll-behavior: auto; }
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--ink);
  line-height: 1.2;
  margin: 0 0 var(--space-2);
  font-weight: 600;
}
h1 { font-size: clamp(2.2rem, 4vw, 3.1rem); letter-spacing: -0.01em; }
h2 { font-size: clamp(1.5rem, 2.6vw, 1.9rem); }
h3 { font-size: 1.2rem; }
p { margin: 0 0 var(--space-2); color: var(--ink-secondary); }
.lede { font-size: 1.15rem; color: var(--ink-secondary); }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: var(--space-1);
  display: block;
}

/* ---- Layout ---- */
.wrap { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }
.wrap-wide { max-width: var(--max-width-wide); margin: 0 auto; padding: 0 1.5rem; }
section { padding: var(--space-5) 0; }
.section-tight { padding: var(--space-4) 0; }
hr.rule { border: none; border-top: 1px solid var(--line); margin: 0; }

/* ---- Top accent bar ---- */
.top-bar {
  height: 4px;
  background: linear-gradient(90deg, var(--navy) 0%, var(--navy) 78%, var(--bronze) 100%);
}

/* ---- Timeline education tag ---- */
.tl-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-bottom: 0.3rem;
}

/* ---- Header / Nav ---- */
header.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 50;
}
.nav-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.01em;
}
nav.primary-nav { display: flex; gap: var(--space-3); align-items: center; }
nav.primary-nav a {
  font-family: var(--font-body);
  font-size: 0.92rem;
  color: var(--ink-secondary);
  text-decoration: none;
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
}
nav.primary-nav a:hover,
nav.primary-nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--bronze);
}
.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 0.4rem 0.6rem;
  cursor: pointer;
}
@media (max-width: 720px) {
  nav.primary-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-2) 1.5rem var(--space-3);
    gap: var(--space-2);
  }
  nav.primary-nav.open { display: flex; }
  .nav-toggle { display: inline-flex; }
}

/* ---- Hero ---- */
.hero {
  padding: var(--space-6) 0 var(--space-5);
}
.hero-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: grid;
  grid-template-columns: 1.3fr 0.9fr;
  gap: var(--space-5);
  align-items: center;
}
@media (max-width: 800px) {
  .hero-inner { grid-template-columns: 1fr; gap: var(--space-4); }
  .hero-photo { order: -1; max-width: 220px; }
}
.hero h1 { margin-bottom: var(--space-1); }
.hero .role {
  font-family: var(--font-body);
  font-size: 1.05rem;
  color: var(--navy);
  font-weight: 500;
  margin-bottom: var(--space-3);
}
.hero-photo img {
  border-radius: var(--radius);
  width: 100%;
  filter: grayscale(8%);
}

/* ---- Highlight cards ---- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
}
@media (max-width: 800px) { .card-grid { grid-template-columns: 1fr; } }
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--space-3);
}
.card h3 { margin-bottom: 0.5rem; font-size: 1.05rem; }
.card p { font-size: 0.94rem; margin-bottom: 0; }

/* ---- Buttons / links ---- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 0.95rem;
  text-decoration: none;
  padding: 0.7rem 1.3rem;
  border-radius: var(--radius);
  border: 1px solid var(--navy);
  color: var(--navy);
  background: transparent;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}
.btn:hover { background: var(--navy); color: #fff; }
.btn-solid { background: var(--navy); color: #fff; }
.btn-solid:hover { background: var(--navy-dark); }
.link-arrow {
  color: var(--navy);
  text-decoration: none;
  font-weight: 500;
  border-bottom: 1px solid var(--line-strong);
}
.link-arrow:hover { border-bottom-color: var(--navy); }

/* ---- Footer ---- */
footer.site-footer {
  border-top: 1px solid var(--line);
  padding: var(--space-3) 0;
  color: var(--ink-muted);
  font-size: 0.85rem;
}
.footer-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
}
footer.site-footer a { color: var(--ink-muted); }

/* ---- Contact section ---- */
.contact-section {
  background: var(--surface-alt);
  border-top: 1px solid var(--line);
}
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  align-items: start;
}
@media (max-width: 800px) { .contact-grid { grid-template-columns: 1fr; } }
form.contact-form { display: flex; flex-direction: column; gap: var(--space-2); }
form.contact-form label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
  margin-bottom: 0.3rem;
  display: block;
}
form.contact-form input,
form.contact-form textarea {
  width: 100%;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--ink);
}
form.contact-form textarea { resize: vertical; min-height: 120px; }

/* ---- Timeline (Experience & Education) ---- */
.timeline { position: relative; padding-left: 28px; }
.timeline::before {
  content: '';
  position: absolute;
  left: 8px; top: 6px; bottom: 6px;
  width: 2px;
  background: var(--line);
}
.tl-group { position: relative; margin-bottom: var(--space-3); }
.tl-group > .tl-dot {
  position: absolute; left: -28px; top: 4px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--navy); border: 3px solid var(--bg);
  box-shadow: 0 0 0 1px var(--line);
}
.tl-group-title { font-size: 1.05rem; font-weight: 600; color: var(--ink); }
.tl-group-dates { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-muted); margin-bottom: 0.7rem; }
.tl-sub { border-left: 2px solid var(--line); margin-left: 2px; padding-left: 16px; }
.tl-item { cursor: pointer; margin-bottom: 0.9rem; }
.tl-item:last-child { margin-bottom: 0; }
.tl-item-dates { font-family: var(--font-mono); font-size: 0.75rem; color: var(--ink-muted); }
.tl-item-role { font-size: 0.98rem; font-weight: 500; color: var(--ink); }
.tl-item-company { font-size: 0.85rem; color: var(--ink-secondary); }
.tl-detail {
  max-height: 0; overflow: hidden;
  transition: max-height 0.25s ease;
  font-size: 0.9rem; color: var(--ink-secondary); line-height: 1.6;
}
.tl-detail ul { margin: 0.5rem 0 0; padding-left: 1.1rem; }
.tl-detail li { margin-bottom: 0.3rem; }
.tl-single { position: relative; margin-bottom: 1.4rem; cursor: pointer; }
.tl-single:last-child { margin-bottom: 0; }
.tl-single .tl-dot {
  position: absolute; left: -28px; top: 4px;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--bg); border: 2px solid var(--ink-muted);
}
.tl-hint { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-muted); margin-top: var(--space-2); }

/* Pivot highlight */
.tl-pivot {
  background: var(--bronze-soft);
  border-left: 3px solid var(--bronze);
  padding: 0.9rem 1rem;
  border-radius: var(--radius);
  margin-left: -16px;
}
.tl-pivot .tl-dot { background: var(--bronze) !important; }
.tl-pivot-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: var(--bronze);
  font-weight: 600;
  margin-bottom: 0.2rem;
}

/* ---- Education list (simple, no timeline) ---- */
.edu-item { margin-bottom: var(--space-3); }
.edu-item h3 { margin-bottom: 0.2rem; }
.edu-item .meta { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-muted); margin-bottom: 0.4rem; }

.cert-list { list-style: none; margin: 0; padding: 0; columns: 2; column-gap: var(--space-4); }
@media (max-width: 640px) { .cert-list { columns: 1; } }
.cert-list li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.92rem;
  color: var(--ink-secondary);
  break-inside: avoid;
}

/* ---- Blog list ---- */
.post-list { display: flex; flex-direction: column; }
.post-row {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
  color: inherit;
}
.post-row:first-child { padding-top: 0; }
@media (max-width: 600px) { .post-row { grid-template-columns: 1fr; gap: 0.3rem; } }
.post-row .post-date { font-family: var(--font-mono); font-size: 0.8rem; color: var(--ink-muted); padding-top: 0.2rem; }
.post-row h3 { margin-bottom: 0.35rem; transition: color 0.15s ease; }
.post-row:hover h3 { color: var(--navy); }
.post-row p { font-size: 0.93rem; margin-bottom: 0; }
.post-row .post-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--bronze);
  margin-top: 0.5rem;
}
.post-row .ext-marker { color: var(--ink-muted); font-size: 0.8rem; }

/* ---- Blog post page ---- */
.post-header { padding: var(--space-5) 0 var(--space-3); }
.post-header .eyebrow a { color: var(--ink-muted); text-decoration: none; }
.post-header h1 { font-size: clamp(1.8rem, 3.6vw, 2.5rem); }
.post-meta { font-family: var(--font-mono); font-size: 0.82rem; color: var(--ink-muted); margin-bottom: var(--space-2); }
.post-motif { width: 100%; max-width: var(--max-width); margin: var(--space-3) auto var(--space-4); }
.post-body { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem var(--space-5); }
.post-body h2 { margin-top: var(--space-4); font-size: 1.35rem; }
.post-body p { font-size: 1.02rem; }
.post-body .eq {
  font-family: var(--font-mono);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.9rem 1.1rem;
  margin: var(--space-2) 0;
  font-size: 0.92rem;
  overflow-x: auto;
}
.post-footer-nav {
  border-top: 1px solid var(--line);
  padding: var(--space-3) 0;
}

/* ---- Publications page ---- */
.pub-block { padding: var(--space-3) 0; border-bottom: 1px solid var(--line); }
.book-grid { display: grid; grid-template-columns: 160px 1fr; gap: var(--space-3); margin-bottom: var(--space-4); }
@media (max-width: 560px) { .book-grid { grid-template-columns: 120px 1fr; } }
.book-grid img { border-radius: 4px; border: 1px solid var(--line); }
.buy-links { display: flex; gap: 0.9rem; flex-wrap: wrap; margin-top: 0.7rem; font-size: 0.88rem; }
.buy-links a { text-decoration: none; color: var(--navy); border-bottom: 1px solid var(--line-strong); }
.buy-links a:hover { border-bottom-color: var(--navy); }

/* ---- About page ---- */
.about-body p { font-size: 1.03rem; }

/* ---- Utility ---- */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap;
}
.center { text-align: center; }
.mt-0 { margin-top: 0; }