/* =============================================================
   Sachin Bharadwaz — Official Professional Website
   css/styles.css
   ============================================================= */

/* --- Custom Properties ------------------------------------ */
:root {
  --color-black:       #0a0a0a;
  --color-white:       #ffffff;
  --color-charcoal:    #1a1a1a;
  --color-gray:        #6b7280;
  --color-gray-mid:    #d1d5db;
  --color-gray-light:  #f5f5f7;
  --color-navy:        #1e3a5f;
  --color-navy-light:  #2a4f7a;
  --color-border:      #e5e7eb;

  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  --font-serif: 'Source Serif Pro', Georgia, 'Times New Roman', serif;

  --space-1:  8px;
  --space-2:  16px;
  --space-3:  24px;
  --space-4:  32px;
  --space-5:  40px;
  --space-6:  48px;
  --space-8:  64px;
  --space-10: 80px;
  --space-12: 96px;
  --space-16: 128px;

  --radius:    4px;
  --radius-md: 8px;

  --nav-height: 64px;
  --max-width:  1200px;
  --transition: 0.18s ease;
}

/* --- Reset ------------------------------------------------ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background-color: var(--color-white);
  color: var(--color-black);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img, svg { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font: inherit; }
input, textarea { font: inherit; }

/* --- Typography ------------------------------------------- */
h1, h2, h3 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--color-black);
}
h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 600;
  line-height: 1.3;
}
h1 { font-size: clamp(2rem, 4.5vw, 3.25rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); }
h3 { font-size: clamp(1.1rem, 2.2vw, 1.35rem); }
h4 { font-size: 1rem; }

p { margin-bottom: var(--space-2); max-width: 70ch; }
p:last-child { margin-bottom: 0; }

strong { font-weight: 600; }

/* --- Layout ----------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-2);
}
@media (min-width: 640px)  { .container { padding: 0 var(--space-4); } }
@media (min-width: 1024px) { .container { padding: 0 var(--space-5); } }

.section { padding: var(--space-10) 0; }
.section + .section { border-top: 1px solid var(--color-border); }
.section--dark {
  background-color: var(--color-charcoal);
  color: var(--color-white);
  border-top: none !important;
}
.section--dark h2,
.section--dark h3,
.section--dark h4 { color: var(--color-white); }
.section--light { background-color: var(--color-gray-light); }

.section-label {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-navy);
  margin-bottom: var(--space-1);
}
.section--dark .section-label { color: #60a5fa; }
.section-heading { margin-bottom: var(--space-2); }
.section-sub {
  font-size: 1.05rem;
  color: var(--color-gray);
  margin-bottom: var(--space-6);
  max-width: 62ch;
  line-height: 1.7;
}
.section--dark .section-sub { color: #9ca3af; }

/* --- Navigation ------------------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(255,255,255,0.97);
  border-bottom: 1px solid var(--color-border);
  height: var(--nav-height);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-2);
  position: relative;
}
@media (min-width: 640px)  { .nav-container { padding: 0 var(--space-4); } }
@media (min-width: 1024px) { .nav-container { padding: 0 var(--space-5); } }

.nav-brand {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--color-black);
  white-space: nowrap;
  transition: color var(--transition);
}
.nav-brand:hover { color: var(--color-navy); }

.nav-links {
  display: none;
  align-items: center;
  gap: 2px;
}
@media (min-width: 768px) { .nav-links { display: flex; } }

.nav-link {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-gray);
  padding: 6px 11px;
  border-radius: var(--radius);
  transition: color var(--transition), background-color var(--transition);
  white-space: nowrap;
}
.nav-link:hover        { color: var(--color-black); background-color: var(--color-gray-light); }
.nav-link.active       { color: var(--color-navy);  font-weight: 600; }
.nav-link[aria-current="page"] { color: var(--color-navy); font-weight: 600; }

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  padding: 8px 6px;
  border-radius: var(--radius);
  transition: background-color var(--transition);
}
.nav-toggle:hover { background-color: var(--color-gray-light); }
@media (min-width: 768px) { .nav-toggle { display: none; } }

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-black);
  border-radius: 2px;
  transition: transform 0.22s ease, opacity 0.22s 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); }

.nav-mobile {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--color-white);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-2) var(--space-2) var(--space-3);
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}
.nav-mobile.open { display: block; }
.nav-mobile .nav-link {
  display: block;
  padding: 11px 14px;
  font-size: 1rem;
  border-radius: var(--radius);
}

/* --- Hero ------------------------------------------------- */
.hero {
  padding: var(--space-16) 0 var(--space-10);
  border-bottom: 1px solid var(--color-border);
}
.hero-inner {
  display: grid;
  gap: var(--space-8);
  align-items: center;
}
@media (min-width: 1024px) {
  .hero-inner { grid-template-columns: 1fr 300px; }
}
.hero-eyebrow {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-navy);
  margin-bottom: var(--space-2);
}
.hero h1 { margin-bottom: var(--space-2); }
.hero-subtitle {
  font-size: 1.2rem;
  color: var(--color-gray);
  margin-bottom: var(--space-4);
  font-weight: 400;
  font-family: var(--font-sans);
}
.hero-body {
  font-size: 1.05rem;
  color: #374151;
  margin-bottom: var(--space-5);
  max-width: 62ch;
  line-height: 1.75;
}
.hero-actions { display: flex; gap: var(--space-2); flex-wrap: wrap; }

.hero-headshot {
  width: 100%;
  max-width: 300px;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  margin: 0 auto;
}
@media (min-width: 1024px) { .hero-headshot { margin: 0; } }

/* --- Buttons ---------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 24px;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius);
  transition: background-color var(--transition), color var(--transition), border-color var(--transition);
  white-space: nowrap;
  line-height: 1;
}
.btn-primary {
  background-color: var(--color-navy);
  color: var(--color-white);
  border: 1px solid var(--color-navy);
}
.btn-primary:hover { background-color: var(--color-navy-light); border-color: var(--color-navy-light); }
.btn-outline {
  background-color: transparent;
  color: var(--color-black);
  border: 1px solid var(--color-border);
}
.btn-outline:hover { border-color: #9ca3af; }

/* --- Card Grid -------------------------------------------- */
.card-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}
@media (min-width: 640px)  { .card-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .card-grid { grid-template-columns: repeat(3, 1fr); } }
.card-grid--2 { grid-template-columns: 1fr; }
@media (min-width: 768px) { .card-grid--2 { grid-template-columns: repeat(2, 1fr); } }
.card-grid--4 { grid-template-columns: 1fr; }
@media (min-width: 640px)  { .card-grid--4 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .card-grid--4 { grid-template-columns: repeat(4, 1fr); } }

.card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  background: var(--color-white);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.card:hover {
  border-color: var(--color-navy);
  box-shadow: 0 2px 12px rgba(30,58,95,0.07);
}
.card-accent {
  width: 32px;
  height: 3px;
  background-color: var(--color-navy);
  border-radius: 2px;
  margin-bottom: var(--space-2);
}
.card-title {
  font-size: 0.95rem;
  font-weight: 700;
  font-family: var(--font-sans);
  color: var(--color-black);
  margin-bottom: 8px;
}
.card-body {
  font-size: 0.875rem;
  color: var(--color-gray);
  line-height: 1.65;
  margin-bottom: 0;
}
.card-org {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-navy);
  margin-bottom: 4px;
}
.card-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.825rem;
  font-weight: 600;
  color: var(--color-navy);
  margin-top: var(--space-2);
  transition: gap var(--transition);
}
.card-link:hover { gap: 8px; }
.card-link::after { content: "→"; }

.card-img-wrap {
  aspect-ratio: 3 / 2;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--color-border);
  margin-bottom: var(--space-3);
}
.card-img-wrap img { width: 100%; height: 100%; object-fit: cover; }

/* --- Timeline --------------------------------------------- */
.timeline { position: relative; padding-left: var(--space-5); }
.timeline::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 12px;
  bottom: 0;
  width: 1px;
  background: linear-gradient(to bottom, var(--color-navy), var(--color-border));
}
.timeline-item { position: relative; padding-bottom: var(--space-8); }
.timeline-item:last-child { padding-bottom: 0; }

.timeline-dot {
  position: absolute;
  left: calc(-1 * var(--space-5) + 7px);
  top: 10px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--color-navy);
  border: 2px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-navy);
}
.timeline-header {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: var(--space-1);
}
@media (min-width: 640px) {
  .timeline-header { flex-direction: row; justify-content: space-between; align-items: baseline; }
}
.timeline-org {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.2rem;
}
.timeline-dates {
  font-size: 0.82rem;
  color: var(--color-gray);
  font-weight: 500;
  white-space: nowrap;
}
.timeline-role {
  font-size: 0.9rem;
  color: var(--color-navy);
  font-weight: 600;
  margin-bottom: var(--space-2);
  font-family: var(--font-sans);
}
.timeline-bullets { padding-left: 0; }
.timeline-bullets li {
  font-size: 0.9rem;
  color: #374151;
  line-height: 1.7;
  margin-bottom: 8px;
  padding-left: var(--space-3);
  position: relative;
}
.timeline-bullets li::before {
  content: "–";
  position: absolute;
  left: 0;
  color: var(--color-gray);
}

/* --- Skills ----------------------------------------------- */
.skills-grid {
  display: grid;
  gap: var(--space-4) var(--space-6);
  grid-template-columns: 1fr;
}
@media (min-width: 640px)  { .skills-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .skills-grid { grid-template-columns: repeat(4, 1fr); } }

.skills-group {}
.skills-group-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-navy);
  margin-bottom: var(--space-2);
  display: block;
}
.skills-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.skill-tag {
  font-size: 0.8rem;
  font-weight: 500;
  color: #374151;
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  padding: 5px 12px;
  border-radius: 100px;
  transition: border-color var(--transition), color var(--transition);
}
.skill-tag:hover { border-color: var(--color-navy); color: var(--color-navy); }
.section--dark .skill-tag {
  background-color: #2e2e2e;
  border-color: #3a3a3a;
  color: #d1d5db;
}

/* --- Gallery ---------------------------------------------- */
.gallery-grid {
  display: grid;
  gap: var(--space-4);
  grid-template-columns: 1fr;
}
@media (min-width: 640px)  { .gallery-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1024px) { .gallery-grid { grid-template-columns: repeat(3, 1fr); } }

.gallery-item {}
.gallery-img-wrap {
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  margin-bottom: var(--space-2);
  transition: border-color var(--transition);
}
.gallery-item:hover .gallery-img-wrap { border-color: var(--color-navy); }
.gallery-img-wrap img { width: 100%; height: 100%; object-fit: cover; }
.gallery-caption {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-black);
  margin-bottom: 6px;
}
.gallery-filename {
  font-size: 0.72rem;
  color: var(--color-gray);
  font-family: 'Courier New', Courier, monospace;
  margin-bottom: 2px;
  display: block;
}
.gallery-alt-note {
  font-size: 0.72rem;
  color: #9ca3af;
  display: block;
  line-height: 1.5;
}

/* --- Preview grid (home media section) -------------------- */
.preview-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: repeat(2, 1fr);
  margin-bottom: var(--space-4);
}
@media (min-width: 768px)  { .preview-grid { grid-template-columns: repeat(3, 1fr); } }
@media (min-width: 1024px) { .preview-grid { grid-template-columns: repeat(5, 1fr); } }

.preview-thumb {
  aspect-ratio: 1 / 1;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition);
}
.preview-thumb:hover { border-color: var(--color-navy); }
.preview-thumb img { width: 100%; height: 100%; object-fit: cover; }

/* --- Inline list (contact/about) -------------------------- */
.detail-list { display: flex; flex-direction: column; gap: var(--space-3); }
.detail-item {}
.detail-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--color-gray);
  display: block;
  margin-bottom: 4px;
}
.detail-value {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-black);
}
.detail-value a { color: var(--color-navy); }
.detail-value a:hover { text-decoration: underline; }

/* --- Cert / award badges ---------------------------------- */
.badge-list { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.badge {
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 14px var(--space-3);
  background: var(--color-white);
}
.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-navy);
  flex-shrink: 0;
}
.badge-text { font-size: 0.875rem; font-weight: 500; color: var(--color-black); }

/* --- CTA block -------------------------------------------- */
.cta-block {
  background-color: var(--color-navy);
  color: var(--color-white);
  padding: var(--space-12) 0;
  text-align: center;
}
.cta-block h2 { color: var(--color-white); margin-bottom: var(--space-2); }
.cta-block p  {
  color: rgba(255,255,255,0.72);
  margin: 0 auto var(--space-5);
  max-width: 55ch;
  font-size: 1.05rem;
}
.cta-block .btn-white {
  background: var(--color-white);
  color: var(--color-navy);
  border: 1px solid var(--color-white);
}
.cta-block .btn-white:hover { background: var(--color-gray-light); }
.cta-block .btn-ghost {
  background: transparent;
  color: var(--color-white);
  border: 1px solid rgba(255,255,255,0.4);
}
.cta-block .btn-ghost:hover { border-color: var(--color-white); }

/* --- Page hero (inner pages) ------------------------------ */
.page-hero {
  padding: var(--space-8) 0 var(--space-6);
  border-bottom: 1px solid var(--color-border);
}
.page-hero h1 { margin-bottom: var(--space-2); }
.page-hero-sub {
  font-size: 1.05rem;
  color: var(--color-gray);
  max-width: 62ch;
  margin: 0;
  line-height: 1.7;
}

/* --- Two-column layout (about, contact) ------------------- */
.two-col {
  display: grid;
  gap: var(--space-8);
}
@media (min-width: 900px) { .two-col { grid-template-columns: 2fr 1fr; } }
.two-col--equal { grid-template-columns: 1fr; }
@media (min-width: 768px) { .two-col--equal { grid-template-columns: 1fr 1fr; } }

/* --- Prose (about bio) ------------------------------------ */
.prose p { font-size: 1.02rem; color: #374151; line-height: 1.8; margin-bottom: var(--space-3); }
.prose p:last-child { margin-bottom: 0; }
.prose h3 { margin-bottom: var(--space-2); margin-top: var(--space-4); }
.prose h3:first-child { margin-top: 0; }

/* --- Project detail --------------------------------------- */
.project-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.project-card-body { padding: var(--space-5); }
.project-card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}
.project-badge {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-white);
  background-color: var(--color-navy);
  padding: 4px 10px;
  border-radius: 100px;
}
.project-tech { display: flex; flex-wrap: wrap; gap: 8px; margin-top: var(--space-3); }
.tech-tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-navy);
  background-color: #eef2f7;
  border: 1px solid #c7d7ea;
  padding: 3px 10px;
  border-radius: 100px;
}

/* --- 404 -------------------------------------------------- */
.error-page {
  min-height: calc(100vh - var(--nav-height) - 200px);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-10) 0;
}
.error-code {
  font-size: clamp(5rem, 15vw, 10rem);
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--color-border);
  line-height: 1;
  margin-bottom: var(--space-3);
  letter-spacing: -0.05em;
}
.error-links { display: flex; flex-wrap: wrap; gap: var(--space-2); justify-content: center; margin-top: var(--space-5); }

/* --- Footer ----------------------------------------------- */
.footer {
  background-color: var(--color-charcoal);
  color: var(--color-white);
  padding: var(--space-8) 0 var(--space-4);
}
.footer-grid {
  display: grid;
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}
@media (min-width: 768px) { .footer-grid { grid-template-columns: 1fr 2fr; align-items: start; } }

.footer-name {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--color-white);
  margin-bottom: 6px;
}
.footer-tagline {
  font-size: 0.825rem;
  color: #9ca3af;
  max-width: none;
  margin: 0;
}
.footer-nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px var(--space-3);
}
.footer-nav-links a {
  font-size: 0.85rem;
  color: #9ca3af;
  transition: color var(--transition);
}
.footer-nav-links a:hover { color: var(--color-white); }
.footer-bottom {
  border-top: 1px solid #2e2e2e;
  padding-top: var(--space-3);
}
.footer-bottom p {
  font-size: 0.78rem;
  color: #6b7280;
  max-width: none;
  margin: 0;
}

/* --- Utilities -------------------------------------------- */
.text-center { text-align: center; }
.text-gray   { color: var(--color-gray) !important; }
.text-navy   { color: var(--color-navy) !important; }
.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mb-0 { margin-bottom: 0 !important; }
.mb-6 { margin-bottom: var(--space-6); }
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}