/* ==========================================================================
   samghatak.dev design system
   Typography-first, one accent, light/dark via custom properties.
   Fonts: IBM Plex Sans (text) + IBM Plex Mono (annotations).
   ========================================================================== */

:root {
  --bg: #ffffff;
  --bg-alt: #f6f8fa;
  --surface: #ffffff;
  --ink: #101828;
  --muted: #475467;
  --faint: #98a2b3;
  --line: #e4e7ec;
  --accent: #1d4ed8;
  --accent-ink: #ffffff;
  --accent-soft: #eff4ff;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
  --radius: 12px;
  --sans: "IBM Plex Sans", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
  color-scheme: light;
}

[data-theme="dark"] {
  --bg: #0c111d;
  --bg-alt: #101828;
  --surface: #141d2e;
  --ink: #eaf0f7;
  --muted: #98a2b3;
  --faint: #667085;
  --line: #1f2a3c;
  --accent: #6ea0ff;
  --accent-ink: #0c111d;
  --accent-soft: #16233c;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4), 0 8px 24px rgba(0, 0, 0, 0.35);
  color-scheme: dark;
}

/* ---------- base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 4.5rem;
}

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 0.5rem 1rem;
  z-index: 100;
}

.skip-link:focus {
  left: 0.5rem;
  top: 0.5rem;
}

.container {
  max-width: 1060px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---------- typography ---------- */

h1, h2, h3, h4 {
  line-height: 1.15;
  margin: 0 0 0.75rem;
  letter-spacing: -0.02em;
  font-weight: 600;
}

h2 {
  font-size: clamp(1.7rem, 3.5vw, 2.25rem);
}

h3 {
  font-size: 1.2rem;
}

p {
  margin: 0 0 1rem;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--accent);
  display: block;
  margin-bottom: 0.75rem;
}

.section-lede {
  color: var(--muted);
  max-width: 46rem;
  font-size: 1.1rem;
  margin-bottom: 2.5rem;
}

.mono {
  font-family: var(--mono);
}

/* ---------- header / nav ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.nav {
  display: flex;
  align-items: center;
  gap: 1rem;
  min-height: 3.75rem;
}

.brand {
  font-family: var(--mono);
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}

.brand:hover {
  text-decoration: none;
  color: var(--accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
  margin: 0 0 0 auto;
  padding: 0;
  flex-wrap: wrap;
}

.nav-links a {
  display: block;
  padding: 0.4rem 0.65rem;
  border-radius: 8px;
  color: var(--muted);
  font-size: 0.925rem;
}

.nav-links a:hover {
  color: var(--ink);
  background: var(--bg-alt);
  text-decoration: none;
}

.nav-links a[aria-current="true"] {
  color: var(--accent);
}

.nav-toggle,
.theme-toggle {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  border-radius: 8px;
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font: inherit;
  line-height: 1;
}

.nav-toggle {
  display: none;
  margin-left: auto;
}

.theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: inline; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

@media (max-width: 840px) {
  .nav-toggle {
    display: inline-block;
  }

  .nav-links {
    display: none;
    position: absolute;
    inset: 100% 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    padding: 0.5rem 1rem 1rem;
  }

  .nav-links.open {
    display: flex;
  }
}

/* ---------- hero ---------- */

.hero {
  padding: clamp(4rem, 10vw, 7.5rem) 0 clamp(3rem, 7vw, 5.5rem);
}

.hero .eyebrow {
  margin-bottom: 1.25rem;
}

.hero h1 {
  font-size: clamp(2.6rem, 7vw, 4.25rem);
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.hero h1 .name-short {
  color: var(--accent);
}

.hero .role {
  font-size: clamp(1.3rem, 3vw, 1.75rem);
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 1rem;
}

.hero .focus-areas {
  font-family: var(--mono);
  font-size: 0.95rem;
  color: var(--muted);
  margin-bottom: 2rem;
}

.hero-metrics {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: 0 0 2.25rem;
  padding: 0;
  list-style: none;
  border-block: 1px solid var(--line);
}

.hero-metrics li {
  padding: 1rem 1.75rem 1rem 0;
  margin-right: 1.75rem;
  border-right: 1px solid var(--line);
}

.hero-metrics li:last-child {
  border-right: 0;
  margin-right: 0;
  padding-right: 0;
}

.hero-metrics strong {
  display: block;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.hero-metrics span {
  font-size: 0.875rem;
  color: var(--muted);
}

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

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 1.15rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  font-weight: 500;
  font-size: 0.95rem;
}

.btn:hover {
  text-decoration: none;
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

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

.btn-primary:hover {
  color: var(--accent-ink);
  opacity: 0.92;
}

/* ---------- sections ---------- */

.section {
  padding: clamp(3.5rem, 8vw, 6rem) 0;
}

.section-alt {
  background: var(--bg-alt);
  border-block: 1px solid var(--line);
}

/* ---------- cards & grids ---------- */

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.grid {
  display: grid;
  gap: 1.25rem;
}

.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

@media (max-width: 840px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 600px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
}

/* ---------- about ---------- */

.about-grid {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 3rem;
  align-items: start;
}

.about-photo img {
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.about-photo figcaption {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--faint);
  margin-top: 0.6rem;
}

.about-text p + p {
  margin-top: 1rem;
}

@media (max-width: 840px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

  .about-photo {
    max-width: 320px;
  }
}

/* ---------- principles (ADR cards) ---------- */

.adr {
  display: flex;
  flex-direction: column;
  transition: border-color 160ms ease, transform 160ms ease;
}

.adr:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.adr-meta {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--faint);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.85rem;
}

.adr-meta .status {
  color: var(--accent);
}

.adr h3 {
  margin-bottom: 0.5rem;
}

.adr p {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ---------- capabilities ---------- */

.capability h3 {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.capability .cap-index {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--accent);
}

.capability p {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ---------- experience ---------- */

.xp-card {
  margin-bottom: 1.25rem;
}

.xp-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.35rem 1rem;
  margin-bottom: 0.35rem;
}

.xp-head h3 {
  margin: 0;
  font-size: 1.3rem;
}

.xp-role {
  color: var(--accent);
  font-weight: 500;
}

.xp-dates {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--faint);
}

.xp-tagline {
  color: var(--muted);
  margin-bottom: 1rem;
}

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

.chips li {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
  background: var(--bg-alt);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.25rem 0.7rem;
}

.section-alt .chips li {
  background: var(--surface);
}

.edu-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2.5rem;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.925rem;
  color: var(--muted);
}

.edu-strip strong {
  color: var(--ink);
  display: block;
}

/* ---------- projects ---------- */

.subheading {
  font-size: 1.05rem;
  font-family: var(--mono);
  color: var(--faint);
  font-weight: 400;
  margin: 3rem 0 1.25rem;
}

.subheading:first-of-type {
  margin-top: 0;
}

.case-study h3 {
  margin-bottom: 0.25rem;
}

.case-study .case-org {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--faint);
  margin-bottom: 1rem;
}

.case-study dl {
  margin: 0;
  display: grid;
  gap: 0.6rem;
}

.case-study dt {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent);
}

.case-study dd {
  margin: 0 0 0.35rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.project-card {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  padding: 0;
  transition: border-color 160ms ease, transform 160ms ease;
}

.project-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.project-thumb {
  background: var(--bg-alt);
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  min-height: 160px;
}

.project-thumb img {
  max-height: 96px;
  width: auto;
}

.project-thumb .glyph {
  font-family: var(--mono);
  font-size: 2.5rem;
  color: var(--accent);
}

.project-body {
  padding: 1.25rem 1.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  flex: 1;
}

.project-body p {
  color: var(--muted);
  font-size: 0.925rem;
  margin: 0;
  flex: 1;
}

.project-links {
  display: flex;
  gap: 1rem;
  font-size: 0.875rem;
  font-family: var(--mono);
}

/* ---------- writing ---------- */

.writing-card {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: border-color 160ms ease, transform 160ms ease;
}

.writing-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.writing-card .read-time {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--faint);
}

.writing-card p {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0;
  flex: 1;
}

.writing-card .read-link {
  font-family: var(--mono);
  font-size: 0.875rem;
}

/* ---------- gallery ---------- */

.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.75rem;
}

.filter-btn {
  font: inherit;
  font-size: 0.875rem;
  padding: 0.35rem 0.9rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--muted);
  cursor: pointer;
}

.filter-btn[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.masonry {
  columns: 4 220px;
  column-gap: 1rem;
}

.masonry figure {
  margin: 0 0 1rem;
  break-inside: avoid;
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--line);
  cursor: zoom-in;
}

.masonry figure.hidden {
  display: none;
}

.masonry img {
  width: 100%;
  transition: transform 300ms ease;
}

.masonry figure:hover img {
  transform: scale(1.03);
}

.masonry figcaption {
  position: absolute;
  inset: auto 0 0 0;
  padding: 1.5rem 0.85rem 0.65rem;
  background: linear-gradient(transparent, rgba(8, 12, 20, 0.75));
  color: #fff;
  font-size: 0.825rem;
  opacity: 0;
  transition: opacity 200ms ease;
}

.masonry figcaption small {
  display: block;
  opacity: 0.75;
}

.masonry figure:hover figcaption,
.masonry figure:focus-within figcaption {
  opacity: 1;
}

/* lightbox */

.lightbox {
  border: 0;
  padding: 0;
  background: transparent;
  max-width: min(92vw, 1100px);
}

.lightbox::backdrop {
  background: rgba(5, 8, 14, 0.88);
}

.lightbox img {
  max-height: 82vh;
  width: auto;
  max-width: 100%;
  margin: 0 auto;
  border-radius: 8px;
}

.lightbox figcaption {
  color: #cbd5e1;
  text-align: center;
  font-size: 0.9rem;
  padding: 0.75rem 0 0;
}

.lightbox-controls {
  position: fixed;
  inset: auto 0 1.25rem 0;
  display: flex;
  justify-content: center;
  gap: 0.75rem;
}

.lightbox-controls button {
  font: inherit;
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 8px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}

/* ---------- expertise ---------- */

.expertise-group h3 {
  font-family: var(--mono);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.75rem;
}

.badge-embed {
  margin-top: 2.5rem;
  display: flex;
  justify-content: flex-start;
}

/* ---------- contact ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

@media (max-width: 840px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

.contact-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0;
  display: grid;
  gap: 0.5rem;
  color: var(--muted);
}

.contact-list .label {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--faint);
  display: inline-block;
  min-width: 5.5rem;
}

.social-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  font-family: var(--mono);
  font-size: 0.875rem;
}

.contact-form {
  display: grid;
  gap: 0.9rem;
}

.contact-form label {
  font-size: 0.875rem;
  font-weight: 500;
  display: grid;
  gap: 0.35rem;
}

.contact-form input,
.contact-form textarea {
  font: inherit;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.6rem 0.8rem;
  width: 100%;
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 0;
  border-color: var(--accent);
}

.form-status {
  font-size: 0.9rem;
  color: var(--accent);
  min-height: 1.4em;
  margin: 0;
}

/* ---------- footer ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 3rem 0 2.5rem;
  font-size: 0.925rem;
  color: var(--muted);
}

.downloads {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin: 1rem 0 2.5rem;
}

.downloads .btn {
  font-size: 0.85rem;
  padding: 0.45rem 0.9rem;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  padding-top: 1.5rem;
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--faint);
}

/* ---------- motion ---------- */

.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 500ms ease, transform 500ms ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}