/* ── Fonts: IBM Plex, self-hosted (SIL OFL, see fonts/LICENSE-IBM-Plex-OFL.txt) ───────── */
@font-face { font-family: "IBM Plex Sans"; font-weight: 400; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-sans-latin-400-normal.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-weight: 500; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-sans-latin-500-normal.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-weight: 600; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-sans-latin-600-normal.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-weight: 700; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-sans-latin-700-normal.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-weight: 400; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-mono-latin-400-normal.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-weight: 600; font-style: normal; font-display: swap; src: url("/fonts/ibm-plex-mono-latin-600-normal.woff2") format("woff2"); }

/* ── Dark theme: navy surfaces, teal accents (the palette of the PDF template) ──────── */
:root {
  /* Backgrounds */
  --bg:           #141933;
  --bg-dark:      #0d1126;
  --bg-hl:        #1f2750;

  /* Borders */
  --border:       rgba(99, 193, 193, 0.22);
  --border-hover: rgba(99, 193, 193, 0.45);

  /* Foreground */
  --fg:           #e8ecf2;
  --fg-dim:       #a9b3c6;
  --fg-muted:     #8a94a8;
  --fg-on-accent: #ffffff;

  /* Accent colors */
  --blue:         #63c1c1;   /* teal: links, accents */
  --blue-dark:    #0390a7;   /* deep teal */
  --sky:          #b3dde2;   /* light blue */
  --green:        #4ade80;
  --amber:        #f59e0b;
  --red:          #f87171;

  /* Derived opacity tints — auto-follow theme via color-mix() */
  --blue-opacity-faint:   color-mix(in srgb, var(--blue)  6%, transparent);
  --blue-opacity-subtle:  color-mix(in srgb, var(--blue) 10%, transparent);
  --blue-opacity-muted:   color-mix(in srgb, var(--blue) 14%, transparent);
  --blue-opacity-light:   color-mix(in srgb, var(--blue) 22%, transparent);
  --blue-opacity-medium:  color-mix(in srgb, var(--blue) 40%, transparent);
  --sky-opacity-faint:    color-mix(in srgb, var(--sky)   8%, transparent);
  --sky-opacity-subtle:   color-mix(in srgb, var(--sky)  15%, transparent);
  --sky-opacity-medium:   color-mix(in srgb, var(--sky)  22%, transparent);

  /* Component surfaces */
  --glass-bg:   rgba(20, 25, 51, 0.72);
  --header-bg:  rgba(20, 25, 51, 0.92);

  /* Shadows */
  --shadow-sm:  0 4px 24px rgba(0, 0, 0, 0.4);
  --shadow-md:  0 8px 40px rgba(0, 0, 0, 0.5);

  /* Motion */
  --duration-fast:   0.15s;
  --duration-normal: 0.2s;

  /* Shape */
  --radius-sm:   6px;
  --radius-md:   10px;
  --radius-lg:   12px;
  --radius-pill: 100px;

  --nav-h: 64px;

  /* The PDF's heading style: strong heading colour with a teal rule */
  --heading:   #ffffff;
  --teal:      #63c1c1;
  --navy:      #141933;
  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

/* ── Light theme ───────────────────────────────────────── */
:root[data-theme="light"] {
  --bg:           #ffffff;
  --bg-dark:      #f6f9fa;
  --bg-hl:        #e4e8ee;
  --border:       rgba(20, 25, 51, 0.14);
  --border-hover: rgba(20, 25, 51, 0.35);
  --fg:           #0f1117;
  --fg-dim:       #4b5563;
  --fg-muted:     #6b7280;
  --fg-on-accent: #ffffff;
  --blue:         #02707f;   /* deep teal ink: AA contrast on white */
  --blue-dark:    #015a66;
  --sky:          #0390a7;
  --green:        #16a34a;
  --amber:        #b45309;
  --red:          #dc2626;
  --glass-bg:     rgba(255, 255, 255, 0.86);
  --header-bg:    rgba(255, 255, 255, 0.94);
  --shadow-sm:    0 4px 24px rgba(20, 25, 51, 0.08);
  --shadow-md:    0 8px 40px rgba(20, 25, 51, 0.12);
  --heading:      #141933;
}

/* ── Reset ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  line-height: 1.7;
  letter-spacing: -0.01em;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background var(--duration-normal), color var(--duration-normal);
}

h1, h2, h3 { letter-spacing: -0.03em; }

/* Subtle engineering dot-grid background */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle, var(--blue-opacity-faint) 1px, transparent 1px);
  background-size: 28px 28px;
  z-index: -2;
  pointer-events: none;
}

/* Theme-aware logo variants */
[data-theme="dark"]  .logo-light { display: none; }
[data-theme="light"] .logo-dark  { display: none; }

/* ── Glass utility ─────────────────────────────────────── */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255, 255, 255, 0.04);
  transition: border-color var(--duration-normal), box-shadow var(--duration-normal), transform var(--duration-normal);
}

.glass:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-md), 0 0 28px var(--blue-opacity-faint);
  transform: translateY(-2px);
}

/* Light: white frosted cards */
[data-theme="light"] .glass {
  box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255, 255, 255, 0.8);
}
[data-theme="light"] .glass:hover {
  box-shadow: var(--shadow-md), 0 0 28px var(--blue-opacity-subtle);
}

/* ── Buttons ───────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--duration-normal), box-shadow var(--duration-normal), transform var(--duration-fast);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--blue);
  border-color: var(--blue);
  color: var(--fg-on-accent);
}
.btn-primary:hover {
  background: var(--blue-dark);
  box-shadow: 0 0 28px var(--blue-opacity-medium);
  transform: translateY(-1px);
  text-decoration: none;
  color: var(--fg-on-accent);
}

.btn-secondary {
  background: var(--blue-opacity-subtle);
  border-color: var(--blue-opacity-light);
  color: var(--sky);
}
.btn-secondary:hover {
  background: var(--blue-opacity-muted);
  box-shadow: 0 0 20px var(--blue-opacity-subtle);
  transform: translateY(-1px);
  text-decoration: none;
}

/* ── Navigation ────────────────────────────────────────── */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: var(--header-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--teal);
  display: flex;
  align-items: center;
  padding: 0 2rem;
  gap: 1rem;
  transition: background var(--duration-normal), border-color var(--duration-normal);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--fg);
  text-decoration: none;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}
.nav-logo-icon {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

/* Day mode — bright sky blue, warm earth, white reference marks */

nav {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  margin-left: auto;
}

nav a {
  color: var(--fg-dim);
  text-decoration: none;
  font-size: 0.875rem;
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  transition: color var(--duration-normal), background var(--duration-normal);
}
nav a:hover { color: var(--fg); background: var(--blue-opacity-subtle); }
nav a.active { color: var(--blue); background: var(--blue-opacity-subtle); }

/* Theme toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  background: var(--blue-opacity-subtle);
  border: 1px solid var(--blue-opacity-muted);
  border-radius: var(--radius-sm);
  color: var(--fg-dim);
  cursor: pointer;
  flex-shrink: 0;
  transition: background var(--duration-normal), color var(--duration-normal), border-color var(--duration-normal);
}
.theme-toggle:hover {
  background: var(--blue-opacity-muted);
  color: var(--fg);
  border-color: var(--border-hover);
}
.theme-toggle svg { width: 16px; height: 16px; }

/* Show sun in dark mode, moon in light mode */
.icon-moon { display: none; }
:root[data-theme="light"] .icon-moon { display: block; }
:root[data-theme="light"] .icon-sun  { display: none; }

/* Hamburger — mobile only */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  flex-shrink: 0;
}
.nav-toggle span {
  display: block;
  width: 22px; height: 2px;
  background: var(--fg-dim);
  border-radius: 2px;
  transition: transform var(--duration-normal), opacity var(--duration-normal);
}

/* ── Layout ────────────────────────────────────────────── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 5rem 0;
}

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 2.25rem;
  gap: 1rem;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--fg);
  line-height: 1.2;
}

.section-link {
  font-size: 0.85rem;
  color: var(--blue);
  text-decoration: none;
  flex-shrink: 0;
  white-space: nowrap;
}
.section-link:hover { text-decoration: underline; }

/* Shared card base — .card and .expertise-card */
.card {
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
}

.card        { gap: 0.5rem; text-decoration: none; color: inherit; }

/* ── Card grid ─────────────────────────────────────────── */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.25rem;
}

.card-tag {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--amber);
}

.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--fg);
  line-height: 1.35;
}

.card-desc {
  font-size: 0.875rem;
  color: var(--fg-dim);
  line-height: 1.65;
  flex: 1;
}

.card-meta {
  font-size: 0.78rem;
  color: var(--fg-muted);
  margin-top: 0.5rem;
}

/* ── Project logo ──────────────────────────────────────── */
.project-logo {
  display: block;
  max-width: 220px;
  height: auto;
  margin-bottom: 1.75rem;
}

/* ── Content pages ─────────────────────────────────────── */
.page-header {
  padding: 5rem 0 3rem;
  border-bottom: 2px solid var(--teal);
  margin-bottom: 3rem;
}

.page-title {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 700;
  line-height: 1.15;
  color: var(--heading);
  margin-bottom: 0.75rem;
}

.page-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  color: var(--fg-dim);
  font-size: 0.875rem;
}

/* Spacing utilities (replaces inline styles) */
.page-body    { padding-bottom: 5rem; }
.page-actions { padding-bottom: 3rem; }
.section-content { margin-bottom: 3rem; }

.content {
  max-width: 760px;
}

.content h1, .content h2, .content h3, .content h4 {
  line-height: 1.3;
  margin: 2.25rem 0 0.75rem;
}
.content h1 { font-size: 1.9rem; color: var(--heading); font-weight: 700; }
.content h2 {
  font-size: 1.35rem;
  color: var(--heading);
  font-weight: 700;
  border-bottom: 2px solid var(--teal);
  padding-bottom: 0.4rem;
}
.content h3 {
  font-size: 1.05rem;
  color: var(--heading);
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.25rem;
}
.content h4 { font-size: 0.95rem; color: var(--blue); font-weight: 600; }

.content p    { margin: 1rem 0; }
.content a    { color: var(--blue); text-underline-offset: 3px; }
.content a:hover { color: var(--sky); }
.content strong { color: var(--fg); font-weight: 600; }
.content em     { color: var(--fg-dim); font-style: italic; }

.content ul, .content ol {
  padding-left: 1.5rem;
  margin: 1rem 0;
}
.content li { margin: 0.4rem 0; color: var(--fg-dim); }

.content blockquote {
  border-left: 3px solid var(--blue);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background: var(--blue-opacity-faint);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--fg-dim);
  font-style: italic;
}

.content code {
  background: var(--bg-dark);
  color: var(--fg);
  padding: 0.15em 0.45em;
  border-radius: 4px;
  font-size: 0.875em;
  font-family: var(--font-mono);
  border: 1px solid var(--border);
}

.content pre {
  background: var(--bg-dark);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
}
.content pre code {
  background: none;
  padding: 0;
  color: var(--fg);
  font-size: 0.875rem;
  border: none;
}

/* Light mode: Zola's syntax highlighter bakes dark inline styles at build time.
   Override them so code blocks are readable in day mode. */
[data-theme="light"] .content pre {
  background: #f6f9fa !important;
  color: #0f1117 !important;
}
[data-theme="light"] .content pre code {
  color: #0f1117 !important;
  background: none !important;
}
[data-theme="light"] .content pre code span {
  color: inherit !important;
  background: none !important;
}

/* ── Tables ────────────────────────────────────────────── */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.75rem 0;
  font-size: 0.875rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
/* The PDF's table: navy header row with white text, striped body rows */
.content thead th {
  text-align: left;
  padding: 0.7rem 1rem;
  background: var(--navy);
  color: #ffffff;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-bottom: 2px solid var(--teal);
}
.content tbody td {
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--fg-dim);
  vertical-align: top;
}
.content tbody tr:nth-child(even) td { background: color-mix(in srgb, var(--bg-hl) 45%, transparent); }
.content tbody tr:last-child td { border-bottom: none; }
.content tbody tr:hover td {
  background: var(--blue-opacity-faint);
  color: var(--fg);
}

/* ── Footer ────────────────────────────────────────────── */
footer {
  border-top: 1px solid var(--border);
  padding: 3rem 1.5rem 2.5rem;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.25rem;
  text-align: center;
}

.footer-logo {
  font-size: 1rem;
  font-weight: 700;
  color: var(--fg-dim);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.footer-tagline {
  font-size: 0.78rem;
  color: var(--fg-muted);
  letter-spacing: 0.06em;
}

.footer-links {
  display: flex;
  gap: 1.75rem;
  flex-wrap: wrap;
  justify-content: center;
}
.footer-links a {
  font-size: 0.82rem;
  color: var(--fg-muted);
  text-decoration: none;
  transition: color var(--duration-normal);
}
.footer-links a:hover { color: var(--blue); }

.footer-copy {
  font-size: 0.78rem;
  color: var(--fg-muted);
}

/* ── Scrollbar ─────────────────────────────────────────── */
::-webkit-scrollbar       { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb { background: var(--bg-hl); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--blue-opacity-medium); }

/* ── Collapsible technical detail ─────────────────────── */
.tech-detail {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin: 2rem 0;
  overflow: hidden;
}

.tech-detail summary {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.25rem;
  background: var(--bg-dark);
  color: var(--fg-dim);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  user-select: none;
  list-style: none;
  transition: background var(--duration-normal), color var(--duration-normal);
}
.tech-detail summary::-webkit-details-marker { display: none; }
.tech-detail summary::before {
  content: "▶";
  font-size: 0.6rem;
  color: var(--blue);
  transition: transform var(--duration-normal);
}
.tech-detail[open] summary::before { transform: rotate(90deg); }
.tech-detail[open] summary {
  color: var(--fg);
  border-bottom: 1px solid var(--border);
}
.tech-detail summary:hover { background: var(--bg-hl); color: var(--fg); }

.tech-detail-body {
  padding: 1.5rem 1.75rem;
}
.tech-detail-body > *:first-child { margin-top: 0; }

/* ── Legal pages ───────────────────────────────────────── */
.legal-content {
  max-width: 680px;
}
.legal-content h2 {
  margin-top: 2.5rem;
}
.legal-content p {
  color: var(--fg-dim);
}

/* ── Responsive ────────────────────────────────────────── */
@media (max-width: 640px) {
  header { padding: 0 1rem; gap: 0.5rem; }

  .nav-toggle { display: flex; }

  /* header nav only: the footer's links are a <nav> too, and this rule would lift them over the page */
  header nav {
    display: none;
    position: absolute;
    top: var(--nav-h);
    left: 0; right: 0;
    flex-direction: column;
    padding: 1rem;
    background: var(--header-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    gap: 0.25rem;
  }
  header nav.open { display: flex; }
  header nav a { width: 100%; padding: 0.75rem 1rem; }

  .card-grid { grid-template-columns: 1fr; }

  .page-header { padding: 3rem 0 2rem; }

  .footer-links { gap: 1.25rem; }
}