/* =============================================================
   BAC To The Data — main.css
   Design tokens → Reset → Layout → Typography → Components
   → Header/Footer → Home → Blog → Portfolio → Post → CV → Project
   ============================================================= */

/* ----- Design Tokens ----- */
:root {
  /* Colours */
  --c-bg:           #F8FAFC;
  --c-surface:      #FFFFFF;
  --c-border:       #E2E8F0;
  --c-border-light: #F1F5F9;
  --c-text:         #1E293B;
  --c-muted:        #64748B;
  --c-accent:       #2563EB;
  --c-accent-light: #DBEAFE;
  --c-accent-hover: #1D4ED8;
  --c-teal:         #0D9488;
  --c-teal-light:   #CCFBF1;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;

  /* Spacing scale */
  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-6: 1.5rem;
  --sp-8: 2rem;
  --sp-12: 3rem;
  --sp-16: 4rem;
  --sp-24: 6rem;

  /* Layout */
  --container: 1100px;
  --nav-h: 64px;

  /* Radius */
  --r:    6px;
  --r-lg: 12px;

  /* Shadow */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.07), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.09), 0 2px 4px rgba(0,0,0,0.05);
}

/* ----- Reset ----- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--c-accent); text-decoration: none; }
a:hover { color: var(--c-accent-hover); }

/* ----- Layout ----- */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--sp-6);
}

/* ----- Typography ----- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  font-weight: 600;
  color: var(--c-text);
}
h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }
p { margin-bottom: var(--sp-4); }
p:last-child { margin-bottom: 0; }
strong { font-weight: 600; }
em { font-style: italic; }

code, kbd {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--c-accent-light);
  color: var(--c-accent-hover);
  padding: 0.1em 0.4em;
  border-radius: 3px;
}
pre {
  background: var(--c-text);
  color: #E2E8F0;
  padding: var(--sp-6);
  border-radius: var(--r);
  overflow-x: auto;
  margin-bottom: var(--sp-6);
}
pre code { background: none; color: inherit; padding: 0; font-size: 0.875rem; }

blockquote {
  border-left: 3px solid var(--c-accent);
  margin: var(--sp-6) 0;
  padding: var(--sp-3) var(--sp-6);
  color: var(--c-muted);
  font-style: italic;
}
ul, ol { padding-left: var(--sp-6); margin-bottom: var(--sp-4); }
li { margin-bottom: var(--sp-2); }
hr { border: none; border-top: 1px solid var(--c-border); margin: var(--sp-8) 0; }

/* ----- Buttons ----- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 0.625rem 1.25rem;
  border-radius: var(--r);
  font-size: 0.9rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  border: none;
  transition: background 0.15s, color 0.15s, box-shadow 0.15s, transform 0.1s;
  text-decoration: none;
  line-height: 1;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn-primary { background: var(--c-accent); color: #fff; }
.btn-primary:hover { background: var(--c-accent-hover); color: #fff; box-shadow: var(--shadow-md); }
.btn-outline {
  background: transparent;
  color: var(--c-accent);
  border: 1.5px solid var(--c-accent);
}
.btn-outline:hover { background: var(--c-accent-light); color: var(--c-accent-hover); }
.btn-sm { padding: 0.4rem 0.875rem; font-size: 0.825rem; }

/* ----- Tags / Badges ----- */
.tag {
  display: inline-block;
  padding: 0.2em 0.65em;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 500;
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
  background: var(--c-accent-light);
  color: var(--c-accent-hover);
}
.tag-teal { background: var(--c-teal-light); color: var(--c-teal); }
.tag-gray { background: var(--c-border-light); color: var(--c-muted); }

/* ----- Cards ----- */
.card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--r-lg);
  overflow: hidden;
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.card-body { padding: var(--sp-6); }

/* =============================================================
   HEADER / NAV
   ============================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--c-border);
}
.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.site-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--c-text);
  letter-spacing: -0.02em;
  text-decoration: none;
}
.site-title:hover { color: var(--c-accent); }
.site-nav { display: flex; gap: var(--sp-6); align-items: center; }
.site-nav a {
  color: var(--c-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
  text-decoration: none;
}
.site-nav a:hover, .site-nav a.active { color: var(--c-accent); }
.site-nav a.active { font-weight: 600; }

/* =============================================================
   FOOTER
   ============================================================= */
.site-footer {
  border-top: 1px solid var(--c-border);
  padding: var(--sp-8) 0;
  margin-top: var(--sp-24);
  color: var(--c-muted);
  font-size: 0.875rem;
}
.site-footer .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--sp-4);
}
.footer-links { display: flex; gap: var(--sp-6); }
.footer-links a { color: var(--c-muted); }
.footer-links a:hover { color: var(--c-accent); }

/* =============================================================
   HOME — HERO
   ============================================================= */
.hero {
  position: relative;
  min-height: 500px;
  display: flex;
  align-items: center;
  /* gradient overlay stacked on banner image */
  background-image:
    linear-gradient(135deg, rgba(30,41,59,0.88) 0%, rgba(37,99,235,0.45) 100%),
    url('/assets/images/banners/Blog_Banner.png');
  background-size: cover;
  background-position: center;
  background-color: var(--c-text); /* fallback if image missing */
}
.hero-content {
  padding: var(--sp-24) 0;
  color: #fff;
}
.hero-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.6);
  margin-bottom: var(--sp-3);
}
.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.75rem);
  font-weight: 700;
  color: #fff;
  line-height: 1.1;
  margin-bottom: var(--sp-4);
  letter-spacing: -0.025em;
}
.hero-subtitle {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.78);
  max-width: 520px;
  margin-bottom: var(--sp-8);
  line-height: 1.65;
}
.hero-actions { display: flex; gap: var(--sp-3); flex-wrap: wrap; }
/* Invert primary button on dark hero */
.hero .btn-primary { background: #fff; color: var(--c-accent); }
.hero .btn-primary:hover { background: var(--c-accent-light); }
.hero .btn-outline { border-color: rgba(255,255,255,0.55); color: #fff; }
.hero .btn-outline:hover { background: rgba(255,255,255,0.12); }

/* =============================================================
   HOME — ABOUT STRIP
   ============================================================= */
.about-strip {
  padding: var(--sp-16) 0;
  background: var(--c-surface);
  border-bottom: 1px solid var(--c-border);
}
.about-strip .container {
  display: flex;
  gap: var(--sp-12);
  align-items: center;
}
.about-strip-text { flex: 1; }
.about-strip-text h2 { margin-bottom: var(--sp-4); }
.about-strip-text p { color: var(--c-muted); margin-bottom: 0; }
.about-strip-logo {
  flex-shrink: 0;
  width: 160px;
}
.about-strip-logo img { width: 100%; height: auto; border-radius: var(--r-lg); }

/* =============================================================
   HOME — SECTIONS (post/project teasers)
   ============================================================= */
.home-section { padding: var(--sp-16) 0; }
.home-section--alt { background: var(--c-surface); }

.section-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--c-accent);
  font-weight: 500;
  margin-bottom: var(--sp-1);
}
.section-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: var(--sp-8);
  padding-bottom: var(--sp-4);
  border-bottom: 1px solid var(--c-border);
}
.section-title { font-size: 1.6rem; font-weight: 600; }
.section-link { font-size: 0.875rem; color: var(--c-accent); white-space: nowrap; }
.section-link:hover { text-decoration: underline; }

/* Post cards */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: var(--sp-6);
}
.post-card { display: flex; flex-direction: column; }
.post-card .card-body { flex: 1; display: flex; flex-direction: column; }
.post-card-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--c-muted);
  margin-bottom: var(--sp-2);
}
.post-card-title { font-size: 1.05rem; font-weight: 600; margin-bottom: var(--sp-3); line-height: 1.35; }
.post-card-title a { color: var(--c-text); }
.post-card-title a:hover { color: var(--c-accent); }
.post-card-excerpt { font-size: 0.88rem; color: var(--c-muted); flex: 1; margin-bottom: var(--sp-4); }
.post-card-tags { display: flex; gap: var(--sp-2); flex-wrap: wrap; margin-top: auto; }

/* Project cards */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: var(--sp-6);
}
.project-card { display: flex; flex-direction: column; }
.project-card .card-body { flex: 1; display: flex; flex-direction: column; }
.project-card-type { margin-bottom: var(--sp-3); }
.project-card-title { font-size: 1.05rem; font-weight: 600; margin-bottom: var(--sp-3); line-height: 1.35; }
.project-card-title a { color: var(--c-text); }
.project-card-title a:hover { color: var(--c-accent); }
.project-card-desc { font-size: 0.88rem; color: var(--c-muted); flex: 1; margin-bottom: var(--sp-4); }
.project-card-links { display: flex; gap: var(--sp-3); flex-wrap: wrap; margin-top: auto; }

.empty-state { color: var(--c-muted); font-size: 0.95rem; }
.empty-state a { color: var(--c-accent); }

/* =============================================================
   PAGE HERO (Blog, Portfolio, CV headers)
   Dot-grid pattern nods to data-viz graph paper
   ============================================================= */
.page-hero {
  padding: var(--sp-16) 0 var(--sp-12);
  background-color: var(--c-surface);
  background-image: radial-gradient(circle, #CBD5E1 1px, transparent 1px);
  background-size: 26px 26px;
  border-bottom: 1px solid var(--c-border);
}
.page-hero h1 { font-size: 2.5rem; margin-bottom: var(--sp-2); letter-spacing: -0.02em; }
.page-hero p { color: var(--c-muted); font-size: 1rem; margin-bottom: 0; max-width: 560px; }

.page-content { padding: var(--sp-16) 0; }

/* =============================================================
   BLOG — post list
   ============================================================= */
.post-list { display: flex; flex-direction: column; }
.post-list-item {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: var(--sp-6);
  padding: var(--sp-6) 0;
  border-bottom: 1px solid var(--c-border);
  align-items: start;
}
.post-list-item:last-child { border-bottom: none; }
.post-list-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--c-muted);
  line-height: 1.4;
  padding-top: 0.25em;
}
.post-list-title { font-size: 1.2rem; font-weight: 600; margin-bottom: var(--sp-2); line-height: 1.3; }
.post-list-title a { color: var(--c-text); }
.post-list-title a:hover { color: var(--c-accent); }
.post-list-excerpt { font-size: 0.9rem; color: var(--c-muted); margin-bottom: var(--sp-3); }
.post-list-tags { display: flex; gap: var(--sp-2); flex-wrap: wrap; }

/* =============================================================
   PORTFOLIO GRID
   ============================================================= */
.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--sp-6);
}
.portfolio-empty { text-align: center; padding: var(--sp-16) 0; color: var(--c-muted); }

/* =============================================================
   INDIVIDUAL POST
   ============================================================= */
.post-layout {
  max-width: 740px;
  margin: 0 auto;
  padding: var(--sp-16) var(--sp-6);
}
.post-header { margin-bottom: var(--sp-6); }
.post-header-meta {
  display: flex;
  gap: var(--sp-3);
  align-items: center;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--c-muted);
  margin-bottom: var(--sp-4);
}
.post-header-sep { color: var(--c-border); }
.post-header h1 { font-size: 2.2rem; letter-spacing: -0.025em; line-height: 1.2; }
.post-divider { border: none; border-top: 2px solid var(--c-border); margin: var(--sp-6) 0 var(--sp-8); }

/* Post body prose */
.post-body h2 { margin: var(--sp-10, 2.5rem) 0 var(--sp-4); font-size: 1.5rem; }
.post-body h3 { margin: var(--sp-8) 0 var(--sp-3); font-size: 1.2rem; }
.post-body p { margin-bottom: var(--sp-4); }
.post-body img { border-radius: var(--r); margin: var(--sp-6) 0; }
.post-body a { text-decoration: underline; text-underline-offset: 2px; }
.post-body ul, .post-body ol { margin-bottom: var(--sp-4); }
.post-body figure { margin: var(--sp-6) 0; }
.post-body figcaption { font-size: 0.85rem; color: var(--c-muted); text-align: center; margin-top: var(--sp-2); }

.post-nav {
  margin-top: var(--sp-12);
  padding-top: var(--sp-6);
  border-top: 1px solid var(--c-border);
}
.post-nav a { color: var(--c-muted); font-size: 0.9rem; }
.post-nav a:hover { color: var(--c-accent); }

/* =============================================================
   PROJECT PAGE
   ============================================================= */
.project-layout {
  max-width: 900px;
  margin: 0 auto;
  padding: var(--sp-16) var(--sp-6);
}
.project-header { margin-bottom: var(--sp-6); }
.project-meta {
  display: flex;
  gap: var(--sp-2);
  flex-wrap: wrap;
  margin-bottom: var(--sp-4);
}
.project-header h1 { font-size: 2.2rem; letter-spacing: -0.025em; line-height: 1.2; margin-bottom: var(--sp-3); }
.project-description { color: var(--c-muted); font-size: 1.05rem; margin-bottom: var(--sp-4); }
.project-links { display: flex; gap: var(--sp-3); flex-wrap: wrap; }

/* =============================================================
   CV PAGE
   ============================================================= */
.cv-layout {
  max-width: 900px;
  margin: 0 auto;
}
.cv-intro { margin-bottom: var(--sp-12); }
.cv-intro p { font-size: 1.05rem; color: var(--c-muted); }

.cv-section { margin-bottom: var(--sp-12); }
.cv-section-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--c-accent);
  font-weight: 500;
  margin-bottom: var(--sp-4);
  display: block;
}

#timeline-embed {
  width: 100%;
  height: 620px;
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid var(--c-border);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--sp-8);
}
.skill-group h4 {
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: var(--sp-3);
  color: var(--c-text);
}
.skill-tags { display: flex; flex-wrap: wrap; gap: var(--sp-2); }

.cv-download { margin-top: var(--sp-8); padding-top: var(--sp-8); border-top: 1px solid var(--c-border); }

/* =============================================================
   RESPONSIVE
   ============================================================= */
@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  .hero { min-height: 420px; }
  .hero-title { font-size: 2.2rem; }
  .hero-subtitle { font-size: 1rem; }
  .about-strip .container { flex-direction: column-reverse; gap: var(--sp-6); }
  .about-strip-logo { width: 100px; }
  .post-list-item { grid-template-columns: 1fr; gap: var(--sp-2); }
  .post-list-date { padding-top: 0; }
  .section-header { flex-direction: column; align-items: flex-start; gap: var(--sp-2); }
  .site-nav { gap: var(--sp-4); }
  .page-hero { padding: var(--sp-12) 0 var(--sp-8); }
  .page-hero h1 { font-size: 2rem; }
}

@media (max-width: 480px) {
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; justify-content: center; }
  .posts-grid,
  .projects-grid,
  .portfolio-grid { grid-template-columns: 1fr; }
  .skills-grid { grid-template-columns: 1fr 1fr; }
  .site-nav { gap: var(--sp-3); }
  .site-nav a { font-size: 0.85rem; }
}